linux-kernel - [kvm-unit-tests PATCH 1/2] x86/pmu: Update rdpmc testcase to cover #GP and emulation path

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Message-Id: <20220905123946.95223-6-likexu@tencent.com>
Date:   Mon,  5 Sep 2022 20:39:45 +0800
From:   Like Xu <like.xu.linux@...il.com>
To:     Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sandipan Das <sandipan.das@....com>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [kvm-unit-tests PATCH 1/2] x86/pmu: Update rdpmc testcase to cover #GP and emulation path

From: Like Xu <likexu@...cent.com>

Specifying an unsupported PMC encoding will cause a #GP(0).
All testcases should be passed when the KVM_FEP prefix is added.

Signed-off-by: Like Xu <likexu@...cent.com>
---
 lib/x86/processor.h |  5 ++++-
 x86/pmu.c           | 13 +++++++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/lib/x86/processor.h b/lib/x86/processor.h
index 10bca27..9c490d9 100644
--- a/lib/x86/processor.h
+++ b/lib/x86/processor.h
@@ -441,7 +441,10 @@ static inline int wrmsr_safe(u32 index, u64 val)
 static inline uint64_t rdpmc(uint32_t index)
 {
 	uint32_t a, d;
-	asm volatile ("rdpmc" : "=a"(a), "=d"(d) : "c"(index));
+	if (is_fep_available())
+		asm volatile (KVM_FEP "rdpmc" : "=a"(a), "=d"(d) : "c"(index));
+	else
+		asm volatile ("rdpmc" : "=a"(a), "=d"(d) : "c"(index));
 	return a | ((uint64_t)d << 32);
 }
 
diff --git a/x86/pmu.c b/x86/pmu.c
index 203a9d4..11607c0 100644
--- a/x86/pmu.c
+++ b/x86/pmu.c
@@ -758,12 +758,25 @@ static bool pmu_is_detected(void)
 	return detect_intel_pmu();
 }
 
+static void rdpmc_unsupported_counter(void *data)
+{
+	rdpmc(64);
+}
+
+static void check_rdpmc_cause_gp(void)
+{
+	report(test_for_exception(GP_VECTOR, rdpmc_unsupported_counter, NULL),
+		"rdpmc with invalid PMC index raises #GP");
+}
+
 int main(int ac, char **av)
 {
 	setup_vm();
 	handle_irq(PC_VECTOR, cnt_overflow);
 	buf = malloc(N*64);
 
+	check_rdpmc_cause_gp();
+
 	if (!pmu_is_detected())
 		return report_summary();
 
-- 
2.37.3