From: Oliver Upton oupton@google.com
commit 86f7e90ce840aa1db407d3ea6e9b3a52b2ce923c upstream.
KVM emulates UMIP on hardware that doesn't support it by setting the 'descriptor table exiting' VM-execution control and performing instruction emulation. When running nested, this emulation is broken as KVM refuses to emulate L2 instructions by default.
Correct this regression by allowing the emulation of descriptor table instructions if L1 hasn't requested 'descriptor table exiting'.
Fixes: 07721feee46b ("KVM: nVMX: Don't emulate instructions in guest mode") Reported-by: Jan Kiszka jan.kiszka@web.de Cc: stable@vger.kernel.org Cc: Paolo Bonzini pbonzini@redhat.com Cc: Jim Mattson jmattson@google.com Signed-off-by: Oliver Upton oupton@google.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/kvm/vmx.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+)
--- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -12370,6 +12370,7 @@ static int vmx_check_intercept_io(struct else intercept = nested_vmx_check_io_bitmaps(vcpu, port, size);
+ /* FIXME: produce nested vmexit and return X86EMUL_INTERCEPTED. */ return intercept ? X86EMUL_UNHANDLEABLE : X86EMUL_CONTINUE; }
@@ -12399,6 +12400,20 @@ static int vmx_check_intercept(struct kv case x86_intercept_outs: return vmx_check_intercept_io(vcpu, info);
+ case x86_intercept_lgdt: + case x86_intercept_lidt: + case x86_intercept_lldt: + case x86_intercept_ltr: + case x86_intercept_sgdt: + case x86_intercept_sidt: + case x86_intercept_sldt: + case x86_intercept_str: + if (!nested_cpu_has2(vmcs12, SECONDARY_EXEC_DESC)) + return X86EMUL_CONTINUE; + + /* FIXME: produce nested vmexit and return X86EMUL_INTERCEPTED. */ + break; + /* TODO: check more intercepts... */ default: break;