From: Anup Patel <anup.patel@wdc.com> To: Palmer Dabbelt <palmer@dabbelt.com>, Palmer Dabbelt <palmerdabbelt@google.com>, Paul Walmsley <paul.walmsley@sifive.com>, Albert Ou <aou@eecs.berkeley.edu>, Paolo Bonzini <pbonzini@redhat.com> Cc: Alexander Graf <graf@amazon.com>, Atish Patra <atish.patra@wdc.com>, Alistair Francis <Alistair.Francis@wdc.com>, Damien Le Moal <damien.lemoal@wdc.com>, Anup Patel <anup@brainfault.org>, kvm@vger.kernel.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, Anup Patel <anup.patel@wdc.com> Subject: [PATCH v16 08/17] RISC-V: KVM: Handle WFI exits for VCPU Date: Fri, 15 Jan 2021 17:48:37 +0530 [thread overview] Message-ID: <20210115121846.114528-9-anup.patel@wdc.com> (raw) In-Reply-To: <20210115121846.114528-1-anup.patel@wdc.com> We get illegal instruction trap whenever Guest/VM executes WFI instruction. This patch handles WFI trap by blocking the trapped VCPU using kvm_vcpu_block() API. The blocked VCPU will be automatically resumed whenever a VCPU interrupt is injected from user-space or from in-kernel IRQCHIP emulation. Signed-off-by: Anup Patel <anup.patel@wdc.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> --- arch/riscv/kvm/vcpu_exit.c | 76 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 76 insertions(+) diff --git a/arch/riscv/kvm/vcpu_exit.c b/arch/riscv/kvm/vcpu_exit.c index cf99567955ad..bacad80686a2 100644 --- a/arch/riscv/kvm/vcpu_exit.c +++ b/arch/riscv/kvm/vcpu_exit.c @@ -12,6 +12,13 @@ #include <linux/kvm_host.h> #include <asm/csr.h> +#define INSN_OPCODE_MASK 0x007c +#define INSN_OPCODE_SHIFT 2 +#define INSN_OPCODE_SYSTEM 28 + +#define INSN_MASK_WFI 0xffffff00 +#define INSN_MATCH_WFI 0x10500000 + #define INSN_MATCH_LB 0x3 #define INSN_MASK_LB 0x707f #define INSN_MATCH_LH 0x1003 @@ -116,6 +123,71 @@ (s32)(((insn) >> 7) & 0x1f)) #define MASK_FUNCT3 0x7000 +static int truly_illegal_insn(struct kvm_vcpu *vcpu, + struct kvm_run *run, + ulong insn) +{ + struct kvm_cpu_trap utrap = { 0 }; + + /* Redirect trap to Guest VCPU */ + utrap.sepc = vcpu->arch.guest_context.sepc; + utrap.scause = EXC_INST_ILLEGAL; + utrap.stval = insn; + kvm_riscv_vcpu_trap_redirect(vcpu, &utrap); + + return 1; +} + +static int system_opcode_insn(struct kvm_vcpu *vcpu, + struct kvm_run *run, + ulong insn) +{ + if ((insn & INSN_MASK_WFI) == INSN_MATCH_WFI) { + vcpu->stat.wfi_exit_stat++; + if (!kvm_arch_vcpu_runnable(vcpu)) { + srcu_read_unlock(&vcpu->kvm->srcu, vcpu->arch.srcu_idx); + kvm_vcpu_block(vcpu); + vcpu->arch.srcu_idx = srcu_read_lock(&vcpu->kvm->srcu); + kvm_clear_request(KVM_REQ_UNHALT, vcpu); + } + vcpu->arch.guest_context.sepc += INSN_LEN(insn); + return 1; + } + + return truly_illegal_insn(vcpu, run, insn); +} + +static int virtual_inst_fault(struct kvm_vcpu *vcpu, struct kvm_run *run, + struct kvm_cpu_trap *trap) +{ + unsigned long insn = trap->stval; + struct kvm_cpu_trap utrap = { 0 }; + struct kvm_cpu_context *ct; + + if (unlikely(INSN_IS_16BIT(insn))) { + if (insn == 0) { + ct = &vcpu->arch.guest_context; + insn = kvm_riscv_vcpu_unpriv_read(vcpu, true, + ct->sepc, + &utrap); + if (utrap.scause) { + utrap.sepc = ct->sepc; + kvm_riscv_vcpu_trap_redirect(vcpu, &utrap); + return 1; + } + } + if (INSN_IS_16BIT(insn)) + return truly_illegal_insn(vcpu, run, insn); + } + + switch ((insn & INSN_OPCODE_MASK) >> INSN_OPCODE_SHIFT) { + case INSN_OPCODE_SYSTEM: + return system_opcode_insn(vcpu, run, insn); + default: + return truly_illegal_insn(vcpu, run, insn); + } +} + static int emulate_load(struct kvm_vcpu *vcpu, struct kvm_run *run, unsigned long fault_addr, unsigned long htinst) { @@ -596,6 +668,10 @@ int kvm_riscv_vcpu_exit(struct kvm_vcpu *vcpu, struct kvm_run *run, ret = -EFAULT; run->exit_reason = KVM_EXIT_UNKNOWN; switch (trap->scause) { + case EXC_VIRTUAL_INST_FAULT: + if (vcpu->arch.guest_context.hstatus & HSTATUS_SPV) + ret = virtual_inst_fault(vcpu, run, trap); + break; case EXC_INST_GUEST_PAGE_FAULT: case EXC_LOAD_GUEST_PAGE_FAULT: case EXC_STORE_GUEST_PAGE_FAULT: -- 2.25.1
WARNING: multiple messages have this Message-ID (diff)
From: Anup Patel <anup.patel@wdc.com> To: Palmer Dabbelt <palmer@dabbelt.com>, Palmer Dabbelt <palmerdabbelt@google.com>, Paul Walmsley <paul.walmsley@sifive.com>, Albert Ou <aou@eecs.berkeley.edu>, Paolo Bonzini <pbonzini@redhat.com> Cc: Damien Le Moal <damien.lemoal@wdc.com>, kvm@vger.kernel.org, Anup Patel <anup@brainfault.org>, Anup Patel <anup.patel@wdc.com>, linux-kernel@vger.kernel.org, Atish Patra <atish.patra@wdc.com>, Alistair Francis <Alistair.Francis@wdc.com>, kvm-riscv@lists.infradead.org, Alexander Graf <graf@amazon.com>, linux-riscv@lists.infradead.org Subject: [PATCH v16 08/17] RISC-V: KVM: Handle WFI exits for VCPU Date: Fri, 15 Jan 2021 17:48:37 +0530 [thread overview] Message-ID: <20210115121846.114528-9-anup.patel@wdc.com> (raw) In-Reply-To: <20210115121846.114528-1-anup.patel@wdc.com> We get illegal instruction trap whenever Guest/VM executes WFI instruction. This patch handles WFI trap by blocking the trapped VCPU using kvm_vcpu_block() API. The blocked VCPU will be automatically resumed whenever a VCPU interrupt is injected from user-space or from in-kernel IRQCHIP emulation. Signed-off-by: Anup Patel <anup.patel@wdc.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> --- arch/riscv/kvm/vcpu_exit.c | 76 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 76 insertions(+) diff --git a/arch/riscv/kvm/vcpu_exit.c b/arch/riscv/kvm/vcpu_exit.c index cf99567955ad..bacad80686a2 100644 --- a/arch/riscv/kvm/vcpu_exit.c +++ b/arch/riscv/kvm/vcpu_exit.c @@ -12,6 +12,13 @@ #include <linux/kvm_host.h> #include <asm/csr.h> +#define INSN_OPCODE_MASK 0x007c +#define INSN_OPCODE_SHIFT 2 +#define INSN_OPCODE_SYSTEM 28 + +#define INSN_MASK_WFI 0xffffff00 +#define INSN_MATCH_WFI 0x10500000 + #define INSN_MATCH_LB 0x3 #define INSN_MASK_LB 0x707f #define INSN_MATCH_LH 0x1003 @@ -116,6 +123,71 @@ (s32)(((insn) >> 7) & 0x1f)) #define MASK_FUNCT3 0x7000 +static int truly_illegal_insn(struct kvm_vcpu *vcpu, + struct kvm_run *run, + ulong insn) +{ + struct kvm_cpu_trap utrap = { 0 }; + + /* Redirect trap to Guest VCPU */ + utrap.sepc = vcpu->arch.guest_context.sepc; + utrap.scause = EXC_INST_ILLEGAL; + utrap.stval = insn; + kvm_riscv_vcpu_trap_redirect(vcpu, &utrap); + + return 1; +} + +static int system_opcode_insn(struct kvm_vcpu *vcpu, + struct kvm_run *run, + ulong insn) +{ + if ((insn & INSN_MASK_WFI) == INSN_MATCH_WFI) { + vcpu->stat.wfi_exit_stat++; + if (!kvm_arch_vcpu_runnable(vcpu)) { + srcu_read_unlock(&vcpu->kvm->srcu, vcpu->arch.srcu_idx); + kvm_vcpu_block(vcpu); + vcpu->arch.srcu_idx = srcu_read_lock(&vcpu->kvm->srcu); + kvm_clear_request(KVM_REQ_UNHALT, vcpu); + } + vcpu->arch.guest_context.sepc += INSN_LEN(insn); + return 1; + } + + return truly_illegal_insn(vcpu, run, insn); +} + +static int virtual_inst_fault(struct kvm_vcpu *vcpu, struct kvm_run *run, + struct kvm_cpu_trap *trap) +{ + unsigned long insn = trap->stval; + struct kvm_cpu_trap utrap = { 0 }; + struct kvm_cpu_context *ct; + + if (unlikely(INSN_IS_16BIT(insn))) { + if (insn == 0) { + ct = &vcpu->arch.guest_context; + insn = kvm_riscv_vcpu_unpriv_read(vcpu, true, + ct->sepc, + &utrap); + if (utrap.scause) { + utrap.sepc = ct->sepc; + kvm_riscv_vcpu_trap_redirect(vcpu, &utrap); + return 1; + } + } + if (INSN_IS_16BIT(insn)) + return truly_illegal_insn(vcpu, run, insn); + } + + switch ((insn & INSN_OPCODE_MASK) >> INSN_OPCODE_SHIFT) { + case INSN_OPCODE_SYSTEM: + return system_opcode_insn(vcpu, run, insn); + default: + return truly_illegal_insn(vcpu, run, insn); + } +} + static int emulate_load(struct kvm_vcpu *vcpu, struct kvm_run *run, unsigned long fault_addr, unsigned long htinst) { @@ -596,6 +668,10 @@ int kvm_riscv_vcpu_exit(struct kvm_vcpu *vcpu, struct kvm_run *run, ret = -EFAULT; run->exit_reason = KVM_EXIT_UNKNOWN; switch (trap->scause) { + case EXC_VIRTUAL_INST_FAULT: + if (vcpu->arch.guest_context.hstatus & HSTATUS_SPV) + ret = virtual_inst_fault(vcpu, run, trap); + break; case EXC_INST_GUEST_PAGE_FAULT: case EXC_LOAD_GUEST_PAGE_FAULT: case EXC_STORE_GUEST_PAGE_FAULT: -- 2.25.1 _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv
next prev parent reply other threads:[~2021-01-15 12:21 UTC|newest] Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-01-15 12:18 [PATCH v16 00/17] KVM RISC-V Support Anup Patel 2021-01-15 12:18 ` Anup Patel 2021-01-15 12:18 ` [PATCH v16 01/17] RISC-V: Add hypervisor extension related CSR defines Anup Patel 2021-01-15 12:18 ` Anup Patel 2021-01-15 12:18 ` [PATCH v16 02/17] RISC-V: Add initial skeletal KVM support Anup Patel 2021-01-15 12:18 ` Anup Patel 2021-01-15 12:18 ` [PATCH v16 03/17] RISC-V: KVM: Implement VCPU create, init and destroy functions Anup Patel 2021-01-15 12:18 ` Anup Patel 2021-01-15 12:18 ` [PATCH v16 04/17] RISC-V: KVM: Implement VCPU interrupts and requests handling Anup Patel 2021-01-15 12:18 ` Anup Patel 2021-01-15 12:18 ` [PATCH v16 05/17] RISC-V: KVM: Implement KVM_GET_ONE_REG/KVM_SET_ONE_REG ioctls Anup Patel 2021-01-15 12:18 ` Anup Patel 2021-01-15 12:18 ` [PATCH v16 06/17] RISC-V: KVM: Implement VCPU world-switch Anup Patel 2021-01-15 12:18 ` Anup Patel 2021-01-15 12:18 ` [PATCH v16 07/17] RISC-V: KVM: Handle MMIO exits for VCPU Anup Patel 2021-01-15 12:18 ` Anup Patel 2021-01-15 12:18 ` Anup Patel [this message] 2021-01-15 12:18 ` [PATCH v16 08/17] RISC-V: KVM: Handle WFI " Anup Patel 2021-01-15 12:18 ` [PATCH v16 09/17] RISC-V: KVM: Implement VMID allocator Anup Patel 2021-01-15 12:18 ` Anup Patel 2021-01-15 12:18 ` [PATCH v16 10/17] RISC-V: KVM: Implement stage2 page table programming Anup Patel 2021-01-15 12:18 ` Anup Patel 2021-01-15 12:18 ` [PATCH v16 11/17] RISC-V: KVM: Implement MMU notifiers Anup Patel 2021-01-15 12:18 ` Anup Patel 2021-01-15 12:18 ` [PATCH v16 12/17] RISC-V: KVM: Add timer functionality Anup Patel 2021-01-15 12:18 ` Anup Patel 2021-01-15 12:18 ` [PATCH v16 13/17] RISC-V: KVM: FP lazy save/restore Anup Patel 2021-01-15 12:18 ` Anup Patel 2021-01-15 12:18 ` [PATCH v16 14/17] RISC-V: KVM: Implement ONE REG interface for FP registers Anup Patel 2021-01-15 12:18 ` Anup Patel 2021-01-15 12:18 ` [PATCH v16 15/17] RISC-V: KVM: Add SBI v0.1 support Anup Patel 2021-01-15 12:18 ` Anup Patel 2021-01-15 12:18 ` [PATCH v16 16/17] RISC-V: KVM: Document RISC-V specific parts of KVM API Anup Patel 2021-01-15 12:18 ` Anup Patel 2021-01-15 12:18 ` [PATCH v16 17/17] RISC-V: KVM: Add MAINTAINERS entry Anup Patel 2021-01-15 12:18 ` Anup Patel 2021-01-23 3:40 ` [PATCH v16 00/17] KVM RISC-V Support Palmer Dabbelt 2021-01-23 3:40 ` Palmer Dabbelt 2021-03-30 5:48 ` Anup Patel 2021-03-30 5:48 ` Anup Patel 2021-03-31 9:21 ` Paolo Bonzini 2021-03-31 9:21 ` Paolo Bonzini 2021-04-01 13:24 ` Anup Patel 2021-04-01 13:24 ` Anup Patel 2021-04-09 18:58 ` Palmer Dabbelt 2021-04-09 18:58 ` Palmer Dabbelt 2021-04-21 4:08 ` Anup Patel 2021-04-21 4:08 ` Anup Patel 2021-04-27 5:43 ` Paul Walmsley 2021-04-27 5:43 ` Paul Walmsley 2021-04-27 6:01 ` Anup Patel 2021-04-27 6:01 ` Anup Patel 2021-04-27 7:04 ` Paolo Bonzini 2021-04-27 7:04 ` Paolo Bonzini 2021-04-28 7:07 ` Anup Patel 2021-04-28 7:07 ` Anup Patel
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