diff options
| -rw-r--r-- | arch/x86/kvm/x86.c | 31 |
1 files changed, 19 insertions, 12 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index bc507d6414f4..b81ef4f497f4 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -8296,7 +8296,7 @@ int kvm_skip_emulated_instruction(struct kvm_vcpu *vcpu) } EXPORT_SYMBOL_GPL(kvm_skip_emulated_instruction); -static bool kvm_vcpu_check_breakpoint(struct kvm_vcpu *vcpu, int *r) +static bool kvm_vcpu_check_code_breakpoint(struct kvm_vcpu *vcpu, int *r) { if (unlikely(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) && (vcpu->arch.guest_debug_dr7 & DR7_BP_EN_MASK)) { @@ -8365,25 +8365,23 @@ static bool is_vmware_backdoor_opcode(struct x86_emulate_ctxt *ctxt) } /* - * Decode to be emulated instruction. Return EMULATION_OK if success. + * Decode an instruction for emulation. The caller is responsible for handling + * code breakpoints. Note, manually detecting code breakpoints is unnecessary + * (and wrong) when emulating on an intercepted fault-like exception[*], as + * code breakpoints have higher priority and thus have already been done by + * hardware. + * + * [*] Except #MC, which is higher priority, but KVM should never emulate in + * response to a machine check. */ int x86_decode_emulated_instruction(struct kvm_vcpu *vcpu, int emulation_type, void *insn, int insn_len) { - int r = EMULATION_OK; struct x86_emulate_ctxt *ctxt = vcpu->arch.emulate_ctxt; + int r; init_emulate_ctxt(vcpu); - /* - * We will reenter on the same instruction since we do not set - * complete_userspace_io. This does not handle watchpoints yet, - * those would be handled in the emulate_ops. - */ - if (!(emulation_type & EMULTYPE_SKIP) && - kvm_vcpu_check_breakpoint(vcpu, &r)) - return r; - r = x86_decode_insn(ctxt, insn, insn_len, emulation_type); trace_kvm_emulate_insn_start(vcpu); @@ -8416,6 +8414,15 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, if (!(emulation_type & EMULTYPE_NO_DECODE)) { kvm_clear_exception_queue(vcpu); + /* + * Return immediately if RIP hits a code breakpoint, such #DBs + * are fault-like and are higher priority than any faults on + * the code fetch itself. + */ + if (!(emulation_type & EMULTYPE_SKIP) && + kvm_vcpu_check_code_breakpoint(vcpu, &r)) + return r; + r = x86_decode_emulated_instruction(vcpu, emulation_type, insn, insn_len); if (r != EMULATION_OK) { |