linux-kernel - [PATCH] KVM: selftests: Add back the missing check of MONITOR/MWAIT availability

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Message-ID: <20250620062219.342930-1-chenyi.qiang@intel.com>
Date: Fri, 20 Jun 2025 14:22:18 +0800
From: Chenyi Qiang <chenyi.qiang@...el.com>
To: Sean Christopherson <seanjc@...gle.com>,
	Paolo Bonzini <pbonzini@...hat.com>,
	Zide Chen <zide.chen@...el.com>
Cc: Chenyi Qiang <chenyi.qiang@...el.com>,
	kvm@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Xuelian Guo <xuelian.guo@...el.com>
Subject: [PATCH] KVM: selftests: Add back the missing check of MONITOR/MWAIT availability

The revamp of monitor/mwait test missed the original check of feature
availability [*]. If MONITOR/MWAIT is not supported or is disabled by
IA32_MISC_ENABLE on the host, executing MONITOR or MWAIT instruction
from guest doesn't cause monitor/mwait VM exits, but a #UD.

[*] https://lore.kernel.org/all/20240411210237.34646-1-zide.chen@intel.com/

Reported-by: Xuelian Guo <xuelian.guo@...el.com>
Fixes: 80fd663590cf ("selftests: kvm: revamp MONITOR/MWAIT tests")
Signed-off-by: Chenyi Qiang <chenyi.qiang@...el.com>
---
 tools/testing/selftests/kvm/x86/monitor_mwait_test.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/testing/selftests/kvm/x86/monitor_mwait_test.c b/tools/testing/selftests/kvm/x86/monitor_mwait_test.c
index 390ae2d87493..0eb371c62ab8 100644
--- a/tools/testing/selftests/kvm/x86/monitor_mwait_test.c
+++ b/tools/testing/selftests/kvm/x86/monitor_mwait_test.c
@@ -74,6 +74,7 @@ int main(int argc, char *argv[])
 	int testcase;
 	char test[80];
 
+	TEST_REQUIRE(this_cpu_has(X86_FEATURE_MWAIT));
 	TEST_REQUIRE(kvm_has_cap(KVM_CAP_DISABLE_QUIRKS2));
 
 	ksft_print_header();
-- 
2.43.5