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authorPaolo Bonzini <pbonzini@redhat.com>2014-09-02 13:18:37 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2014-09-03 10:18:54 +0200
commit5e352519519623a0b62587c606280e534d0cf1d9 (patch)
tree776ecf76c11f6092c28d2125e7e79cd49a937f9b
parenta0c0feb57992c5caed170feab8a68c51306eb7c3 (diff)
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 <pbonzini@redhat.com>
-rw-r--r--arch/x86/kvm/paging_tmpl.h12
-rw-r--r--arch/x86/kvm/svm.c24
2 files changed, 32 insertions, 4 deletions
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 41077652826..df1a044d92d 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 8ef70403737..d0a61a05a89 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);
}