| Message ID | 20210224005627.657028-1-seanjc@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: SVM: Fix nested VM-Exit on #GP interception handling | expand |
On 24/02/21 01:56, Sean Christopherson wrote: > Fix the interpreation of nested_svm_vmexit()'s return value when > synthesizing a nested VM-Exit after intercepting an SVM instruction while > L2 was running. The helper returns '0' on success, whereas a return > value of '0' in the exit handler path means "exit to userspace". The > incorrect return value causes KVM to exit to userspace without filling > the run state, e.g. QEMU logs "KVM: unknown exit, hardware reason 0". > > Fixes: 14c2bf81fcd2 ("KVM: SVM: Fix #GP handling for doubly-nested virtualization") > Signed-off-by: Sean Christopherson <seanjc@google.com> > --- > arch/x86/kvm/svm/svm.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c > index 14e41dddc7eb..c4f2f2f6b945 100644 > --- a/arch/x86/kvm/svm/svm.c > +++ b/arch/x86/kvm/svm/svm.c > @@ -2200,13 +2200,18 @@ static int emulate_svm_instr(struct kvm_vcpu *vcpu, int opcode) > [SVM_INSTR_VMSAVE] = vmsave_interception, > }; > struct vcpu_svm *svm = to_svm(vcpu); > + int ret; > > if (is_guest_mode(vcpu)) { > svm->vmcb->control.exit_code = guest_mode_exit_codes[opcode]; > svm->vmcb->control.exit_info_1 = 0; > svm->vmcb->control.exit_info_2 = 0; > > - return nested_svm_vmexit(svm); > + /* Returns '1' or -errno on failure, '0' on success. */ > + ret = nested_svm_vmexit(svm); > + if (ret) > + return ret; > + return 1; > } > return svm_instr_handlers[opcode](vcpu); > } > Queued, thanks. Paolo
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 14e41dddc7eb..c4f2f2f6b945 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -2200,13 +2200,18 @@ static int emulate_svm_instr(struct kvm_vcpu *vcpu, int opcode) [SVM_INSTR_VMSAVE] = vmsave_interception, }; struct vcpu_svm *svm = to_svm(vcpu); + int ret; if (is_guest_mode(vcpu)) { svm->vmcb->control.exit_code = guest_mode_exit_codes[opcode]; svm->vmcb->control.exit_info_1 = 0; svm->vmcb->control.exit_info_2 = 0; - return nested_svm_vmexit(svm); + /* Returns '1' or -errno on failure, '0' on success. */ + ret = nested_svm_vmexit(svm); + if (ret) + return ret; + return 1; } return svm_instr_handlers[opcode](vcpu); }
Fix the interpreation of nested_svm_vmexit()'s return value when synthesizing a nested VM-Exit after intercepting an SVM instruction while L2 was running. The helper returns '0' on success, whereas a return value of '0' in the exit handler path means "exit to userspace". The incorrect return value causes KVM to exit to userspace without filling the run state, e.g. QEMU logs "KVM: unknown exit, hardware reason 0". Fixes: 14c2bf81fcd2 ("KVM: SVM: Fix #GP handling for doubly-nested virtualization") Signed-off-by: Sean Christopherson <seanjc@google.com> --- arch/x86/kvm/svm/svm.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)