[v3,10/32] arm64: KVM: system register handling

Commit Message

Marc Zyngier April 8, 2013, 4:17 p.m. UTC

Provide 64bit system register handling, modeled after the cp15
handling for ARM.

Reviewed-by: Christopher Covington <[e-mail]>
Signed-off-by: Marc Zyngier <[e-mail]>
---
 arch/arm64/include/asm/kvm_coproc.h |  51 +++
 arch/arm64/include/uapi/asm/kvm.h   |  29 ++
 arch/arm64/kvm/sys_regs.c           | 871 ++++++++++++++++++++++++++++++++++++
 arch/arm64/kvm/sys_regs.h           | 138 ++++++
 include/uapi/linux/kvm.h            |   1 +
 5 files changed, 1090 insertions(+)
 create mode 100644 arch/arm64/include/asm/kvm_coproc.h
 create mode 100644 arch/arm64/kvm/sys_regs.c
 create mode 100644 arch/arm64/kvm/sys_regs.h

Comments

Will Deacon April 10, 2013, 5:04 p.m. UTC | #1

On Mon, Apr 08, 2013 at 05:17:12PM +0100, Marc Zyngier wrote:
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> new file mode 100644
> index 0000000..9df3b32
> --- /dev/null
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -0,0 +1,871 @@
> +/*
> + * Copyright (C) 2012,2013 - ARM Ltd
> + * Author: Marc Zyngier <[e-mail]>
> + *
> + * Derived from arch/arm/kvm/coproc.c:
> + * Copyright (C) 2012 - Virtual Open Systems and Columbia University
> + * Authors: Rusty Russell <[e-mail]>
> + *          Christoffer Dall <[e-mail]>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License, version 2, as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <linux/mm.h>
> +#include <linux/kvm_host.h>
> +#include <linux/uaccess.h>
> +#include <asm/kvm_arm.h>
> +#include <asm/kvm_host.h>
> +#include <asm/kvm_emulate.h>
> +#include <asm/kvm_coproc.h>
> +#include <asm/cacheflush.h>
> +#include <asm/cputype.h>
> +#include <trace/events/kvm.h>
> +
> +#include "sys_regs.h"
> +
> +/*
> + * All of this file is extremly similar to the ARM coproc.c, but the
> + * types are different. My gut feeling is that it should be pretty
> + * easy to merge, but that would be an ABI breakage -- again. VFP
> + * would also need to be abstracted.
> + */

Yes, there's a lot of duplication here.

> +/* 3 bits per cache level, as per CLIDR, but non-existent caches always 0 */
> +static u32 cache_levels;
> +
> +/* CSSELR values; used to index KVM_REG_ARM_DEMUX_ID_CCSIDR */
> +#define CSSELR_MAX 12
> +
> +/* Which cache CCSIDR represents depends on CSSELR value. */
> +static u32 get_ccsidr(u32 csselr)
> +{
> +       u32 ccsidr;
> +
> +       /* Make sure noone else changes CSSELR during this! */
> +       local_irq_disable();
> +       /* Put value into CSSELR */
> +       asm volatile("msr csselr_el1, %x0" : : "r" (csselr));
> +       /* Read result out of CCSIDR */
> +       asm volatile("mrs %0, ccsidr_el1" : "=r" (ccsidr));
> +       local_irq_enable();

Case in point: you're missing an isb here, which I remember pointing out
when Christoffer made the same mistake...

> +       return ccsidr;
> +}
> +
> +static void do_dc_cisw(u32 val)
> +{
> +       asm volatile("dc cisw, %x0" : : "r" (val));
> +}
> +
> +static void do_dc_csw(u32 val)
> +{
> +       asm volatile("dc csw, %x0" : : "r" (val));
> +}

You don't have any barriers here. Whilst you could expect the guest to take
care of barriers, I don't think that works if you are preempted and handle
this on a different core.

> +/* See note at ARM ARM B1.14.4 */
> +static bool access_dcsw(struct kvm_vcpu *vcpu,
> +                       const struct sys_reg_params *p,
> +                       const struct sys_reg_desc *r)
> +{
> +       unsigned long val;
> +       int cpu;
> +
> +       cpu = get_cpu();
> +
> +       if (!p->is_write)
> +               return read_from_write_only(vcpu, p);

Missing put_cpu().

Will
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Marc Zyngier April 12, 2013, 3:48 p.m. UTC | #2

On 10/04/13 18:04, Will Deacon wrote:
> On Mon, Apr 08, 2013 at 05:17:12PM +0100, Marc Zyngier wrote:
>> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
>> new file mode 100644
>> index 0000000..9df3b32
>> --- /dev/null
>> +++ b/arch/arm64/kvm/sys_regs.c
>> @@ -0,0 +1,871 @@
>> +/*
>> + * Copyright (C) 2012,2013 - ARM Ltd
>> + * Author: Marc Zyngier <[e-mail]>
>> + *
>> + * Derived from arch/arm/kvm/coproc.c:
>> + * Copyright (C) 2012 - Virtual Open Systems and Columbia University
>> + * Authors: Rusty Russell <[e-mail]>
>> + *          Christoffer Dall <[e-mail]>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License, version 2, as
>> + * published by the Free Software Foundation.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> + * GNU General Public License for more details.
>> + *
>> + * You should have received a copy of the GNU General Public License
>> + * along with this program.  If not, see <http://www.gnu.org/licenses/>.
>> + */
>> +
>> +#include <linux/mm.h>
>> +#include <linux/kvm_host.h>
>> +#include <linux/uaccess.h>
>> +#include <asm/kvm_arm.h>
>> +#include <asm/kvm_host.h>
>> +#include <asm/kvm_emulate.h>
>> +#include <asm/kvm_coproc.h>
>> +#include <asm/cacheflush.h>
>> +#include <asm/cputype.h>
>> +#include <trace/events/kvm.h>
>> +
>> +#include "sys_regs.h"
>> +
>> +/*
>> + * All of this file is extremly similar to the ARM coproc.c, but the
>> + * types are different. My gut feeling is that it should be pretty
>> + * easy to merge, but that would be an ABI breakage -- again. VFP
>> + * would also need to be abstracted.
>> + */
> 
> Yes, there's a lot of duplication here.

Tell me about it...

>> +/* 3 bits per cache level, as per CLIDR, but non-existent caches always 0 */
>> +static u32 cache_levels;
>> +
>> +/* CSSELR values; used to index KVM_REG_ARM_DEMUX_ID_CCSIDR */
>> +#define CSSELR_MAX 12
>> +
>> +/* Which cache CCSIDR represents depends on CSSELR value. */
>> +static u32 get_ccsidr(u32 csselr)
>> +{
>> +       u32 ccsidr;
>> +
>> +       /* Make sure noone else changes CSSELR during this! */
>> +       local_irq_disable();
>> +       /* Put value into CSSELR */
>> +       asm volatile("msr csselr_el1, %x0" : : "r" (csselr));
>> +       /* Read result out of CCSIDR */
>> +       asm volatile("mrs %0, ccsidr_el1" : "=r" (ccsidr));
>> +       local_irq_enable();
> 
> Case in point: you're missing an isb here, which I remember pointing out
> when Christoffer made the same mistake...

Yup. Will fix.

>> +       return ccsidr;
>> +}
>> +
>> +static void do_dc_cisw(u32 val)
>> +{
>> +       asm volatile("dc cisw, %x0" : : "r" (val));
>> +}
>> +
>> +static void do_dc_csw(u32 val)
>> +{
>> +       asm volatile("dc csw, %x0" : : "r" (val));
>> +}
> 
> You don't have any barriers here. Whilst you could expect the guest to take
> care of barriers, I don't think that works if you are preempted and handle
> this on a different core.

If we've been preempted, we don't execute this code at all, but do a
cache_flush_all instead. But I agree the code is pretty fragile as it
stands, and relies on barriers in the guest (or somewhere else in the
preempting code).

I'll add them, if only for peace of mind...

>> +/* See note at ARM ARM B1.14.4 */
>> +static bool access_dcsw(struct kvm_vcpu *vcpu,
>> +                       const struct sys_reg_params *p,
>> +                       const struct sys_reg_desc *r)
>> +{
>> +       unsigned long val;
>> +       int cpu;
>> +
>> +       cpu = get_cpu();
>> +
>> +       if (!p->is_write)
>> +               return read_from_write_only(vcpu, p);
> 
> Missing put_cpu().

Yeah! Another 32bit bug to be fixed! ;-)

Thanks,

	M.

Christoffer Dall April 23, 2013, 11:01 p.m. UTC | #3

On Mon, Apr 08, 2013 at 05:17:12PM +0100, Marc Zyngier wrote:
> Provide 64bit system register handling, modeled after the cp15
> handling for ARM.
>
> Reviewed-by: Christopher Covington <[e-mail]>
> Signed-off-by: Marc Zyngier <[e-mail]>
> ---
>  arch/arm64/include/asm/kvm_coproc.h |  51 +++
>  arch/arm64/include/uapi/asm/kvm.h   |  29 ++
>  arch/arm64/kvm/sys_regs.c           | 871 ++++++++++++++++++++++++++++++++++++
>  arch/arm64/kvm/sys_regs.h           | 138 ++++++
>  include/uapi/linux/kvm.h            |   1 +
>  5 files changed, 1090 insertions(+)
>  create mode 100644 arch/arm64/include/asm/kvm_coproc.h
>  create mode 100644 arch/arm64/kvm/sys_regs.c
>  create mode 100644 arch/arm64/kvm/sys_regs.h
>
> diff --git a/arch/arm64/include/asm/kvm_coproc.h b/arch/arm64/include/asm/kvm_coproc.h
> new file mode 100644
> index 0000000..9b4477a
> --- /dev/null
> +++ b/arch/arm64/include/asm/kvm_coproc.h
> @@ -0,0 +1,51 @@
> +/*
> + * Copyright (C) 2012,2013 - ARM Ltd
> + * Author: Marc Zyngier <[e-mail]>
> + *
> + * Derived from arch/arm/include/asm/kvm_coproc.h
> + * Copyright (C) 2012 Rusty Russell IBM Corporation
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#ifndef __ARM64_KVM_COPROC_H__
> +#define __ARM64_KVM_COPROC_H__
> +
> +#include <linux/kvm_host.h>
> +
> +void kvm_reset_sys_regs(struct kvm_vcpu *vcpu);
> +
> +struct kvm_sys_reg_table {
> + const struct sys_reg_desc *table;
> + size_t num;
> +};
> +
> +struct kvm_sys_reg_target_table {
> + struct kvm_sys_reg_table table64;
> +};
> +
> +void kvm_register_target_sys_reg_table(unsigned int target,
> +       struct kvm_sys_reg_target_table *table);
> +
> +int kvm_handle_sys_reg(struct kvm_vcpu *vcpu, struct kvm_run *run);
> +
> +#define kvm_coproc_table_init kvm_sys_reg_table_init
> +void kvm_sys_reg_table_init(void);
> +
> +struct kvm_one_reg;
> +int kvm_arm_copy_sys_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices);
> +int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *);
> +int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *);
> +unsigned long kvm_arm_num_sys_reg_descs(struct kvm_vcpu *vcpu);
> +
> +#endif /* __ARM64_KVM_COPROC_H__ */
> diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
> index 4e64570..ebac919 100644
> --- a/arch/arm64/include/uapi/asm/kvm.h
> +++ b/arch/arm64/include/uapi/asm/kvm.h
> @@ -92,6 +92,35 @@ struct kvm_sync_regs {
>  struct kvm_arch_memory_slot {
>  };
>  
> +/* If you need to interpret the index values, here is the key: */
> +#define KVM_REG_ARM_COPROC_MASK 0x000000000FFF0000
> +#define KVM_REG_ARM_COPROC_SHIFT 16
> +
> +/* Normal registers are mapped as coprocessor 16. */
> +#define KVM_REG_ARM_CORE (0x0010 << KVM_REG_ARM_COPROC_SHIFT)
> +#define KVM_REG_ARM_CORE_REG(name) (offsetof(struct kvm_regs, name) / sizeof(__u32))
> +
> +/* Some registers need more space to represent values. */
> +#define KVM_REG_ARM_DEMUX (0x0011 << KVM_REG_ARM_COPROC_SHIFT)
> +#define KVM_REG_ARM_DEMUX_ID_MASK 0x000000000000FF00
> +#define KVM_REG_ARM_DEMUX_ID_SHIFT 8
> +#define KVM_REG_ARM_DEMUX_ID_CCSIDR (0x00 << KVM_REG_ARM_DEMUX_ID_SHIFT)
> +#define KVM_REG_ARM_DEMUX_VAL_MASK 0x00000000000000FF
> +#define KVM_REG_ARM_DEMUX_VAL_SHIFT 0
> +
> +/* AArch64 system registers */
> +#define KVM_REG_ARM64_SYSREG (0x0013 << KVM_REG_ARM_COPROC_SHIFT)
> +#define KVM_REG_ARM64_SYSREG_OP0_MASK 0x000000000000c000
> +#define KVM_REG_ARM64_SYSREG_OP0_SHIFT 14
> +#define KVM_REG_ARM64_SYSREG_OP1_MASK 0x0000000000003800
> +#define KVM_REG_ARM64_SYSREG_OP1_SHIFT 11
> +#define KVM_REG_ARM64_SYSREG_CRN_MASK 0x0000000000000780
> +#define KVM_REG_ARM64_SYSREG_CRN_SHIFT 7
> +#define KVM_REG_ARM64_SYSREG_CRM_MASK 0x0000000000000078
> +#define KVM_REG_ARM64_SYSREG_CRM_SHIFT 3
> +#define KVM_REG_ARM64_SYSREG_OP2_MASK 0x0000000000000007
> +#define KVM_REG_ARM64_SYSREG_OP2_SHIFT 0
> +
>  /* KVM_IRQ_LINE irq field index values */
>  #define KVM_ARM_IRQ_TYPE_SHIFT 24
>  #define KVM_ARM_IRQ_TYPE_MASK 0xff
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> new file mode 100644
> index 0000000..9df3b32
> --- /dev/null
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -0,0 +1,871 @@
> +/*
> + * Copyright (C) 2012,2013 - ARM Ltd
> + * Author: Marc Zyngier <[e-mail]>
> + *
> + * Derived from arch/arm/kvm/coproc.c:
> + * Copyright (C) 2012 - Virtual Open Systems and Columbia University
> + * Authors: Rusty Russell <[e-mail]>
> + *          Christoffer Dall <[e-mail]>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License, version 2, as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <linux/mm.h>
> +#include <linux/kvm_host.h>
> +#include <linux/uaccess.h>
> +#include <asm/kvm_arm.h>
> +#include <asm/kvm_host.h>
> +#include <asm/kvm_emulate.h>
> +#include <asm/kvm_coproc.h>
> +#include <asm/cacheflush.h>
> +#include <asm/cputype.h>
> +#include <trace/events/kvm.h>
> +
> +#include "sys_regs.h"
> +
> +/*
> + * All of this file is extremly similar to the ARM coproc.c, but the
> + * types are different. My gut feeling is that it should be pretty
> + * easy to merge, but that would be an ABI breakage -- again. VFP
> + * would also need to be abstracted.
> + */

What API would we break here by sharing more of the code? Can you
elaborate.

VFP should probably be separated into its own file on the arm side as
well in any case.

> +
> +/* 3 bits per cache level, as per CLIDR, but non-existent caches always 0 */
> +static u32 cache_levels;
> +
> +/* CSSELR values; used to index KVM_REG_ARM_DEMUX_ID_CCSIDR */
> +#define CSSELR_MAX 12
> +
> +/* Which cache CCSIDR represents depends on CSSELR value. */
> +static u32 get_ccsidr(u32 csselr)
> +{
> + u32 ccsidr;
> +
> + /* Make sure noone else changes CSSELR during this! */
> + local_irq_disable();
> + /* Put value into CSSELR */
> + asm volatile("msr csselr_el1, %x0" : : "r" (csselr));
> + /* Read result out of CCSIDR */
> + asm volatile("mrs %0, ccsidr_el1" : "=r" (ccsidr));
> + local_irq_enable();
> +
> + return ccsidr;
> +}
> +
> +static void do_dc_cisw(u32 val)
> +{
> + asm volatile("dc cisw, %x0" : : "r" (val));
> +}
> +
> +static void do_dc_csw(u32 val)
> +{
> + asm volatile("dc csw, %x0" : : "r" (val));
> +}
> +
> +/* See note at ARM ARM B1.14.4 */
> +static bool access_dcsw(struct kvm_vcpu *vcpu,
> + const struct sys_reg_params *p,
> + const struct sys_reg_desc *r)
> +{
> + unsigned long val;
> + int cpu;
> +
> + cpu = get_cpu();

you have that unbalanced get_cpu here again, but you know that
already...

> +
> + if (!p->is_write)
> + return read_from_write_only(vcpu, p);
> +
> + cpumask_setall(&vcpu->arch.require_dcache_flush);
> + cpumask_clear_cpu(cpu, &vcpu->arch.require_dcache_flush);
> +
> + /* If we were already preempted, take the long way around */
> + if (cpu != vcpu->arch.last_pcpu) {
> + flush_cache_all();
> + goto done;
> + }
> +
> + val = *vcpu_reg(vcpu, p->Rt);
> +
> + switch (p->CRm) {
> + case 6: /* Upgrade DCISW to DCCISW, as per HCR.SWIO */
> + case 14: /* DCCISW */
> + do_dc_cisw(val);
> + break;
> +
> + case 10: /* DCCSW */
> + do_dc_csw(val);
> + break;
> + }
> +
> +done:
> + put_cpu();
> +
> + return true;
> +}
> +
> +/*
> + * We could trap ID_DFR0 and tell the guest we don't support performance
> + * monitoring.  Unfortunately the patch to make the kernel check ID_DFR0 was
> + * NAKed, so it will read the PMCR anyway.
> + *
> + * Therefore we tell the guest we have 0 counters.  Unfortunately, we
> + * must always support PMCCNTR (the cycle counter): we just RAZ/WI for
> + * all PM registers, which doesn't crash the guest kernel at least.
> + */
> +static bool pm_fake(struct kvm_vcpu *vcpu,
> +    const struct sys_reg_params *p,
> +    const struct sys_reg_desc *r)
> +{
> + if (p->is_write)
> + return ignore_write(vcpu, p);
> + else
> + return read_zero(vcpu, p);
> +}
> +
> +static void reset_amair_el1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> +{
> + u64 amair;
> +
> + asm volatile("mrs %0, amair_el1\n" : "=r" (amair));
> + vcpu_sys_reg(vcpu, AMAIR_EL1) = amair;
> +}
> +
> +static void reset_mpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> +{
> + /*
> + * Simply map the vcpu_id into the Aff0 field of the MPIDR.
> + */
> + vcpu_sys_reg(vcpu, MPIDR_EL1) = (1 << 31) | (vcpu->vcpu_id & 0xff);
> +}
> +
> +/*
> + * Architected system registers.
> + * Important: Must be sorted ascending by Op0, Op1, CRn, CRm, Op2
> + */
> +static const struct sys_reg_desc sys_reg_descs[] = {
> + /* DC ISW */
> + { Op0(0b01), Op1(0b000), CRn(0b0111), CRm(0b0110), Op2(0b010),
> +  access_dcsw },
> + /* DC CSW */
> + { Op0(0b01), Op1(0b000), CRn(0b0111), CRm(0b1010), Op2(0b010),
> +  access_dcsw },
> + /* DC CISW */
> + { Op0(0b01), Op1(0b000), CRn(0b0111), CRm(0b1110), Op2(0b010),
> +  access_dcsw },
> +
> + /* MPIDR_EL1 */
> + { Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0000), Op2(0b101),
> +  NULL, reset_mpidr, MPIDR_EL1 },
> + /* SCTLR_EL1 */
> + { Op0(0b11), Op1(0b000), CRn(0b0001), CRm(0b0000), Op2(0b000),
> +  NULL, reset_val, SCTLR_EL1, 0x00C50078 },
> + /* CPACR_EL1 */
> + { Op0(0b11), Op1(0b000), CRn(0b0001), CRm(0b0000), Op2(0b010),
> +  NULL, reset_val, CPACR_EL1, 0 },
> + /* TTBR0_EL1 */
> + { Op0(0b11), Op1(0b000), CRn(0b0010), CRm(0b0000), Op2(0b000),
> +  NULL, reset_unknown, TTBR0_EL1 },
> + /* TTBR1_EL1 */
> + { Op0(0b11), Op1(0b000), CRn(0b0010), CRm(0b0000), Op2(0b001),
> +  NULL, reset_unknown, TTBR1_EL1 },
> + /* TCR_EL1 */
> + { Op0(0b11), Op1(0b000), CRn(0b0010), CRm(0b0000), Op2(0b010),
> +  NULL, reset_val, TCR_EL1, 0 },
> +
> + /* AFSR0_EL1 */
> + { Op0(0b11), Op1(0b000), CRn(0b0101), CRm(0b0001), Op2(0b000),
> +  NULL, reset_unknown, AFSR0_EL1 },
> + /* AFSR1_EL1 */
> + { Op0(0b11), Op1(0b000), CRn(0b0101), CRm(0b0001), Op2(0b001),
> +  NULL, reset_unknown, AFSR1_EL1 },
> + /* ESR_EL1 */
> + { Op0(0b11), Op1(0b000), CRn(0b0101), CRm(0b0010), Op2(0b000),
> +  NULL, reset_unknown, ESR_EL1 },
> + /* FAR_EL1 */
> + { Op0(0b11), Op1(0b000), CRn(0b0110), CRm(0b0000), Op2(0b000),
> +  NULL, reset_unknown, FAR_EL1 },
> +
> + /* PMINTENSET_EL1 */
> + { Op0(0b11), Op1(0b000), CRn(0b1001), CRm(0b1110), Op2(0b001),
> +  pm_fake },
> + /* PMINTENCLR_EL1 */
> + { Op0(0b11), Op1(0b000), CRn(0b1001), CRm(0b1110), Op2(0b010),
> +  pm_fake },
> +
> + /* MAIR_EL1 */
> + { Op0(0b11), Op1(0b000), CRn(0b1010), CRm(0b0010), Op2(0b000),
> +  NULL, reset_unknown, MAIR_EL1 },
> + /* AMAIR_EL1 */
> + { Op0(0b11), Op1(0b000), CRn(0b1010), CRm(0b0011), Op2(0b000),
> +  NULL, reset_amair_el1, AMAIR_EL1 },
> +
> + /* VBAR_EL1 */
> + { Op0(0b11), Op1(0b000), CRn(0b1100), CRm(0b0000), Op2(0b000),
> +  NULL, reset_val, VBAR_EL1, 0 },
> + /* CONTEXTIDR_EL1 */
> + { Op0(0b11), Op1(0b000), CRn(0b1101), CRm(0b0000), Op2(0b001),
> +  NULL, reset_val, CONTEXTIDR_EL1, 0 },
> + /* TPIDR_EL1 */
> + { Op0(0b11), Op1(0b000), CRn(0b1101), CRm(0b0000), Op2(0b100),
> +  NULL, reset_unknown, TPIDR_EL1 },
> +
> + /* CNTKCTL_EL1 */
> + { Op0(0b11), Op1(0b000), CRn(0b1110), CRm(0b0001), Op2(0b000),
> +  NULL, reset_val, CNTKCTL_EL1, 0},
> +
> + /* CSSELR_EL1 */
> + { Op0(0b11), Op1(0b010), CRn(0b0000), CRm(0b0000), Op2(0b000),
> +  NULL, reset_unknown, CSSELR_EL1 },
> +
> + /* PMCR_EL0 */
> + { Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b000),
> +  pm_fake },
> + /* PMCNTENSET_EL0 */
> + { Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b001),
> +  pm_fake },
> + /* PMCNTENCLR_EL0 */
> + { Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b010),
> +  pm_fake },
> + /* PMOVSCLR_EL0 */
> + { Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b011),
> +  pm_fake },
> + /* PMSWINC_EL0 */
> + { Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b100),
> +  pm_fake },
> + /* PMSELR_EL0 */
> + { Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b101),
> +  pm_fake },
> + /* PMCEID0_EL0 */
> + { Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b110),
> +  pm_fake },
> + /* PMCEID1_EL0 */
> + { Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b111),
> +  pm_fake },
> + /* PMCCNTR_EL0 */
> + { Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1101), Op2(0b000),
> +  pm_fake },
> + /* PMXEVTYPER_EL0 */
> + { Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1101), Op2(0b001),
> +  pm_fake },
> + /* PMXEVCNTR_EL0 */
> + { Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1101), Op2(0b010),
> +  pm_fake },
> + /* PMUSERENR_EL0 */
> + { Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1110), Op2(0b000),
> +  pm_fake },
> + /* PMOVSSET_EL0 */
> + { Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1110), Op2(0b011),
> +  pm_fake },
> +
> + /* TPIDR_EL0 */
> + { Op0(0b11), Op1(0b011), CRn(0b1101), CRm(0b0000), Op2(0b010),
> +  NULL, reset_unknown, TPIDR_EL0 },
> + /* TPIDRRO_EL0 */
> + { Op0(0b11), Op1(0b011), CRn(0b1101), CRm(0b0000), Op2(0b011),
> +  NULL, reset_unknown, TPIDRRO_EL0 },
> +};
> +
> +/* Target specific emulation tables */
> +static struct kvm_sys_reg_target_table *target_tables[KVM_ARM_NUM_TARGETS];
> +
> +void kvm_register_target_sys_reg_table(unsigned int target,
> +       struct kvm_sys_reg_target_table *table)
> +{
> + target_tables[target] = table;
> +}
> +
> +/* Get specific register table for this target. */
> +static const struct sys_reg_desc *get_target_table(unsigned target, size_t *num)
> +{
> + struct kvm_sys_reg_target_table *table;
> +
> + table = target_tables[target];
> + *num = table->table64.num;
> + return table->table64.table;
> +}
> +
> +static const struct sys_reg_desc *find_reg(const struct sys_reg_params *params,
> + const struct sys_reg_desc table[],
> + unsigned int num)
> +{
> + unsigned int i;
> +
> + for (i = 0; i < num; i++) {
> + const struct sys_reg_desc *r = &table[i];
> +
> + if (params->Op0 != r->Op0)
> + continue;
> + if (params->Op1 != r->Op1)
> + continue;
> + if (params->CRn != r->CRn)
> + continue;
> + if (params->CRm != r->CRm)
> + continue;
> + if (params->Op2 != r->Op2)
> + continue;
> +
> + return r;
> + }
> + return NULL;
> +}
> +
> +static int emulate_sys_reg(struct kvm_vcpu *vcpu,
> +   const struct sys_reg_params *params)
> +{
> + size_t num;
> + const struct sys_reg_desc *table, *r;
> +
> + table = get_target_table(vcpu->arch.target, &num);
> +
> + /* Search target-specific then generic table. */
> + r = find_reg(params, table, num);
> + if (!r)
> + r = find_reg(params, sys_reg_descs, ARRAY_SIZE(sys_reg_descs));
> +
> + if (likely(r)) {
> + /* If we don't have an accessor, we should never get here! */
> + BUG_ON(!r->access);

that's a little rough, you don't have to stop the entire host kernel...

> +
> + if (likely(r->access(vcpu, params, r))) {
> + /* Skip instruction, since it was emulated */
> + kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
> + return 1;
> + }
> + /* If access function fails, it should complain. */
> + } else {
> + kvm_err("Unsupported guest sys_reg access at: %lx\n",
> + *vcpu_pc(vcpu));
> + print_sys_reg_instr(params);
> + }
> + kvm_inject_undefined(vcpu);
> + return 1;
> +}
> +
> +static void reset_sys_reg_descs(struct kvm_vcpu *vcpu,
> +      const struct sys_reg_desc *table, size_t num)
> +{
> + unsigned long i;
> +
> + for (i = 0; i < num; i++)
> + if (table[i].reset)
> + table[i].reset(vcpu, &table[i]);
> +}
> +
> +/**
> + * kvm_handle_sys_reg -- handles a mrs/msr trap on a guest sys_reg access
> + * @vcpu: The VCPU pointer
> + * @run:  The kvm_run struct
> + */
> +int kvm_handle_sys_reg(struct kvm_vcpu *vcpu, struct kvm_run *run)
> +{
> + struct sys_reg_params params;
> + unsigned long esr = kvm_vcpu_get_hsr(vcpu);
> +
> + params.Op0 = (esr >> 20) & 3;
> + params.Op1 = (esr >> 14) & 0x7;
> + params.CRn = (esr >> 10) & 0xf;
> + params.CRm = (esr >> 1) & 0xf;
> + params.Op2 = (esr >> 17) & 0x7;
> + params.Rt = (esr >> 5) & 0x1f;
> + params.is_write = !(esr & 1);
> +
> + return emulate_sys_reg(vcpu, &params);
> +}
> +
> +/******************************************************************************
> + * Userspace API
> + *****************************************************************************/
> +
> +static bool index_to_params(u64 id, struct sys_reg_params *params)
> +{
> + switch (id & KVM_REG_SIZE_MASK) {
> + case KVM_REG_SIZE_U64:
> + /* Any unused index bits means it's not valid. */
> + if (id & ~(KVM_REG_ARCH_MASK | KVM_REG_SIZE_MASK
> +      | KVM_REG_ARM_COPROC_MASK
> +      | KVM_REG_ARM64_SYSREG_OP0_MASK
> +      | KVM_REG_ARM64_SYSREG_OP1_MASK
> +      | KVM_REG_ARM64_SYSREG_CRN_MASK
> +      | KVM_REG_ARM64_SYSREG_CRM_MASK
> +      | KVM_REG_ARM64_SYSREG_OP2_MASK))
> + return false;
> + params->Op0 = ((id & KVM_REG_ARM64_SYSREG_OP0_MASK)
> +       >> KVM_REG_ARM64_SYSREG_OP0_SHIFT);
> + params->Op1 = ((id & KVM_REG_ARM64_SYSREG_OP1_MASK)
> +       >> KVM_REG_ARM64_SYSREG_OP1_SHIFT);
> + params->CRn = ((id & KVM_REG_ARM64_SYSREG_CRN_MASK)
> +       >> KVM_REG_ARM64_SYSREG_CRN_SHIFT);
> + params->CRm = ((id & KVM_REG_ARM64_SYSREG_CRM_MASK)
> +       >> KVM_REG_ARM64_SYSREG_CRM_SHIFT);
> + params->Op2 = ((id & KVM_REG_ARM64_SYSREG_OP2_MASK)
> +       >> KVM_REG_ARM64_SYSREG_OP2_SHIFT);
> + return true;
> + default:
> + return false;
> + }
> +}
> +
> +/* Decode an index value, and find the sys_reg_desc entry. */
> +static const struct sys_reg_desc *index_to_sys_reg_desc(struct kvm_vcpu *vcpu,
> +    u64 id)
> +{
> + size_t num;
> + const struct sys_reg_desc *table, *r;
> + struct sys_reg_params params;
> +
> + /* We only do sys_reg for now. */
> + if ((id & KVM_REG_ARM_COPROC_MASK) != KVM_REG_ARM64_SYSREG)
> + return NULL;
> +
> + if (!index_to_params(id, &params))
> + return NULL;
> +
> + table = get_target_table(vcpu->arch.target, &num);
> + r = find_reg(&params, table, num);
> + if (!r)
> + r = find_reg(&params, sys_reg_descs, ARRAY_SIZE(sys_reg_descs));
> +
> + /* Not saved in the sys_reg array? */
> + if (r && !r->reg)
> + r = NULL;
> +
> + return r;
> +}
> +
> +/*
> + * These are the invariant sys_reg registers: we let the guest see the
> + * host versions of these, so they're part of the guest state.
> + *
> + * A future CPU may provide a mechanism to present different values to
> + * the guest, or a future kvm may trap them.
> + */
> +
> +#define FUNCTION_INVARIANT(reg) \
> + static void get_##reg(struct kvm_vcpu *v, \
> +      const struct sys_reg_desc *r) \
> + { \
> + u64 val; \
> + \
> + asm volatile("mrs %0, " __stringify(reg) "\n" \
> +     : "=r" (val)); \
> + ((struct sys_reg_desc *)r)->val = val; \
> + }
> +
> +FUNCTION_INVARIANT(midr_el1)
> +FUNCTION_INVARIANT(ctr_el0)
> +FUNCTION_INVARIANT(revidr_el1)
> +FUNCTION_INVARIANT(id_pfr0_el1)
> +FUNCTION_INVARIANT(id_pfr1_el1)
> +FUNCTION_INVARIANT(id_dfr0_el1)
> +FUNCTION_INVARIANT(id_afr0_el1)
> +FUNCTION_INVARIANT(id_mmfr0_el1)
> +FUNCTION_INVARIANT(id_mmfr1_el1)
> +FUNCTION_INVARIANT(id_mmfr2_el1)
> +FUNCTION_INVARIANT(id_mmfr3_el1)
> +FUNCTION_INVARIANT(id_isar0_el1)
> +FUNCTION_INVARIANT(id_isar1_el1)
> +FUNCTION_INVARIANT(id_isar2_el1)
> +FUNCTION_INVARIANT(id_isar3_el1)
> +FUNCTION_INVARIANT(id_isar4_el1)
> +FUNCTION_INVARIANT(id_isar5_el1)
> +FUNCTION_INVARIANT(clidr_el1)
> +FUNCTION_INVARIANT(aidr_el1)
> +
> +/* ->val is filled in by kvm_invariant_sys_reg_table_init() */

kvm_sys_reg_table_init ?

> +static struct sys_reg_desc invariant_sys_regs[] = {
> + { Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0000), Op2(0b000),
> +  NULL, get_midr_el1 },
> + { Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0000), Op2(0b110),
> +  NULL, get_revidr_el1 },
> + { Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0001), Op2(0b000),
> +  NULL, get_id_pfr0_el1 },
> + { Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0001), Op2(0b001),
> +  NULL, get_id_pfr1_el1 },
> + { Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0001), Op2(0b010),
> +  NULL, get_id_dfr0_el1 },
> + { Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0001), Op2(0b011),
> +  NULL, get_id_afr0_el1 },
> + { Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0001), Op2(0b100),
> +  NULL, get_id_mmfr0_el1 },
> + { Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0001), Op2(0b101),
> +  NULL, get_id_mmfr1_el1 },
> + { Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0001), Op2(0b110),
> +  NULL, get_id_mmfr2_el1 },
> + { Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0001), Op2(0b111),
> +  NULL, get_id_mmfr3_el1 },
> + { Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0010), Op2(0b000),
> +  NULL, get_id_isar0_el1 },
> + { Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0010), Op2(0b001),
> +  NULL, get_id_isar1_el1 },
> + { Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0010), Op2(0b010),
> +  NULL, get_id_isar2_el1 },
> + { Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0010), Op2(0b011),
> +  NULL, get_id_isar3_el1 },
> + { Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0010), Op2(0b100),
> +  NULL, get_id_isar4_el1 },
> + { Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0010), Op2(0b101),
> +  NULL, get_id_isar5_el1 },
> + { Op0(0b11), Op1(0b001), CRn(0b0000), CRm(0b0000), Op2(0b001),
> +  NULL, get_clidr_el1 },
> + { Op0(0b11), Op1(0b001), CRn(0b0000), CRm(0b0000), Op2(0b111),
> +  NULL, get_aidr_el1 },
> + { Op0(0b11), Op1(0b011), CRn(0b0000), CRm(0b0000), Op2(0b001),
> +  NULL, get_ctr_el0 },
> +};

would you consider using spaces instead of tabs here, this becomes completely unreadable on an 80 chars display...

> +
> +static int reg_from_user(void *val, const void __user *uaddr, u64 id)
> +{
> + /* This Just Works because we are little endian. */
> + if (copy_from_user(val, uaddr, KVM_REG_SIZE(id)) != 0)
> + return -EFAULT;
> + return 0;
> +}
> +
> +static int reg_to_user(void __user *uaddr, const void *val, u64 id)
> +{
> + /* This Just Works because we are little endian. */
> + if (copy_to_user(uaddr, val, KVM_REG_SIZE(id)) != 0)
> + return -EFAULT;
> + return 0;
> +}
> +
> +static int get_invariant_sys_reg(u64 id, void __user *uaddr)
> +{
> + struct sys_reg_params params;
> + const struct sys_reg_desc *r;
> +
> + if (!index_to_params(id, &params))
> + return -ENOENT;
> +
> + r = find_reg(&params, invariant_sys_regs, ARRAY_SIZE(invariant_sys_regs));
> + if (!r)
> + return -ENOENT;
> +
> + return reg_to_user(uaddr, &r->val, id);
> +}
> +
> +static int set_invariant_sys_reg(u64 id, void __user *uaddr)
> +{
> + struct sys_reg_params params;
> + const struct sys_reg_desc *r;
> + int err;
> + u64 val = 0; /* Make sure high bits are 0 for 32-bit regs */
> +
> + if (!index_to_params(id, &params))
> + return -ENOENT;
> + r = find_reg(&params, invariant_sys_regs, ARRAY_SIZE(invariant_sys_regs));
> + if (!r)
> + return -ENOENT;
> +
> + err = reg_from_user(&val, uaddr, id);
> + if (err)
> + return err;
> +
> + /* This is what we mean by invariant: you can't change it. */
> + if (r->val != val)
> + return -EINVAL;
> +
> + return 0;
> +}
> +
> +static bool is_valid_cache(u32 val)
> +{
> + u32 level, ctype;
> +
> + if (val >= CSSELR_MAX)
> + return -ENOENT;
> +
> + /* Bottom bit is Instruction or Data bit.  Next 3 bits are level. */
> +        level = (val >> 1);
> +        ctype = (cache_levels >> (level * 3)) & 7;

replace spaces with tab here

> +
> + switch (ctype) {
> + case 0: /* No cache */
> + return false;
> + case 1: /* Instruction cache only */
> + return (val & 1);
> + case 2: /* Data cache only */
> + case 4: /* Unified cache */
> + return !(val & 1);
> + case 3: /* Separate instruction and data caches */
> + return true;
> + default: /* Reserved: we can't know instruction or data. */
> + return false;
> + }
> +}
> +
> +static int demux_c15_get(u64 id, void __user *uaddr)
> +{
> + u32 val;
> + u32 __user *uval = uaddr;
> +
> + /* Fail if we have unknown bits set. */
> + if (id & ~(KVM_REG_ARCH_MASK|KVM_REG_SIZE_MASK|KVM_REG_ARM_COPROC_MASK
> +   | ((1 << KVM_REG_ARM_COPROC_SHIFT)-1)))
> + return -ENOENT;
> +
> + switch (id & KVM_REG_ARM_DEMUX_ID_MASK) {
> + case KVM_REG_ARM_DEMUX_ID_CCSIDR:
> + if (KVM_REG_SIZE(id) != 4)
> + return -ENOENT;
> + val = (id & KVM_REG_ARM_DEMUX_VAL_MASK)
> + >> KVM_REG_ARM_DEMUX_VAL_SHIFT;
> + if (!is_valid_cache(val))
> + return -ENOENT;
> +
> + return put_user(get_ccsidr(val), uval);
> + default:
> + return -ENOENT;
> + }
> +}
> +
> +static int demux_c15_set(u64 id, void __user *uaddr)
> +{
> + u32 val, newval;
> + u32 __user *uval = uaddr;
> +
> + /* Fail if we have unknown bits set. */
> + if (id & ~(KVM_REG_ARCH_MASK|KVM_REG_SIZE_MASK|KVM_REG_ARM_COPROC_MASK
> +   | ((1 << KVM_REG_ARM_COPROC_SHIFT)-1)))
> + return -ENOENT;
> +
> + switch (id & KVM_REG_ARM_DEMUX_ID_MASK) {
> + case KVM_REG_ARM_DEMUX_ID_CCSIDR:
> + if (KVM_REG_SIZE(id) != 4)
> + return -ENOENT;
> + val = (id & KVM_REG_ARM_DEMUX_VAL_MASK)
> + >> KVM_REG_ARM_DEMUX_VAL_SHIFT;
> + if (!is_valid_cache(val))
> + return -ENOENT;
> +
> + if (get_user(newval, uval))
> + return -EFAULT;
> +
> + /* This is also invariant: you can't change it. */
> + if (newval != get_ccsidr(val))
> + return -EINVAL;
> + return 0;
> + default:
> + return -ENOENT;
> + }
> +}
> +
> +int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
> +{
> + const struct sys_reg_desc *r;
> + void __user *uaddr = (void __user *)(unsigned long)reg->addr;
> +
> + if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_DEMUX)
> + return demux_c15_get(reg->id, uaddr);
> +
> + r = index_to_sys_reg_desc(vcpu, reg->id);
> + if (!r)
> + return get_invariant_sys_reg(reg->id, uaddr);
> +
> + /* Note: copies two regs if size is 64 bit. */

is this still true?

> + return reg_to_user(uaddr, &vcpu_sys_reg(vcpu, r->reg), reg->id);
> +}
> +
> +int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
> +{
> + const struct sys_reg_desc *r;
> + void __user *uaddr = (void __user *)(unsigned long)reg->addr;
> +
> + if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_DEMUX)
> + return demux_c15_set(reg->id, uaddr);
> +
> + r = index_to_sys_reg_desc(vcpu, reg->id);
> + if (!r)
> + return set_invariant_sys_reg(reg->id, uaddr);
> +
> + /* Note: copies two regs if size is 64 bit */

is this still true?

> + return reg_from_user(&vcpu_sys_reg(vcpu, r->reg), uaddr, reg->id);
> +}
> +
> +static unsigned int num_demux_regs(void)
> +{
> + unsigned int i, count = 0;
> +
> + for (i = 0; i < CSSELR_MAX; i++)
> + if (is_valid_cache(i))
> + count++;
> +
> + return count;
> +}
> +
> +static int write_demux_regids(u64 __user *uindices)
> +{
> + u64 val = KVM_REG_ARM | KVM_REG_SIZE_U32 | KVM_REG_ARM_DEMUX;
> + unsigned int i;
> +
> + val |= KVM_REG_ARM_DEMUX_ID_CCSIDR;
> + for (i = 0; i < CSSELR_MAX; i++) {
> + if (!is_valid_cache(i))
> + continue;
> + if (put_user(val | i, uindices))
> + return -EFAULT;
> + uindices++;
> + }
> + return 0;
> +}
> +
> +static u64 sys_reg_to_index(const struct sys_reg_desc *reg)
> +{
> + return (KVM_REG_ARM64 | KVM_REG_SIZE_U64 |
> + KVM_REG_ARM64_SYSREG |
> + (reg->Op0 << KVM_REG_ARM64_SYSREG_OP0_SHIFT) |
> + (reg->Op1 << KVM_REG_ARM64_SYSREG_OP1_SHIFT) |
> + (reg->CRn << KVM_REG_ARM64_SYSREG_CRN_SHIFT) |
> + (reg->CRm << KVM_REG_ARM64_SYSREG_CRM_SHIFT) |
> + (reg->Op2 << KVM_REG_ARM64_SYSREG_OP2_SHIFT));
> +}
> +
> +static bool copy_reg_to_user(const struct sys_reg_desc *reg, u64 __user **uind)
> +{
> + if (!*uind)
> + return true;
> +
> + if (put_user(sys_reg_to_index(reg), *uind))
> + return false;
> +
> + (*uind)++;
> + return true;
> +}
> +
> +/* Assumed ordered tables, see kvm_sys_reg_table_init. */
> +static int walk_sys_regs(struct kvm_vcpu *vcpu, u64 __user *uind)
> +{
> + const struct sys_reg_desc *i1, *i2, *end1, *end2;
> + unsigned int total = 0;
> + size_t num;
> +
> + /* We check for duplicates here, to allow arch-specific overrides. */
> + i1 = get_target_table(vcpu->arch.target, &num);
> + end1 = i1 + num;
> + i2 = sys_reg_descs;
> + end2 = sys_reg_descs + ARRAY_SIZE(sys_reg_descs);
> +
> + BUG_ON(i1 == end1 || i2 == end2);
> +
> + /* Walk carefully, as both tables may refer to the same register. */
> + while (i1 || i2) {
> + int cmp = cmp_sys_reg(i1, i2);
> + /* target-specific overrides generic entry. */
> + if (cmp <= 0) {
> + /* Ignore registers we trap but don't save. */
> + if (i1->reg) {
> + if (!copy_reg_to_user(i1, &uind))
> + return -EFAULT;
> + total++;
> + }
> + } else {
> + /* Ignore registers we trap but don't save. */
> + if (i2->reg) {
> + if (!copy_reg_to_user(i2, &uind))
> + return -EFAULT;
> + total++;
> + }
> + }
> +
> + if (cmp <= 0 && ++i1 == end1)
> + i1 = NULL;
> + if (cmp >= 0 && ++i2 == end2)
> + i2 = NULL;
> + }
> + return total;
> +}
> +
> +unsigned long kvm_arm_num_sys_reg_descs(struct kvm_vcpu *vcpu)
> +{
> + return ARRAY_SIZE(invariant_sys_regs)
> + + num_demux_regs()
> + + walk_sys_regs(vcpu, (u64 __user *)NULL);
> +}
> +
> +int kvm_arm_copy_sys_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
> +{
> + unsigned int i;
> + int err;
> +
> + /* Then give them all the invariant registers' indices. */
> + for (i = 0; i < ARRAY_SIZE(invariant_sys_regs); i++) {
> + if (put_user(sys_reg_to_index(&invariant_sys_regs[i]), uindices))
> + return -EFAULT;
> + uindices++;
> + }
> +
> + err = walk_sys_regs(vcpu, uindices);
> + if (err < 0)
> + return err;
> + uindices += err;
> +
> + return write_demux_regids(uindices);
> +}
> +
> +void kvm_sys_reg_table_init(void)
> +{
> + unsigned int i;
> + struct sys_reg_desc clidr;
> +
> + /* Make sure tables are unique and in order. */
> + for (i = 1; i < ARRAY_SIZE(sys_reg_descs); i++)
> + BUG_ON(cmp_sys_reg(&sys_reg_descs[i-1], &sys_reg_descs[i]) >= 0);
> +
> + /* We abuse the reset function to overwrite the table itself. */
> + for (i = 0; i < ARRAY_SIZE(invariant_sys_regs); i++)
> + invariant_sys_regs[i].reset(NULL, &invariant_sys_regs[i]);
> +
> + /*
> + * CLIDR format is awkward, so clean it up.  See ARM B4.1.20:
> + *
> + *   If software reads the Cache Type fields from Ctype1
> + *   upwards, once it has seen a value of 0b000, no caches
> + *   exist at further-out levels of the hierarchy. So, for
> + *   example, if Ctype3 is the first Cache Type field with a
> + *   value of 0b000, the values of Ctype4 to Ctype7 must be
> + *   ignored.
> + */
> + get_clidr_el1(NULL, &clidr); /* Ugly... */
> + cache_levels = clidr.val;
> + for (i = 0; i < 7; i++)
> + if (((cache_levels >> (i*3)) & 7) == 0)
> + break;
> + /* Clear all higher bits. */
> + cache_levels &= (1 << (i*3))-1;
> +}
> +
> +/**
> + * kvm_reset_sys_regs - sets system registers to reset value
> + * @vcpu: The VCPU pointer
> + *
> + * This function finds the right table above and sets the registers on the
> + * virtual CPU struct to their architecturally defined reset values.
> + */
> +void kvm_reset_sys_regs(struct kvm_vcpu *vcpu)
> +{
> + size_t num;
> + const struct sys_reg_desc *table;
> +
> + /* Catch someone adding a register without putting in reset entry. */
> + memset(&vcpu->arch.ctxt.sys_regs, 0x42, sizeof(vcpu->arch.ctxt.sys_regs));
> +
> + /* Generic chip reset first (so target could override). */
> + reset_sys_reg_descs(vcpu, sys_reg_descs, ARRAY_SIZE(sys_reg_descs));
> +
> + table = get_target_table(vcpu->arch.target, &num);
> + reset_sys_reg_descs(vcpu, table, num);
> +
> + for (num = 1; num < NR_SYS_REGS; num++)
> + if (vcpu_sys_reg(vcpu, num) == 0x4242424242424242)
> + panic("Didn't reset vcpu_sys_reg(%zi)", num);
> +}
> diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h
> new file mode 100644
> index 0000000..d50d372
> --- /dev/null
> +++ b/arch/arm64/kvm/sys_regs.h
> @@ -0,0 +1,138 @@
> +/*
> + * Copyright (C) 2012,2013 - ARM Ltd
> + * Author: Marc Zyngier <[e-mail]>
> + *
> + * Derived from arch/arm/kvm/coproc.h
> + * Copyright (C) 2012 - Virtual Open Systems and Columbia University
> + * Authors: Christoffer Dall <[e-mail]>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License, version 2, as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#ifndef __ARM64_KVM_SYS_REGS_LOCAL_H__
> +#define __ARM64_KVM_SYS_REGS_LOCAL_H__
> +
> +struct sys_reg_params {
> + u8 Op0;
> + u8 Op1;
> + u8 CRn;
> + u8 CRm;
> + u8 Op2;
> + u8 Rt;
> + bool is_write;
> +};
> +
> +struct sys_reg_desc {
> + /* MRS/MSR instruction which accesses it. */
> + u8 Op0;
> + u8 Op1;
> + u8 CRn;
> + u8 CRm;
> + u8 Op2;
> +
> + /* Trapped access from guest, if non-NULL. */
> + bool (*access)(struct kvm_vcpu *,
> +       const struct sys_reg_params *,
> +       const struct sys_reg_desc *);
> +
> + /* Initialization for vcpu. */
> + void (*reset)(struct kvm_vcpu *, const struct sys_reg_desc *);
> +
> + /* Index into sys_reg[], or 0 if we don't need to save it. */
> + int reg;
> +
> + /* Value (usually reset value) */
> + u64 val;
> +};
> +
> +static inline void print_sys_reg_instr(const struct sys_reg_params *p)
> +{
> + /* Look, we even formatted it for you to paste into the table! */
> + kvm_pr_unimpl(" { Op0(%2u), Op1(%2u), CRn(%2u), CRm(%2u), Op2(%2u), func_%s },\n",
> +      p->Op0, p->Op1, p->CRn, p->CRm, p->Op2, p->is_write ? "write" : "read");
> +}
> +
> +static inline bool ignore_write(struct kvm_vcpu *vcpu,
> + const struct sys_reg_params *p)
> +{
> + return true;
> +}
> +
> +static inline bool read_zero(struct kvm_vcpu *vcpu,
> +     const struct sys_reg_params *p)
> +{
> + *vcpu_reg(vcpu, p->Rt) = 0;
> + return true;
> +}
> +
> +static inline bool write_to_read_only(struct kvm_vcpu *vcpu,
> +      const struct sys_reg_params *params)
> +{
> + kvm_debug("sys_reg write to read-only register at: %lx\n",
> +  *vcpu_pc(vcpu));
> + print_sys_reg_instr(params);
> + return false;
> +}
> +
> +static inline bool read_from_write_only(struct kvm_vcpu *vcpu,
> + const struct sys_reg_params *params)
> +{
> + kvm_debug("sys_reg read to write-only register at: %lx\n",
> +  *vcpu_pc(vcpu));
> + print_sys_reg_instr(params);
> + return false;
> +}
> +
> +/* Reset functions */
> +static inline void reset_unknown(struct kvm_vcpu *vcpu,
> + const struct sys_reg_desc *r)
> +{
> + BUG_ON(!r->reg);
> + BUG_ON(r->reg >= NR_SYS_REGS);
> + vcpu_sys_reg(vcpu, r->reg) = 0x1de7ec7edbadc0deULL;
> +}
> +
> +static inline void reset_val(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> +{
> + BUG_ON(!r->reg);
> + BUG_ON(r->reg >= NR_SYS_REGS);
> + vcpu_sys_reg(vcpu, r->reg) = r->val;
> +}
> +
> +static inline int cmp_sys_reg(const struct sys_reg_desc *i1,
> +      const struct sys_reg_desc *i2)
> +{
> + BUG_ON(i1 == i2);
> + if (!i1)
> + return 1;
> + else if (!i2)
> + return -1;
> + if (i1->Op0 != i2->Op0)
> + return i1->Op0 - i2->Op0;
> + if (i1->Op1 != i2->Op1)
> + return i1->Op1 - i2->Op1;
> + if (i1->CRn != i2->CRn)
> + return i1->CRn - i2->CRn;
> + if (i1->CRm != i2->CRm)
> + return i1->CRm - i2->CRm;
> + return i1->Op2 - i2->Op2;
> +}
> +
> +
> +#define Op0(_x) .Op0 = _x
> +#define Op1(_x) .Op1 = _x
> +#define CRn(_x) .CRn = _x
> +#define CRm(_x) .CRm = _x
> +#define Op2(_x) .Op2 = _x
> +
> +#endif /* __ARM64_KVM_SYS_REGS_LOCAL_H__ */
> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
> index 3c56ba3..2bf42b0 100644
> --- a/include/uapi/linux/kvm.h
> +++ b/include/uapi/linux/kvm.h
> @@ -782,6 +782,7 @@ struct kvm_dirty_tlb {
>  #define KVM_REG_IA64 0x3000000000000000ULL
>  #define KVM_REG_ARM 0x4000000000000000ULL
>  #define KVM_REG_S390 0x5000000000000000ULL
> +#define KVM_REG_ARM64 0x6000000000000000ULL
>  
>  #define KVM_REG_SIZE_SHIFT 52
>  #define KVM_REG_SIZE_MASK 0x00f0000000000000ULL
> --
> 1.8.1.4
>
>
> --
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Marc Zyngier April 24, 2013, 1:37 p.m. UTC | #4

On 24/04/13 00:01, Christoffer Dall wrote:
> On Mon, Apr 08, 2013 at 05:17:12PM +0100, Marc Zyngier wrote:
>> Provide 64bit system register handling, modeled after the cp15
>> handling for ARM.
>>
>> Reviewed-by: Christopher Covington <[e-mail]>
>> Signed-off-by: Marc Zyngier <[e-mail]>
>> ---
>>  arch/arm64/include/asm/kvm_coproc.h |  51 +++
>>  arch/arm64/include/uapi/asm/kvm.h   |  29 ++
>>  arch/arm64/kvm/sys_regs.c           | 871 ++++++++++++++++++++++++++++++++++++
>>  arch/arm64/kvm/sys_regs.h           | 138 ++++++
>>  include/uapi/linux/kvm.h            |   1 +
>>  5 files changed, 1090 insertions(+)
>>  create mode 100644 arch/arm64/include/asm/kvm_coproc.h
>>  create mode 100644 arch/arm64/kvm/sys_regs.c
>>  create mode 100644 arch/arm64/kvm/sys_regs.h
>>
>> diff --git a/arch/arm64/include/asm/kvm_coproc.h b/arch/arm64/include/asm/kvm_coproc.h
>> new file mode 100644
>> index 0000000..9b4477a
>> --- /dev/null
>> +++ b/arch/arm64/include/asm/kvm_coproc.h
>> @@ -0,0 +1,51 @@
>> +/*
>> + * Copyright (C) 2012,2013 - ARM Ltd
>> + * Author: Marc Zyngier <[e-mail]>
>> + *
>> + * Derived from arch/arm/include/asm/kvm_coproc.h
>> + * Copyright (C) 2012 Rusty Russell IBM Corporation
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 as
>> + * published by the Free Software Foundation.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> + * GNU General Public License for more details.
>> + *
>> + * You should have received a copy of the GNU General Public License
>> + * along with this program.  If not, see <http://www.gnu.org/licenses/>.
>> + */
>> +
>> +#ifndef __ARM64_KVM_COPROC_H__
>> +#define __ARM64_KVM_COPROC_H__
>> +
>> +#include <linux/kvm_host.h>
>> +
>> +void kvm_reset_sys_regs(struct kvm_vcpu *vcpu);
>> +
>> +struct kvm_sys_reg_table {
>> + const struct sys_reg_desc *table;
>> + size_t num;
>> +};
>> +
>> +struct kvm_sys_reg_target_table {
>> + struct kvm_sys_reg_table table64;
>> +};
>> +
>> +void kvm_register_target_sys_reg_table(unsigned int target,
>> +       struct kvm_sys_reg_target_table *table);
>> +
>> +int kvm_handle_sys_reg(struct kvm_vcpu *vcpu, struct kvm_run *run);
>> +
>> +#define kvm_coproc_table_init kvm_sys_reg_table_init
>> +void kvm_sys_reg_table_init(void);
>> +
>> +struct kvm_one_reg;
>> +int kvm_arm_copy_sys_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices);
>> +int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *);
>> +int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *);
>> +unsigned long kvm_arm_num_sys_reg_descs(struct kvm_vcpu *vcpu);
>> +
>> +#endif /* __ARM64_KVM_COPROC_H__ */
>> diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
>> index 4e64570..ebac919 100644
>> --- a/arch/arm64/include/uapi/asm/kvm.h
>> +++ b/arch/arm64/include/uapi/asm/kvm.h
>> @@ -92,6 +92,35 @@ struct kvm_sync_regs {
>>  struct kvm_arch_memory_slot {
>>  };
>>
>> +/* If you need to interpret the index values, here is the key: */
>> +#define KVM_REG_ARM_COPROC_MASK 0x000000000FFF0000
>> +#define KVM_REG_ARM_COPROC_SHIFT 16
>> +
>> +/* Normal registers are mapped as coprocessor 16. */
>> +#define KVM_REG_ARM_CORE (0x0010 << KVM_REG_ARM_COPROC_SHIFT)
>> +#define KVM_REG_ARM_CORE_REG(name) (offsetof(struct kvm_regs, name) / sizeof(__u32))
>> +
>> +/* Some registers need more space to represent values. */
>> +#define KVM_REG_ARM_DEMUX (0x0011 << KVM_REG_ARM_COPROC_SHIFT)
>> +#define KVM_REG_ARM_DEMUX_ID_MASK 0x000000000000FF00
>> +#define KVM_REG_ARM_DEMUX_ID_SHIFT 8
>> +#define KVM_REG_ARM_DEMUX_ID_CCSIDR (0x00 << KVM_REG_ARM_DEMUX_ID_SHIFT)
>> +#define KVM_REG_ARM_DEMUX_VAL_MASK 0x00000000000000FF
>> +#define KVM_REG_ARM_DEMUX_VAL_SHIFT 0
>> +
>> +/* AArch64 system registers */
>> +#define KVM_REG_ARM64_SYSREG (0x0013 << KVM_REG_ARM_COPROC_SHIFT)
>> +#define KVM_REG_ARM64_SYSREG_OP0_MASK 0x000000000000c000
>> +#define KVM_REG_ARM64_SYSREG_OP0_SHIFT 14
>> +#define KVM_REG_ARM64_SYSREG_OP1_MASK 0x0000000000003800
>> +#define KVM_REG_ARM64_SYSREG_OP1_SHIFT 11
>> +#define KVM_REG_ARM64_SYSREG_CRN_MASK 0x0000000000000780
>> +#define KVM_REG_ARM64_SYSREG_CRN_SHIFT 7
>> +#define KVM_REG_ARM64_SYSREG_CRM_MASK 0x0000000000000078
>> +#define KVM_REG_ARM64_SYSREG_CRM_SHIFT 3
>> +#define KVM_REG_ARM64_SYSREG_OP2_MASK 0x0000000000000007
>> +#define KVM_REG_ARM64_SYSREG_OP2_SHIFT 0
>> +
>>  /* KVM_IRQ_LINE irq field index values */
>>  #define KVM_ARM_IRQ_TYPE_SHIFT 24
>>  #define KVM_ARM_IRQ_TYPE_MASK 0xff
>> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
>> new file mode 100644
>> index 0000000..9df3b32
>> --- /dev/null
>> +++ b/arch/arm64/kvm/sys_regs.c
>> @@ -0,0 +1,871 @@
>> +/*
>> + * Copyright (C) 2012,2013 - ARM Ltd
>> + * Author: Marc Zyngier <[e-mail]>
>> + *
>> + * Derived from arch/arm/kvm/coproc.c:
>> + * Copyright (C) 2012 - Virtual Open Systems and Columbia University
>> + * Authors: Rusty Russell <[e-mail]>
>> + *          Christoffer Dall <[e-mail]>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License, version 2, as
>> + * published by the Free Software Foundation.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> + * GNU General Public License for more details.
>> + *
>> + * You should have received a copy of the GNU General Public License
>> + * along with this program.  If not, see <http://www.gnu.org/licenses/>.
>> + */
>> +
>> +#include <linux/mm.h>
>> +#include <linux/kvm_host.h>
>> +#include <linux/uaccess.h>
>> +#include <asm/kvm_arm.h>
>> +#include <asm/kvm_host.h>
>> +#include <asm/kvm_emulate.h>
>> +#include <asm/kvm_coproc.h>
>> +#include <asm/cacheflush.h>
>> +#include <asm/cputype.h>
>> +#include <trace/events/kvm.h>
>> +
>> +#include "sys_regs.h"
>> +
>> +/*
>> + * All of this file is extremly similar to the ARM coproc.c, but the
>> + * types are different. My gut feeling is that it should be pretty
>> + * easy to merge, but that would be an ABI breakage -- again. VFP
>> + * would also need to be abstracted.
>> + */
> 
> What API would we break here by sharing more of the code? Can you
> elaborate.

The sys_regs encoding has 5 fields, while cp15 only has 4. If we change
this, we break the ABI.

> VFP should probably be separated into its own file on the arm side as
> well in any case.
> 
>> +
>> +/* 3 bits per cache level, as per CLIDR, but non-existent caches always 0 */
>> +static u32 cache_levels;
>> +
>> +/* CSSELR values; used to index KVM_REG_ARM_DEMUX_ID_CCSIDR */
>> +#define CSSELR_MAX 12
>> +
>> +/* Which cache CCSIDR represents depends on CSSELR value. */
>> +static u32 get_ccsidr(u32 csselr)
>> +{
>> + u32 ccsidr;
>> +
>> + /* Make sure noone else changes CSSELR during this! */
>> + local_irq_disable();
>> + /* Put value into CSSELR */
>> + asm volatile("msr csselr_el1, %x0" : : "r" (csselr));
>> + /* Read result out of CCSIDR */
>> + asm volatile("mrs %0, ccsidr_el1" : "=r" (ccsidr));
>> + local_irq_enable();
>> +
>> + return ccsidr;
>> +}
>> +
>> +static void do_dc_cisw(u32 val)
>> +{
>> + asm volatile("dc cisw, %x0" : : "r" (val));
>> +}
>> +
>> +static void do_dc_csw(u32 val)
>> +{
>> + asm volatile("dc csw, %x0" : : "r" (val));
>> +}
>> +
>> +/* See note at ARM ARM B1.14.4 */
>> +static bool access_dcsw(struct kvm_vcpu *vcpu,
>> + const struct sys_reg_params *p,
>> + const struct sys_reg_desc *r)
>> +{
>> + unsigned long val;
>> + int cpu;
>> +
>> + cpu = get_cpu();
> 
> you have that unbalanced get_cpu here again, but you know that
> already...

I do. It's fixed in my tree already.

[...]

>> +static int emulate_sys_reg(struct kvm_vcpu *vcpu,
>> +   const struct sys_reg_params *params)
>> +{
>> + size_t num;
>> + const struct sys_reg_desc *table, *r;
>> +
>> + table = get_target_table(vcpu->arch.target, &num);
>> +
>> + /* Search target-specific then generic table. */
>> + r = find_reg(params, table, num);
>> + if (!r)
>> + r = find_reg(params, sys_reg_descs, ARRAY_SIZE(sys_reg_descs));
>> +
>> + if (likely(r)) {
>> + /* If we don't have an accessor, we should never get here! */
>> + BUG_ON(!r->access);
> 
> that's a little rough, you don't have to stop the entire host kernel...

I'm not sure. It means you've decided to trap a sys_reg, but you're not
prepared to handle it... Surely that's a bug.

I'll probably turn that into an UNDEF and a big fat screaming warning,
but you may want to do something about it on the 32bit side too.

[...]

>> +/* ->val is filled in by kvm_invariant_sys_reg_table_init() */
> 
> kvm_sys_reg_table_init ?

Ah, yes. Thanks.

>> +static struct sys_reg_desc invariant_sys_regs[] = {
>> + { Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0000), Op2(0b000),
>> +  NULL, get_midr_el1 },
>> + { Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0000), Op2(0b110),
>> +  NULL, get_revidr_el1 },
>> + { Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0001), Op2(0b000),
>> +  NULL, get_id_pfr0_el1 },
>> + { Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0001), Op2(0b001),
>> +  NULL, get_id_pfr1_el1 },
>> + { Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0001), Op2(0b010),
>> +  NULL, get_id_dfr0_el1 },
>> + { Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0001), Op2(0b011),
>> +  NULL, get_id_afr0_el1 },
>> + { Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0001), Op2(0b100),
>> +  NULL, get_id_mmfr0_el1 },
>> + { Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0001), Op2(0b101),
>> +  NULL, get_id_mmfr1_el1 },
>> + { Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0001), Op2(0b110),
>> +  NULL, get_id_mmfr2_el1 },
>> + { Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0001), Op2(0b111),
>> +  NULL, get_id_mmfr3_el1 },
>> + { Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0010), Op2(0b000),
>> +  NULL, get_id_isar0_el1 },
>> + { Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0010), Op2(0b001),
>> +  NULL, get_id_isar1_el1 },
>> + { Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0010), Op2(0b010),
>> +  NULL, get_id_isar2_el1 },
>> + { Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0010), Op2(0b011),
>> +  NULL, get_id_isar3_el1 },
>> + { Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0010), Op2(0b100),
>> +  NULL, get_id_isar4_el1 },
>> + { Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0010), Op2(0b101),
>> +  NULL, get_id_isar5_el1 },
>> + { Op0(0b11), Op1(0b001), CRn(0b0000), CRm(0b0000), Op2(0b001),
>> +  NULL, get_clidr_el1 },
>> + { Op0(0b11), Op1(0b001), CRn(0b0000), CRm(0b0000), Op2(0b111),
>> +  NULL, get_aidr_el1 },
>> + { Op0(0b11), Op1(0b011), CRn(0b0000), CRm(0b0000), Op2(0b001),
>> +  NULL, get_ctr_el0 },
>> +};
> 
> would you consider using spaces instead of tabs here, this becomes completely unreadable on an 80 chars display...

Sure.

[...]

>> +static bool is_valid_cache(u32 val)
>> +{
>> + u32 level, ctype;
>> +
>> + if (val >= CSSELR_MAX)
>> + return -ENOENT;
>> +
>> + /* Bottom bit is Instruction or Data bit.  Next 3 bits are level. */
>> +        level = (val >> 1);
>> +        ctype = (cache_levels >> (level * 3)) & 7;
> 
> replace spaces with tab here

OK.

[...]

>> +int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
>> +{
>> + const struct sys_reg_desc *r;
>> + void __user *uaddr = (void __user *)(unsigned long)reg->addr;
>> +
>> + if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_DEMUX)
>> + return demux_c15_get(reg->id, uaddr);
>> +
>> + r = index_to_sys_reg_desc(vcpu, reg->id);
>> + if (!r)
>> + return get_invariant_sys_reg(reg->id, uaddr);
>> +
>> + /* Note: copies two regs if size is 64 bit. */
> 
> is this still true?

Hmmm... Not any more. It is actually an arbitrary size, and should be
validated.

	M.

Patch

diff --git a/arch/arm64/include/asm/kvm_coproc.h b/arch/arm64/include/asm/kvm_coproc.h
new file mode 100644
index 0000000..9b4477a
--- /dev/null
+++ b/arch/arm64/include/asm/kvm_coproc.h
@@ -0,0 +1,51 @@ 
+/*
+ * Copyright (C) 2012,2013 - ARM Ltd
+ * Author: Marc Zyngier <[e-mail]>
+ *
+ * Derived from arch/arm/include/asm/kvm_coproc.h
+ * Copyright (C) 2012 Rusty Russell IBM Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __ARM64_KVM_COPROC_H__
+#define __ARM64_KVM_COPROC_H__
+
+#include <linux/kvm_host.h>
+
+void kvm_reset_sys_regs(struct kvm_vcpu *vcpu);
+
+struct kvm_sys_reg_table {
+	const struct sys_reg_desc *table;
+	size_t num;
+};
+
+struct kvm_sys_reg_target_table {
+	struct kvm_sys_reg_table table64;
+};
+
+void kvm_register_target_sys_reg_table(unsigned int target,
+				       struct kvm_sys_reg_target_table *table);
+
+int kvm_handle_sys_reg(struct kvm_vcpu *vcpu, struct kvm_run *run);
+
+#define kvm_coproc_table_init kvm_sys_reg_table_init
+void kvm_sys_reg_table_init(void);
+
+struct kvm_one_reg;
+int kvm_arm_copy_sys_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices);
+int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *);
+int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *);
+unsigned long kvm_arm_num_sys_reg_descs(struct kvm_vcpu *vcpu);
+
+#endif /* __ARM64_KVM_COPROC_H__ */
diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
index 4e64570..ebac919 100644
--- a/arch/arm64/include/uapi/asm/kvm.h
+++ b/arch/arm64/include/uapi/asm/kvm.h
@@ -92,6 +92,35 @@  struct kvm_sync_regs {
 struct kvm_arch_memory_slot {
 };
 
+/* If you need to interpret the index values, here is the key: */
+#define KVM_REG_ARM_COPROC_MASK		0x000000000FFF0000
+#define KVM_REG_ARM_COPROC_SHIFT	16
+
+/* Normal registers are mapped as coprocessor 16. */
+#define KVM_REG_ARM_CORE		(0x0010 << KVM_REG_ARM_COPROC_SHIFT)
+#define KVM_REG_ARM_CORE_REG(name)	(offsetof(struct kvm_regs, name) / sizeof(__u32))
+
+/* Some registers need more space to represent values. */
+#define KVM_REG_ARM_DEMUX		(0x0011 << KVM_REG_ARM_COPROC_SHIFT)
+#define KVM_REG_ARM_DEMUX_ID_MASK	0x000000000000FF00
+#define KVM_REG_ARM_DEMUX_ID_SHIFT	8
+#define KVM_REG_ARM_DEMUX_ID_CCSIDR	(0x00 << KVM_REG_ARM_DEMUX_ID_SHIFT)
+#define KVM_REG_ARM_DEMUX_VAL_MASK	0x00000000000000FF
+#define KVM_REG_ARM_DEMUX_VAL_SHIFT	0
+
+/* AArch64 system registers */
+#define KVM_REG_ARM64_SYSREG		(0x0013 << KVM_REG_ARM_COPROC_SHIFT)
+#define KVM_REG_ARM64_SYSREG_OP0_MASK	0x000000000000c000
+#define KVM_REG_ARM64_SYSREG_OP0_SHIFT	14
+#define KVM_REG_ARM64_SYSREG_OP1_MASK	0x0000000000003800
+#define KVM_REG_ARM64_SYSREG_OP1_SHIFT	11
+#define KVM_REG_ARM64_SYSREG_CRN_MASK	0x0000000000000780
+#define KVM_REG_ARM64_SYSREG_CRN_SHIFT	7
+#define KVM_REG_ARM64_SYSREG_CRM_MASK	0x0000000000000078
+#define KVM_REG_ARM64_SYSREG_CRM_SHIFT	3
+#define KVM_REG_ARM64_SYSREG_OP2_MASK	0x0000000000000007
+#define KVM_REG_ARM64_SYSREG_OP2_SHIFT	0
+
 /* KVM_IRQ_LINE irq field index values */
 #define KVM_ARM_IRQ_TYPE_SHIFT		24
 #define KVM_ARM_IRQ_TYPE_MASK		0xff
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
new file mode 100644
index 0000000..9df3b32
--- /dev/null
+++ b/arch/arm64/kvm/sys_regs.c
@@ -0,0 +1,871 @@ 
+/*
+ * Copyright (C) 2012,2013 - ARM Ltd
+ * Author: Marc Zyngier <[e-mail]>
+ *
+ * Derived from arch/arm/kvm/coproc.c:
+ * Copyright (C) 2012 - Virtual Open Systems and Columbia University
+ * Authors: Rusty Russell <[e-mail]>
+ *          Christoffer Dall <[e-mail]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2, as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/mm.h>
+#include <linux/kvm_host.h>
+#include <linux/uaccess.h>
+#include <asm/kvm_arm.h>
+#include <asm/kvm_host.h>
+#include <asm/kvm_emulate.h>
+#include <asm/kvm_coproc.h>
+#include <asm/cacheflush.h>
+#include <asm/cputype.h>
+#include <trace/events/kvm.h>
+
+#include "sys_regs.h"
+
+/*
+ * All of this file is extremly similar to the ARM coproc.c, but the
+ * types are different. My gut feeling is that it should be pretty
+ * easy to merge, but that would be an ABI breakage -- again. VFP
+ * would also need to be abstracted.
+ */
+
+/* 3 bits per cache level, as per CLIDR, but non-existent caches always 0 */
+static u32 cache_levels;
+
+/* CSSELR values; used to index KVM_REG_ARM_DEMUX_ID_CCSIDR */
+#define CSSELR_MAX 12
+
+/* Which cache CCSIDR represents depends on CSSELR value. */
+static u32 get_ccsidr(u32 csselr)
+{
+	u32 ccsidr;
+
+	/* Make sure noone else changes CSSELR during this! */
+	local_irq_disable();
+	/* Put value into CSSELR */
+	asm volatile("msr csselr_el1, %x0" : : "r" (csselr));
+	/* Read result out of CCSIDR */
+	asm volatile("mrs %0, ccsidr_el1" : "=r" (ccsidr));
+	local_irq_enable();
+
+	return ccsidr;
+}
+
+static void do_dc_cisw(u32 val)
+{
+	asm volatile("dc cisw, %x0" : : "r" (val));
+}
+
+static void do_dc_csw(u32 val)
+{
+	asm volatile("dc csw, %x0" : : "r" (val));
+}
+
+/* See note at ARM ARM B1.14.4 */
+static bool access_dcsw(struct kvm_vcpu *vcpu,
+			const struct sys_reg_params *p,
+			const struct sys_reg_desc *r)
+{
+	unsigned long val;
+	int cpu;
+
+	cpu = get_cpu();
+
+	if (!p->is_write)
+		return read_from_write_only(vcpu, p);
+
+	cpumask_setall(&vcpu->arch.require_dcache_flush);
+	cpumask_clear_cpu(cpu, &vcpu->arch.require_dcache_flush);
+
+	/* If we were already preempted, take the long way around */
+	if (cpu != vcpu->arch.last_pcpu) {
+		flush_cache_all();
+		goto done;
+	}
+
+	val = *vcpu_reg(vcpu, p->Rt);
+
+	switch (p->CRm) {
+	case 6:			/* Upgrade DCISW to DCCISW, as per HCR.SWIO */
+	case 14:		/* DCCISW */
+		do_dc_cisw(val);
+		break;
+
+	case 10:		/* DCCSW */
+		do_dc_csw(val);
+		break;
+	}
+
+done:
+	put_cpu();
+
+	return true;
+}
+
+/*
+ * We could trap ID_DFR0 and tell the guest we don't support performance
+ * monitoring.  Unfortunately the patch to make the kernel check ID_DFR0 was
+ * NAKed, so it will read the PMCR anyway.
+ *
+ * Therefore we tell the guest we have 0 counters.  Unfortunately, we
+ * must always support PMCCNTR (the cycle counter): we just RAZ/WI for
+ * all PM registers, which doesn't crash the guest kernel at least.
+ */
+static bool pm_fake(struct kvm_vcpu *vcpu,
+		    const struct sys_reg_params *p,
+		    const struct sys_reg_desc *r)
+{
+	if (p->is_write)
+		return ignore_write(vcpu, p);
+	else
+		return read_zero(vcpu, p);
+}
+
+static void reset_amair_el1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
+{
+	u64 amair;
+
+	asm volatile("mrs %0, amair_el1\n" : "=r" (amair));
+	vcpu_sys_reg(vcpu, AMAIR_EL1) = amair;
+}
+
+static void reset_mpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
+{
+	/*
+	 * Simply map the vcpu_id into the Aff0 field of the MPIDR.
+	 */
+	vcpu_sys_reg(vcpu, MPIDR_EL1) = (1 << 31) | (vcpu->vcpu_id & 0xff);
+}
+
+/*
+ * Architected system registers.
+ * Important: Must be sorted ascending by Op0, Op1, CRn, CRm, Op2
+ */
+static const struct sys_reg_desc sys_reg_descs[] = {
+	/* DC ISW */
+	{ Op0(0b01), Op1(0b000), CRn(0b0111), CRm(0b0110), Op2(0b010),
+	  access_dcsw },
+	/* DC CSW */
+	{ Op0(0b01), Op1(0b000), CRn(0b0111), CRm(0b1010), Op2(0b010),
+	  access_dcsw },
+	/* DC CISW */
+	{ Op0(0b01), Op1(0b000), CRn(0b0111), CRm(0b1110), Op2(0b010),
+	  access_dcsw },
+
+	/* MPIDR_EL1 */
+	{ Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0000), Op2(0b101),
+	  NULL, reset_mpidr, MPIDR_EL1 },
+	/* SCTLR_EL1 */
+	{ Op0(0b11), Op1(0b000), CRn(0b0001), CRm(0b0000), Op2(0b000),
+	  NULL, reset_val, SCTLR_EL1, 0x00C50078 },
+	/* CPACR_EL1 */
+	{ Op0(0b11), Op1(0b000), CRn(0b0001), CRm(0b0000), Op2(0b010),
+	  NULL, reset_val, CPACR_EL1, 0 },
+	/* TTBR0_EL1 */
+	{ Op0(0b11), Op1(0b000), CRn(0b0010), CRm(0b0000), Op2(0b000),
+	  NULL, reset_unknown, TTBR0_EL1 },
+	/* TTBR1_EL1 */
+	{ Op0(0b11), Op1(0b000), CRn(0b0010), CRm(0b0000), Op2(0b001),
+	  NULL, reset_unknown, TTBR1_EL1 },
+	/* TCR_EL1 */
+	{ Op0(0b11), Op1(0b000), CRn(0b0010), CRm(0b0000), Op2(0b010),
+	  NULL, reset_val, TCR_EL1, 0 },
+
+	/* AFSR0_EL1 */
+	{ Op0(0b11), Op1(0b000), CRn(0b0101), CRm(0b0001), Op2(0b000),
+	  NULL, reset_unknown, AFSR0_EL1 },
+	/* AFSR1_EL1 */
+	{ Op0(0b11), Op1(0b000), CRn(0b0101), CRm(0b0001), Op2(0b001),
+	  NULL, reset_unknown, AFSR1_EL1 },
+	/* ESR_EL1 */
+	{ Op0(0b11), Op1(0b000), CRn(0b0101), CRm(0b0010), Op2(0b000),
+	  NULL, reset_unknown, ESR_EL1 },
+	/* FAR_EL1 */
+	{ Op0(0b11), Op1(0b000), CRn(0b0110), CRm(0b0000), Op2(0b000),
+	  NULL, reset_unknown, FAR_EL1 },
+
+	/* PMINTENSET_EL1 */
+	{ Op0(0b11), Op1(0b000), CRn(0b1001), CRm(0b1110), Op2(0b001),
+	  pm_fake },
+	/* PMINTENCLR_EL1 */
+	{ Op0(0b11), Op1(0b000), CRn(0b1001), CRm(0b1110), Op2(0b010),
+	  pm_fake },
+
+	/* MAIR_EL1 */
+	{ Op0(0b11), Op1(0b000), CRn(0b1010), CRm(0b0010), Op2(0b000),
+	  NULL, reset_unknown, MAIR_EL1 },
+	/* AMAIR_EL1 */
+	{ Op0(0b11), Op1(0b000), CRn(0b1010), CRm(0b0011), Op2(0b000),
+	  NULL, reset_amair_el1, AMAIR_EL1 },
+
+	/* VBAR_EL1 */
+	{ Op0(0b11), Op1(0b000), CRn(0b1100), CRm(0b0000), Op2(0b000),
+	  NULL, reset_val, VBAR_EL1, 0 },
+	/* CONTEXTIDR_EL1 */
+	{ Op0(0b11), Op1(0b000), CRn(0b1101), CRm(0b0000), Op2(0b001),
+	  NULL, reset_val, CONTEXTIDR_EL1, 0 },
+	/* TPIDR_EL1 */
+	{ Op0(0b11), Op1(0b000), CRn(0b1101), CRm(0b0000), Op2(0b100),
+	  NULL, reset_unknown, TPIDR_EL1 },
+
+	/* CNTKCTL_EL1 */
+	{ Op0(0b11), Op1(0b000), CRn(0b1110), CRm(0b0001), Op2(0b000),
+	  NULL, reset_val, CNTKCTL_EL1, 0},
+
+	/* CSSELR_EL1 */
+	{ Op0(0b11), Op1(0b010), CRn(0b0000), CRm(0b0000), Op2(0b000),
+	  NULL, reset_unknown, CSSELR_EL1 },
+
+	/* PMCR_EL0 */
+	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b000),
+	  pm_fake },
+	/* PMCNTENSET_EL0 */
+	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b001),
+	  pm_fake },
+	/* PMCNTENCLR_EL0 */
+	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b010),
+	  pm_fake },
+	/* PMOVSCLR_EL0 */
+	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b011),
+	  pm_fake },
+	/* PMSWINC_EL0 */
+	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b100),
+	  pm_fake },
+	/* PMSELR_EL0 */
+	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b101),
+	  pm_fake },
+	/* PMCEID0_EL0 */
+	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b110),
+	  pm_fake },
+	/* PMCEID1_EL0 */
+	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b111),
+	  pm_fake },
+	/* PMCCNTR_EL0 */
+	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1101), Op2(0b000),
+	  pm_fake },
+	/* PMXEVTYPER_EL0 */
+	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1101), Op2(0b001),
+	  pm_fake },
+	/* PMXEVCNTR_EL0 */
+	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1101), Op2(0b010),
+	  pm_fake },
+	/* PMUSERENR_EL0 */
+	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1110), Op2(0b000),
+	  pm_fake },
+	/* PMOVSSET_EL0 */
+	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1110), Op2(0b011),
+	  pm_fake },
+
+	/* TPIDR_EL0 */
+	{ Op0(0b11), Op1(0b011), CRn(0b1101), CRm(0b0000), Op2(0b010),
+	  NULL, reset_unknown, TPIDR_EL0 },
+	/* TPIDRRO_EL0 */
+	{ Op0(0b11), Op1(0b011), CRn(0b1101), CRm(0b0000), Op2(0b011),
+	  NULL, reset_unknown, TPIDRRO_EL0 },
+};
+
+/* Target specific emulation tables */
+static struct kvm_sys_reg_target_table *target_tables[KVM_ARM_NUM_TARGETS];
+
+void kvm_register_target_sys_reg_table(unsigned int target,
+				       struct kvm_sys_reg_target_table *table)
+{
+	target_tables[target] = table;
+}
+
+/* Get specific register table for this target. */
+static const struct sys_reg_desc *get_target_table(unsigned target, size_t *num)
+{
+	struct kvm_sys_reg_target_table *table;
+
+	table = target_tables[target];
+	*num = table->table64.num;
+	return table->table64.table;
+}
+
+static const struct sys_reg_desc *find_reg(const struct sys_reg_params *params,
+					 const struct sys_reg_desc table[],
+					 unsigned int num)
+{
+	unsigned int i;
+
+	for (i = 0; i < num; i++) {
+		const struct sys_reg_desc *r = &table[i];
+
+		if (params->Op0 != r->Op0)
+			continue;
+		if (params->Op1 != r->Op1)
+			continue;
+		if (params->CRn != r->CRn)
+			continue;
+		if (params->CRm != r->CRm)
+			continue;
+		if (params->Op2 != r->Op2)
+			continue;
+
+		return r;
+	}
+	return NULL;
+}
+
+static int emulate_sys_reg(struct kvm_vcpu *vcpu,
+			   const struct sys_reg_params *params)
+{
+	size_t num;
+	const struct sys_reg_desc *table, *r;
+
+	table = get_target_table(vcpu->arch.target, &num);
+
+	/* Search target-specific then generic table. */
+	r = find_reg(params, table, num);
+	if (!r)
+		r = find_reg(params, sys_reg_descs, ARRAY_SIZE(sys_reg_descs));
+
+	if (likely(r)) {
+		/* If we don't have an accessor, we should never get here! */
+		BUG_ON(!r->access);
+
+		if (likely(r->access(vcpu, params, r))) {
+			/* Skip instruction, since it was emulated */
+			kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
+			return 1;
+		}
+		/* If access function fails, it should complain. */
+	} else {
+		kvm_err("Unsupported guest sys_reg access at: %lx\n",
+			*vcpu_pc(vcpu));
+		print_sys_reg_instr(params);
+	}
+	kvm_inject_undefined(vcpu);
+	return 1;
+}
+
+static void reset_sys_reg_descs(struct kvm_vcpu *vcpu,
+			      const struct sys_reg_desc *table, size_t num)
+{
+	unsigned long i;
+
+	for (i = 0; i < num; i++)
+		if (table[i].reset)
+			table[i].reset(vcpu, &table[i]);
+}
+
+/**
+ * kvm_handle_sys_reg -- handles a mrs/msr trap on a guest sys_reg access
+ * @vcpu: The VCPU pointer
+ * @run:  The kvm_run struct
+ */
+int kvm_handle_sys_reg(struct kvm_vcpu *vcpu, struct kvm_run *run)
+{
+	struct sys_reg_params params;
+	unsigned long esr = kvm_vcpu_get_hsr(vcpu);
+
+	params.Op0 = (esr >> 20) & 3;
+	params.Op1 = (esr >> 14) & 0x7;
+	params.CRn = (esr >> 10) & 0xf;
+	params.CRm = (esr >> 1) & 0xf;
+	params.Op2 = (esr >> 17) & 0x7;
+	params.Rt = (esr >> 5) & 0x1f;
+	params.is_write = !(esr & 1);
+
+	return emulate_sys_reg(vcpu, &params);
+}
+
+/******************************************************************************
+ * Userspace API
+ *****************************************************************************/
+
+static bool index_to_params(u64 id, struct sys_reg_params *params)
+{
+	switch (id & KVM_REG_SIZE_MASK) {
+	case KVM_REG_SIZE_U64:
+		/* Any unused index bits means it's not valid. */
+		if (id & ~(KVM_REG_ARCH_MASK | KVM_REG_SIZE_MASK
+			      | KVM_REG_ARM_COPROC_MASK
+			      | KVM_REG_ARM64_SYSREG_OP0_MASK
+			      | KVM_REG_ARM64_SYSREG_OP1_MASK
+			      | KVM_REG_ARM64_SYSREG_CRN_MASK
+			      | KVM_REG_ARM64_SYSREG_CRM_MASK
+			      | KVM_REG_ARM64_SYSREG_OP2_MASK))
+			return false;
+		params->Op0 = ((id & KVM_REG_ARM64_SYSREG_OP0_MASK)
+			       >> KVM_REG_ARM64_SYSREG_OP0_SHIFT);
+		params->Op1 = ((id & KVM_REG_ARM64_SYSREG_OP1_MASK)
+			       >> KVM_REG_ARM64_SYSREG_OP1_SHIFT);
+		params->CRn = ((id & KVM_REG_ARM64_SYSREG_CRN_MASK)
+			       >> KVM_REG_ARM64_SYSREG_CRN_SHIFT);
+		params->CRm = ((id & KVM_REG_ARM64_SYSREG_CRM_MASK)
+			       >> KVM_REG_ARM64_SYSREG_CRM_SHIFT);
+		params->Op2 = ((id & KVM_REG_ARM64_SYSREG_OP2_MASK)
+			       >> KVM_REG_ARM64_SYSREG_OP2_SHIFT);
+		return true;
+	default:
+		return false;
+	}
+}
+
+/* Decode an index value, and find the sys_reg_desc entry. */
+static const struct sys_reg_desc *index_to_sys_reg_desc(struct kvm_vcpu *vcpu,
+						    u64 id)
+{
+	size_t num;
+	const struct sys_reg_desc *table, *r;
+	struct sys_reg_params params;
+
+	/* We only do sys_reg for now. */
+	if ((id & KVM_REG_ARM_COPROC_MASK) != KVM_REG_ARM64_SYSREG)
+		return NULL;
+
+	if (!index_to_params(id, &params))
+		return NULL;
+
+	table = get_target_table(vcpu->arch.target, &num);
+	r = find_reg(&params, table, num);
+	if (!r)
+		r = find_reg(&params, sys_reg_descs, ARRAY_SIZE(sys_reg_descs));
+
+	/* Not saved in the sys_reg array? */
+	if (r && !r->reg)
+		r = NULL;
+
+	return r;
+}
+
+/*
+ * These are the invariant sys_reg registers: we let the guest see the
+ * host versions of these, so they're part of the guest state.
+ *
+ * A future CPU may provide a mechanism to present different values to
+ * the guest, or a future kvm may trap them.
+ */
+
+#define FUNCTION_INVARIANT(reg)						\
+	static void get_##reg(struct kvm_vcpu *v,			\
+			      const struct sys_reg_desc *r)		\
+	{								\
+		u64 val;						\
+									\
+		asm volatile("mrs %0, " __stringify(reg) "\n"		\
+			     : "=r" (val));				\
+		((struct sys_reg_desc *)r)->val = val;			\
+	}
+
+FUNCTION_INVARIANT(midr_el1)
+FUNCTION_INVARIANT(ctr_el0)
+FUNCTION_INVARIANT(revidr_el1)
+FUNCTION_INVARIANT(id_pfr0_el1)
+FUNCTION_INVARIANT(id_pfr1_el1)
+FUNCTION_INVARIANT(id_dfr0_el1)
+FUNCTION_INVARIANT(id_afr0_el1)
+FUNCTION_INVARIANT(id_mmfr0_el1)
+FUNCTION_INVARIANT(id_mmfr1_el1)
+FUNCTION_INVARIANT(id_mmfr2_el1)
+FUNCTION_INVARIANT(id_mmfr3_el1)
+FUNCTION_INVARIANT(id_isar0_el1)
+FUNCTION_INVARIANT(id_isar1_el1)
+FUNCTION_INVARIANT(id_isar2_el1)
+FUNCTION_INVARIANT(id_isar3_el1)
+FUNCTION_INVARIANT(id_isar4_el1)
+FUNCTION_INVARIANT(id_isar5_el1)
+FUNCTION_INVARIANT(clidr_el1)
+FUNCTION_INVARIANT(aidr_el1)
+
+/* ->val is filled in by kvm_invariant_sys_reg_table_init() */
+static struct sys_reg_desc invariant_sys_regs[] = {
+	{ Op0(0b11),	Op1(0b000),	CRn(0b0000),	CRm(0b0000),	Op2(0b000),
+	  NULL, get_midr_el1 },
+	{ Op0(0b11),	Op1(0b000),	CRn(0b0000),	CRm(0b0000),	Op2(0b110),
+	  NULL, get_revidr_el1 },
+	{ Op0(0b11),	Op1(0b000),	CRn(0b0000),	CRm(0b0001),	Op2(0b000),
+	  NULL, get_id_pfr0_el1 },
+	{ Op0(0b11),	Op1(0b000),	CRn(0b0000),	CRm(0b0001),	Op2(0b001),
+	  NULL, get_id_pfr1_el1 },
+	{ Op0(0b11),	Op1(0b000),	CRn(0b0000),	CRm(0b0001),	Op2(0b010),
+	  NULL, get_id_dfr0_el1 },
+	{ Op0(0b11),	Op1(0b000),	CRn(0b0000),	CRm(0b0001),	Op2(0b011),
+	  NULL, get_id_afr0_el1 },
+	{ Op0(0b11),	Op1(0b000),	CRn(0b0000),	CRm(0b0001),	Op2(0b100),
+	  NULL, get_id_mmfr0_el1 },
+	{ Op0(0b11),	Op1(0b000),	CRn(0b0000),	CRm(0b0001),	Op2(0b101),
+	  NULL, get_id_mmfr1_el1 },
+	{ Op0(0b11),	Op1(0b000),	CRn(0b0000),	CRm(0b0001),	Op2(0b110),
+	  NULL, get_id_mmfr2_el1 },
+	{ Op0(0b11),	Op1(0b000),	CRn(0b0000),	CRm(0b0001),	Op2(0b111),
+	  NULL, get_id_mmfr3_el1 },
+	{ Op0(0b11),	Op1(0b000),	CRn(0b0000),	CRm(0b0010),	Op2(0b000),
+	  NULL, get_id_isar0_el1 },
+	{ Op0(0b11),	Op1(0b000),	CRn(0b0000),	CRm(0b0010),	Op2(0b001),
+	  NULL, get_id_isar1_el1 },
+	{ Op0(0b11),	Op1(0b000),	CRn(0b0000),	CRm(0b0010),	Op2(0b010),
+	  NULL, get_id_isar2_el1 },
+	{ Op0(0b11),	Op1(0b000),	CRn(0b0000),	CRm(0b0010),	Op2(0b011),
+	  NULL, get_id_isar3_el1 },
+	{ Op0(0b11),	Op1(0b000),	CRn(0b0000),	CRm(0b0010),	Op2(0b100),
+	  NULL, get_id_isar4_el1 },
+	{ Op0(0b11),	Op1(0b000),	CRn(0b0000),	CRm(0b0010),	Op2(0b101),
+	  NULL, get_id_isar5_el1 },
+	{ Op0(0b11),	Op1(0b001),	CRn(0b0000),	CRm(0b0000),	Op2(0b001),
+	  NULL, get_clidr_el1 },
+	{ Op0(0b11),	Op1(0b001),	CRn(0b0000),	CRm(0b0000),	Op2(0b111),
+	  NULL, get_aidr_el1 },
+	{ Op0(0b11),	Op1(0b011),	CRn(0b0000),	CRm(0b0000),	Op2(0b001),
+	  NULL, get_ctr_el0 },
+};
+
+static int reg_from_user(void *val, const void __user *uaddr, u64 id)
+{
+	/* This Just Works because we are little endian. */
+	if (copy_from_user(val, uaddr, KVM_REG_SIZE(id)) != 0)
+		return -EFAULT;
+	return 0;
+}
+
+static int reg_to_user(void __user *uaddr, const void *val, u64 id)
+{
+	/* This Just Works because we are little endian. */
+	if (copy_to_user(uaddr, val, KVM_REG_SIZE(id)) != 0)
+		return -EFAULT;
+	return 0;
+}
+
+static int get_invariant_sys_reg(u64 id, void __user *uaddr)
+{
+	struct sys_reg_params params;
+	const struct sys_reg_desc *r;
+
+	if (!index_to_params(id, &params))
+		return -ENOENT;
+
+	r = find_reg(&params, invariant_sys_regs, ARRAY_SIZE(invariant_sys_regs));
+	if (!r)
+		return -ENOENT;
+
+	return reg_to_user(uaddr, &r->val, id);
+}
+
+static int set_invariant_sys_reg(u64 id, void __user *uaddr)
+{
+	struct sys_reg_params params;
+	const struct sys_reg_desc *r;
+	int err;
+	u64 val = 0; /* Make sure high bits are 0 for 32-bit regs */
+
+	if (!index_to_params(id, &params))
+		return -ENOENT;
+	r = find_reg(&params, invariant_sys_regs, ARRAY_SIZE(invariant_sys_regs));
+	if (!r)
+		return -ENOENT;
+
+	err = reg_from_user(&val, uaddr, id);
+	if (err)
+		return err;
+
+	/* This is what we mean by invariant: you can't change it. */
+	if (r->val != val)
+		return -EINVAL;
+
+	return 0;
+}
+
+static bool is_valid_cache(u32 val)
+{
+	u32 level, ctype;
+
+	if (val >= CSSELR_MAX)
+		return -ENOENT;
+
+	/* Bottom bit is Instruction or Data bit.  Next 3 bits are level. */
+        level = (val >> 1);
+        ctype = (cache_levels >> (level * 3)) & 7;
+
+	switch (ctype) {
+	case 0: /* No cache */
+		return false;
+	case 1: /* Instruction cache only */
+		return (val & 1);
+	case 2: /* Data cache only */
+	case 4: /* Unified cache */
+		return !(val & 1);
+	case 3: /* Separate instruction and data caches */
+		return true;
+	default: /* Reserved: we can't know instruction or data. */
+		return false;
+	}
+}
+
+static int demux_c15_get(u64 id, void __user *uaddr)
+{
+	u32 val;
+	u32 __user *uval = uaddr;
+
+	/* Fail if we have unknown bits set. */
+	if (id & ~(KVM_REG_ARCH_MASK|KVM_REG_SIZE_MASK|KVM_REG_ARM_COPROC_MASK
+		   | ((1 << KVM_REG_ARM_COPROC_SHIFT)-1)))
+		return -ENOENT;
+
+	switch (id & KVM_REG_ARM_DEMUX_ID_MASK) {
+	case KVM_REG_ARM_DEMUX_ID_CCSIDR:
+		if (KVM_REG_SIZE(id) != 4)
+			return -ENOENT;
+		val = (id & KVM_REG_ARM_DEMUX_VAL_MASK)
+			>> KVM_REG_ARM_DEMUX_VAL_SHIFT;
+		if (!is_valid_cache(val))
+			return -ENOENT;
+
+		return put_user(get_ccsidr(val), uval);
+	default:
+		return -ENOENT;
+	}
+}
+
+static int demux_c15_set(u64 id, void __user *uaddr)
+{
+	u32 val, newval;
+	u32 __user *uval = uaddr;
+
+	/* Fail if we have unknown bits set. */
+	if (id & ~(KVM_REG_ARCH_MASK|KVM_REG_SIZE_MASK|KVM_REG_ARM_COPROC_MASK
+		   | ((1 << KVM_REG_ARM_COPROC_SHIFT)-1)))
+		return -ENOENT;
+
+	switch (id & KVM_REG_ARM_DEMUX_ID_MASK) {
+	case KVM_REG_ARM_DEMUX_ID_CCSIDR:
+		if (KVM_REG_SIZE(id) != 4)
+			return -ENOENT;
+		val = (id & KVM_REG_ARM_DEMUX_VAL_MASK)
+			>> KVM_REG_ARM_DEMUX_VAL_SHIFT;
+		if (!is_valid_cache(val))
+			return -ENOENT;
+
+		if (get_user(newval, uval))
+			return -EFAULT;
+
+		/* This is also invariant: you can't change it. */
+		if (newval != get_ccsidr(val))
+			return -EINVAL;
+		return 0;
+	default:
+		return -ENOENT;
+	}
+}
+
+int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
+{
+	const struct sys_reg_desc *r;
+	void __user *uaddr = (void __user *)(unsigned long)reg->addr;
+
+	if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_DEMUX)
+		return demux_c15_get(reg->id, uaddr);
+
+	r = index_to_sys_reg_desc(vcpu, reg->id);
+	if (!r)
+		return get_invariant_sys_reg(reg->id, uaddr);
+
+	/* Note: copies two regs if size is 64 bit. */
+	return reg_to_user(uaddr, &vcpu_sys_reg(vcpu, r->reg), reg->id);
+}
+
+int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
+{
+	const struct sys_reg_desc *r;
+	void __user *uaddr = (void __user *)(unsigned long)reg->addr;
+
+	if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_DEMUX)
+		return demux_c15_set(reg->id, uaddr);
+
+	r = index_to_sys_reg_desc(vcpu, reg->id);
+	if (!r)
+		return set_invariant_sys_reg(reg->id, uaddr);
+
+	/* Note: copies two regs if size is 64 bit */
+	return reg_from_user(&vcpu_sys_reg(vcpu, r->reg), uaddr, reg->id);
+}
+
+static unsigned int num_demux_regs(void)
+{
+	unsigned int i, count = 0;
+
+	for (i = 0; i < CSSELR_MAX; i++)
+		if (is_valid_cache(i))
+			count++;
+
+	return count;
+}
+
+static int write_demux_regids(u64 __user *uindices)
+{
+	u64 val = KVM_REG_ARM | KVM_REG_SIZE_U32 | KVM_REG_ARM_DEMUX;
+	unsigned int i;
+
+	val |= KVM_REG_ARM_DEMUX_ID_CCSIDR;
+	for (i = 0; i < CSSELR_MAX; i++) {
+		if (!is_valid_cache(i))
+			continue;
+		if (put_user(val | i, uindices))
+			return -EFAULT;
+		uindices++;
+	}
+	return 0;
+}
+
+static u64 sys_reg_to_index(const struct sys_reg_desc *reg)
+{
+	return (KVM_REG_ARM64 | KVM_REG_SIZE_U64 |
+		KVM_REG_ARM64_SYSREG |
+		(reg->Op0 << KVM_REG_ARM64_SYSREG_OP0_SHIFT) |
+		(reg->Op1 << KVM_REG_ARM64_SYSREG_OP1_SHIFT) |
+		(reg->CRn << KVM_REG_ARM64_SYSREG_CRN_SHIFT) |
+		(reg->CRm << KVM_REG_ARM64_SYSREG_CRM_SHIFT) |
+		(reg->Op2 << KVM_REG_ARM64_SYSREG_OP2_SHIFT));
+}
+
+static bool copy_reg_to_user(const struct sys_reg_desc *reg, u64 __user **uind)
+{
+	if (!*uind)
+		return true;
+
+	if (put_user(sys_reg_to_index(reg), *uind))
+		return false;
+
+	(*uind)++;
+	return true;
+}
+
+/* Assumed ordered tables, see kvm_sys_reg_table_init. */
+static int walk_sys_regs(struct kvm_vcpu *vcpu, u64 __user *uind)
+{
+	const struct sys_reg_desc *i1, *i2, *end1, *end2;
+	unsigned int total = 0;
+	size_t num;
+
+	/* We check for duplicates here, to allow arch-specific overrides. */
+	i1 = get_target_table(vcpu->arch.target, &num);
+	end1 = i1 + num;
+	i2 = sys_reg_descs;
+	end2 = sys_reg_descs + ARRAY_SIZE(sys_reg_descs);
+
+	BUG_ON(i1 == end1 || i2 == end2);
+
+	/* Walk carefully, as both tables may refer to the same register. */
+	while (i1 || i2) {
+		int cmp = cmp_sys_reg(i1, i2);
+		/* target-specific overrides generic entry. */
+		if (cmp <= 0) {
+			/* Ignore registers we trap but don't save. */
+			if (i1->reg) {
+				if (!copy_reg_to_user(i1, &uind))
+					return -EFAULT;
+				total++;
+			}
+		} else {
+			/* Ignore registers we trap but don't save. */
+			if (i2->reg) {
+				if (!copy_reg_to_user(i2, &uind))
+					return -EFAULT;
+				total++;
+			}
+		}
+
+		if (cmp <= 0 && ++i1 == end1)
+			i1 = NULL;
+		if (cmp >= 0 && ++i2 == end2)
+			i2 = NULL;
+	}
+	return total;
+}
+
+unsigned long kvm_arm_num_sys_reg_descs(struct kvm_vcpu *vcpu)
+{
+	return ARRAY_SIZE(invariant_sys_regs)
+		+ num_demux_regs()
+		+ walk_sys_regs(vcpu, (u64 __user *)NULL);
+}
+
+int kvm_arm_copy_sys_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
+{
+	unsigned int i;
+	int err;
+
+	/* Then give them all the invariant registers' indices. */
+	for (i = 0; i < ARRAY_SIZE(invariant_sys_regs); i++) {
+		if (put_user(sys_reg_to_index(&invariant_sys_regs[i]), uindices))
+			return -EFAULT;
+		uindices++;
+	}
+
+	err = walk_sys_regs(vcpu, uindices);
+	if (err < 0)
+		return err;
+	uindices += err;
+
+	return write_demux_regids(uindices);
+}
+
+void kvm_sys_reg_table_init(void)
+{
+	unsigned int i;
+	struct sys_reg_desc clidr;
+
+	/* Make sure tables are unique and in order. */
+	for (i = 1; i < ARRAY_SIZE(sys_reg_descs); i++)
+		BUG_ON(cmp_sys_reg(&sys_reg_descs[i-1], &sys_reg_descs[i]) >= 0);
+
+	/* We abuse the reset function to overwrite the table itself. */
+	for (i = 0; i < ARRAY_SIZE(invariant_sys_regs); i++)
+		invariant_sys_regs[i].reset(NULL, &invariant_sys_regs[i]);
+
+	/*
+	 * CLIDR format is awkward, so clean it up.  See ARM B4.1.20:
+	 *
+	 *   If software reads the Cache Type fields from Ctype1
+	 *   upwards, once it has seen a value of 0b000, no caches
+	 *   exist at further-out levels of the hierarchy. So, for
+	 *   example, if Ctype3 is the first Cache Type field with a
+	 *   value of 0b000, the values of Ctype4 to Ctype7 must be
+	 *   ignored.
+	 */
+	get_clidr_el1(NULL, &clidr); /* Ugly... */
+	cache_levels = clidr.val;
+	for (i = 0; i < 7; i++)
+		if (((cache_levels >> (i*3)) & 7) == 0)
+			break;
+	/* Clear all higher bits. */
+	cache_levels &= (1 << (i*3))-1;
+}
+
+/**
+ * kvm_reset_sys_regs - sets system registers to reset value
+ * @vcpu: The VCPU pointer
+ *
+ * This function finds the right table above and sets the registers on the
+ * virtual CPU struct to their architecturally defined reset values.
+ */
+void kvm_reset_sys_regs(struct kvm_vcpu *vcpu)
+{
+	size_t num;
+	const struct sys_reg_desc *table;
+
+	/* Catch someone adding a register without putting in reset entry. */
+	memset(&vcpu->arch.ctxt.sys_regs, 0x42, sizeof(vcpu->arch.ctxt.sys_regs));
+
+	/* Generic chip reset first (so target could override). */
+	reset_sys_reg_descs(vcpu, sys_reg_descs, ARRAY_SIZE(sys_reg_descs));
+
+	table = get_target_table(vcpu->arch.target, &num);
+	reset_sys_reg_descs(vcpu, table, num);
+
+	for (num = 1; num < NR_SYS_REGS; num++)
+		if (vcpu_sys_reg(vcpu, num) == 0x4242424242424242)
+			panic("Didn't reset vcpu_sys_reg(%zi)", num);
+}
diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h
new file mode 100644
index 0000000..d50d372
--- /dev/null
+++ b/arch/arm64/kvm/sys_regs.h
@@ -0,0 +1,138 @@ 
+/*
+ * Copyright (C) 2012,2013 - ARM Ltd
+ * Author: Marc Zyngier <[e-mail]>
+ *
+ * Derived from arch/arm/kvm/coproc.h
+ * Copyright (C) 2012 - Virtual Open Systems and Columbia University
+ * Authors: Christoffer Dall <[e-mail]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2, as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __ARM64_KVM_SYS_REGS_LOCAL_H__
+#define __ARM64_KVM_SYS_REGS_LOCAL_H__
+
+struct sys_reg_params {
+	u8	Op0;
+	u8	Op1;
+	u8	CRn;
+	u8	CRm;
+	u8	Op2;
+	u8	Rt;
+	bool	is_write;
+};
+
+struct sys_reg_desc {
+	/* MRS/MSR instruction which accesses it. */
+	u8	Op0;
+	u8	Op1;
+	u8	CRn;
+	u8	CRm;
+	u8	Op2;
+
+	/* Trapped access from guest, if non-NULL. */
+	bool (*access)(struct kvm_vcpu *,
+		       const struct sys_reg_params *,
+		       const struct sys_reg_desc *);
+
+	/* Initialization for vcpu. */
+	void (*reset)(struct kvm_vcpu *, const struct sys_reg_desc *);
+
+	/* Index into sys_reg[], or 0 if we don't need to save it. */
+	int reg;
+
+	/* Value (usually reset value) */
+	u64 val;
+};
+
+static inline void print_sys_reg_instr(const struct sys_reg_params *p)
+{
+	/* Look, we even formatted it for you to paste into the table! */
+	kvm_pr_unimpl(" { Op0(%2u), Op1(%2u), CRn(%2u), CRm(%2u), Op2(%2u), func_%s },\n",
+		      p->Op0, p->Op1, p->CRn, p->CRm, p->Op2, p->is_write ? "write" : "read");
+}
+
+static inline bool ignore_write(struct kvm_vcpu *vcpu,
+				const struct sys_reg_params *p)
+{
+	return true;
+}
+
+static inline bool read_zero(struct kvm_vcpu *vcpu,
+			     const struct sys_reg_params *p)
+{
+	*vcpu_reg(vcpu, p->Rt) = 0;
+	return true;
+}
+
+static inline bool write_to_read_only(struct kvm_vcpu *vcpu,
+				      const struct sys_reg_params *params)
+{
+	kvm_debug("sys_reg write to read-only register at: %lx\n",
+		  *vcpu_pc(vcpu));
+	print_sys_reg_instr(params);
+	return false;
+}
+
+static inline bool read_from_write_only(struct kvm_vcpu *vcpu,
+					const struct sys_reg_params *params)
+{
+	kvm_debug("sys_reg read to write-only register at: %lx\n",
+		  *vcpu_pc(vcpu));
+	print_sys_reg_instr(params);
+	return false;
+}
+
+/* Reset functions */
+static inline void reset_unknown(struct kvm_vcpu *vcpu,
+				 const struct sys_reg_desc *r)
+{
+	BUG_ON(!r->reg);
+	BUG_ON(r->reg >= NR_SYS_REGS);
+	vcpu_sys_reg(vcpu, r->reg) = 0x1de7ec7edbadc0deULL;
+}
+
+static inline void reset_val(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
+{
+	BUG_ON(!r->reg);
+	BUG_ON(r->reg >= NR_SYS_REGS);
+	vcpu_sys_reg(vcpu, r->reg) = r->val;
+}
+
+static inline int cmp_sys_reg(const struct sys_reg_desc *i1,
+			      const struct sys_reg_desc *i2)
+{
+	BUG_ON(i1 == i2);
+	if (!i1)
+		return 1;
+	else if (!i2)
+		return -1;
+	if (i1->Op0 != i2->Op0)
+		return i1->Op0 - i2->Op0;
+	if (i1->Op1 != i2->Op1)
+		return i1->Op1 - i2->Op1;
+	if (i1->CRn != i2->CRn)
+		return i1->CRn - i2->CRn;
+	if (i1->CRm != i2->CRm)
+		return i1->CRm - i2->CRm;
+	return i1->Op2 - i2->Op2;
+}
+
+
+#define Op0(_x) 	.Op0 = _x
+#define Op1(_x) 	.Op1 = _x
+#define CRn(_x)		.CRn = _x
+#define CRm(_x) 	.CRm = _x
+#define Op2(_x) 	.Op2 = _x
+
+#endif /* __ARM64_KVM_SYS_REGS_LOCAL_H__ */
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 3c56ba3..2bf42b0 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -782,6 +782,7 @@  struct kvm_dirty_tlb {
 #define KVM_REG_IA64		0x3000000000000000ULL
 #define KVM_REG_ARM		0x4000000000000000ULL
 #define KVM_REG_S390		0x5000000000000000ULL
+#define KVM_REG_ARM64		0x6000000000000000ULL
 
 #define KVM_REG_SIZE_SHIFT	52
 #define KVM_REG_SIZE_MASK	0x00f0000000000000ULL