From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f200.google.com (mail-pl1-f200.google.com [209.85.214.200]) (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 E404F442B14 for ; Tue, 4 Aug 2026 23:39:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.200 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785886776; cv=none; b=gYaASL+J9QJL2Tm58iPF6gG1U6724bHY6xlFUEViqiljYD7DCHLgC2FKIQ7Oh2v9risl2QijiCeUUy9KPmup1PgTDDa00bfMAtlW+mC3yUVQ3QqQv0LVFR6Z5zVnkY/bKX8McJMSQY4eMR4cL5cwzrIXx+2ybtrIJ6mbPv4jrRY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785886776; c=relaxed/simple; bh=KehEpJaIvmjEDR8tAws9CYU8Ggr/kbnv/XQ+wxDFWrc=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=JJFzyqx3C0DwgXiCGEaujfgdDBgwe8pu78Vl8ceKih/J5VgH/H5UY85AFm4MBrgEzInsTUEzadUg/rxAUz5LKtnvO6UESV5Nh4hyckQkKkc6Ud2isj4+SwucN7BJR5Df9PYhSYjXEnGKFnNOKXoAwiveDhbxv/B3kYgC2eS5Gwg= 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=R2TFwAJJ; arc=none smtp.client-ip=209.85.214.200 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="R2TFwAJJ" Received: by mail-pl1-f200.google.com with SMTP id d9443c01a7336-2cee894b3d8so6199075ad.2 for ; Tue, 04 Aug 2026 16:39:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1785886774; x=1786491574; 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=SIdV9g/PsGWm2rzYrQ2UqZD2cXobDRmK0jleLEJwTrk=; b=R2TFwAJJRf4/O9R7t9O8AhP09DPxrcf1sl0ma5AqlAPNOQ0Sah56v7e65V2Gn/YCvO j/W70Tm/9g7ifNKCwvzn+/0OeOfog+dMqcf4Jjp+ljbj23kdGkYuQb77eHwzwMXlmC+e jJbJR+CX/raZLzXb3fJdBzI0wfgn2UU6wpy+jl+bL7Mp8F5unitsfyQYcoR0GqpC4D4Q 1z7V/5qAkYrXfIJihE3oBnGQxIg/uK4x3URRPM9pryMWGPyWrRKeBwhi6xccUkGOSpQa rZwTpegIQ+fy/vTxDl4ZQbqJXvA21ncvxM7UTagZxtTsFRjtyLvcQL8AOOfMH3AizSlP jEgw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1785886774; x=1786491574; 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=SIdV9g/PsGWm2rzYrQ2UqZD2cXobDRmK0jleLEJwTrk=; b=Cst8LAgp79s9X9Vg9ELzZudLjAabRuBWVscb3j2o31g+L38vqbgnnddS13q7iUBH89 i9mK3V6EyyyoF6KYiGsYFN4MxM7y6VDG3i6P8PzGP1xuzvT+KVCs4IfnR9qRwQxNpUZS yvd2A+anc5uTvBmP7lnOU7iOwft4KliZnOn/Q6k/L5uL4ahUeTFJf1DylJqeymV5l+ix FvdtlEDwbDfOh6v2Mb/GfJane7qgiDA3LCq4Xk9A3nCo59ZOXSB+12mdaeU44gDHj1mc emEcLBnZUp5H6iyKl5F4ffZmKSH64/FC8eyvxim9o4/2Tv7/hfqmMpwmYnx1imAHrUIA h6sw== X-Gm-Message-State: AOJu0Yz7Y5KMjAY/H4SYPyemIXmYkNT82DmzQgzeIfRKNOhHG2UzG5Fo gh4H7RGrrbLwKlIkJEpDQSjy8GwZk6mXc2N9jRWlDj61S7D7hp5ouuH+1pCa2iC1ZPM1ORsQIuf juQylTg== X-Received: from pllq15.prod.google.com ([2002:a17:902:788f:b0:2ca:d209:8089]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:902:da87:b0:2cc:a977:4260 with SMTP id d9443c01a7336-2d0ca9fe0d7mr23375665ad.21.1785886774079; Tue, 04 Aug 2026 16:39:34 -0700 (PDT) Reply-To: Sean Christopherson Date: Tue, 4 Aug 2026 16:39:11 -0700 In-Reply-To: <20260804233923.3504629-1-seanjc@google.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260804233923.3504629-1-seanjc@google.com> X-Mailer: git-send-email 2.55.0.571.g244d577d93-goog Message-ID: <20260804233923.3504629-8-seanjc@google.com> Subject: [PATCH v8 07/17] 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 use 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 | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 0c0bf4c14bc5..8666bd0337b8 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; @@ -1684,8 +1690,6 @@ 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; } } @@ -1695,8 +1699,11 @@ 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)); } -- 2.55.0.571.g244d577d93-goog