From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f200.google.com (mail-pf1-f200.google.com [209.85.210.200]) (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 98A05425886 for ; Mon, 10 Aug 2026 22:55:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.200 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786402515; cv=none; b=J3B9uByHko4iemo3i4HrQpXkcF/vsJv23dtQIFnGWgx9pXL526axWYP5M/VI/CsEuFAnACegIuS7iT0Oq2LlyMOtQ8N4X6OPfAKbVSYe5jx1svH+7UTu4cA35GZpk6lKC1uTJRg9CeVS2Mx/0NwLn+FVO/5XWmL1jk6zDYum0kA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786402515; c=relaxed/simple; bh=es4fCK6dWHmOsuq74FJz6dq2gHBwrNsXF0MHmvd49x0=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=kuNk7ingglK1nonf5Z6aIv7U2znVrDCwkJ1dB37GLEy4fLqTLUPjUIXfNjyFf9NfCG6bZwIRNxv06iauYq6qGOowrUFHNDRijsdac+KVAmBF9FNHVXSh7S4tMW5P5MePCYYHv1uvXP72q20UqSXO+cr0ofjbnNJH3QCKtsU6gyE= 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=bIsPqNPa; arc=none smtp.client-ip=209.85.210.200 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="bIsPqNPa" Received: by mail-pf1-f200.google.com with SMTP id d2e1a72fcca58-84eee2147ffso3094043b3a.0 for ; Mon, 10 Aug 2026 15:55:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1786402513; x=1787007313; darn=vger.kernel.org; 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=6mJNwRsIdlgcDx1k8DwIZJ30uuN1iHndQUOpDPZR580=; b=bIsPqNPasVfvxZyKkp4PenPvUlebq2+0r1UxFcYdFRRvy9UY4tmluknNt60g6FuUNP /CJ8dIJjOatLfvK3zXDrCav9BJjCMgZKJGWPe06MyYZV3EftqjUh/cc+LrSMQv+Gfd+C Srn3re9OUlqcgo4BFymm6Ovr/miIJue29t4RbaZT+8eC9KKognEquT/isVavBJjyUq6d 6dGZrYT5uD17WWQvK/I/AyqRz2GDh+KffCu34q1EwNx0VRZDonLtL0y06F+ZgAZS/ljZ TACCuahtX1RWETo+uRNl7a6Ol+vjEycV/fHDLc7V1BbJTs7DmTkBNRvZ8MoET5WQwAez kqHA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1786402513; x=1787007313; 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=6mJNwRsIdlgcDx1k8DwIZJ30uuN1iHndQUOpDPZR580=; b=g3CTU+kjU76KETzMhUERsynDp3cKvvOYQ0m/tGlds39QGp4AMIlK+taFPA3oc1Fam4 HrS2sBUnL2MfmHgIRtQxtv5k3P/XOXoScGujwkorIWaUqSFWH4l0Z1w9bM5mXDNtWLWs YTuBQ8vdaik7o1LNfvM7ADnlq/OyZ6AHlUAC4vWTJcHDnBKkgqLAtK2SsSHnIrEQ2X3i kSzEG20LZeygxX3Oz2pIkbkuU9vllZNA6TPTswfz74TrYYzxUb7T1hZKLrn9bnCZdKTu wsG08PoZxDTdJ7gHb2ZtOD2TF6NwGRnGWJlsB2rksd+THqotDvHf8C6CBkwHaWd7iGFi b6qQ== X-Gm-Message-State: AOJu0YzxkfSbVG80De8FzU23n2d1wwSfrOU5tVEZzbmjqxvn8vIdv/ng B1bySzN5MfsESkE7ll7Fre0p3fMSZozl9C/D5dzrqVq5LdktJ/COQz6E1SK7wt7f2w4iJ06gNJG mG+nXzA== X-Received: from pfx36.prod.google.com ([2002:a05:6a00:a464:b0:84b:44f4:2d62]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:3316:b0:845:36a0:9eb2 with SMTP id d2e1a72fcca58-84f69770781mr26628844b3a.34.1786402512910; Mon, 10 Aug 2026 15:55:12 -0700 (PDT) Reply-To: Sean Christopherson Date: Mon, 10 Aug 2026 15:54:46 -0700 In-Reply-To: <20260810225500.869288-1-seanjc@google.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260810225500.869288-1-seanjc@google.com> X-Mailer: git-send-email 2.55.0.679.g6767b8d81c-goog Message-ID: <20260810225500.869288-9-seanjc@google.com> Subject: [PATCH v9 08/21] KVM: x86: Move "no master clock" fallback from __get_kvmclock() to get_kvmclock() From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Paul Durrant , David Woodhouse , Dongli Zhang Content-Type: text/plain; charset="UTF-8" Move the fallback logic for getting the current kvmclock when not in master clock mode out of __get_kvmclock() and into its sole caller, get_kvmclock(). This will allow using early-return logic in the master clock code, without having to resort to a do-while() loop and/or gotos. No functional change intended. Signed-off-by: Sean Christopherson --- arch/x86/kvm/x86.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 56e095b14441..e0d623a122eb 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1651,12 +1651,16 @@ static unsigned long get_cpu_tsc_khz(void) } /* Called within read_seqcount_begin/retry for kvm->pvclock_sc. */ -static void __get_kvmclock(struct kvm *kvm, struct kvm_clock_data *data) +static bool __get_kvmclock_master_clock(struct kvm *kvm, + struct kvm_clock_data *data) { struct kvm_arch *ka = &kvm->arch; struct pvclock_vcpu_time_info hv_clock; u64 tsc_hz; + if (!ka->use_master_clock) + return false; + /* * Snapshot and validate the TSC frequency as kvmclock_cpu_down_prep() * zeros the per-CPU value when a CPU is going offline. @@ -1665,8 +1669,10 @@ static void __get_kvmclock(struct kvm *kvm, struct kvm_clock_data *data) tsc_hz = (u64)get_cpu_tsc_khz() * HZ_PER_KHZ; put_cpu(); - data->flags = 0; - if (ka->use_master_clock && tsc_hz) { + if (!tsc_hz) + return false; + + { #ifdef CONFIG_X86_64 struct timespec64 ts; @@ -1684,9 +1690,9 @@ static void __get_kvmclock(struct kvm *kvm, struct kvm_clock_data *data) &hv_clock.tsc_shift, &hv_clock.tsc_to_system_mul); data->clock = __pvclock_read_cycles(&hv_clock, data->host_tsc); - } else { - data->clock = get_kvmclock_base_ns() + ka->kvmclock_offset; } + + return true; } static void get_kvmclock(struct kvm *kvm, struct kvm_clock_data *data) @@ -1695,8 +1701,11 @@ static void get_kvmclock(struct kvm *kvm, struct kvm_clock_data *data) unsigned seq; do { + data->flags = 0; + seq = read_seqcount_begin(&ka->pvclock_sc); - __get_kvmclock(kvm, data); + if (!__get_kvmclock_master_clock(kvm, data)) + data->clock = get_kvmclock_base_ns() + ka->kvmclock_offset; } while (read_seqcount_retry(&ka->pvclock_sc, seq)); } -- 2.55.0.679.g6767b8d81c-goog