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Fri, 2 Aug 2019 07:48:02 +0000 Received: from MN2PR04MB6061.namprd04.prod.outlook.com ([fe80::a815:e61a:b4aa:60c8]) by MN2PR04MB6061.namprd04.prod.outlook.com ([fe80::a815:e61a:b4aa:60c8%7]) with mapi id 15.20.2136.010; Fri, 2 Aug 2019 07:48:02 +0000 From: Anup Patel To: Palmer Dabbelt , Paul Walmsley , Paolo Bonzini , Radim K CC: Daniel Lezcano , Thomas Gleixner , Atish Patra , Alistair Francis , Damien Le Moal , Christoph Hellwig , Anup Patel , "kvm@vger.kernel.org" , "linux-riscv@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Anup Patel Subject: [RFC PATCH v2 11/19] RISC-V: KVM: Implement VMID allocator Thread-Topic: [RFC PATCH v2 11/19] RISC-V: KVM: Implement VMID allocator Thread-Index: AQHVSQac3scKLsu6jkGzn8MXjWKofA== Date: Fri, 2 Aug 2019 07:48:02 +0000 Message-ID: <20190802074620.115029-12-anup.patel@wdc.com> References: <20190802074620.115029-1-anup.patel@wdc.com> In-Reply-To: <20190802074620.115029-1-anup.patel@wdc.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-clientproxiedby: PN1PR01CA0111.INDPRD01.PROD.OUTLOOK.COM (2603:1096:c00::27) To MN2PR04MB6061.namprd04.prod.outlook.com (2603:10b6:208:d8::15) authentication-results: spf=none (sender IP is ) smtp.mailfrom=Anup.Patel@wdc.com; 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x-ms-exchange-senderadcheck: 1 x-microsoft-antispam-message-info: pq6cQNAFlRmDaWYSTlDjq0uSwOZ3wwcXxhxUg9oTt87e6/ybuIIRuDMiQtSYpwfCjaxPNzQSsszKa9BDBQVxyMHuyQviwVvm0FtHBTl5XESo+bld7SMw67WyodSmhVWmmeiij69OcbEpG0PLKT2H5+ZeBuFvSB4K/UqAtnMkHkWHl07NKlbj+Ts/+70cb0jvupQdpS4zRApViWI4weIMQV7iaihOBjgwCE2CRkQ9ijIhy1u/Ne56J36/mkcOEZ0K0uP7FIEYlTRvMGNAxdYqdxw2Y6s1ntAR3Peqqx6y+YP73KFlU5T0OIbVxTiZsJ51HpVqmFWButFUHhCKBUbix+x30xt6kSu42VXNHd4txu6X+xFQf7SJUWKZlFUzik1g+JnlTFYGkADmZnMlL4t4FWlyMMhUIkBc9MqMkbwSILo= MIME-Version: 1.0 X-OriginatorOrg: wdc.com X-MS-Exchange-CrossTenant-Network-Message-Id: b1b62651-be07-44d6-df7a-08d7171dbf30 X-MS-Exchange-CrossTenant-originalarrivaltime: 02 Aug 2019 07:48:02.7694 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: b61c8803-16f3-4c35-9b17-6f65f441df86 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: Anup.Patel@wdc.com X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN2PR04MB5566 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP We implement a simple VMID allocator for Guests/VMs which: 1. Detects number of VMID bits at boot-time 2. Uses atomic number to track VMID version and increments VMID version whenever we run-out of VMIDs 3. Flushes Guest TLBs on all host CPUs whenever we run-out of VMIDs 4. Force updates HW Stage2 VMID for each Guest VCPU whenever VMID changes using VCPU request KVM_REQ_UPDATE_HGATP Signed-off-by: Anup Patel --- arch/riscv/include/asm/kvm_host.h | 21 +++++ arch/riscv/kvm/Makefile | 3 +- arch/riscv/kvm/main.c | 4 + arch/riscv/kvm/tlb.S | 43 +++++++++++ arch/riscv/kvm/vcpu.c | 6 ++ arch/riscv/kvm/vm.c | 6 ++ arch/riscv/kvm/vmid.c | 124 ++++++++++++++++++++++++++++++ 7 files changed, 206 insertions(+), 1 deletion(-) create mode 100644 arch/riscv/kvm/tlb.S create mode 100644 arch/riscv/kvm/vmid.c diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h index 45225baa7d0c..ca2b4f2b558c 100644 --- a/arch/riscv/include/asm/kvm_host.h +++ b/arch/riscv/include/asm/kvm_host.h @@ -27,6 +27,7 @@ #define KVM_REQ_SLEEP \ KVM_ARCH_REQ_FLAGS(0, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP) #define KVM_REQ_VCPU_RESET KVM_ARCH_REQ(1) +#define KVM_REQ_UPDATE_HGATP KVM_ARCH_REQ(2) struct kvm_vm_stat { ulong remote_tlb_flush; @@ -47,7 +48,15 @@ struct kvm_vcpu_stat { struct kvm_arch_memory_slot { }; +struct kvm_vmid { + unsigned long vmid_version; + unsigned long vmid; +}; + struct kvm_arch { + /* stage2 vmid */ + struct kvm_vmid vmid; + /* stage2 page table */ pgd_t *pgd; phys_addr_t pgd_phys; @@ -155,6 +164,12 @@ static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {} static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {} static inline void kvm_arch_vcpu_block_finish(struct kvm_vcpu *vcpu) {} +extern void __kvm_riscv_hfence_gvma_vmid_gpa(unsigned long vmid, + unsigned long gpa); +extern void __kvm_riscv_hfence_gvma_vmid(unsigned long vmid); +extern void __kvm_riscv_hfence_gvma_gpa(unsigned long gpa); +extern void __kvm_riscv_hfence_gvma_all(void); + int kvm_riscv_stage2_map(struct kvm_vcpu *vcpu, gpa_t gpa, unsigned long hva, bool is_write); void kvm_riscv_stage2_flush_cache(struct kvm_vcpu *vcpu); @@ -162,6 +177,12 @@ int kvm_riscv_stage2_alloc_pgd(struct kvm *kvm); void kvm_riscv_stage2_free_pgd(struct kvm *kvm); void kvm_riscv_stage2_update_hgatp(struct kvm_vcpu *vcpu); +void kvm_riscv_stage2_vmid_detect(void); +unsigned long kvm_riscv_stage2_vmid_bits(void); +int kvm_riscv_stage2_vmid_init(struct kvm *kvm); +bool kvm_riscv_stage2_vmid_ver_changed(struct kvm_vmid *vmid); +void kvm_riscv_stage2_vmid_update(struct kvm_vcpu *vcpu); + int kvm_riscv_vcpu_mmio_return(struct kvm_vcpu *vcpu, struct kvm_run *run); int kvm_riscv_vcpu_exit(struct kvm_vcpu *vcpu, struct kvm_run *run, unsigned long scause, unsigned long stval); diff --git a/arch/riscv/kvm/Makefile b/arch/riscv/kvm/Makefile index 845579273727..c0f57f26c13d 100644 --- a/arch/riscv/kvm/Makefile +++ b/arch/riscv/kvm/Makefile @@ -8,6 +8,7 @@ ccflags-y := -Ivirt/kvm -Iarch/riscv/kvm kvm-objs := $(common-objs-y) -kvm-objs += main.o vm.o mmu.o vcpu.o vcpu_exit.o vcpu_switch.o +kvm-objs += main.o vm.o vmid.o tlb.o mmu.o +kvm-objs += vcpu.o vcpu_exit.o vcpu_switch.o obj-$(CONFIG_KVM) += kvm.o diff --git a/arch/riscv/kvm/main.c b/arch/riscv/kvm/main.c index a26a68df7cfc..379fc960d412 100644 --- a/arch/riscv/kvm/main.c +++ b/arch/riscv/kvm/main.c @@ -64,8 +64,12 @@ int kvm_arch_init(void *opaque) return -ENODEV; } + kvm_riscv_stage2_vmid_detect(); + kvm_info("hypervisor extension available\n"); + kvm_info("host has %ld VMID bits\n", kvm_riscv_stage2_vmid_bits()); + return 0; } diff --git a/arch/riscv/kvm/tlb.S b/arch/riscv/kvm/tlb.S new file mode 100644 index 000000000000..453fca8d7940 --- /dev/null +++ b/arch/riscv/kvm/tlb.S @@ -0,0 +1,43 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2019 Western Digital Corporation or its affiliates. + * + * Authors: + * Anup Patel + */ + +#include +#include + + .text + .altmacro + .option norelax + + /* + * Instruction encoding of hfence.gvma is: + * 0110001 rs2(5) rs1(5) 000 00000 1110011 + */ + +ENTRY(__kvm_riscv_hfence_gvma_vmid_gpa) + /* hfence.gvma a1, a0 */ + .word 0x62a60073 + ret +ENDPROC(__kvm_riscv_hfence_gvma_vmid_gpa) + +ENTRY(__kvm_riscv_hfence_gvma_vmid) + /* hfence.gvma zero, a0 */ + .word 0x62a00073 + ret +ENDPROC(__kvm_riscv_hfence_gvma_vmid) + +ENTRY(__kvm_riscv_hfence_gvma_gpa) + /* hfence.gvma a0 */ + .word 0x62050073 + ret +ENDPROC(__kvm_riscv_hfence_gvma_gpa) + +ENTRY(__kvm_riscv_hfence_gvma_all) + /* hfence.gvma */ + .word 0x62000073 + ret +ENDPROC(__kvm_riscv_hfence_gvma_all) diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c index 652004aa1c2b..69548ddaa272 100644 --- a/arch/riscv/kvm/vcpu.c +++ b/arch/riscv/kvm/vcpu.c @@ -625,6 +625,9 @@ static void kvm_riscv_check_vcpu_requests(struct kvm_vcpu *vcpu) if (kvm_check_request(KVM_REQ_VCPU_RESET, vcpu)) kvm_riscv_reset_vcpu(vcpu); + + if (kvm_check_request(KVM_REQ_UPDATE_HGATP, vcpu)) + kvm_riscv_stage2_update_hgatp(vcpu); } } @@ -656,6 +659,8 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) /* Check conditions before entering the guest */ cond_resched(); + kvm_riscv_stage2_vmid_update(vcpu); + kvm_riscv_check_vcpu_requests(vcpu); preempt_disable(); @@ -686,6 +691,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) kvm_riscv_vcpu_flush_interrupts(vcpu, true); if (ret <= 0 || + kvm_riscv_stage2_vmid_ver_changed(&vcpu->kvm->arch.vmid) || kvm_request_pending(vcpu)) { vcpu->mode = OUTSIDE_GUEST_MODE; local_irq_enable(); diff --git a/arch/riscv/kvm/vm.c b/arch/riscv/kvm/vm.c index ac0211820521..c5aab5478c38 100644 --- a/arch/riscv/kvm/vm.c +++ b/arch/riscv/kvm/vm.c @@ -26,6 +26,12 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) if (r) return r; + r = kvm_riscv_stage2_vmid_init(kvm); + if (r) { + kvm_riscv_stage2_free_pgd(kvm); + return r; + } + return 0; } diff --git a/arch/riscv/kvm/vmid.c b/arch/riscv/kvm/vmid.c new file mode 100644 index 000000000000..deee60013890 --- /dev/null +++ b/arch/riscv/kvm/vmid.c @@ -0,0 +1,124 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2019 Western Digital Corporation or its affiliates. + * + * Authors: + * Anup Patel + */ + +#include +#include +#include +#include +#include +#include +#include + +static unsigned long vmid_version = 1; +static unsigned long vmid_next; +static unsigned long vmid_bits; +static DEFINE_SPINLOCK(vmid_lock); + +void kvm_riscv_stage2_vmid_detect(void) +{ + unsigned long old; + + /* Figure-out number of VMID bits in HW */ + old = csr_read(CSR_HGATP); + csr_write(CSR_HGATP, old | HGATP_VMID_MASK); + vmid_bits = csr_read(CSR_HGATP); + vmid_bits = (vmid_bits & HGATP_VMID_MASK) >> HGATP_VMID_SHIFT; + vmid_bits = fls_long(vmid_bits); + csr_write(CSR_HGATP, old); + + /* We polluted local TLB so flush all guest TLB */ + __kvm_riscv_hfence_gvma_all(); + + /* We don't use VMID bits if they are not sufficient */ + if ((1UL << vmid_bits) < num_possible_cpus()) + vmid_bits = 0; +} + +unsigned long kvm_riscv_stage2_vmid_bits(void) +{ + return vmid_bits; +} + +int kvm_riscv_stage2_vmid_init(struct kvm *kvm) +{ + /* Mark the initial VMID and VMID version invalid */ + kvm->arch.vmid.vmid_version = 0; + kvm->arch.vmid.vmid = 0; + + return 0; +} + +static void local_guest_tlb_flush(void *info) +{ + __kvm_riscv_hfence_gvma_all(); +} + +static void force_exit_and_guest_tlb_flush(const cpumask_t *mask) +{ + preempt_disable(); + smp_call_function_many(mask, local_guest_tlb_flush, NULL, true); + preempt_enable(); +} + +bool kvm_riscv_stage2_vmid_ver_changed(struct kvm_vmid *vmid) +{ + if (!vmid_bits) + return false; + + return unlikely(READ_ONCE(vmid->vmid_version) != + READ_ONCE(vmid_version)); +} + +void kvm_riscv_stage2_vmid_update(struct kvm_vcpu *vcpu) +{ + int i; + struct kvm_vcpu *v; + struct kvm_vmid *vmid = &vcpu->kvm->arch.vmid; + + if (!kvm_riscv_stage2_vmid_ver_changed(vmid)) + return; + + spin_lock(&vmid_lock); + + /* + * We need to re-check the vmid_version here to ensure that if + * another vcpu already allocated a valid vmid for this vm. + */ + if (!kvm_riscv_stage2_vmid_ver_changed(vmid)) { + spin_unlock(&vmid_lock); + return; + } + + /* First user of a new VMID version? */ + if (unlikely(vmid_next == 0)) { + WRITE_ONCE(vmid_version, READ_ONCE(vmid_version) + 1); + vmid_next = 1; + + /* + * On SMP we know no other CPUs can use this CPU's or + * each other's VMID after forced exit returns since the + * vmid_lock blocks them from re-entry to the guest. + */ + force_exit_and_guest_tlb_flush(cpu_all_mask); + } + + vmid->vmid = vmid_next; + vmid_next++; + vmid_next &= (1 << vmid_bits) - 1; + + /* Ensure VMID next update is completed */ + smp_wmb(); + + WRITE_ONCE(vmid->vmid_version, READ_ONCE(vmid_version)); + + spin_unlock(&vmid_lock); + + /* Request stage2 page table update for all VCPUs */ + kvm_for_each_vcpu(i, v, vcpu->kvm) + kvm_make_request(KVM_REQ_UPDATE_HGATP, v); +}