From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f74.google.com (mail-pj1-f74.google.com [209.85.216.74]) (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 1DFE31A3178 for ; Sat, 15 Feb 2025 00:56:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.74 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739581019; cv=none; b=pEcViUvJ8/8DZhNT9ZUYa3guECUWQyeKMAG1RqH+Nj1TYZNDEZ/Cg3z79SBzmCFrRoVMkuPTZ2iq7ZZJK3mk0vlBKUBtuF8lvixldeE0xVAdVdQWFG5PSfc0x+MMAmloZeGAeQik4BAYjg1jIBzG8pioVvaC4JvzbNhJwFkuUdw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739581019; c=relaxed/simple; bh=+KR+FPyiWdY6nzi5E/xfi5ZIbXs6yttfbKTh2BzTWUY=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=HuwVzv6ZzhHu0UDGEeV0+ostPdMmyEbYDCyaHhIL4K0MIpufWUOVQRJ4oPp67CN9pDqfYVbhq6FWaEmaK/0fiq1NNXZv+k4khntT5igg+8GRBdA0yMZkKCFS9QGzEENPyRo1C/EPJ25XSM04R6B4OBWAZYNBRHSlI5gfmyf5PrE= 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=eJAEfnto; arc=none smtp.client-ip=209.85.216.74 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="eJAEfnto" Received: by mail-pj1-f74.google.com with SMTP id 98e67ed59e1d1-2fc1eabf4f7so4000998a91.1 for ; Fri, 14 Feb 2025 16:56:57 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1739581017; x=1740185817; 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=dYdp5KEOM09jg9p9N6DLn1QBn6Otq5JJd2KkgOh4RdE=; b=eJAEfntoM5S7pFhA8vMKB2H7G2qIcnGiPNWXo9/+Sln0so7OC9g0UG1j9RNCrBO6AM gjL+F2RmurdArV+u5GUUEQsdGDfxrIyUdSTVYOCkZYNlXiKAtblppNCBt3ByvgGqeDnC 3AufWoNpIDXXYNDRjnbnSlTohQLfcIv6qVLbt+j+gIttQjZzauV7NU0EoaMMblkWG91r RECLEeRmh3JmHDbLE9IzCnrs+13du4SEnhkoa7G0HuuATq7uWC7fqgx2sFE9LsPhB0HE TtHj0jgiuO35KV3B5ftz/oD852t3st3tbaF3gNGrR0qs01tjrm9McOuC+39df5H7AQQ9 DiNQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1739581017; x=1740185817; 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=dYdp5KEOM09jg9p9N6DLn1QBn6Otq5JJd2KkgOh4RdE=; b=h2VdNINoZGQObdVfOSJpU6+y2broNRatLxetygGtbOlwBBfEdCpNjDVZHKol1JSqNR P4C3cHubbzfOUTNQ8S+NVrOji5VDgfCENeIae3NRaoTvJfC0cAYHEWd96bYX0QmoUctY nG0X7++7yJqp6Mw05hff5w5fjfQcjwaqcrs2FUFI+qBeIIYU4f6qxq10J0mAAKPDDkve DBM9iAbM7bjbf2QQ7biojo+cWMWlSDU6x42cp6sMHABt559OW/lWUHbXbe/KgLxwjG5h PsIDAv/K082egPTzHZjPTBvae4plfRY+cWFXSojghe4pxzRmdnJx6OG4Ae+PJzkWEwxv aqYg== X-Forwarded-Encrypted: i=1; AJvYcCUT8nF/LSKccJcEGFXUXSLza2wEH1bHf2vrbGo8M5fYOOxW8tOb84wHa+T5J4AAOCif147yxpGbmgOWhh0=@vger.kernel.org X-Gm-Message-State: AOJu0YySpEPezWaFvwQogbKJbG+jzS7i5Kb46w+NH2q3G5QuCFaJzIa7 efDjZvrtzbAzxNs7Vxv6DTfkAFR3IsLmcX/Csl1bsZMKYDNKawCpe2wnhj+LBztJzKbt6fbBLI7 QHQ== X-Google-Smtp-Source: AGHT+IFyXn/jnfPe9MBamhPWud5uhVvBM7H05Zvnq/KLsngCiWW3jisWRrlgNP9Gm+ydmlhJ/vnEjK2DQMw= X-Received: from pjboh15.prod.google.com ([2002:a17:90b:3a4f:b0:2fc:3022:36b4]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:2d8d:b0:2f7:4cce:ae37 with SMTP id 98e67ed59e1d1-2fc40f22cd2mr2192939a91.18.1739581017169; Fri, 14 Feb 2025 16:56:57 -0800 (PST) Date: Fri, 14 Feb 2025 16:50:41 -0800 In-Reply-To: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250201011400.669483-1-seanjc@google.com> X-Mailer: git-send-email 2.48.1.601.g30ceb7b040-goog Message-ID: <173958006311.1187438.11536700176929455.b4-ty@google.com> Subject: Re: [PATCH] KVM: x86/xen: Only write Xen hypercall page for guest writes to MSR From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini , Paul Durrant , David Woodhouse Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, syzbot+cdeaeec70992eca2d920@syzkaller.appspotmail.com, Joao Martins Content-Type: text/plain; charset="utf-8" On Thu, 06 Feb 2025 19:14:19 +0000, David Woodhouse wrote: > The Xen hypercall page MSR is write-only. When the guest writes an address > to the MSR, the hypervisor populates the referenced page with hypercall > functions. > > There is no reason for the host ever to write to the MSR, and it isn't > even readable. > > [...] Applied to kvm-x86 xen, thanks! I'll post v2 of my series on top. [1/1] KVM: x86/xen: Only write Xen hypercall page for guest writes to MSR https://github.com/kvm-x86/linux/commit/3617c0ee7dec -- https://github.com/kvm-x86/linux/tree/next