From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f201.google.com (mail-pg1-f201.google.com [209.85.215.201]) (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 7ACBF2DF13A for ; Mon, 13 Oct 2025 21:54:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760392454; cv=none; b=fi7LOSj9ZWd5JFntjGDFW3emnVPqvXQiT+zjhm69i6Fn019/b1cTfsGi9po4j7UgOcasZcaW1HK4nuIBxgSOWk3YP5qCBZbkzmBiPy7MDVVKnpeO7gkIe5o7x9gk10p0imursqmYOLcUTaoOV6yom5eIR8C+3JvpiwYbhJsME24= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760392454; c=relaxed/simple; bh=c8PgEYT1UO/0f1Wh2jOegSR8o5GUTjmlEtS5G3nllTA=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=ACiklF/rersjwz7gdbd/+axURXQTPKD85YNtsq1ljn+gHCo3Y6g/hHc8qurHy5sJt4FYneTuK2vbTo332jv//sWzhyvkx5co3j1RdzXU5PMG5sCpf3OxgANcOVs/9NW84O7G8XvdoHIiJ1qqupFK2zPqWsWuYVA2tHcTaiXVq6s= 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=esP8N1wr; arc=none smtp.client-ip=209.85.215.201 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="esP8N1wr" Received: by mail-pg1-f201.google.com with SMTP id 41be03b00d2f7-b57c2371182so8808255a12.1 for ; Mon, 13 Oct 2025 14:54:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1760392453; x=1760997253; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=+QP3Cy0vKPQw+tIJxZZU82amYw2x80Sms+suxE5xk9Y=; b=esP8N1wrxTGlJPV4qIraBmdCvN8xfCR7twttGlRbHytVkVzftTXloMt7dYBhPKRpEe vtD3D+Lr5WoPcUx4m3BE0WZAonXJuY/Lr8tzsZcWGCnDttGTD90gf3nI6o4LpOhUWqAv 1csQ8sOUJrxLOGsjefNUoPL2gew6Jz3bHPbRyQUD83e5W/WzMMRnVu0+X6jmvFRXJmL0 vR/I4cLRJ7nkYqhlFb1F6USMOrIRc3M6vkJNQnVwtUHoJapOsV2lxTgvWY+DN2MKHX21 VgqJPIHdEaolKO6d7Xj9dsgOuL29gN87Ayx/5dbUNkFbDKV0s02H4sdz93GbARJdhYIH MAsQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1760392453; x=1760997253; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=+QP3Cy0vKPQw+tIJxZZU82amYw2x80Sms+suxE5xk9Y=; b=dVToFkVOm0aV/ESaDdmBO1PTMEZsbwz1RmWuCt5ETATvkdl2MMUMKu8ocZcIiOr49y wCCwz9V+eAE5uUNdGlf9wZZ2oTp1X/SNQkHO3sYUi0gKA3d6tgcUlzH29oOR+AKNIKZC 0W304IvJEjTR0/4V66rFq8V2MSFPdwOYFOEImSSd2yiqBWyK55zTLNy7SpxCkedpHv2p Z7tRpulZIwPAfvJqZYgjyTTa4f+T4zeh4Yuplca45aOS6bntnGMD+/iqeUi733FNTdXx CaTyeXmQ5HAz3PdFZYPNz+/MeepeCwpN063hJlhZAIt0fUL/yn+fdsIp3bGYy5/Il5wQ fKWg== X-Forwarded-Encrypted: i=1; AJvYcCU3nj/ADhxsPLF7RGOKZ/Rq19MM3dK1G/w/CORx3QJJGMq+hU2rRORxcQmOGQ/2NuDYtN0=@vger.kernel.org X-Gm-Message-State: AOJu0YxranMr34MvWmiEfd7QyEbg1o7WP9jvYwmg0pT/BfpP97TSHtal KAmObw1vn3TxPjeWxlq1kGLBRg/9E7rbjNntwQulT0IaZF66vTGobHp1hn23P9feoUBPW5M8eU4 xJvjUBw== X-Google-Smtp-Source: AGHT+IH+OvpGiH0IgYJpMd8LjnAd5lINrWxs0pvJ0oYogGsEcPQWDdgkN8WnNPjHzTrFeO+4uDyp/AksaYY= X-Received: from pjbst8.prod.google.com ([2002:a17:90b:1fc8:b0:330:523b:2b23]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a20:6a0b:b0:2f5:6466:af20 with SMTP id adf61e73a8af0-32da83e40c1mr33805676637.40.1760392452762; Mon, 13 Oct 2025 14:54:12 -0700 (PDT) Date: Mon, 13 Oct 2025 14:54:11 -0700 In-Reply-To: <20250922162935.621409-1-jmattson@google.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250922162935.621409-1-jmattson@google.com> Message-ID: Subject: Re: [PATCH 0/2] KVM: SVM: Aggressively clear vmcb02 clean bits From: Sean Christopherson To: Jim Mattson Cc: Paolo Bonzini , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="us-ascii" On Mon, Sep 22, 2025, Jim Mattson wrote: > It is unlikely that L1 will toggle the MSR intercept bit in vmcb02, > or that L1 will change its own IA32_PAT MSR. However, if it does, > the affected fields in vmcb02 should not be marked clean. > > An alternative approach would be to implement a set of mutators for > vmcb02 fields, and to clear the associated clean bit whenever a field > is modified. Any reason not to tag these for stable@? I can't think of any meaningful downsides, so erring on the side of caution seems prudent.