linux-kernel - [PATCH v5 12/14] x86/kvmclock: Skip kvmclock when Secure TSC is available

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Message-ID: <20231030063652.68675-13-nikunj@amd.com>
Date:   Mon, 30 Oct 2023 12:06:50 +0530
From:   Nikunj A Dadhania <nikunj@....com>
To:     <linux-kernel@...r.kernel.org>, <thomas.lendacky@....com>,
        <x86@...nel.org>, <kvm@...r.kernel.org>
CC:     <bp@...en8.de>, <mingo@...hat.com>, <tglx@...utronix.de>,
        <dave.hansen@...ux.intel.com>, <dionnaglaze@...gle.com>,
        <pgonda@...gle.com>, <seanjc@...gle.com>, <pbonzini@...hat.com>,
        <nikunj@....com>
Subject: [PATCH v5 12/14] x86/kvmclock: Skip kvmclock when Secure TSC is available

For AMD SNP guests having Secure TSC enabled, skip using the kvmclock.
The guest kernel will fallback and use Secure TSC based clocksource.

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

diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
index fb8f52149be9..779e7311fa6f 100644
--- a/arch/x86/kernel/kvmclock.c
+++ b/arch/x86/kernel/kvmclock.c
@@ -288,7 +288,7 @@ void __init kvmclock_init(void)
 {
 	u8 flags;
 
-	if (!kvm_para_available() || !kvmclock)
+	if (!kvm_para_available() || !kvmclock || cc_platform_has(CC_ATTR_GUEST_SECURE_TSC))
 		return;
 
 	if (kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE2)) {
-- 
2.34.1