在 2023/11/10 10:13, Sean Christopherson 写道:
Extend the read/write PMU counters subtest to verify that RDPMC also reads
back the written value. Opportunsitically verify that attempting to use
the "fast" mode of RDPMC fails, as the "fast" flag is only supported by
non-architectural PMUs, which KVM doesn't virtualize.
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
.../selftests/kvm/x86_64/pmu_counters_test.c | 31 +++++++++++++++++++
1 file changed, 31 insertions(+)
diff --git a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
index cb808ac827ba..248ebe8c0577 100644
--- a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
+++ b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
@@ -328,6 +328,7 @@ __GUEST_ASSERT(expect_gp ? vector == GP_VECTOR : !vector, \
static void guest_rd_wr_counters(uint32_t base_msr, uint8_t nr_possible_counters,
uint8_t nr_counters, uint32_t or_mask)
{
+ const bool pmu_has_fast_mode = !guest_get_pmu_version();
uint8_t i;
for (i = 0; i < nr_possible_counters; i++) {
@@ -352,6 +353,7 @@ static void guest_rd_wr_counters(uint32_t base_msr, uint8_t nr_possible_counters
const uint64_t expected_val = expect_success ? test_val : 0;
const bool expect_gp = !expect_success && msr != MSR_P6_PERFCTR0 &&
msr != MSR_P6_PERFCTR1;
+ uint32_t rdpmc_idx;
uint8_t vector;
uint64_t val;
@@ -365,6 +367,35 @@ static void guest_rd_wr_counters(uint32_t base_msr, uint8_t nr_possible_counters
if (!expect_gp)
GUEST_ASSERT_PMC_VALUE(RDMSR, msr, val, expected_val);
+ rdpmc_idx = i;
+ if (base_msr == MSR_CORE_PERF_FIXED_CTR0)
+ rdpmc_idx |= INTEL_RDPMC_FIXED;
+
+ /* Redo the read tests with RDPMC, and with forced emulation. */
+ vector = rdpmc_safe(rdpmc_idx, &val);
+ GUEST_ASSERT_PMC_MSR_ACCESS(RDPMC, rdpmc_idx, !expect_success, vector);
+ if (expect_success)
+ GUEST_ASSERT_PMC_VALUE(RDPMC, rdpmc_idx, val, expected_val);
+
+ vector = rdpmc_safe_fep(rdpmc_idx, &val);
+ GUEST_ASSERT_PMC_MSR_ACCESS(RDPMC, rdpmc_idx, !expect_success, vector);
+ if (expect_success)
+ GUEST_ASSERT_PMC_VALUE(RDPMC, rdpmc_idx, val, expected_val);
+
+ /*
+ * KVM doesn't support non-architectural PMUs, i.e. it should
+ * impossible to have fast mode RDPMC. Verify that attempting
+ * to use fast RDPMC always #GPs.
+ */
+ GUEST_ASSERT(!expect_success || !pmu_has_fast_mode);
+ rdpmc_idx |= INTEL_RDPMC_FAST;
+
+ vector = rdpmc_safe(rdpmc_idx, &val);
+ GUEST_ASSERT_PMC_MSR_ACCESS(RDPMC, rdpmc_idx, true, vector);
+
+ vector = rdpmc_safe_fep(rdpmc_idx, &val);
+ GUEST_ASSERT_PMC_MSR_ACCESS(RDPMC, rdpmc_idx, true, vector);
+
vector = wrmsr_safe(msr, 0);
GUEST_ASSERT_PMC_MSR_ACCESS(WRMSR, msr, expect_gp, vector);
}
This test case failed on my Intel machine.
Error message：
Testing arch events, PMU version 0, perf_caps = 0
Testing GP counters, PMU version 0, perf_caps = 0
==== Test Assertion Failure ====
lib/x86_64/processor.c:1100: Unhandled exception in guest
pid=464480 tid=464480 errno=4 - Interrupted system call
1 0x00000000004120e1: assert_on_unhandled_exception 于
processor.c:1146
2 0x00000000004062d9: _vcpu_run 于 kvm_util.c:1634
3 0x00000000004062fa: vcpu_run 于 kvm_util.c:1645
4 0x0000000000403697: run_vcpu 于 pmu_counters_test.c:56
5 0x00000000004026fc: test_gp_counters 于 pmu_counters_test.c:434
6 (已内连入)test_intel_counters 于 pmu_counters_test.c:580
7 (已内连入)main 于 pmu_counters_test.c:604
8 0x00007f7a2f03ad84: ?? ??:0
9 0x00000000004028bd: _start 于 ??:?
Unhandled exception '0x6' at guest RIP '0x402bab'
