[v2 PATCH] KVM: nVMX: consult PFEC_MASK and PFEC_MATCH when generating #PF VM-exit

Eugene Korenevsky
2014-12-16T19:34:18Z

When generating #PF VM-exit, check equality:
(PFEC & PFEC_MASK) == PFEC_MATCH
If there is equality, the 14 bit of exception bitmap is used to take decision
about generating #PF VM-exit. If there is inequality, inverted 14 bit is used.

Signed-off-by: Eugene Korenevsky <ekorenevsky@gmail.com>
---
arch/x86/kvm/vmx.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 09ccf6c..a8ef8265 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -8206,6 +8206,18 @@ static void nested_ept_uninit_mmu_context(struct kvm_vcpu *vcpu)
vcpu->arch.walk_mmu = &vcpu->arch.mmu;
}

+static bool nested_vmx_is_page_fault_vmexit(struct vmcs12 *vmcs12,
+ u16 error_code)
+{
+ bool inequality, bit;
+
+ bit = (vmcs12->exception_bitmap & (1u << PF_VECTOR)) != 0;
+ inequality =
+ (error_code & vmcs12->page_fault_error_code_mask) !=
+ vmcs12->page_fault_error_code_match;
+ return inequality ^ bit;
+}
+
static void vmx_inject_page_fault_nested(struct kvm_vcpu *vcpu,
struct x86_exception *fault)
{
@@ -8213,8 +8225,7 @@ static void vmx_inject_page_fault_nested(struct kvm_vcpu *vcpu,

WARN_ON(!is_guest_mode(vcpu));

- /* TODO: also check PFEC_MATCH/MASK, not just EB.PF. */
- if (vmcs12->exception_bitmap & (1u << PF_VECTOR))
+ if (nested_vmx_is_page_fault_vmexit(vmcs12, fault->error_code))
nested_vmx_vmexit(vcpu, to_vmx(vcpu)->exit_reason,
vmcs_read32(VM_EXIT_INTR_INFO),
vmcs_readl(EXIT_QUALIFICATION));
--
2.0.4