From 5e352519519623a0b62587c606280e534d0cf1d9 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Tue, 2 Sep 2014 13:18:37 +0200 Subject: KVM: nSVM: propagate the NPF EXITINFO to the guest This is similar to what the EPT code does with the exit qualification. This allows the guest to see a valid value for bits 33:32. Signed-off-by: Paolo Bonzini --- arch/x86/kvm/paging_tmpl.h | 12 ++++++++++++ arch/x86/kvm/svm.c | 24 ++++++++++++++++++++---- 2 files changed, 32 insertions(+), 4 deletions(-) (limited to 'arch') diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h index 410776528265..df1a044d92de 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -322,8 +322,20 @@ retry_walk: real_gfn = mmu->translate_gpa(vcpu, gfn_to_gpa(table_gfn), PFERR_USER_MASK|PFERR_WRITE_MASK); + + /* + * FIXME: This can happen if emulation (for of an INS/OUTS + * instruction) triggers a nested page fault. The exit + * qualification / exit info field will incorrectly have + * "guest page access" as the nested page fault's cause, + * instead of "guest page structure access". To fix this, + * the x86_exception struct should be augmented with enough + * information to fix the exit_qualification or exit_info_1 + * fields. + */ if (unlikely(real_gfn == UNMAPPED_GVA)) goto error; + real_gfn = gpa_to_gfn(real_gfn); host_addr = gfn_to_hva_prot(vcpu->kvm, real_gfn, diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 8ef704037370..d0a61a05a891 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -1974,10 +1974,26 @@ static void nested_svm_inject_npf_exit(struct kvm_vcpu *vcpu, { struct vcpu_svm *svm = to_svm(vcpu); - svm->vmcb->control.exit_code = SVM_EXIT_NPF; - svm->vmcb->control.exit_code_hi = 0; - svm->vmcb->control.exit_info_1 = fault->error_code; - svm->vmcb->control.exit_info_2 = fault->address; + if (svm->vmcb->control.exit_code != SVM_EXIT_NPF) { + /* + * TODO: track the cause of the nested page fault, and + * correctly fill in the high bits of exit_info_1. + */ + svm->vmcb->control.exit_code = SVM_EXIT_NPF; + svm->vmcb->control.exit_code_hi = 0; + svm->vmcb->control.exit_info_1 = (1ULL << 32); + svm->vmcb->control.exit_info_2 = fault->address; + } + + svm->vmcb->control.exit_info_1 &= ~0xffffffffULL; + svm->vmcb->control.exit_info_1 |= fault->error_code; + + /* + * The present bit is always zero for page structure faults on real + * hardware. + */ + if (svm->vmcb->control.exit_info_1 & (2ULL << 32)) + svm->vmcb->control.exit_info_1 &= ~1; nested_svm_vmexit(svm); } -- cgit v1.2.3