From a04aead144fd938c2d9869eb187e5b9ea0009bae Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Thu, 18 Feb 2021 07:16:59 -0500 Subject: [PATCH] KVM: nSVM: fix running nested guests when npt=0 In case of npt=0 on host, nSVM needs the same .inject_page_fault tweak as VMX has, to make sure that shadow mmu faults are injected as vmexits. It is not clear why this is needed at all, but for now keep the same code as VMX and we'll fix it for both. Based on a patch by Maxim Levitsky . Fixes: 7c86663b68ba ("KVM: nSVM: inject exceptions via svm_check_nested_events") Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm/nested.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index bcf466d2d807..92d3aaaac612 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -51,6 +51,23 @@ static void nested_svm_inject_npf_exit(struct kvm_vcpu *vcpu, nested_svm_vmexit(svm); } +static void svm_inject_page_fault_nested(struct kvm_vcpu *vcpu, struct x86_exception *fault) +{ + struct vcpu_svm *svm = to_svm(vcpu); + WARN_ON(!is_guest_mode(vcpu)); + + if (vmcb_is_intercept(&svm->nested.ctl, INTERCEPT_EXCEPTION_OFFSET + PF_VECTOR) && + !svm->nested.nested_run_pending) { + svm->vmcb->control.exit_code = SVM_EXIT_EXCP_BASE + PF_VECTOR; + svm->vmcb->control.exit_code_hi = 0; + svm->vmcb->control.exit_info_1 = fault->error_code; + svm->vmcb->control.exit_info_2 = fault->address; + nested_svm_vmexit(svm); + } else { + kvm_inject_page_fault(vcpu, fault); + } +} + static u64 nested_svm_get_tdp_pdptr(struct kvm_vcpu *vcpu, int index) { struct vcpu_svm *svm = to_svm(vcpu); @@ -460,6 +477,9 @@ int enter_svm_guest_mode(struct vcpu_svm *svm, u64 vmcb12_gpa, if (ret) return ret; + if (!npt_enabled) + svm->vcpu.arch.mmu->inject_page_fault = svm_inject_page_fault_nested; + svm_set_gif(svm, true); return 0; -- 2.34.1