From nobody Mon Feb 9 02:27:16 2026 Received: from mail-pl1-f201.google.com (mail-pl1-f201.google.com [209.85.214.201]) (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 492FD145B00 for ; Sat, 1 Feb 2025 01:38:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738373922; cv=none; b=XVUwx6Bi/KvdCfD3kCoERDOcyrcxyD19NAuSSB+2uXHqNmYzwoD1dP+K+Saem/i3NIXgaMt0o/WBkuw/iLyr7bmrxNJruj6EZH019+tpp8/hS4QRdDraG/T0NZoWJ2nngUSv4XEt8SOxzi65xgsUn3KQ/U+3sXXBXeLn3j4i4+E= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738373922; c=relaxed/simple; bh=FxR3NlhqjaxyvZuR88P+kPdnNxxn6TSgaLJ91JhSPhM=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=TAVwxG/ALNLIfBzZLeD5Y7XjoBw5JNQzzROq51xr1O91cCMycftC6DCCQlsIZsdH0IlgafhWUxOwqC2fELvTvduqg6/S/pviygQ7nqICKwF4OeC9K1bLEdDd6I7VVefsuJS8bNm3rlB547B0RCu6INh8Q8Ar/gDA4pPOljStxVM= 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=KWsKTAKh; arc=none smtp.client-ip=209.85.214.201 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="KWsKTAKh" Received: by mail-pl1-f201.google.com with SMTP id d9443c01a7336-2161d185f04so37799755ad.3 for ; Fri, 31 Jan 2025 17:38:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1738373920; x=1738978720; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=MZzFZJ/ti1ZasZwSICIUNU12dHfHQJu6sx5F72/iN6A=; b=KWsKTAKhdKSiyVZNP/v/akSGiJtQVE0gZGu4ff7b3WiJyTLZmlPTreRQkmdiqv9+ck ShWKvvsF6JE6S89ymCC4sWOZhCPAdWh/m06ZJ6VYt4tpGVByKmKVYPveJbK2ofPH1OkA 58o2mfNa8l1kosAjf4Y1NZBlkKfuKcSl+XtbiqNXiQtNE68tSOQ75QKMtV37FTCRQSs+ rNn5yBb154pw/ULbVxtVnbtuOk2S79Kx5UQHT4NncimFVt0beod+MjtVidzAo2RwFgBD qJ3LBC4DM3fgHWjp0K81SpwPFhiun5Dmq9J6vkTRV+cSR/Ou6UbY41bN1Qd/RsCs9ZB8 3Vfw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1738373920; x=1738978720; h=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; bh=MZzFZJ/ti1ZasZwSICIUNU12dHfHQJu6sx5F72/iN6A=; b=kDTORw0V2IGo4e1NgVU7LQqcWy4BzXXzbU8on9hot8+qFkwhpKUTi6dHw2I8JO5LMD Bfy7ATFXBGCGQzLeIAwnTcwm0n9TC4/9V6nPyzFLrPsEw9MQgGChsEsIhPyoWocjEk4Z OmuUAVgO7eUuegIF0XLagT4hbsydp8+HlxVz6SQXEPjxk1AwXrYYiwWNH3k3MyUaXz4U wLXQD1A4cvEaQ8Hzkpk2FN6VP0o5OvfEoZp6dWaisyJ3v29E7hNh8lQiF/fH7TZ2c+an wazocKNAY89zzds9IOE7BMuA8asfuAW1FjTcfUV2O6uiUQXXdtON+Xzx+I5RwZ/+pXY6 0BAQ== X-Forwarded-Encrypted: i=1; AJvYcCUKk/w+iEqm95BFAp/x7f0tJ4HwBjzskCejEWrRhV04ERV92Pcm7Z3oROzJWFGs2uy+Ak9YwvNbpQuh7o4=@vger.kernel.org X-Gm-Message-State: AOJu0YyD9Obw2ZRlx9ueShXj+OeEcGioub0AF93uGUeB3FUss4de6SeJ 5zujzlD9MiYECUep6I1zffU2d74+w1sKaQ5eni9uZkIHcqW/RMUAAmjHgyEh96vHDPoB1RKrxHJ xEQ== X-Google-Smtp-Source: AGHT+IGINrKcjMYRORFQEHt3bDlZ15bD44RFlDg8hRTr/ZtpYuPlB3mzVJHhLezZwRgBsysW3kb9Q+jlHIU= X-Received: from plkp2.prod.google.com ([2002:a17:902:6b82:b0:20c:a78c:2b70]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:903:166d:b0:215:6489:cfb8 with SMTP id d9443c01a7336-21dd7c4c2aamr232050175ad.10.1738373920608; Fri, 31 Jan 2025 17:38:40 -0800 (PST) Reply-To: Sean Christopherson Date: Fri, 31 Jan 2025 17:38:22 -0800 In-Reply-To: <20250201013827.680235-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250201013827.680235-1-seanjc@google.com> X-Mailer: git-send-email 2.48.1.362.g079036d154-goog Message-ID: <20250201013827.680235-7-seanjc@google.com> Subject: [PATCH v2 06/11] KVM: x86: Don't bleed PVCLOCK_GUEST_STOPPED across PV clocks From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini , David Woodhouse , Paul Durrant Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, syzbot+352e553a86e0d75f5120@syzkaller.appspotmail.com, Paul Durrant , David Woodhouse , Vitaly Kuznetsov Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" When updating a specific PV clock, make a full copy of KVM's reference copy/cache so that PVCLOCK_GUEST_STOPPED doesn't bleed across clocks. E.g. in the unlikely scenario the guest has enabled both kvmclock and Xen PV clock, a dangling GUEST_STOPPED in kvmclock would bleed into Xen PV clock. Using a local copy of the pvclock structure also sets the stage for eliminating the per-vCPU copy/cache (only the TSC frequency information actually "needs" to be cached/persisted). Fixes: aa096aa0a05f ("KVM: x86/xen: setup pvclock updates") Signed-off-by: Sean Christopherson Reviewed-by: Paul Durrant --- arch/x86/kvm/x86.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index de281c328cb1..3971a13bddbe 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3123,8 +3123,11 @@ static void kvm_setup_guest_pvclock(struct kvm_vcpu = *v, { struct kvm_vcpu_arch *vcpu =3D &v->arch; struct pvclock_vcpu_time_info *guest_hv_clock; + struct pvclock_vcpu_time_info hv_clock; unsigned long flags; =20 + memcpy(&hv_clock, &vcpu->hv_clock, sizeof(hv_clock)); + read_lock_irqsave(&gpc->lock, flags); while (!kvm_gpc_check(gpc, offset + sizeof(*guest_hv_clock))) { read_unlock_irqrestore(&gpc->lock, flags); @@ -3144,25 +3147,25 @@ static void kvm_setup_guest_pvclock(struct kvm_vcpu= *v, * it is consistent. */ =20 - guest_hv_clock->version =3D vcpu->hv_clock.version =3D (guest_hv_clock->v= ersion + 1) | 1; + guest_hv_clock->version =3D hv_clock.version =3D (guest_hv_clock->version= + 1) | 1; smp_wmb(); =20 /* retain PVCLOCK_GUEST_STOPPED if set in guest copy */ - vcpu->hv_clock.flags |=3D (guest_hv_clock->flags & PVCLOCK_GUEST_STOPPED); + hv_clock.flags |=3D (guest_hv_clock->flags & PVCLOCK_GUEST_STOPPED); =20 - memcpy(guest_hv_clock, &vcpu->hv_clock, sizeof(*guest_hv_clock)); + memcpy(guest_hv_clock, &hv_clock, sizeof(*guest_hv_clock)); =20 if (force_tsc_unstable) guest_hv_clock->flags &=3D ~PVCLOCK_TSC_STABLE_BIT; =20 smp_wmb(); =20 - guest_hv_clock->version =3D ++vcpu->hv_clock.version; + guest_hv_clock->version =3D ++hv_clock.version; =20 kvm_gpc_mark_dirty_in_slot(gpc); read_unlock_irqrestore(&gpc->lock, flags); =20 - trace_kvm_pvclock_update(v->vcpu_id, &vcpu->hv_clock); + trace_kvm_pvclock_update(v->vcpu_id, &hv_clock); } =20 static int kvm_guest_time_update(struct kvm_vcpu *v) --=20 2.48.1.362.g079036d154-goog