From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.alien8.de (mail.alien8.de [65.109.113.108]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E3A2239448D; Thu, 15 Jan 2026 12:22:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=65.109.113.108 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768479743; cv=none; b=Sq22l+fZC5DKXpLM5HZPP7EuhARa5XpGno1VybsT59a2hNcFDdXuPntk7lxIZk3Fq0mcecl8L9oZYLds0htegWiBO+9SNsO1fNKzoggpzL1QqTEqB8DtYAdpWrcmTcGW2oTXkVGH6ouP2r51qUXwwpz+QKzGIRuTdTIpsmOY5EQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768479743; c=relaxed/simple; bh=KORvh1MyZgMzdPmPRb40/rhDwnPtKZUev0F1g4FCIcc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=jtYHVT0hosZm2wnq/UtE2tYMhpkOeBIH3ActAv1+tSOomfdQSKSMtpCln0meDnGiQjtTfAkop9I4VqaZGHpRi4E3xQwFNeCXg2l+EEWnU/tmn/wYv7JmtZpnfv/FW0wFpZSmIPCe8U/M54mA3WFgHxtkjw/Bcrkb7dCTftX6YCc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=alien8.de; spf=pass smtp.mailfrom=alien8.de; dkim=pass (4096-bit key) header.d=alien8.de header.i=@alien8.de header.b=bd9OIs0x; arc=none smtp.client-ip=65.109.113.108 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=alien8.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=alien8.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (4096-bit key) header.d=alien8.de header.i=@alien8.de header.b="bd9OIs0x" Received: from localhost (localhost.localdomain [127.0.0.1]) by mail.alien8.de (SuperMail on ZX Spectrum 128k) with ESMTP id ED31A40E0252; Thu, 15 Jan 2026 12:22:19 +0000 (UTC) X-Virus-Scanned: Debian amavisd-new at mail.alien8.de Authentication-Results: mail.alien8.de (amavisd-new); dkim=pass (4096-bit key) header.d=alien8.de Received: from mail.alien8.de ([127.0.0.1]) by localhost (mail.alien8.de [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id C8BwZ1faih1S; Thu, 15 Jan 2026 12:22:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=alien8; t=1768479736; bh=HQDhVSHI3W24FOLXJfNfwsQ94RkXEs4kVh9VD8xEDq8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=bd9OIs0xbVOj84crKZbZVzWNMCMG71oHoSW40LtTAovORp/n08sbJ6AWrIIwitZAw FSASiEGLcgKenkljlqIh3ifO/tjrZV+sL4MxCoN1bcXtnR9J8+aF8qW495eICUctDE H7H7FooBq6Y631mkl0LnDe+ydSFTseFG/3OCeEDnFD4NvgP830dcVUlvaAarScNlt+ L9MB/2uGV9v2X61hOSMCvnnKLSWgBf/d7PEZFKqk6btIZzmsnXHfDlqCNiMo0G8cIJ D2GdNm4Ftj9O9z/n75CEBjvSu9lHWbJ6WKUdRjhj7V9f1qk5UE79VRl6IZP3e9Fwxm PVfGfiIw6xe0dHtn+9X/nWw5Iu5Ih7QQRoJV1dMBJsl1+hHtBpFwl7oJECkk4jqf7W 43F/pSQNLLNYXBGT+YF1xSwRNh/GjElaMJGzMXYMPw+21rLbfHoY2QjpKizsVm7UP0 h7+V9FWC0EHVzHywG7fCOviQZuv0NUlOXkSuxBXo5jrnMRC8XTPer9uldA1LOlNirp qI9/s66F1qlFKIFKmcEz7qyUqaSOdi8k46iTFDolVRiJP+M0l1ezk5VlXRomNLT8b2 4zIpyDEEPKyxsx4QmmjbDYlTGD4CnuHZmf48/zeqKf66lv8nmj4LAFa9IScOaHBD6I CgUJBwGwxUMhGM8MQMpCOOOY= Received: from zn.tnic (pd953023b.dip0.t-ipconnect.de [217.83.2.59]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature ECDSA (P-256) server-digest SHA256) (No client certificate requested) by mail.alien8.de (SuperMail on ZX Spectrum 128k) with UTF8SMTPSA id 3474840E0028; Thu, 15 Jan 2026 12:22:11 +0000 (UTC) Date: Thu, 15 Jan 2026 13:22:04 +0100 From: Borislav Petkov To: Paolo Bonzini Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, seanjc@google.com, x86@kernel.org Subject: Re: [PATCH v2 0/4] x86, fpu/kvm: fix crash with AMX Message-ID: <20260115122204.GDaWjb7Npp80GK-mFn@fat_crate.local> References: <20260101090516.316883-1-pbonzini@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20260101090516.316883-1-pbonzini@redhat.com> On Thu, Jan 01, 2026 at 10:05:12AM +0100, Paolo Bonzini wrote: > Fix a possible host panic, due to an unexpected #NM, when a KVM guest > is using AMX features. > > The guest's XFD value, which is stored in fpstate->xfd, is used for both > guest execution and host XSAVE operations. This already sounds weird. Why? Why don't we carry separate XFD copies - guest and host - which we use for the guest and the host, respectively? -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette