[v2] nSVM: Test: Test VMRUN/VMEXIT's canonicalization of segement base addresses

Commit Message

Krish Sadhukhan May 25, 2021, 1:12 a.m. UTC

According to section "Canonicalization and Consistency Checks" in APM vol 2,

    VMRUN canonicalizes (i.e., sign-extend to bit 63) all base addresses
    in the segment registers that have been loaded.

Signed-off-by: Krish Sadhukhan <[e-mail]>
---
 x86/svm_tests.c | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

Patch

diff --git a/x86/svm_tests.c b/x86/svm_tests.c
index d689e73..eb6e73e 100644
--- a/x86/svm_tests.c
+++ b/x86/svm_tests.c
@@ -2499,6 +2499,37 @@  static void test_msrpm_iopm_bitmap_addrs(void)
 	vmcb->control.intercept = saved_intercept;
 }
 
+#define TEST_CANONICAL(seg_base, msg, is_canonicalized)	{		\
+	u64 saved_addr = seg_base;					\
+	int ret;							\
+									\
+	seg_base = NONCANONICAL;					\
+	ret = svm_vmrun();						\
+	report(ret == SVM_EXIT_VMMCALL &&				\
+	    is_canonical(seg_base) == is_canonicalized, "%s.base: on "	\
+	    "VMRUN %llx, on VMEXIT: %lx", msg, NONCANONICAL, seg_base);	\
+	seg_base = saved_addr;						\
+}
+
+/*
+ * VMRUN canonicalizes (i.e., sign-extend to bit 63) all base addresses
+ • in the segment registers that have been loaded.
+ */
+static void test_vmrun_canonicalization(void)
+{
+
+	TEST_CANONICAL(vmcb->save.es.base, "ES", false);
+	TEST_CANONICAL(vmcb->save.cs.base, "CS", false);
+	TEST_CANONICAL(vmcb->save.ss.base, "SS", false);
+	TEST_CANONICAL(vmcb->save.ds.base, "DS", false);
+	TEST_CANONICAL(vmcb->save.fs.base, "FS", true);
+	TEST_CANONICAL(vmcb->save.gs.base, "GS", true);
+	TEST_CANONICAL(vmcb->save.gdtr.base, "GDTR", false);
+	TEST_CANONICAL(vmcb->save.ldtr.base, "LDTR", true);
+	TEST_CANONICAL(vmcb->save.idtr.base, "IDTR", false);
+	TEST_CANONICAL(vmcb->save.tr.base, "TR", true);
+}
+
 static void svm_guest_state_test(void)
 {
 	test_set_guest(basic_guest_main);
@@ -2508,6 +2539,7 @@  static void svm_guest_state_test(void)
 	test_cr4();
 	test_dr();
 	test_msrpm_iopm_bitmap_addrs();
+	test_vmrun_canonicalization();
 }