linux-kernel - [PATCH v2 10/11] x86/tsc: Mark Secure TSC as reliable clocksource

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Date:   Sun, 26 Mar 2023 20:17:00 +0530
From:   Nikunj A Dadhania <nikunj@....com>
To:     <linux-kernel@...r.kernel.org>, <x86@...nel.org>
CC:     <bp@...en8.de>, <thomas.lendacky@....com>,
        <dionnaglaze@...gle.com>, <pgonda@...gle.com>, <seanjc@...gle.com>,
        <pbonzini@...hat.com>, <nikunj@....com>, <michael.roth@....com>,
        <ketanch@...k.ac.in>
Subject: [PATCH v2 10/11] x86/tsc: Mark Secure TSC as reliable clocksource

AMD SNP guests may have Secure TSC feature enabled. Secure TSC as
clocksource is wrongly marked as unstable, mark Secure TSC as
reliable.

Signed-off-by: Nikunj A Dadhania <nikunj@....com>
---
 arch/x86/kernel/tsc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 344698852146..5f1e2b51ae3b 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -1221,7 +1221,7 @@ static void __init check_system_tsc_reliable(void)
 			tsc_clocksource_reliable = 1;
 	}
 #endif
-	if (boot_cpu_has(X86_FEATURE_TSC_RELIABLE))
+	if (boot_cpu_has(X86_FEATURE_TSC_RELIABLE) || cc_platform_has(CC_ATTR_GUEST_SECURE_TSC))
 		tsc_clocksource_reliable = 1;
 
 	/*
-- 
2.34.1