linux-kernel - [PATCH v9 23/24] x86/cpu/amd: Do not print FW

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Message-ID: <20240531043038.3370793-24-nikunj@amd.com>
Date: Fri, 31 May 2024 10:00:37 +0530
From: Nikunj A Dadhania <nikunj@....com>
To: <linux-kernel@...r.kernel.org>, <thomas.lendacky@....com>, <bp@...en8.de>,
	<x86@...nel.org>, <kvm@...r.kernel.org>
CC: <mingo@...hat.com>, <tglx@...utronix.de>, <dave.hansen@...ux.intel.com>,
	<pgonda@...gle.com>, <seanjc@...gle.com>, <pbonzini@...hat.com>,
	<nikunj@....com>
Subject: [PATCH v9 23/24] x86/cpu/amd: Do not print FW_BUG for Secure TSC

When SecureTSC is enabled and TscInvariant (bit 8) in CPUID_8000_0007_edx
is set, kernel complains with the below firmware bug:

[Firmware Bug]: TSC doesn't count with P0 frequency!

Secure TSC need not run at P0 frequency, the TSC frequency is set by the
VMM as part of the SNP_LAUNCH_START command. Avoid the check when Secure
TSC is enabled

Signed-off-by: Nikunj A Dadhania <nikunj@....com>
Tested-by: Peter Gonda <pgonda@...gle.com>
---
 arch/x86/kernel/cpu/amd.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 44df3f11e731..905e57ca324f 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -370,7 +370,8 @@ static void bsp_determine_snp(struct cpuinfo_x86 *c)
 
 static void bsp_init_amd(struct cpuinfo_x86 *c)
 {
-	if (cpu_has(c, X86_FEATURE_CONSTANT_TSC)) {
+	if (cpu_has(c, X86_FEATURE_CONSTANT_TSC) &&
+	    !cc_platform_has(CC_ATTR_GUEST_SECURE_TSC)) {
 
 		if (c->x86 > 0x10 ||
 		    (c->x86 == 0x10 && c->x86_model >= 0x2)) {
-- 
2.34.1