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

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Message-ID: <20230130120327.977460-11-nikunj@amd.com>
Date:   Mon, 30 Jan 2023 17:33:26 +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>, <jroedel@...e.de>,
        <mingo@...hat.com>, <tglx@...utronix.de>,
        <dave.hansen@...ux.intel.com>, <seanjc@...gle.com>,
        <pbonzini@...hat.com>, <nikunj@....com>, <michael.roth@....com>,
        <ketanch@...k.ac.in>
Subject: [RFC PATCH 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 a78e73da4a74..7a7a5eaacb54 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -1200,7 +1200,7 @@ 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;
 
 	/*
-- 
2.32.0