@@ -349,4 +349,21 @@
#define CPACR_EL1_DEFAULT (CPACR_EL1_FPEN_EL0EN | CPACR_EL1_FPEN_EL1EN |\
CPACR_EL1_ZEN_EL1EN)
+#define kvm_mode_names \
+ { PSR_MODE_EL0t, "EL0t" }, \
+ { PSR_MODE_EL1t, "EL1t" }, \
+ { PSR_MODE_EL1h, "EL1h" }, \
+ { PSR_MODE_EL2t, "EL2t" }, \
+ { PSR_MODE_EL2h, "EL2h" }, \
+ { PSR_MODE_EL3t, "EL3t" }, \
+ { PSR_MODE_EL3h, "EL3h" }, \
+ { PSR_AA32_MODE_USR, "32-bit USR" }, \
+ { PSR_AA32_MODE_FIQ, "32-bit FIQ" }, \
+ { PSR_AA32_MODE_IRQ, "32-bit IRQ" }, \
+ { PSR_AA32_MODE_SVC, "32-bit SVC" }, \
+ { PSR_AA32_MODE_ABT, "32-bit ABT" }, \
+ { PSR_AA32_MODE_HYP, "32-bit HYP" }, \
+ { PSR_AA32_MODE_UND, "32-bit UND" }, \
+ { PSR_AA32_MODE_SYS, "32-bit SYS" }
+
#endif /* __ARM64_KVM_ARM_H__ */
@@ -33,6 +33,12 @@ enum exception_type {
except_type_serror = 0x180,
};
+#define kvm_exception_type_names \
+ { except_type_sync, "SYNC" }, \
+ { except_type_irq, "IRQ" }, \
+ { except_type_fiq, "FIQ" }, \
+ { except_type_serror, "SERROR" }
+
bool kvm_condition_valid32(const struct kvm_vcpu *vcpu);
void kvm_skip_instr32(struct kvm_vcpu *vcpu);
@@ -44,6 +50,10 @@ void kvm_inject_size_fault(struct kvm_vcpu *vcpu);
void kvm_vcpu_wfi(struct kvm_vcpu *vcpu);
+void kvm_emulate_nested_eret(struct kvm_vcpu *vcpu);
+int kvm_inject_nested_sync(struct kvm_vcpu *vcpu, u64 esr_el2);
+int kvm_inject_nested_irq(struct kvm_vcpu *vcpu);
+
#if defined(__KVM_VHE_HYPERVISOR__) || defined(__KVM_NVHE_HYPERVISOR__)
static __always_inline bool vcpu_el1_is_32bit(struct kvm_vcpu *vcpu)
{
@@ -634,7 +634,7 @@ struct kvm_vcpu_arch {
#define EXCEPT_AA64_EL1_IRQ __vcpu_except_flags(1)
#define EXCEPT_AA64_EL1_FIQ __vcpu_except_flags(2)
#define EXCEPT_AA64_EL1_SERR __vcpu_except_flags(3)
-/* For AArch64 with NV (one day): */
+/* For AArch64 with NV: */
#define EXCEPT_AA64_EL2_SYNC __vcpu_except_flags(4)
#define EXCEPT_AA64_EL2_IRQ __vcpu_except_flags(5)
#define EXCEPT_AA64_EL2_FIQ __vcpu_except_flags(6)
@@ -14,7 +14,7 @@ kvm-y += arm.o mmu.o mmio.o psci.o hypercalls.o pvtime.o \
inject_fault.o va_layout.o handle_exit.o \
guest.o debug.o reset.o sys_regs.o stacktrace.o \
vgic-sys-reg-v3.o fpsimd.o pkvm.o \
- arch_timer.o trng.o vmid.o \
+ arch_timer.o trng.o vmid.o emulate-nested.o \
vgic/vgic.o vgic/vgic-init.o \
vgic/vgic-irqfd.o vgic/vgic-v2.o \
vgic/vgic-v3.o vgic/vgic-v4.o \
new file mode 100644
@@ -0,0 +1,203 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2016 - Linaro and Columbia University
+ * Author: Jintack Lim <jintack.lim@linaro.org>
+ */
+
+#include <linux/kvm.h>
+#include <linux/kvm_host.h>
+
+#include <asm/kvm_emulate.h>
+#include <asm/kvm_nested.h>
+
+#include "hyp/include/hyp/adjust_pc.h"
+
+#include "trace.h"
+
+static u64 kvm_check_illegal_exception_return(struct kvm_vcpu *vcpu, u64 spsr)
+{
+ u64 mode = spsr & PSR_MODE_MASK;
+
+ /*
+ * Possible causes for an Illegal Exception Return from EL2:
+ * - trying to return to EL3
+ * - trying to return to an illegal M value
+ * - trying to return to a 32bit EL
+ * - trying to return to EL1 with HCR_EL2.TGE set
+ */
+ if (mode == PSR_MODE_EL3t || mode == PSR_MODE_EL3h ||
+ mode == 0b00001 || (mode & BIT(1)) ||
+ (spsr & PSR_MODE32_BIT) ||
+ (vcpu_el2_tge_is_set(vcpu) && (mode == PSR_MODE_EL1t ||
+ mode == PSR_MODE_EL1h))) {
+ /*
+ * The guest is playing with our nerves. Preserve EL, SP,
+ * masks, flags from the existing PSTATE, and set IL.
+ * The HW will then generate an Illegal State Exception
+ * immediately after ERET.
+ */
+ spsr = *vcpu_cpsr(vcpu);
+
+ spsr &= (PSR_D_BIT | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT |
+ PSR_N_BIT | PSR_Z_BIT | PSR_C_BIT | PSR_V_BIT |
+ PSR_MODE_MASK | PSR_MODE32_BIT);
+ spsr |= PSR_IL_BIT;
+ }
+
+ return spsr;
+}
+
+void kvm_emulate_nested_eret(struct kvm_vcpu *vcpu)
+{
+ u64 spsr, elr, mode;
+ bool direct_eret;
+
+ /*
+ * Going through the whole put/load motions is a waste of time
+ * if this is a VHE guest hypervisor returning to its own
+ * userspace, or the hypervisor performing a local exception
+ * return. No need to save/restore registers, no need to
+ * switch S2 MMU. Just do the canonical ERET.
+ */
+ spsr = vcpu_read_sys_reg(vcpu, SPSR_EL2);
+ spsr = kvm_check_illegal_exception_return(vcpu, spsr);
+
+ mode = spsr & (PSR_MODE_MASK | PSR_MODE32_BIT);
+
+ direct_eret = (mode == PSR_MODE_EL0t &&
+ vcpu_el2_e2h_is_set(vcpu) &&
+ vcpu_el2_tge_is_set(vcpu));
+ direct_eret |= (mode == PSR_MODE_EL2h || mode == PSR_MODE_EL2t);
+
+ if (direct_eret) {
+ *vcpu_pc(vcpu) = vcpu_read_sys_reg(vcpu, ELR_EL2);
+ *vcpu_cpsr(vcpu) = spsr;
+ trace_kvm_nested_eret(vcpu, *vcpu_pc(vcpu), spsr);
+ return;
+ }
+
+ preempt_disable();
+ kvm_arch_vcpu_put(vcpu);
+
+ elr = __vcpu_sys_reg(vcpu, ELR_EL2);
+
+ trace_kvm_nested_eret(vcpu, elr, spsr);
+
+ /*
+ * Note that the current exception level is always the virtual EL2,
+ * since we set HCR_EL2.NV bit only when entering the virtual EL2.
+ */
+ *vcpu_pc(vcpu) = elr;
+ *vcpu_cpsr(vcpu) = spsr;
+
+ kvm_arch_vcpu_load(vcpu, smp_processor_id());
+ preempt_enable();
+}
+
+static void kvm_inject_el2_exception(struct kvm_vcpu *vcpu, u64 esr_el2,
+ enum exception_type type)
+{
+ trace_kvm_inject_nested_exception(vcpu, esr_el2, type);
+
+ switch (type) {
+ case except_type_sync:
+ kvm_pend_exception(vcpu, EXCEPT_AA64_EL2_SYNC);
+ vcpu_write_sys_reg(vcpu, esr_el2, ESR_EL2);
+ break;
+ case except_type_irq:
+ kvm_pend_exception(vcpu, EXCEPT_AA64_EL2_IRQ);
+ break;
+ default:
+ WARN_ONCE(1, "Unsupported EL2 exception injection %d\n", type);
+ }
+}
+
+/*
+ * Emulate taking an exception to EL2.
+ * See ARM ARM J8.1.2 AArch64.TakeException()
+ */
+static int kvm_inject_nested(struct kvm_vcpu *vcpu, u64 esr_el2,
+ enum exception_type type)
+{
+ u64 pstate, mode;
+ bool direct_inject;
+
+ if (!vcpu_has_nv(vcpu)) {
+ kvm_err("Unexpected call to %s for the non-nesting configuration\n",
+ __func__);
+ return -EINVAL;
+ }
+
+ /*
+ * As for ERET, we can avoid doing too much on the injection path by
+ * checking that we either took the exception from a VHE host
+ * userspace or from vEL2. In these cases, there is no change in
+ * translation regime (or anything else), so let's do as little as
+ * possible.
+ */
+ pstate = *vcpu_cpsr(vcpu);
+ mode = pstate & (PSR_MODE_MASK | PSR_MODE32_BIT);
+
+ direct_inject = (mode == PSR_MODE_EL0t &&
+ vcpu_el2_e2h_is_set(vcpu) &&
+ vcpu_el2_tge_is_set(vcpu));
+ direct_inject |= (mode == PSR_MODE_EL2h || mode == PSR_MODE_EL2t);
+
+ if (direct_inject) {
+ kvm_inject_el2_exception(vcpu, esr_el2, type);
+ return 1;
+ }
+
+ preempt_disable();
+
+ /*
+ * We may have an exception or PC update in the EL0/EL1 context.
+ * Commit it before entering EL2.
+ */
+ __kvm_adjust_pc(vcpu);
+
+ kvm_arch_vcpu_put(vcpu);
+
+ kvm_inject_el2_exception(vcpu, esr_el2, type);
+
+ /*
+ * A hard requirement is that a switch between EL1 and EL2
+ * contexts has to happen between a put/load, so that we can
+ * pick the correct timer and interrupt configuration, among
+ * other things.
+ *
+ * Make sure the exception actually took place before we load
+ * the new context.
+ */
+ __kvm_adjust_pc(vcpu);
+
+ kvm_arch_vcpu_load(vcpu, smp_processor_id());
+ preempt_enable();
+
+ return 1;
+}
+
+int kvm_inject_nested_sync(struct kvm_vcpu *vcpu, u64 esr_el2)
+{
+ return kvm_inject_nested(vcpu, esr_el2, except_type_sync);
+}
+
+int kvm_inject_nested_irq(struct kvm_vcpu *vcpu)
+{
+ /*
+ * Do not inject an irq if the:
+ * - Current exception level is EL2, and
+ * - virtual HCR_EL2.TGE == 0
+ * - virtual HCR_EL2.IMO == 0
+ *
+ * See Table D1-17 "Physical interrupt target and masking when EL3 is
+ * not implemented and EL2 is implemented" in ARM DDI 0487C.a.
+ */
+
+ if (vcpu_is_el2(vcpu) && !vcpu_el2_tge_is_set(vcpu) &&
+ !(__vcpu_sys_reg(vcpu, HCR_EL2) & HCR_IMO))
+ return 1;
+
+ /* esr_el2 value doesn't matter for exits due to irqs. */
+ return kvm_inject_nested(vcpu, 0, except_type_irq);
+}
@@ -14,6 +14,7 @@
#include <linux/kvm_host.h>
#include <asm/kvm_emulate.h>
#include <asm/kvm_mmu.h>
+#include <asm/kvm_nested.h>
#if !defined (__KVM_NVHE_HYPERVISOR__) && !defined (__KVM_VHE_HYPERVISOR__)
#error Hypervisor code only!
@@ -23,7 +24,9 @@ static inline u64 __vcpu_read_sys_reg(const struct kvm_vcpu *vcpu, int reg)
{
u64 val;
- if (__vcpu_read_sys_reg_from_cpu(reg, &val))
+ if (unlikely(vcpu_has_nv(vcpu)))
+ return vcpu_read_sys_reg(vcpu, reg);
+ else if (__vcpu_read_sys_reg_from_cpu(reg, &val))
return val;
return __vcpu_sys_reg(vcpu, reg);
@@ -31,18 +34,25 @@ static inline u64 __vcpu_read_sys_reg(const struct kvm_vcpu *vcpu, int reg)
static inline void __vcpu_write_sys_reg(struct kvm_vcpu *vcpu, u64 val, int reg)
{
- if (__vcpu_write_sys_reg_to_cpu(val, reg))
- return;
-
- __vcpu_sys_reg(vcpu, reg) = val;
+ if (unlikely(vcpu_has_nv(vcpu)))
+ vcpu_write_sys_reg(vcpu, val, reg);
+ else if (!__vcpu_write_sys_reg_to_cpu(val, reg))
+ __vcpu_sys_reg(vcpu, reg) = val;
}
-static void __vcpu_write_spsr(struct kvm_vcpu *vcpu, u64 val)
+static void __vcpu_write_spsr(struct kvm_vcpu *vcpu, unsigned long target_mode,
+ u64 val)
{
- if (has_vhe())
+ if (unlikely(vcpu_has_nv(vcpu))) {
+ if (target_mode == PSR_MODE_EL1h)
+ vcpu_write_sys_reg(vcpu, val, SPSR_EL1);
+ else
+ vcpu_write_sys_reg(vcpu, val, SPSR_EL2);
+ } else if (has_vhe()) {
write_sysreg_el1(val, SYS_SPSR);
- else
+ } else {
__vcpu_sys_reg(vcpu, SPSR_EL1) = val;
+ }
}
static void __vcpu_write_spsr_abt(struct kvm_vcpu *vcpu, u64 val)
@@ -101,6 +111,11 @@ static void enter_exception64(struct kvm_vcpu *vcpu, unsigned long target_mode,
sctlr = __vcpu_read_sys_reg(vcpu, SCTLR_EL1);
__vcpu_write_sys_reg(vcpu, *vcpu_pc(vcpu), ELR_EL1);
break;
+ case PSR_MODE_EL2h:
+ vbar = __vcpu_read_sys_reg(vcpu, VBAR_EL2);
+ sctlr = __vcpu_read_sys_reg(vcpu, SCTLR_EL2);
+ __vcpu_write_sys_reg(vcpu, *vcpu_pc(vcpu), ELR_EL2);
+ break;
default:
/* Don't do that */
BUG();
@@ -153,7 +168,7 @@ static void enter_exception64(struct kvm_vcpu *vcpu, unsigned long target_mode,
new |= target_mode;
*vcpu_cpsr(vcpu) = new;
- __vcpu_write_spsr(vcpu, old);
+ __vcpu_write_spsr(vcpu, target_mode, old);
}
/*
@@ -323,11 +338,20 @@ static void kvm_inject_exception(struct kvm_vcpu *vcpu)
case unpack_vcpu_flag(EXCEPT_AA64_EL1_SYNC):
enter_exception64(vcpu, PSR_MODE_EL1h, except_type_sync);
break;
+
+ case unpack_vcpu_flag(EXCEPT_AA64_EL2_SYNC):
+ enter_exception64(vcpu, PSR_MODE_EL2h, except_type_sync);
+ break;
+
+ case unpack_vcpu_flag(EXCEPT_AA64_EL2_IRQ):
+ enter_exception64(vcpu, PSR_MODE_EL2h, except_type_irq);
+ break;
+
default:
/*
- * Only EL1_SYNC makes sense so far, EL2_{SYNC,IRQ}
- * will be implemented at some point. Everything
- * else gets silently ignored.
+ * Only EL1_SYNC and EL2_{SYNC,IRQ} makes
+ * sense so far. Everything else gets silently
+ * ignored.
*/
break;
}
@@ -12,17 +12,55 @@
#include <linux/kvm_host.h>
#include <asm/kvm_emulate.h>
+#include <asm/kvm_nested.h>
#include <asm/esr.h>
+static void pend_sync_exception(struct kvm_vcpu *vcpu)
+{
+ /* If not nesting, EL1 is the only possible exception target */
+ if (likely(!vcpu_has_nv(vcpu))) {
+ kvm_pend_exception(vcpu, EXCEPT_AA64_EL1_SYNC);
+ return;
+ }
+
+ /*
+ * With NV, we need to pick between EL1 and EL2. Note that we
+ * never deal with a nesting exception here, hence never
+ * changing context, and the exception itself can be delayed
+ * until the next entry.
+ */
+ switch(*vcpu_cpsr(vcpu) & PSR_MODE_MASK) {
+ case PSR_MODE_EL2h:
+ case PSR_MODE_EL2t:
+ kvm_pend_exception(vcpu, EXCEPT_AA64_EL2_SYNC);
+ break;
+ case PSR_MODE_EL1h:
+ case PSR_MODE_EL1t:
+ kvm_pend_exception(vcpu, EXCEPT_AA64_EL1_SYNC);
+ break;
+ case PSR_MODE_EL0t:
+ if (vcpu_el2_tge_is_set(vcpu))
+ kvm_pend_exception(vcpu, EXCEPT_AA64_EL2_SYNC);
+ else
+ kvm_pend_exception(vcpu, EXCEPT_AA64_EL1_SYNC);
+ break;
+ default:
+ BUG();
+ }
+}
+
+static bool match_target_el(struct kvm_vcpu *vcpu, unsigned long target)
+{
+ return (vcpu_get_flag(vcpu, EXCEPT_MASK) == target);
+}
+
static void inject_abt64(struct kvm_vcpu *vcpu, bool is_iabt, unsigned long addr)
{
unsigned long cpsr = *vcpu_cpsr(vcpu);
bool is_aarch32 = vcpu_mode_is_32bit(vcpu);
u64 esr = 0;
- kvm_pend_exception(vcpu, EXCEPT_AA64_EL1_SYNC);
-
- vcpu_write_sys_reg(vcpu, addr, FAR_EL1);
+ pend_sync_exception(vcpu);
/*
* Build an {i,d}abort, depending on the level and the
@@ -43,14 +81,22 @@ static void inject_abt64(struct kvm_vcpu *vcpu, bool is_iabt, unsigned long addr
if (!is_iabt)
esr |= ESR_ELx_EC_DABT_LOW << ESR_ELx_EC_SHIFT;
- vcpu_write_sys_reg(vcpu, esr | ESR_ELx_FSC_EXTABT, ESR_EL1);
+ esr |= ESR_ELx_FSC_EXTABT;
+
+ if (match_target_el(vcpu, unpack_vcpu_flag(EXCEPT_AA64_EL1_SYNC))) {
+ vcpu_write_sys_reg(vcpu, addr, FAR_EL1);
+ vcpu_write_sys_reg(vcpu, esr, ESR_EL1);
+ } else {
+ vcpu_write_sys_reg(vcpu, addr, FAR_EL2);
+ vcpu_write_sys_reg(vcpu, esr, ESR_EL2);
+ }
}
static void inject_undef64(struct kvm_vcpu *vcpu)
{
u64 esr = (ESR_ELx_EC_UNKNOWN << ESR_ELx_EC_SHIFT);
- kvm_pend_exception(vcpu, EXCEPT_AA64_EL1_SYNC);
+ pend_sync_exception(vcpu);
/*
* Build an unknown exception, depending on the instruction
@@ -59,7 +105,10 @@ static void inject_undef64(struct kvm_vcpu *vcpu)
if (kvm_vcpu_trap_il_is32bit(vcpu))
esr |= ESR_ELx_IL;
- vcpu_write_sys_reg(vcpu, esr, ESR_EL1);
+ if (match_target_el(vcpu, unpack_vcpu_flag(EXCEPT_AA64_EL1_SYNC)))
+ vcpu_write_sys_reg(vcpu, esr, ESR_EL1);
+ else
+ vcpu_write_sys_reg(vcpu, esr, ESR_EL2);
}
#define DFSR_FSC_EXTABT_LPAE 0x10
@@ -2,6 +2,7 @@
#if !defined(_TRACE_ARM_ARM64_KVM_H) || defined(TRACE_HEADER_MULTI_READ)
#define _TRACE_ARM_ARM64_KVM_H
+#include <asm/kvm_emulate.h>
#include <kvm/arm_arch_timer.h>
#include <linux/tracepoint.h>
@@ -301,6 +302,64 @@ TRACE_EVENT(kvm_timer_emulate,
__entry->timer_idx, __entry->should_fire)
);
+TRACE_EVENT(kvm_nested_eret,
+ TP_PROTO(struct kvm_vcpu *vcpu, unsigned long elr_el2,
+ unsigned long spsr_el2),
+ TP_ARGS(vcpu, elr_el2, spsr_el2),
+
+ TP_STRUCT__entry(
+ __field(struct kvm_vcpu *, vcpu)
+ __field(unsigned long, elr_el2)
+ __field(unsigned long, spsr_el2)
+ __field(unsigned long, target_mode)
+ __field(unsigned long, hcr_el2)
+ ),
+
+ TP_fast_assign(
+ __entry->vcpu = vcpu;
+ __entry->elr_el2 = elr_el2;
+ __entry->spsr_el2 = spsr_el2;
+ __entry->target_mode = spsr_el2 & (PSR_MODE_MASK | PSR_MODE32_BIT);
+ __entry->hcr_el2 = __vcpu_sys_reg(vcpu, HCR_EL2);
+ ),
+
+ TP_printk("elr_el2: 0x%lx spsr_el2: 0x%08lx (M: %s) hcr_el2: %lx",
+ __entry->elr_el2, __entry->spsr_el2,
+ __print_symbolic(__entry->target_mode, kvm_mode_names),
+ __entry->hcr_el2)
+);
+
+TRACE_EVENT(kvm_inject_nested_exception,
+ TP_PROTO(struct kvm_vcpu *vcpu, u64 esr_el2, int type),
+ TP_ARGS(vcpu, esr_el2, type),
+
+ TP_STRUCT__entry(
+ __field(struct kvm_vcpu *, vcpu)
+ __field(unsigned long, esr_el2)
+ __field(int, type)
+ __field(unsigned long, spsr_el2)
+ __field(unsigned long, pc)
+ __field(unsigned long, source_mode)
+ __field(unsigned long, hcr_el2)
+ ),
+
+ TP_fast_assign(
+ __entry->vcpu = vcpu;
+ __entry->esr_el2 = esr_el2;
+ __entry->type = type;
+ __entry->spsr_el2 = *vcpu_cpsr(vcpu);
+ __entry->pc = *vcpu_pc(vcpu);
+ __entry->source_mode = *vcpu_cpsr(vcpu) & (PSR_MODE_MASK | PSR_MODE32_BIT);
+ __entry->hcr_el2 = __vcpu_sys_reg(vcpu, HCR_EL2);
+ ),
+
+ TP_printk("%s: esr_el2 0x%lx elr_el2: 0x%lx spsr_el2: 0x%08lx (M: %s) hcr_el2: %lx",
+ __print_symbolic(__entry->type, kvm_exception_type_names),
+ __entry->esr_el2, __entry->pc, __entry->spsr_el2,
+ __print_symbolic(__entry->source_mode, kvm_mode_names),
+ __entry->hcr_el2)
+);
+
#endif /* _TRACE_ARM_ARM64_KVM_H */
#undef TRACE_INCLUDE_PATH