From 7396d337cfadc7c0b32dfd46581e9daff6666e84 Mon Sep 17 00:00:00 2001 From: Liran Alon Date: Mon, 26 Aug 2019 13:16:43 +0300 Subject: KVM: x86: Return to userspace with internal error on unexpected exit reason Receiving an unexpected exit reason from hardware should be considered as a severe bug in KVM. Therefore, instead of just injecting #UD to guest and ignore it, exit to userspace on internal error so that it could handle it properly (probably by terminating guest). In addition, prefer to use vcpu_unimpl() instead of WARN_ONCE() as handling unexpected exit reason should be a rare unexpected event (that was expected to never happen) and we prefer to print a message on it every time it occurs to guest. Furthermore, dump VMCS/VMCB to dmesg to assist diagnosing such cases. Reviewed-by: Mihai Carabas Reviewed-by: Nikita Leshenko Reviewed-by: Joao Martins Signed-off-by: Liran Alon Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm.c | 11 ++++++++--- arch/x86/kvm/vmx/vmx.c | 9 +++++++-- 2 files changed, 15 insertions(+), 5 deletions(-) (limited to 'arch/x86') diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 890b1bffcf7c..fdeaf8f44949 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -4981,9 +4981,14 @@ static int handle_exit(struct kvm_vcpu *vcpu) if (exit_code >= ARRAY_SIZE(svm_exit_handlers) || !svm_exit_handlers[exit_code]) { - WARN_ONCE(1, "svm: unexpected exit reason 0x%x\n", exit_code); - kvm_queue_exception(vcpu, UD_VECTOR); - return 1; + vcpu_unimpl(vcpu, "svm: unexpected exit reason 0x%x\n", exit_code); + dump_vmcb(vcpu); + vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR; + vcpu->run->internal.suberror = + KVM_INTERNAL_ERROR_UNEXPECTED_EXIT_REASON; + vcpu->run->internal.ndata = 1; + vcpu->run->internal.data[0] = exit_code; + return 0; } return svm_exit_handlers[exit_code](svm); diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 024cb9bf5ad3..d95c2f3c027c 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -5870,8 +5870,13 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu) else { vcpu_unimpl(vcpu, "vmx: unexpected exit reason 0x%x\n", exit_reason); - kvm_queue_exception(vcpu, UD_VECTOR); - return 1; + dump_vmcs(); + vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR; + vcpu->run->internal.suberror = + KVM_INTERNAL_ERROR_UNEXPECTED_EXIT_REASON; + vcpu->run->internal.ndata = 1; + vcpu->run->internal.data[0] = exit_reason; + return 0; } } -- cgit v1.2.3