kvm: nVMX: Add support for fast unprotection of nested guest page tables

This is the same as commit 147277540bbc ("kvm: svm: Add support for
additional SVM NPF error codes", 2016-11-23), but for Intel processors.
In this case, the exit qualification field's bit 8 says whether the
EPT violation occurred while translating the guest's final physical
address or rather while translating the guest page tables.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

3 files changed, 5 insertions, 6 deletions

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 1679aabcabe5..9e4862e0e978 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -204,7 +204,6 @@ enum {
 #define PFERR_GUEST_PAGE_MASK (1ULL << PFERR_GUEST_PAGE_BIT)
 
 #define PFERR_NESTED_GUEST_PAGE (PFERR_GUEST_PAGE_MASK |        \
-                                 PFERR_USER_MASK |              \
                                  PFERR_WRITE_MASK |             \
                                  PFERR_PRESENT_MASK)
 
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 454d81dc8913..7ee21c087c83 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -4836,12 +4836,9 @@ int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u64 error_code,
          * This can occur when using nested virtualization with nested
          * paging in both guests. If true, we simply unprotect the page
          * and resume the guest.
-         *
-         * Note: AMD only (since it supports the PFERR_GUEST_PAGE_MASK used
-         *       in PFERR_NEXT_GUEST_PAGE)
          */
         if (vcpu->arch.mmu.direct_map &&
-                error_code == PFERR_NESTED_GUEST_PAGE) {
+            (error_code & PFERR_NESTED_GUEST_PAGE) == PFERR_NESTED_GUEST_PAGE) {
                 kvm_mmu_unprotect_page(vcpu->kvm, gpa_to_gfn(cr2));
                 return 1;
         }
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index c7cf5b11994a..ed1074e98b8e 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -6358,7 +6358,7 @@ static int handle_ept_violation(struct kvm_vcpu *vcpu)
 {
         unsigned long exit_qualification;
         gpa_t gpa;
-        u32 error_code;
+        u64 error_code;
 
         exit_qualification = vmcs_readl(EXIT_QUALIFICATION);
 
@@ -6390,6 +6390,9 @@ static int handle_ept_violation(struct kvm_vcpu *vcpu)
                         EPT_VIOLATION_EXECUTABLE))
                       ? PFERR_PRESENT_MASK : 0;
 
+        error_code |= (exit_qualification & 0x100) != 0 ?
+               PFERR_GUEST_FINAL_MASK : PFERR_GUEST_PAGE_MASK;
+
         vcpu->arch.gpa_available = true;
         vcpu->arch.exit_qualification = exit_qualification;