Set the to-be-tested {RD,WR}MSR's associated MSRPM bit on-demand when
verifying KVM's emulation of MSR interception. Setting all bits in the
bitmap creates a massive blind spot in the test coverage, e.g. KVM could
completely ignore the bitmap, and the test would still pass.
Run the test with all bits initially clear, and all bits initially set,
mostly in prepartion for adding coverage of MSR passthrough in a future
commit.
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
x86/svm_tests.c | 104 ++++++++++++++++++++++++++++++++++++++++++++----
1 file changed, 96 insertions(+), 8 deletions(-)
diff --git a/x86/svm_tests.c b/x86/svm_tests.c
index 5d06249f..ef8c2cec 100644
--- a/x86/svm_tests.c
+++ b/x86/svm_tests.c
@@ -312,12 +312,41 @@ static void prepare_msr_intercept(struct svm_test *test)
{
default_prepare(test);
vmcb->control.intercept |= (1ULL << INTERCEPT_MSR_PROT);
- memset(msr_bitmap, 0xff, MSR_BITMAP_SIZE);
+
+ memset(msr_bitmap, 0, MSR_BITMAP_SIZE);
+}
+
+#define SVM_MSRPM_BYTES_PER_RANGE 2048
+#define SVM_BITS_PER_MSR 2
+#define SVM_MSRS_PER_BYTE 4
+#define SVM_MSRS_PER_RANGE 8192
+#define SVM_MSRPM_OFFSET_MASK (SVM_MSRS_PER_RANGE - 1)
+
+static int get_msrpm_bit_nr(u32 msr)
+{
+ int range_nr;
+
+ switch (msr & ~SVM_MSRPM_OFFSET_MASK) {
+ case 0:
+ range_nr = 0;
+ break;
+ case 0xc0000000:
+ range_nr = 1;
+ break;
+ case 0xc0010000:
+ range_nr = 2;
+ break;
+ default:
+ return - 1;
+ }
+
+ return range_nr * SVM_MSRPM_BYTES_PER_RANGE * BITS_PER_BYTE +
+ (msr & SVM_MSRPM_OFFSET_MASK) * SVM_BITS_PER_MSR;
}
-static void test_msr_intercept(struct svm_test *test)
+static void __test_msr_intercept(struct svm_test *test)
{
- u64 ignored, arb_val = 0xef8056791234abcd; /* Arbitrary value */
+ u64 val, arb_val = 0xef8056791234abcd; /* Arbitrary value */
int vector;
u32 msr;
@@ -341,9 +370,12 @@ static void test_msr_intercept(struct svm_test *test)
else if (msr == 0xc0002000 + 1)
msr = 0xc0010000 - 1;
+ test->scratch = msr;
+ vmmcall();
+
test->scratch = -1;
- vector = rdmsr_safe(msr, &ignored);
+ vector = rdmsr_safe(msr, &val);
if (vector)
report_fail("Expected RDMSR(0x%x) to #VMEXIT, got exception '%u'",
msr, vector);
@@ -351,12 +383,17 @@ static void test_msr_intercept(struct svm_test *test)
report_fail("Expected RDMSR(0x%x) to #VMEXIT, got scratch '%ld",
msr, test->scratch);
+ test->scratch = BIT_ULL(32) | msr;
+ vmmcall();
+
/*
* Poor man approach to generate a value that
* seems arbitrary each time around the loop.
*/
arb_val += (arb_val << 1);
+ test->scratch = -1;
+
vector = wrmsr_safe(msr, arb_val);
if (vector)
report_fail("Expected WRMSR(0x%x) to #VMEXIT, got exception '%u'",
@@ -364,17 +401,69 @@ static void test_msr_intercept(struct svm_test *test)
else if (test->scratch != arb_val)
report_fail("Expected WRMSR(0x%x) to #VMEXIT, got scratch '%ld' (wanted %ld)",
msr, test->scratch, arb_val);
+
+ test->scratch = BIT_ULL(33) | msr;
+ vmmcall();
}
+}
+
+static void test_msr_intercept(struct svm_test *test)
+{
+ __test_msr_intercept(test);
test->scratch = -2;
+ vmmcall();
+
+ __test_msr_intercept(test);
+
+ test->scratch = -3;
+}
+
+static void restore_msrpm_bit(int bit_nr, bool set)
+{
+ if (set)
+ __set_bit(bit_nr, msr_bitmap);
+ else
+ __clear_bit(bit_nr, msr_bitmap);
}
static bool msr_intercept_finished(struct svm_test *test)
{
u32 exit_code = vmcb->control.exit_code;
+ bool all_set = false;
+ int bit_nr;
- if (exit_code == SVM_EXIT_VMMCALL)
- return true;
+ if (exit_code == SVM_EXIT_VMMCALL) {
+ vmcb->save.rip += 3;
+
+ if (test->scratch == -3)
+ return true;
+
+ if (test->scratch == -2) {
+ all_set = true;
+ memset(msr_bitmap, 0xff, MSR_BITMAP_SIZE);
+ return false;
+ }
+
+ bit_nr = get_msrpm_bit_nr(test->scratch & -1u);
+ if (bit_nr < 0)
+ return false;
+
+ switch (test->scratch >> 32) {
+ case 0:
+ __set_bit(bit_nr, msr_bitmap);
+ return false;
+ case 1:
+ restore_msrpm_bit(bit_nr, all_set);
+ __set_bit(bit_nr + 1, msr_bitmap);
+ return false;
+ case 2:
+ restore_msrpm_bit(bit_nr + 1, all_set);
+ return false;
+ default:
+ return true;
+ }
+ }
if (exit_code != SVM_EXIT_MSR) {
report_fail("Wanted MSR VM-Exit, got reason 0x%x", exit_code);
@@ -402,8 +491,7 @@ static bool msr_intercept_finished(struct svm_test *test)
static bool check_msr_intercept(struct svm_test *test)
{
- memset(msr_bitmap, 0, MSR_BITMAP_SIZE);
- return (test->scratch == -2);
+ return (test->scratch == -3);
}
static void prepare_mode_switch(struct svm_test *test)
--
2.50.0.rc0.604.gd4ff7b7c86-goog
