From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ed2-f12.google.com (mail-ed2-f12.google.com [74.125.228.76]) (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 181EF2FC00D for ; Sat, 5 Sep 2026 00:45:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=74.125.228.76 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788569106; cv=pass; b=E0176YcQ02ZSxbswSiutiyT3GgvbYaIo51FfrZWvyzUBTI4+cu36LbQYY0W+GofQYiozHP7L1RvKijRGjBtkl3OZMGProJ/6jq6/oTZy8wIhEUNu7ISMwj5J3ozypuhJCRo+/G+k6sUC6wpNw2w5mfzB+Lr31cwnsVKKgzG/My0= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788569106; c=relaxed/simple; bh=DW6wbmUxstvUjLcrpQZmIK9RqXPWAOU7XHIXv6Rvtno=; h=MIME-Version:References:In-Reply-To:From:Date:Message-ID:Subject: To:Cc:Content-Type; b=g+avSRRf5FesLSastw7A7Crfw4zKT35KqWH1lZJudOurEFcXJnIgN83ibsECl964+gHJX26t0tSBXbcmi67lKfsNHgzjZaxlV0j8VXcW5nSqOP4yG7gMpKU9qkksta+i0rATeV0ZsaLiB0u/8Ght4qQmtA8oqjSxj2kj4u2wsus= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=OyI9fs46; arc=pass smtp.client-ip=74.125.228.76 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=google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="OyI9fs46" Received: by mail-ed2-f12.google.com with SMTP id 4fb4d7f45d1cf-6a5d8fd8d8dso1789a12.1 for ; Fri, 04 Sep 2026 17:45:03 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1788569102; cv=none; d=google.com; s=arc-20260327; b=GIpjBzDqMVKJTZO2I5AjKopjtxhv6vzO8I/5frB27c8siXYwnhlgoG4MugFUasMCVV zZa6sOZZaYYbo5cLelfquJXfYp4nq4Lh6LVYymtiepPLl8/AoO9NW6NcWhbSjSnU4gGl GbwHVYB9owQ1eUDpfVurTOJeHuGpRjVYKJIYW0HUvgm4JhG69AEWiZLZR08jHrocqZqx JvlOMUqH1Q9uvLPGlbp+BH5dvnNSgflGIksfjL+zUj6zrrdQrPPNBGSM2dgNxatxfbZ6 5zmu/ZhdsGo9gZWmY58tjYfloYUbYeMgqJMe1z8DDmKx4REaxLYslY3SjvD+k9acUBlz BCOA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20260327; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:dkim-signature; bh=P0qdXiSaaoLWSkRGl4kXPpi2MGKhx4sNOFo2eMkbT7Q=; fh=vK9Iv+Pc3jGh1i955OBbTI+QrvWFFqR6ep0fQKCrVu0=; b=baxoeUdL+jmx00Npo8nwj3VV5LEOBol9vw+QtHVGsb04InpIrU+sC/+xnuM8e79ErM W+owbjlUUnGT8S84XL28XmbquUa3zYU+zuXUPdFc6MYGIVq6pc7bn6LwTSWSTtXY0K0e svdXiKI8W7S8FSGnMOhYLaJIIAv6Idr5+t7pYfNi3wSN+QcQYFMpqE7qYCS5MBUj/e2C /92o05btVR7/b5Ef1XG7oU+QH536Y+rfR9l5gBGRcqAEzjhMCuZh3NyRYRpH9Ur91IlE DcGDo0sndLj6pFtSnpPjY8FtMgDHVcCAYUqAa5zC4JV/FWdMutE2X6tu4ziO+3q1JNVZ R6ew==; darn=vger.kernel.org ARC-Authentication-Results: i=1; mx.google.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1788569102; x=1789173902; darn=vger.kernel.org; h=content-transfer-encoding:content-type:cc:to:subject:message-id :date:from:in-reply-to:references:mime-version:from:to:cc:subject :date:message-id:reply-to:content-type; bh=P0qdXiSaaoLWSkRGl4kXPpi2MGKhx4sNOFo2eMkbT7Q=; b=OyI9fs46s9KMNJD7zN0urJ2M2pLl4IzvJarbo0V33R8l8ylqpl+3wEZEfwkXElkoz4 21yBThMXt8LoGu3v2xbogXWB9+B+xIUmd8M/qipodHejCfYlyS8hdfd62LlEOOk+xqSg ly5l3fjwbyDs8MRaKow1+6UyH/NQ72+RU31PfGmrCT41jPfib50DlRzDqjW5Gn2067sa w8paSdpGcdO9f1XEM18/kNr+aGlRQOm04nKJar490EwIxSOa2dFCDem/CHTj7Vs6hISm EMtPPDpVU2jexo2y48QtYW0/C9aJ81cO9p3gTrvVpLoFx7ILMVH35lVkRYv9HbJlrs6k BkjA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1788569102; x=1789173902; h=content-transfer-encoding:content-type:cc:to:subject:message-id :date:from:in-reply-to:references:mime-version:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=P0qdXiSaaoLWSkRGl4kXPpi2MGKhx4sNOFo2eMkbT7Q=; b=L2+qmXRDhVTn7YWYwu7b+HJaxv5vF3h6dqYft/IRPpmFBCRrqJ4g/5iWvdwhS3YE60 pAqZepPBZTDqmI6NriCWA1dGJbrNfcVf5Fo0T8vYkTyWTjG9/AnlQ8XgjQK2vMnKPnL+ bNnn3fAwKxF1RsFsn5wJiRx6wzvGUiMC5AxfPvCGSIvXEAuao6W/Uv6uQVaIj0xfki68 HRORkpaxbRtKkJ29jkg7kq3eVaiJA0QbpvkJViRAZCAFa55JDkYlJOdR7n1EH7G7XEQa 47SM9TOOcKpCFbqO4TzEcdoR6vFS5kpjJMQ1dsoCfYODf/zAqBT1zxBQFJPQ43fsK+ro D5NQ== X-Forwarded-Encrypted: i=1; AKwUvBz/72+r3JW2uUxY2BXNaDWGcVeaG7G5NDXgiKqN2OaI6Y7WJlGvAu7ER84lAmWBhpuZvF15wpAo66eSTh0=@vger.kernel.org X-Gm-Message-State: AFuF++lZSLxrbT0FgMsOsNqc5L6CRbiYSr56Q6XW5ZVQbruagb5M3T1K bIrvNV30XSoZCM6ielT7GN9m9SmfdB+F8atDCeuIM1SKiaV+4fFIA2tcis1VB/MspSOrdB7t3nu zpZzlsbiB91Fm4s9QBC01s4Fe27HqRoMIqV0jPxrJ X-Gm-Gg: AYBFou0Oui8NY64+StzqGvf4A/hVuxAJkWH9BCM8YSkDDrRHK07T/KkNF76+bKq4NXv aMVEJL6aYRmZDcyVGtZ/MWXmrqJm7h9dK888Lte3doUD8NTHOZK4DoPZQosLTcBTSlkssGhHKYC ND54hZdV1dewd1Pd8UK3qSWoJBwSg4lbfhfnRYrTLXArYOnNNzgn5V7Hy3mermTAIsP5Eq1gAYD PfsWqtJzS27eh1UHplHevn9unZS6uxh41ufGqKPhC/uKc29VVChdHG2gy7V/0oTvS4sMS5GpbMb mrVx8bQZyU/HCRwVKpAp1cABR6SeMG6HVUDkn5slzl/3gMoT/D3mVeY= X-Received: by 2002:a05:6402:1a4c:b0:6a6:9d10:f52b with SMTP id 4fb4d7f45d1cf-6a7f682636amr13303a12.12.1788569101906; Fri, 04 Sep 2026 17:45:01 -0700 (PDT) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <20260824123954.315112-1-zhang_wei@open-hieco.net> <20260824123954.315112-8-zhang_wei@open-hieco.net> In-Reply-To: <20260824123954.315112-8-zhang_wei@open-hieco.net> From: Jim Mattson Date: Fri, 4 Sep 2026 17:44:47 -0700 X-Gm-Features: AcwNN1UZwSKJ9MC3qwJwI8ljAn8Hu3imGZF6CsHrJI6l7M3IeDffrx60t7WpNbE Message-ID: Subject: Re: [PATCH v5 7/8] KVM: nSVM: Advertise DecodeAssists to L1 To: Tina Zhang Cc: Sean Christopherson , kvm@vger.kernel.org, Paolo Bonzini , Shuah Khan , zhouyanjing@hygon.cn, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Mon, Aug 24, 2026 at 5:40=E2=80=AFAM Tina Zhang wrote: > > Advertise DecodeAssists to L1 now that KVM virtualizes the > guest-visible DecodeAssist state in VMCB12: EXITINFO1 decode data for > MOV CR/DR, INTn, and INVLPG exits, plus instruction bytes for nested > page faults and intercepted #PF exits. INVLPGA's linear address remains > available directly from the saved guest rAX, as required by the APM. > > Expose the feature only when supported by hardware, as KVM still relies > on hardware DecodeAssists for VM-Exits that are reflected directly from > L2. > > With DecodeAssists exposed, QEMU configurations that require the feature > (e.g. "-cpu ...,+decodeassists,...,enforce") are no longer rejected. > > Signed-off-by: Tina Zhang Once the implementation issues are addressed... Reviewed-by: Jim Mattson