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Tue, 28 Apr 2020 07:34:49 +0000 From: Anup Patel To: Palmer Dabbelt , Palmer Dabbelt , Paul Walmsley , Albert Ou , Paolo Bonzini Cc: Alexander Graf , Atish Patra , Alistair Francis , Damien Le Moal , Anup Patel , kvm@vger.kernel.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, Anup Patel Subject: [PATCH v12 09/17] RISC-V: KVM: Implement VMID allocator Date: Tue, 28 Apr 2020 13:03:04 +0530 Message-Id: <20200428073312.324684-10-anup.patel@wdc.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200428073312.324684-1-anup.patel@wdc.com> References: <20200428073312.324684-1-anup.patel@wdc.com> Content-Transfer-Encoding: 8bit Content-Type: text/plain X-ClientProxiedBy: MAXPR01CA0073.INDPRD01.PROD.OUTLOOK.COM (2603:1096:a00:49::15) To DM6PR04MB6201.namprd04.prod.outlook.com (2603:10b6:5:127::32) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from wdc.com (106.51.31.156) by MAXPR01CA0073.INDPRD01.PROD.OUTLOOK.COM (2603:1096:a00:49::15) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2958.19 via Frontend Transport; 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X-Microsoft-Antispam-Message-Info: Yk4drcRfrGBrVWBIjYeBX+cJWGNDbh71iwH1hsjCfdwIX96NwVKGK7sYyGUrN40AYCWuhE8tLlEdG+tanDUudT/V4lJtQyYgCWsgBDXrY8LZlADgxYnxrtf4ppmK5WVKLV6V6F3u96S+0nJHv2M7EBYpx1PBcRyao3eCwBgb4mxuao1pelVkouDAySXLpqstdtu6Ltad+zb25442jrZGQZ75bb0h7BQ+ck4isR6bs38iMZ/gQL3tFIzyOsNR/93+CRUUg53VlSsJH8Sm4RxEz3+rVBszboTsWae+qbntKhzzF/3rp1Hbg5073p7f72je08RNptuTr8kSXumT7dzNU15q0WCP+tlWWRqecXEsy3nyapuPjo+39n5KYJd9TL4dkJGBICD/QALaLfNsG3SJiZsMDSB2iD2ni1gnUfvXSw/05qk8UrG3jwDQYUT7R4ys X-MS-Exchange-AntiSpam-MessageData: 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 X-OriginatorOrg: wdc.com X-MS-Exchange-CrossTenant-Network-Message-Id: 8234b5a5-d5bc-4707-66f6-08d7eb46a1c6 X-MS-Exchange-CrossTenant-OriginalArrivalTime: 28 Apr 2020 07:34:49.3544 (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: lEx156acio/mq/sk7HOkHfJVgHnKokEYGhPfXomgy0+E8AdhFVMP4mo8uqufbkW+uy5FprAoYqF57Q4SsU4xYg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM6PR04MB5929 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org 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 Acked-by: Paolo Bonzini Reviewed-by: Paolo Bonzini Reviewed-by: Alexander Graf --- arch/riscv/include/asm/kvm_host.h | 25 +++++++ arch/riscv/kvm/Makefile | 3 +- arch/riscv/kvm/main.c | 4 + arch/riscv/kvm/tlb.S | 43 +++++++++++ arch/riscv/kvm/vcpu.c | 9 +++ arch/riscv/kvm/vm.c | 6 ++ arch/riscv/kvm/vmid.c | 120 ++++++++++++++++++++++++++++++ 7 files changed, 209 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 05c84c745c61..296a5b13b3a6 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 +48,19 @@ struct kvm_vcpu_stat { struct kvm_arch_memory_slot { }; +struct kvm_vmid { + /* + * Writes to vmid_version and vmid happen with vmid_lock held + * whereas reads happen without any lock held. + */ + 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; @@ -175,6 +188,12 @@ 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) {} +void __kvm_riscv_hfence_gvma_vmid_gpa(unsigned long vmid, + unsigned long gpa); +void __kvm_riscv_hfence_gvma_vmid(unsigned long vmid); +void __kvm_riscv_hfence_gvma_gpa(unsigned long gpa); +void __kvm_riscv_hfence_gvma_all(void); + int kvm_riscv_stage2_map(struct kvm_vcpu *vcpu, struct kvm_memory_slot *memslot, gpa_t gpa, unsigned long hva, bool is_write); @@ -183,6 +202,12 @@ 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); + void __kvm_riscv_unpriv_trap(void); unsigned long kvm_riscv_vcpu_unpriv_read(struct kvm_vcpu *vcpu, 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 4dee84f5c440..6915ac6888a7 100644 --- a/arch/riscv/kvm/main.c +++ b/arch/riscv/kvm/main.c @@ -77,8 +77,12 @@ 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 de94e1a26117..8e75c92fe37c 100644 --- a/arch/riscv/kvm/vcpu.c +++ b/arch/riscv/kvm/vcpu.c @@ -632,6 +632,12 @@ 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); + + if (kvm_check_request(KVM_REQ_TLB_FLUSH, vcpu)) + __kvm_riscv_hfence_gvma_all(); } } @@ -676,6 +682,8 @@ 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(); @@ -712,6 +720,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) kvm_riscv_update_hvip(vcpu); 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..2c6253b293bc --- /dev/null +++ b/arch/riscv/kvm/vmid.c @@ -0,0 +1,120 @@ +// 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 +#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; +} + +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 cpumask hmask; + 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; + + /* + * We ran out of VMIDs so we increment vmid_version and + * start assigning VMIDs from 1. + * + * This also means existing VMIDs assignement to all Guest + * instances is invalid and we have force VMID re-assignement + * for all Guest instances. The Guest instances that were not + * running will automatically pick-up new VMIDs because will + * call kvm_riscv_stage2_vmid_update() whenever they enter + * in-kernel run loop. For Guest instances that are already + * running, we force VM exits on all host CPUs using IPI and + * flush all Guest TLBs. + */ + riscv_cpuid_to_hartid_mask(cpu_online_mask, &hmask); + sbi_remote_hfence_gvma(cpumask_bits(&hmask), 0, 0); + } + + vmid->vmid = vmid_next; + vmid_next++; + vmid_next &= (1 << vmid_bits) - 1; + + 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); +} -- 2.25.1