The next patch would use kvm_emulate_instruction() with EMULTYPE_SKIP in complete_userspace_io callback to fix a problem in msr access emulation. However, EMULTYPE_SKIP only updates RIP, more things like updating interruptibility state and injecting single-step #DBs would be done in the callback. Since the emulator also does those things after x86_emulate_insn(), add a new emulation type to pair with EMULTYPE_SKIP to do those things for completion of user exits within the emulator. Suggested-by: Sean Christopherson <seanjc@xxxxxxxxxx> Signed-off-by: Hou Wenlong <houwenlong93@xxxxxxxxxxxxxxxxx> --- arch/x86/include/asm/kvm_host.h | 8 +++++++- arch/x86/kvm/x86.c | 13 ++++++++++--- 2 files changed, 17 insertions(+), 4 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 88fce6ab4bbd..b99e62b39097 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1635,7 +1635,8 @@ extern u64 kvm_mce_cap_supported; * * EMULTYPE_SKIP - Set when emulating solely to skip an instruction, i.e. to * decode the instruction length. For use *only* by - * kvm_x86_ops.skip_emulated_instruction() implementations. + * kvm_x86_ops.skip_emulated_instruction() implementations if + * EMULTYPE_COMPLETE_USER_EXIT is not set. * * EMULTYPE_ALLOW_RETRY_PF - Set when the emulator should resume the guest to * retry native execution under certain conditions, @@ -1655,6 +1656,10 @@ extern u64 kvm_mce_cap_supported; * * EMULTYPE_PF - Set when emulating MMIO by way of an intercepted #PF, in which * case the CR2/GPA value pass on the stack is valid. + * + * EMULTYPE_COMPLETE_USER_EXIT - Set when the emulator should update interruptibility + * state and inject single-step #DBs after skipping + * an instruction (after completing userspace I/O). */ #define EMULTYPE_NO_DECODE (1 << 0) #define EMULTYPE_TRAP_UD (1 << 1) @@ -1663,6 +1668,7 @@ extern u64 kvm_mce_cap_supported; #define EMULTYPE_TRAP_UD_FORCED (1 << 4) #define EMULTYPE_VMWARE_GP (1 << 5) #define EMULTYPE_PF (1 << 6) +#define EMULTYPE_COMPLETE_USER_EXIT (1 << 7) int kvm_emulate_instruction(struct kvm_vcpu *vcpu, int emulation_type); int kvm_emulate_instruction_from_buffer(struct kvm_vcpu *vcpu, diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 3d7fc5c21ceb..a961b49c8c44 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -8119,9 +8119,10 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, } /* - * Note, EMULTYPE_SKIP is intended for use *only* by vendor callbacks - * for kvm_skip_emulated_instruction(). The caller is responsible for - * updating interruptibility state and injecting single-step #DBs. + * EMULTYPE_SKIP without EMULTYPE_COMPLETE_USER_EXIT is intended for + * use *only* by vendor callbacks for kvm_skip_emulated_instruction(). + * The caller is responsible for updating interruptibility state and + * injecting single-step #DBs. */ if (emulation_type & EMULTYPE_SKIP) { if (ctxt->mode != X86EMUL_MODE_PROT64) @@ -8129,6 +8130,11 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, else ctxt->eip = ctxt->_eip; + if (emulation_type & EMULTYPE_COMPLETE_USER_EXIT) { + r = 1; + goto writeback; + } + kvm_rip_write(vcpu, ctxt->eip); if (ctxt->eflags & X86_EFLAGS_RF) kvm_set_rflags(vcpu, ctxt->eflags & ~X86_EFLAGS_RF); @@ -8198,6 +8204,7 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, else r = 1; +writeback: if (writeback) { unsigned long rflags = static_call(kvm_x86_get_rflags)(vcpu); toggle_interruptibility(vcpu, ctxt->interruptibility); -- 2.31.1