From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f198.google.com (mail-pg1-f198.google.com [209.85.215.198]) (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 12E3348A8CC for ; Wed, 26 Aug 2026 21:33:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.198 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787779996; cv=none; b=nNnNxAPS3nQLiIfYoNKhbVBQZ1iAgplUnAM3WmflqF0UvK5ZULbUH9GED98R5XVrR8FeyEE3njhxSVermBI+ZH2p4IZyXWIrC6KITudr2kcJnHDu/6GAPcCUETtyCrq4bqgIaVi7wP68VQnF8NrMXuKVIcg/Wgb8p218Quc7PYk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787779996; c=relaxed/simple; bh=dsaCIkuhvZqCjTZVeCEPOV45bBjnIf2n5TfEJj18Yb0=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=Djp0Vp/6kEB5PbZAuHoElvkRljefB2gJOP+eH8HTLVQIlzk3ayTgy/9SWf0E8F8vBaxcMqelCk9BDZd2fIF+Yv2x0f6kZGx19zKh6ZUtgVnstSRTz9IhqVK5kwC5lOkNqQAZUYZgdyb+c9utwxwE/69KiXNnc47bb9XW1zGTllk= 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=Ixan4xUQ; arc=none smtp.client-ip=209.85.215.198 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="Ixan4xUQ" Received: by mail-pg1-f198.google.com with SMTP id 41be03b00d2f7-cc11b5dd54dso2662565a12.3 for ; Wed, 26 Aug 2026 14:33:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1787779994; x=1788384794; 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=l1eygQedJKM5ekEKsn/E9bXYihX3nGywRp8RfIbS/YY=; b=Ixan4xUQea9JGSo9sfaaaA5G2Afb1fK8nv24uSr3maw5mEo6dbYrGj2QiLVFRcmtKj kr1oA0MR+nnSx7+KpfUacFC6GNd8u4aoNOTZSReu2AR3ExvkdeRru2szuYnzO01iQOJE 3NkOstxS+tJ3wSv2zoWqSzyVkpdSCQ9c/qCiKU2JsiLQKLSsjS7orfxB5yqIfIKUK20d It8qSa31O4TotRd+CA5SMr82oTyGWKEngZjf/z7Y26ID/Ej+mvs3Pp0G7YyMApJMgWEv GHOSNoN3cNWP7oqBbyOl1gA03IgrIqHU5JOfXNUYmHYLDNIJ/lumpUPZoVHf1V6SLKG0 oIqA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1787779994; x=1788384794; 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=l1eygQedJKM5ekEKsn/E9bXYihX3nGywRp8RfIbS/YY=; b=iB8tpWDKw//s71unml/o6hfSzCbXBe2QNNA0YEJmX8RARQ0bg8EYcQcv4aK4Rcdrk4 Eej74B9m0EhKkiJY834IISuRG/o70BYZRjGrFq8I6m1L0Lvzj0V9tAghS3zumHCQUJ8i rxfxvMNhj3KPw8Ti/LmG6uUUk0R8FzOdfqlbx0WLlwbLfaenEQZ5/ToCESMWcuFzaY8H 7dwhZXfc0fXWOjvB0g1r5VA0xij5+IlBEBPb3HxJORMqO/XGrJREkZRyjnJn5X4MQiF2 J7RAig26E37zehlBsOx4sYLI2VhaDgfiaVRTPvxsQ4evGsy8n4nsXvNCF3l3+ZbZCgDI WaEw== X-Gm-Message-State: AFuF++lKyNJcvDxTB4BvMKdHZ2PxR4VOWu9l35Me1t0lrv8KKS47fEp4 JHVnfHGQYYnCAsfC6vduF2U7EeMOvxdTVm/tMFr+nMoM15v25KWY6GLUTHRM2bkIK4RCZWmRFGr LtHQHQA== X-Received: from pgbs63.prod.google.com ([2002:a63:5e42:0:b0:cbe:947d:d145]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a20:9c86:b0:3c3:bbe6:95c7 with SMTP id adf61e73a8af0-3cf84e4b0f8mr20727681637.17.1787779994090; Wed, 26 Aug 2026 14:33:14 -0700 (PDT) Reply-To: Sean Christopherson Date: Wed, 26 Aug 2026 14:32:48 -0700 In-Reply-To: <20260826213303.914988-1-seanjc@google.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260826213303.914988-1-seanjc@google.com> X-Mailer: git-send-email 2.55.0.887.g758fc8c411-goog Message-ID: <20260826213303.914988-9-seanjc@google.com> Subject: [PATCH v10 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 75b689ec074d..4f98cc71a671 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1653,12 +1653,16 @@ 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. @@ -1667,8 +1671,10 @@ 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; @@ -1686,9 +1692,9 @@ 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) @@ -1697,8 +1703,11 @@ 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)); } -- 2.55.0.887.g758fc8c411-goog