[PATCH 3/3 v4] kvm-unit-tests: nSVM: Test that MBZ bits in CR3 and CR4 are not set on vmrun of nested guests

[Krish Sadhukhan <krish.sadhukhan@oracle.com>]

According to section "Canonicalization and Consistency Checks" in APM vol. 2,
the following guest state is illegal:

	"Any MBZ bit of CR3 is set."
	"Any MBZ bit of CR4 is set."

Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
---
 x86/svm.h       |  5 +++
 x86/svm_tests.c | 94 ++++++++++++++++++++++++++++++++++++++++++++++++++++++---
 2 files changed, 95 insertions(+), 4 deletions(-)

diff --git a/x86/svm.h b/x86/svm.h
index 457ce3c..f6b9a31 100644
--- a/x86/svm.h
+++ b/x86/svm.h
@@ -325,6 +325,11 @@ struct __attribute__ ((__packed__)) vmcb {
 #define SVM_CR0_SELECTIVE_MASK (X86_CR0_TS | X86_CR0_MP)
 
 #define	SVM_CR0_RESERVED_MASK			0xffffffff00000000U
+#define	SVM_CR3_LEGACY_RESERVED_MASK		0xfe7U
+#define	SVM_CR3_LEGACY_PAE_RESERVED_MASK	0x7U
+#define	SVM_CR3_LONG_RESERVED_MASK		0xfff0000000000fe7U
+#define	SVM_CR4_LEGACY_RESERVED_MASK		0xffbaf000U
+#define	SVM_CR4_RESERVED_MASK			0xffffffffffbaf000U
 #define	SVM_DR6_RESERVED_MASK			0xffffffffffff1ff0U
 #define	SVM_DR7_RESERVED_MASK			0xffffffff0000cc00U
 #define	SVM_EFER_RESERVED_MASK			0xffffffffffff0200U
diff --git a/x86/svm_tests.c b/x86/svm_tests.c
index d4d130f..c59e7eb 100644
--- a/x86/svm_tests.c
+++ b/x86/svm_tests.c
@@ -1913,6 +1913,31 @@ static void basic_guest_main(struct svm_test *test)
         }								\
 }
 
+#define SVM_TEST_CR_RESERVED_BITS(start, end, inc, cr, val, resv_mask)	\
+{									\
+	u64 tmp, mask;							\
+	int i;								\
+									\
+	for (i = start; i <= end; i = i + inc) {			\
+		mask = 1ull << i;					\
+		if (!(mask & resv_mask))				\
+			continue;					\
+		tmp = val | mask;					\
+		switch (cr) {						\
+		case 0:							\
+			vmcb->save.cr0 = tmp;				\
+			break;						\
+		case 3:							\
+			vmcb->save.cr3 = tmp;				\
+			break;						\
+		case 4:							\
+			vmcb->save.cr4 = tmp;				\
+		}							\
+		report(svm_vmrun() == SVM_EXIT_ERR, "Test CR%d %d:%d: %lx",\
+		    cr, end, start, tmp);				\
+	}								\
+}
+
 static void svm_guest_state_test(void)
 {
 	test_set_guest(basic_guest_main);
@@ -1938,17 +1963,21 @@ static void svm_guest_state_test(void)
 	cr0 |= X86_CR0_CD;
 	cr0 &= ~X86_CR0_NW;
 	vmcb->save.cr0 = cr0;
-	report (svm_vmrun() == SVM_EXIT_VMMCALL, "CR0: %lx", cr0);
+	report (svm_vmrun() == SVM_EXIT_VMMCALL, "Test CR0 CD=1,NW=0: %lx",
+	    cr0);
 	cr0 |= X86_CR0_NW;
 	vmcb->save.cr0 = cr0;
-	report (svm_vmrun() == SVM_EXIT_VMMCALL, "CR0: %lx", cr0);
+	report (svm_vmrun() == SVM_EXIT_VMMCALL, "Test CR0 CD=1,NW=1: %lx",
+	    cr0);
 	cr0 &= ~X86_CR0_NW;
 	cr0 &= ~X86_CR0_CD;
 	vmcb->save.cr0 = cr0;
-	report (svm_vmrun() == SVM_EXIT_VMMCALL, "CR0: %lx", cr0);
+	report (svm_vmrun() == SVM_EXIT_VMMCALL, "Test CR0 CD=0,NW=0: %lx",
+	    cr0);
 	cr0 |= X86_CR0_NW;
 	vmcb->save.cr0 = cr0;
-	report (svm_vmrun() == SVM_EXIT_ERR, "CR0: %lx", cr0);
+	report (svm_vmrun() == SVM_EXIT_ERR, "Test CR0 CD=0,NW=1: %lx",
+	    cr0);
 	vmcb->save.cr0 = cr0_saved;
 
 	/*
@@ -1961,6 +1990,63 @@ static void svm_guest_state_test(void)
 	vmcb->save.cr0 = cr0_saved;
 
 	/*
+	 * CR3 MBZ bits based on different modes:
+	 *   [2:0]		    - legacy PAE
+	 *   [2:0], [11:5]	    - legacy non-PAE
+	 *   [2:0], [11:5], [63:52] - long mode
+	 */
+	u64 cr3_saved = vmcb->save.cr3;
+	u64 cr4_saved = vmcb->save.cr4;
+	u64 cr4 = cr4_saved;
+	efer_saved = vmcb->save.efer;
+	efer = efer_saved;
+
+	efer &= ~EFER_LMA;
+	vmcb->save.efer = efer;
+	cr4 |= X86_CR4_PAE;
+	vmcb->save.cr4 = cr4;
+	SVM_TEST_CR_RESERVED_BITS(0, 2, 1, 3, cr3_saved,
+	    SVM_CR3_LEGACY_PAE_RESERVED_MASK);
+
+	cr4 = cr4_saved & ~X86_CR4_PAE;
+	vmcb->save.cr4 = cr4;
+	SVM_TEST_CR_RESERVED_BITS(0, 11, 2, 3, cr3_saved,
+	    SVM_CR3_LEGACY_RESERVED_MASK);
+
+	cr4 |= X86_CR4_PAE;
+	vmcb->save.cr4 = cr4;
+	efer |= EFER_LMA;
+	vmcb->save.efer = efer;
+	SVM_TEST_CR_RESERVED_BITS(0, 63, 2, 3, cr3_saved,
+	    SVM_CR3_LONG_RESERVED_MASK);
+
+	vmcb->save.cr4 = cr4_saved;
+	vmcb->save.cr3 = cr3_saved;
+	vmcb->save.efer = efer_saved;
+
+	/*
+	 * CR4 MBZ bits based on different modes:
+	 *   [15:12], 17, 19, [31:22] - legacy mode
+	 *   [15:12], 17, 19, [63:22] - long mode
+	 */
+	cr4_saved = vmcb->save.cr4;
+	efer_saved = vmcb->save.efer;
+	efer &= ~EFER_LMA;
+	vmcb->save.efer = efer;
+	SVM_TEST_CR_RESERVED_BITS(12, 31, 2, 4, cr4_saved,
+	    SVM_CR4_LEGACY_RESERVED_MASK);
+
+	efer |= EFER_LMA;
+	vmcb->save.efer = efer;
+	SVM_TEST_CR_RESERVED_BITS(12, 31, 2, 4, cr4_saved,
+	    SVM_CR4_RESERVED_MASK);
+	SVM_TEST_CR_RESERVED_BITS(32, 63, 4, 4, cr4_saved,
+	    SVM_CR4_RESERVED_MASK);
+
+	vmcb->save.cr4 = cr4_saved;
+	vmcb->save.efer = efer_saved;
+
+	/*
 	 * DR6[63:32] and DR7[63:32] are MBZ
 	 */
 	u64 dr_saved = vmcb->save.dr6;
-- 
1.8.3.1