From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f199.google.com (mail-pg1-f199.google.com [209.85.215.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D9427494250 for ; Thu, 6 Aug 2026 23:36:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786059404; cv=none; b=kAx6SuPevhmQefwmNjFQ25tXX7DiZqC2/U08BiTS1+GLFGzOKI2iOOBK8byICGQb4+qyz3c5qCQRFmiy5mtf14ahuDBUsMYxG9jk1GVtn4TtIKbOGGr2/wmtomjgsc2trDKV7miPi4XReljLVRTIJ5INwuiWbtOSrfYssZw2wuA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786059404; c=relaxed/simple; bh=M65IyX8rm7dTt45KlwDHi8ahXU+KWS/raGfMe6r6K7w=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=vAd0c+0Zw8JNB1YSUfDgd6UiocM1eii89ReogL9QSP2lcIUMRWLvPsPXiIhTtPL8Aj7MIorGFRSiuE0sL3oUnl2wyF2Per2W3R+6hQNJI5ew6ufqSZNTbA0xlXRVUynLMafKryiRFfuXKHeR/Fw1T2k6AWg3ZVcDs+80zSEndaA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=bJCHvnhJ; arc=none smtp.client-ip=209.85.215.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="bJCHvnhJ" Received: by mail-pg1-f199.google.com with SMTP id 41be03b00d2f7-cbe62e01567so2345748a12.2 for ; Thu, 06 Aug 2026 16:36:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1786059401; x=1786664201; darn=lists.linux.dev; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:reply-to:from:to:cc:subject:date:message-id :reply-to:content-type; bh=xHY7WhZzoR4x+WtFqsSoEfBU4PaM9Rhz3R83jbux6ZU=; b=bJCHvnhJNCTiMVAucBuVNVfK3/o81CLC1xA8F52jplatsMTI8LSkAj+1hVnh8m64rY Kol9FIa++MFHhWkEZiJeN2smmZW8MR1Tm91qKZ1i1DbJibTeXADQhMTnwwSB2efB1u3Y pxop4HCcyOabz13amBBbvqGsHjimX/9jkgzuBEhM2NKUsvO7I39CC2AOP0qQMWywRaB7 Nn2DX0I7YVo6Wp+NBUbtBbBHAfTl7bmmJBqp2wbKqZy8fUvXaAM0fjJdzQCSJAOLvSJj +EbAuUBnXvnmm0uQfBdJbx22hXTt47ZDhc6JbY3coVPSV4e0HJNBDkd5fPIo446CglEF zJYw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1786059401; x=1786664201; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:reply-to:x-gm-message-state:from:to:cc:subject :date:message-id:reply-to:content-type; bh=xHY7WhZzoR4x+WtFqsSoEfBU4PaM9Rhz3R83jbux6ZU=; b=VK8/U+L4wBH5n57Lc8ChnVo/iDbxj3WwO5KI+/6GWo4+055okANdOIPosf9VYFiizH +960XqPoK7cAX/IdNZzvTV2+J0yuYVxy3Se03FrmiT10B4Zc7ShULdZFh/Uc5dlmNfaW cJJiT48KvhxwAfSVd1xGECBrJec8RaffkZtU96tDXdfuAFSrTOxVPXGlCZcx6x28xrq1 FkFZAAqAyAHYWd0k3A5bFEjM1XrjJQlI5VrwDW/zy4XlowJWmj86o1p2Kin1N9byFRUw Ac1hr7DbaOLfL9J3eFxHoPtft6OeSlV2blV63edFtoqv2boHc4i+bkjDh2BCJyVrc4sl gBtA== X-Forwarded-Encrypted: i=1; AHgh+RrbqQDpOySXle7PHz/P6rkOrnlUuDk0uoVEc/yCNgeo7mqO2iyRmV66oOd2qtHHrTq0SU/T7Kl2U0f0@lists.linux.dev X-Gm-Message-State: AOJu0Yw8c2pwTyk9d66LgYT2nrHv1jOKxU2eNJgCR1aAZohdHr8SzIxC vrMQuUzpYWuIPWashaIKjb4UA+VcyS03tvDbF7GOpWStijmBCN6rOH4BqE9thyBy9xyt9RlEkNG +kIIojQ== X-Received: from pfbbu11.prod.google.com ([2002:a05:6a00:410b:b0:848:8b16:23d6]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:2383:b0:842:5b66:3c7f with SMTP id d2e1a72fcca58-84f2dedf356mr20263411b3a.0.1786059400868; Thu, 06 Aug 2026 16:36:40 -0700 (PDT) Reply-To: Sean Christopherson Date: Thu, 6 Aug 2026 16:35:31 -0700 In-Reply-To: <20260806233609.212337-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260806233609.212337-1-seanjc@google.com> X-Mailer: git-send-email 2.55.0.679.g6767b8d81c-goog Message-ID: <20260806233609.212337-15-seanjc@google.com> Subject: [PATCH v6 14/51] x86/tsc: Consolidate forcing of X86_FEATURE_TSC_KNOWN_FREQ for PV code From: Sean Christopherson To: Kiryl Shutsemau , Rick Edgecombe , Sean Christopherson , Paolo Bonzini , "K. Y. Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Long Li , Ajay Kaher , Alexey Makhalov , Jan Kiszka , Dave Hansen , Andy Lutomirski , Peter Zijlstra , Juergen Gross , Daniel Lezcano , Thomas Gleixner , John Stultz Cc: Vitaly Kuznetsov , Broadcom internal kernel review list , Boris Ostrovsky , Stephen Boyd , Miroslav Lichvar , x86@kernel.org, linux-coco@lists.linux.dev, kvm@vger.kernel.org, linux-hyperv@vger.kernel.org, virtualization@lists.linux.dev, linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org, Michael Kelley , Tom Lendacky , Nikunj A Dadhania , David Woodhouse , David Woodhouse , Thomas Gleixner Content-Type: text/plain; charset="UTF-8" Now that all paravirt code that explicitly specifies the TSC frequency also sets X86_FEATURE_TSC_KNOWN_FREQ, replace all of the one-off code and simply set X86_FEATURE_TSC_KNOWN_FREQ if the TSC frequency is known. Do NOT force set TSC_KNOWN_FREQ if the "known" TSC frequency was provided by the user. Per commit bd35c77e32e4 ("x86/tsc: Add tsc_early_khz command line parameter"), one of the goals of the param is to allow the refined calibration work "to do meaningful error checking". No functional change intended. Reviewed-by: Michael Kelley Signed-off-by: Sean Christopherson --- arch/x86/coco/sev/core.c | 1 - arch/x86/coco/tdx/tdx.c | 1 - arch/x86/kernel/cpu/acrn.c | 1 - arch/x86/kernel/cpu/mshyperv.c | 1 - arch/x86/kernel/cpu/vmware.c | 2 -- arch/x86/kernel/jailhouse.c | 1 - arch/x86/kernel/kvmclock.c | 1 - arch/x86/kernel/tsc.c | 13 ++++++++++--- arch/x86/xen/time.c | 1 - 9 files changed, 10 insertions(+), 12 deletions(-) diff --git a/arch/x86/coco/sev/core.c b/arch/x86/coco/sev/core.c index bc5ae9ef74da..72313b36b6f5 100644 --- a/arch/x86/coco/sev/core.c +++ b/arch/x86/coco/sev/core.c @@ -2027,7 +2027,6 @@ unsigned int __init snp_secure_tsc_init(void) secrets = (__force struct snp_secrets_page *)mem; - setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ); setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE); rdmsrq(MSR_AMD64_GUEST_TSC_FREQ, tsc_freq_mhz); diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c index ec28a15e26ac..21a574e60e0f 100644 --- a/arch/x86/coco/tdx/tdx.c +++ b/arch/x86/coco/tdx/tdx.c @@ -1203,7 +1203,6 @@ unsigned int __init tdx_tsc_init(void) /* TSC is the only reliable clock in TDX guest */ setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE); - setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ); return info.crystal_khz * info.numerator / info.denominator; } diff --git a/arch/x86/kernel/cpu/acrn.c b/arch/x86/kernel/cpu/acrn.c index 3818f6ae0629..dc71a6fdd461 100644 --- a/arch/x86/kernel/cpu/acrn.c +++ b/arch/x86/kernel/cpu/acrn.c @@ -40,7 +40,6 @@ static void __init acrn_init_platform(void) if (acrn_tsc_khz_cpuid) { x86_init.hyper.get_tsc_khz = acrn_get_tsc_khz; x86_init.hyper.get_cpu_khz = acrn_get_tsc_khz; - setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ); } } diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c index 4a0cdda0c49e..3bca987e05c3 100644 --- a/arch/x86/kernel/cpu/mshyperv.c +++ b/arch/x86/kernel/cpu/mshyperv.c @@ -575,7 +575,6 @@ static void __init ms_hyperv_init_platform(void) ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) { x86_init.hyper.get_tsc_khz = hv_get_tsc_khz; x86_init.hyper.get_cpu_khz = hv_get_tsc_khz; - setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ); } if (ms_hyperv.priv_high & HV_ISOLATION) { diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c index 3f1dab69d90e..cbe8b59ab79f 100644 --- a/arch/x86/kernel/cpu/vmware.c +++ b/arch/x86/kernel/cpu/vmware.c @@ -390,8 +390,6 @@ static void __init vmware_set_capabilities(void) { setup_force_cpu_cap(X86_FEATURE_CONSTANT_TSC); setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE); - if (vmware_tsc_khz) - setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ); if (vmware_hypercall_mode == CPUID_VMWARE_FEATURES_ECX_VMCALL) setup_force_cpu_cap(X86_FEATURE_VMCALL); else if (vmware_hypercall_mode == CPUID_VMWARE_FEATURES_ECX_VMMCALL) diff --git a/arch/x86/kernel/jailhouse.c b/arch/x86/kernel/jailhouse.c index 595cd28f9a9f..8107c28eb2bc 100644 --- a/arch/x86/kernel/jailhouse.c +++ b/arch/x86/kernel/jailhouse.c @@ -255,7 +255,6 @@ static void __init jailhouse_init_platform(void) pr_debug("Jailhouse: PM-Timer IO Port: %#x\n", pmtmr_ioport); precalibrated_tsc_khz = setup_data.v1.tsc_khz; - setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ); pci_probe = 0; diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c index 4f8299303a19..35a879d33e9e 100644 --- a/arch/x86/kernel/kvmclock.c +++ b/arch/x86/kernel/kvmclock.c @@ -138,7 +138,6 @@ static inline void kvm_sched_clock_init(bool stable) */ static unsigned int __init kvm_get_tsc_khz(void) { - setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ); return pvclock_tsc_khz(this_cpu_pvti()); } diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index 7f1ca6df0004..f42872c9ae99 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -1541,11 +1541,18 @@ void __init tsc_early_init(void) if (!known_tsc_khz && x86_init.hyper.get_tsc_khz) known_tsc_khz = x86_init.hyper.get_tsc_khz(); + /* + * Mark the TSC frequency as known if it was obtained from a hypervisor + * or trusted firmware. + */ + if (known_tsc_khz) + setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ); + /* * Ignore the user-provided TSC frequency if the exact frequency was - * obtained from trusted firmware or the hypervisor, as the user- - * provided frequency is intended as a "starting point", not a known, - * guaranteed frequency. + * obtained from trusted firmware or the hypervisor, and don't mark the + * frequency as known, as the user-provided frequency is intended as a + * "starting point", not a known, guaranteed frequency */ if (!known_tsc_khz) known_tsc_khz = tsc_early_khz; diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c index 1adb44fdddb2..487ad838c441 100644 --- a/arch/x86/xen/time.c +++ b/arch/x86/xen/time.c @@ -43,7 +43,6 @@ static unsigned int __init xen_tsc_khz(void) struct pvclock_vcpu_time_info *info = &HYPERVISOR_shared_info->vcpu_info[0].time; - setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ); return pvclock_tsc_khz(info); } -- 2.55.0.679.g6767b8d81c-goog