diff options
| author | Vitaly Kuznetsov <vkuznets@redhat.com> | 2019-08-13 15:53:30 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2019-08-22 10:09:19 +0200 |
| commit | f8ea7c6049d5d0766b84c8107583ed0094773d06 (patch) | |
| tree | 39d640e2cd1236203daf92bea3d4fe5b2b860d92 /arch/x86/kvm/x86.c | |
| parent | 05402f64544f054edbe41f45f6ec52dbe0c1a324 (diff) | |
| download | lwn-f8ea7c6049d5d0766b84c8107583ed0094773d06.tar.gz lwn-f8ea7c6049d5d0766b84c8107583ed0094773d06.zip | |
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 <sean.j.christopherson@intel.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/x86.c')
| -rw-r--r-- | arch/x86/kvm/x86.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 6b81c7609d09..73825abb92b3 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -6390,9 +6390,11 @@ static void kvm_vcpu_do_singlestep(struct kvm_vcpu *vcpu, int *r) int kvm_skip_emulated_instruction(struct kvm_vcpu *vcpu) { unsigned long rflags = kvm_x86_ops->get_rflags(vcpu); - int r = EMULATE_DONE; + int r; - kvm_x86_ops->skip_emulated_instruction(vcpu); + r = kvm_x86_ops->skip_emulated_instruction(vcpu); + if (unlikely(r != EMULATE_DONE)) + return 0; /* * rflags is the old, "raw" value of the flags. The new value has |