From f8ea7c6049d5d0766b84c8107583ed0094773d06 Mon Sep 17 00:00:00 2001 From: Vitaly Kuznetsov Date: Tue, 13 Aug 2019 15:53:30 +0200 Subject: x86: kvm: svm: propagate errors from skip_emulated_instruction() On AMD, kvm_x86_ops->skip_emulated_instruction(vcpu) can, in theory, fail: in !nrips case we call kvm_emulate_instruction(EMULTYPE_SKIP). Currently, we only do printk(KERN_DEBUG) when this happens and this is not ideal. Propagate the error up the stack. On VMX, skip_emulated_instruction() doesn't fail, we have two call sites calling it explicitly: handle_exception_nmi() and handle_task_switch(), we can just ignore the result. On SVM, we also have two explicit call sites: svm_queue_exception() and it seems we don't need to do anything there as we check if RIP was advanced or not. In task_switch_interception(), however, we are better off not proceeding to kvm_task_switch() in case skip_emulated_instruction() failed. Suggested-by: Sean Christopherson Signed-off-by: Vitaly Kuznetsov Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx/vmx.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) (limited to 'arch/x86/kvm/vmx') diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 42ed3faa6af8..26cf4fe2ff5c 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -1472,8 +1472,11 @@ static int vmx_rtit_ctl_check(struct kvm_vcpu *vcpu, u64 data) return 0; } - -static void skip_emulated_instruction(struct kvm_vcpu *vcpu) +/* + * Returns an int to be compatible with SVM implementation (which can fail). + * Do not use directly, use skip_emulated_instruction() instead. + */ +static int __skip_emulated_instruction(struct kvm_vcpu *vcpu) { unsigned long rip; @@ -1483,6 +1486,13 @@ static void skip_emulated_instruction(struct kvm_vcpu *vcpu) /* skipping an emulated instruction also counts */ vmx_set_interrupt_shadow(vcpu, 0); + + return EMULATE_DONE; +} + +static inline void skip_emulated_instruction(struct kvm_vcpu *vcpu) +{ + (void)__skip_emulated_instruction(vcpu); } static void vmx_clear_hlt(struct kvm_vcpu *vcpu) @@ -7705,7 +7715,7 @@ static struct kvm_x86_ops vmx_x86_ops __ro_after_init = { .run = vmx_vcpu_run, .handle_exit = vmx_handle_exit, - .skip_emulated_instruction = skip_emulated_instruction, + .skip_emulated_instruction = __skip_emulated_instruction, .set_interrupt_shadow = vmx_set_interrupt_shadow, .get_interrupt_shadow = vmx_get_interrupt_shadow, .patch_hypercall = vmx_patch_hypercall, -- cgit