x86: svm: use PML4E in npt_rsvd_pfwalk_prepare

According to AMD manual bit 8 of the PDPE is not reserved, but it is in PML4E.

Reported-by: Nadav Amit <namit@vmware.com>
Message-Id: <20200630094516.22983-5-namit@vmware.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

3 files changed, 8 insertions, 2 deletions

diff --git a/x86/svm.c b/x86/svm.c
index 0fcad8d..62907fd 100644
--- a/x86/svm.c
+++ b/x86/svm.c
@@ -49,6 +49,11 @@ u64 *npt_get_pdpe(void)
 	return pdpe;
 }
 
+u64 *npt_get_pml4e(void)
+{
+	return pml4e;
+}
+
 bool smp_supported(void)
 {
 	return cpu_count() > 1;
diff --git a/x86/svm.h b/x86/svm.h
index 645deb7..8d688b6 100644
--- a/x86/svm.h
+++ b/x86/svm.h
@@ -365,6 +365,7 @@ typedef void (*test_guest_func)(struct svm_test *);
 u64 *npt_get_pte(u64 address);
 u64 *npt_get_pde(u64 address);
 u64 *npt_get_pdpe(void);
+u64 *npt_get_pml4e(void);
 bool smp_supported(void);
 bool default_supported(void);
 void default_prepare(struct svm_test *test);
diff --git a/x86/svm_tests.c b/x86/svm_tests.c
index 92cefaf..b540527 100644
--- a/x86/svm_tests.c
+++ b/x86/svm_tests.c
@@ -824,13 +824,13 @@ static void npt_rsvd_pfwalk_prepare(struct svm_test *test)
     u64 *pdpe;
     vmcb_ident(vmcb);
 
-    pdpe = npt_get_pdpe();
+    pdpe = npt_get_pml4e();
     pdpe[0] |= (1ULL << 8);
 }
 
 static bool npt_rsvd_pfwalk_check(struct svm_test *test)
 {
-    u64 *pdpe = npt_get_pdpe();
+    u64 *pdpe = npt_get_pml4e();
     pdpe[0] &= ~(1ULL << 8);
 
     return (vmcb->control.exit_code == SVM_EXIT_NPF)