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| author | Anup Patel <anup.patel@wdc.com> | 2021-09-27 14:40:07 +0300 |
|---|---|---|
| committer | Anup Patel <anup@brainfault.org> | 2021-10-04 13:25:01 +0300 |
| commit | 5a5d79acd7daebeb813a7c0654ca91c5ea7c228e (patch) | |
| tree | eb389e40031e2ab24b9d4244f52d4e4a9b7268ef /arch/riscv/kvm/vcpu_exit.c | |
| parent | 9f7013265112a92340cef5debec8d02ec8d1de06 (diff) | |
| download | linux-5a5d79acd7daebeb813a7c0654ca91c5ea7c228e.tar.xz | |
RISC-V: KVM: Handle WFI exits for VCPU
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>
Acked-by: Palmer Dabbelt <palmerdabbelt@google.com>
Diffstat (limited to 'arch/riscv/kvm/vcpu_exit.c')
| -rw-r--r-- | arch/riscv/kvm/vcpu_exit.c | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/arch/riscv/kvm/vcpu_exit.c b/arch/riscv/kvm/vcpu_exit.c index dc66be032ad7..f659be94231d 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 0xffffffff +#define INSN_MATCH_WFI 0x10500073 + #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: |