From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp-fw-52002.amazon.com (smtp-fw-52002.amazon.com [52.119.213.150]) (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 9E2B317556B for ; Wed, 3 Jul 2024 17:35:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=52.119.213.150 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720028106; cv=none; b=iz4fG7ycTxZDWJSZu7TQIJFgKkOK3Fi1q0qh49oDfyJk1NBMmEUmB5EeQZfrVZkMshSzn1lZcr4zi08juc+gho8GQEe03331tAcHs54+8Q454SIWBkhklo6F6LY/uPI2orNhHtOonApl0hM8fnK0OxfLUJ/tvSqtsnzwcCJcjWI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720028106; c=relaxed/simple; bh=l06SvAx10y5w/WW2XMiTPjF51PJgC3s5dbBuT2H9W1U=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=B8aKNGxuf2iIs8U31AzmbgEjRHwq7zklO31nN6PXLdfIAK2RIPwfzrcLiWqNF/Q4us8RRTIY8+6PqWaFYjiGhZIICRD1Yj71TD4TFzV6KKc09dmvQOr2eQrl9fFnZfX1FzZvIo0e2Ll1TUUmhkjmXdgjGh3V4VkOyfmThppmBFg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com; spf=pass smtp.mailfrom=amazon.co.uk; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b=bUtwtLOZ; arc=none smtp.client-ip=52.119.213.150 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=amazon.co.uk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="bUtwtLOZ" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1720028105; x=1751564105; h=message-id:date:mime-version:reply-to:subject:to:cc: references:from:in-reply-to:content-transfer-encoding; bh=b9HAF+WS9MkSfOWQwYRmuQh0tn+3sT67Es33DhKyTRg=; b=bUtwtLOZsnMbs7XPx6/zsTXyui/G1xhE0+EbsRSsZy17vKekQN9Am9mF qwiS0TmUOy6+bqrXHYyW0le+91U+cjIU2sfIPlUbYo9ClSyKKsG4XziBe r5v8CyJWTDSMuvABG1x9aKQ6w+7OnGleh38Rv7PJ+//YM3tk42ErNOQ6d I=; X-IronPort-AV: E=Sophos;i="6.09,182,1716249600"; d="scan'208";a="643425421" Received: from iad12-co-svc-p1-lb1-vlan3.amazon.com (HELO smtpout.prod.us-west-2.prod.farcaster.email.amazon.dev) ([10.43.8.6]) by smtp-border-fw-52002.iad7.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Jul 2024 17:35:02 +0000 Received: from EX19MTAEUC001.ant.amazon.com [10.0.10.100:28952] by smtpin.naws.eu-west-1.prod.farcaster.email.amazon.dev [10.0.19.28:2525] with esmtp (Farcaster) id c1c9f286-5528-40e7-9d33-3101ee09a74d; Wed, 3 Jul 2024 17:35:00 +0000 (UTC) X-Farcaster-Flow-ID: c1c9f286-5528-40e7-9d33-3101ee09a74d Received: from EX19D022EUC002.ant.amazon.com (10.252.51.137) by EX19MTAEUC001.ant.amazon.com (10.252.51.155) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1258.34; Wed, 3 Jul 2024 17:35:00 +0000 Received: from [192.168.6.66] (10.106.82.27) by EX19D022EUC002.ant.amazon.com (10.252.51.137) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1258.34; Wed, 3 Jul 2024 17:34:59 +0000 Message-ID: <923126dd-5f23-4f99-8327-9e8738540efb@amazon.com> Date: Wed, 3 Jul 2024 18:34:58 +0100 Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Reply-To: Subject: Re: [PATCH v7 06/14] KVM: Add memslot flag to let userspace force an exit on missing hva mappings To: David Matlack CC: Sean Christopherson , Anish Moorthy , , , , , , , , , , , Oliver Upton , , References: <20240215235405.368539-1-amoorthy@google.com> <20240215235405.368539-7-amoorthy@google.com> Content-Language: en-US From: Nikita Kalyazin Autocrypt: addr=kalyazin@amazon.com; keydata= xjMEY+ZIvRYJKwYBBAHaRw8BAQdA9FwYskD/5BFmiiTgktstviS9svHeszG2JfIkUqjxf+/N JU5pa2l0YSBLYWx5YXppbiA8a2FseWF6aW5AYW1hem9uLmNvbT7CjwQTFggANxYhBGhhGDEy BjLQwD9FsK+SyiCpmmTzBQJj5ki9BQkDwmcAAhsDBAsJCAcFFQgJCgsFFgIDAQAACgkQr5LK IKmaZPOR1wD/UTcn4GbLC39QIwJuWXW0DeLoikxFBYkbhYyZ5CbtrtAA/2/rnR/zKZmyXqJ6 ULlSE8eWA3ywAIOH8jIETF2fCaUCzjgEY+ZIvRIKKwYBBAGXVQEFAQEHQCqd7/nb2tb36vZt ubg1iBLCSDctMlKHsQTp7wCnEc4RAwEIB8J+BBgWCAAmFiEEaGEYMTIGMtDAP0Wwr5LKIKma ZPMFAmPmSL0FCQPCZwACGwwACgkQr5LKIKmaZPNCxAEAxwnrmyqSC63nf6hoCFCfJYQapghC abLV0+PWemntlwEA/RYx8qCWD6zOEn4eYhQAucEwtg6h1PBbeGK94khVMooF In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-ClientProxiedBy: EX19D009EUA002.ant.amazon.com (10.252.50.88) To EX19D022EUC002.ant.amazon.com (10.252.51.137) Hi David, On 11/03/2024 16:20, David Matlack wrote: > On Sun, Mar 10, 2024 at 9:46 PM Oliver Upton wrote: >>>> >>>> 2. What is your best guess as to when KVM userfault patches will be available, >>>> even if only in RFC form? >>> >>> We're aiming for the end of April for RFC with KVM/ARM support. >> >> Just to make sure everyone is read in on what this entails -- is this >> the implementation that only worries about vCPUs touching non-present >> memory, leaving the question of other UAPIs that consume guest memory >> (e.g. GIC/ITS table save/restore) up for further discussion? > > Yes. The initial version will only support returning to userspace on > invalid vCPU accesses with KVM_EXIT_MEMORY_FAULT. Non-vCPU accesses to > invalid pages (e.g. GIC/ITS table save/restore) will trigger an error > return from __gfn_to_hva_many() (which will cause the corresponding > ioctl to fail). It will be userspace's responsibility to clear the > invalid attribute before invoking those ioctls. > > For x86 we may need an blocking kernel-to-userspace notification > mechanism for code paths in the emulator, but we'd like to investigate > and discuss if there are any other cleaner alternatives before going > too far down that route. I wasn't able to locate any follow-ups on the LKML about this topic. May I know if you are still working on or planning to work on this? Thanks, Nikita