linux-kernel - [PATCH v3 12/14] x86/kvmclock: Skip kvmclock when Secure TSC is available

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Message-ID: <20230722111909.15166-13-nikunj@amd.com>
Date:   Sat, 22 Jul 2023 16:49:07 +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>
Subject: [PATCH v3 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 0f35d44c56fe..1be342064851 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