linux-kernel - [PATCH 04/16] x86/sev: Mark TSC as reliable when configuring Secure TSC

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Message-ID: <20250201021718.699411-5-seanjc@google.com>
Date: Fri, 31 Jan 2025 18:17:06 -0800
From: Sean Christopherson <seanjc@...gle.com>
To: Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>, 
	Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org, 
	"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>, Juergen Gross <jgross@...e.com>, 
	"K. Y. Srinivasan" <kys@...rosoft.com>, Haiyang Zhang <haiyangz@...rosoft.com>, Wei Liu <wei.liu@...nel.org>, 
	Dexuan Cui <decui@...rosoft.com>, Ajay Kaher <ajay.kaher@...adcom.com>, 
	Alexey Makhalov <alexey.amakhalov@...adcom.com>, Jan Kiszka <jan.kiszka@...mens.com>, 
	Paolo Bonzini <pbonzini@...hat.com>, Andy Lutomirski <luto@...nel.org>, 
	Peter Zijlstra <peterz@...radead.org>
Cc: linux-kernel@...r.kernel.org, linux-coco@...ts.linux.dev, 
	virtualization@...ts.linux.dev, linux-hyperv@...r.kernel.org, 
	jailhouse-dev@...glegroups.com, kvm@...r.kernel.org, 
	xen-devel@...ts.xenproject.org, Sean Christopherson <seanjc@...gle.com>, 
	Nikunj A Dadhania <nikunj@....com>, Tom Lendacky <thomas.lendacky@....com>
Subject: [PATCH 04/16] x86/sev: Mark TSC as reliable when configuring Secure TSC

Move the code to mark the TSC as reliable from sme_early_init() to
snp_secure_tsc_init().  The only reader of TSC_RELIABLE is the aptly
named check_system_tsc_reliable(), which runs in tsc_init(), i.e.
after snp_secure_tsc_init().

This will allow consolidating the handling of TSC_KNOWN_FREQ and
TSC_RELIABLE when overriding the TSC calibration routine.

Cc: Nikunj A Dadhania <nikunj@....com>
Cc: Tom Lendacky <thomas.lendacky@....com>
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/coco/sev/core.c      | 2 ++
 arch/x86/mm/mem_encrypt_amd.c | 3 ---
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/x86/coco/sev/core.c b/arch/x86/coco/sev/core.c
index 684cef70edc1..e6ce4ca72465 100644
--- a/arch/x86/coco/sev/core.c
+++ b/arch/x86/coco/sev/core.c
@@ -3288,6 +3288,8 @@ void __init snp_secure_tsc_init(void)
 		return;
 
 	setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ);
+	setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE);
+
 	rdmsrl(MSR_AMD64_GUEST_TSC_FREQ, tsc_freq_mhz);
 	snp_tsc_freq_khz = (unsigned long)(tsc_freq_mhz * 1000);
 
diff --git a/arch/x86/mm/mem_encrypt_amd.c b/arch/x86/mm/mem_encrypt_amd.c
index b56c5c073003..774f9677458f 100644
--- a/arch/x86/mm/mem_encrypt_amd.c
+++ b/arch/x86/mm/mem_encrypt_amd.c
@@ -541,9 +541,6 @@ void __init sme_early_init(void)
 	 * kernel mapped.
 	 */
 	snp_update_svsm_ca();
-
-	if (sev_status & MSR_AMD64_SNP_SECURE_TSC)
-		setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE);
 }
 
 void __init mem_encrypt_free_decrypted_mem(void)
-- 
2.48.1.362.g079036d154-goog