KVM: prevent spurious exit to userspace during task switch emulation.
If kvm_task_switch() fails code exits to userspace without specifying
exit reason, so the previous exit reason is reused by userspace. Fix
this by specifying exit reason correctly.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 78af522..ab78eb8 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -2266,8 +2266,14 @@
(int_vec == OF_VECTOR || int_vec == BP_VECTOR)))
skip_emulated_instruction(&svm->vcpu);
- return kvm_task_switch(&svm->vcpu, tss_selector, reason,
- has_error_code, error_code);
+ if (kvm_task_switch(&svm->vcpu, tss_selector, reason,
+ has_error_code, error_code) == EMULATE_FAIL) {
+ svm->vcpu.run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
+ svm->vcpu.run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION;
+ svm->vcpu.run->internal.ndata = 0;
+ return 0;
+ }
+ return 1;
}
static int cpuid_interception(struct vcpu_svm *svm)