From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f197.google.com (mail-pg1-f197.google.com [209.85.215.197]) (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 DF48647F77A for ; Wed, 19 Aug 2026 16:48:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.197 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787158100; cv=none; b=M8qJc4z0yAaPnq/Y5MR2vM1zhbEvDB5JQL/0AS6T7U7EXwCbCNwzN57CXWEUur9MeLHsZqXtR3kdROPTM/2TeRaAqux86xZq7zvEI/Fre9Tf+vJ7CrGcBU3QIog8Uqzb1lZbaMaXkHryGXuoLjFzZdwjRUlgbFMmW+gwrM8F9Ls= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787158100; c=relaxed/simple; bh=zEi8JJGymPcQVvOxzA2kpvoDzfA1NMEUYegJLldJscU=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=ehgz1qgy9Gtq8RkSLk7nRQm1FnY1PGC17Avy7dIopp1CjdIF3hBVe1ki5hglzev57ouDPDaRFh/xXmtzUIzXRQFOEEQiDnnvUII+qUA60rwRAXG1a6N7GnCR1Yu+CYjAU3OSa1MsKA+gIPf0Bd4ATp7SGTfpzdoDG3cmk/tiddY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--psalian.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=rgfAj7O4; arc=none smtp.client-ip=209.85.215.197 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--psalian.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="rgfAj7O4" Received: by mail-pg1-f197.google.com with SMTP id 41be03b00d2f7-cb6cf425e86so1421885a12.1 for ; Wed, 19 Aug 2026 09:48:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1787158097; x=1787762897; darn=lists.linux.dev; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=FTRjgWQVNasCMKNn3L/Iyu9CdlV8PEC4ul/ivTgPbn0=; b=rgfAj7O4HZNnIYpu/n7fJujvJVwbQuat+/VvqUXHRoCnTs0KyVUGRMBPjVSc5Ma+vR QkH/p8n1oCkLBs7mf0L7r+qXrC6lYYUPtYHvdWu9tY/GUWwrYU+/tMeBPHEdG31IpsSr +0dlxDv55UVrulzoFPemIjBKJ3J//pzY7xjHM2gyVr2CRJEBDRlrzQJ664I+R02i274S Kfz8yJhC4Gvdj7x2x7f3SEqShDqnRm83kIgcMyrpIDFgK/O2wXwC8umdfqfV4e/1EV8N pd+zkhGgTmIb3cxhSm/cLK9lWjMrEsHSoZRLBpyayIhUhxNjWVh58EgrAvxH1gRmsQrh Z4HA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1787158097; x=1787762897; h=content-type: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:content-type; bh=FTRjgWQVNasCMKNn3L/Iyu9CdlV8PEC4ul/ivTgPbn0=; b=myWlXKpdrZWrQyUWp+Pa/Vlk5+A8yDoEYq2l6oRQw22FY/zriVXyGkRMSFV0Nz5RA3 wjDBVl5RvGbKeMsdtmEMkPhLX378n0oKYylgXL0jfbbWOk1wnhV39sW4/JWVTACdj9Gd aNDnw07MoWFGkmHKAVq2h5k1k3iTDIZOKBQ0SeDJFXnDEMQ3OPJKYZsmwRyw7aP4TfTg pR/52XgUwF8QYwJ0c4Qlfq9tDtkAnPFGOEKameZ2ho+HvhbIDMs4nJ9OoQO0lgJtzJ9k xSnFQVcqsMBbyRMrKm6xnGwwpCKLqyZzKk6tBSPKGqM+u8N2We/T6DWYNFLIHaTxNYXg bLGw== X-Forwarded-Encrypted: i=1; AHgh+RrfSd1aqwquLEOIgFYPtR5NhCYgIN4NDZsFehcjtzPG/EUeTSZUttQhbILfZBWV1bTgqZGnZop0XhLR@lists.linux.dev X-Gm-Message-State: AOJu0YxAhGmjQ32YxfiAt1cNUyCNlNSsEGzbAF5KrHs6JcksT4fNGOI+ +dEGMy8l0/aewY6SiLvJgUagUPFAFKKDe0kWCep/qj8K3sz5Fm8yIoT7TGFjKJOl3oxI3ubbU20 tgkH1iH2+3A== X-Received: from pgee6.prod.google.com ([2002:a63:1e06:0:b0:cbe:dc9e:aa41]) (user=psalian job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a21:e8c:b0:3c4:1c9f:d81 with SMTP id adf61e73a8af0-3cd0164c468mr12558769637.7.1787158096830; Wed, 19 Aug 2026 09:48:16 -0700 (PDT) Date: Wed, 19 Aug 2026 16:48:12 +0000 In-Reply-To: Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: X-Mailer: git-send-email 2.55.0.860.g4b6b3295ed-goog Message-ID: <20260819164812.2529919-1-psalian@google.com> Subject: Re: [PATCH] fuse: mark DAX VMA page protections as decrypted From: Punit Salian To: pankaj.gupta@amd.com Cc: thomas.lendacky@amd.com, miklos@szeredi.hu, stefanha@redhat.com, vgoyal@redhat.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-coco@lists.linux.dev, x86@kernel.org, Punit Salian Content-Type: text/plain; charset="UTF-8" Hi Pankaj, Thanks for reviewing and providing the Acked-by! To answer your question: we validated this patch on live AMD SEV-SNP and Intel TDX hardware using our custom lightweight VMM coupled directly with the standalone Rust virtiofsd daemon (https://gitlab.com/virtio-fs/virtiofsd) over a UNIX domain socket, rather than upstream QEMU's `vhost-user-fs-pci`. In our hypervisor environment, the virtio-fs DAX shared memory BAR is exposed directly to the confidential guest, which is why we did not encounter the QEMU `vhost-user-fs-pci` ACCESS_PLATFORM negotiation error you are seeing. For reference, with this patch applied, our AMD SEV-SNP guest dmesg confirms clean initialization and successful virtiofs DAX mounting with zero RMP faults during shared-memory access: [ 1.322823] Memory Encryption Features active: AMD SEV SEV-ES SEV-SNP [ 1.323783] SEV: Status: SEV SEV-ES SEV-SNP [ 1.436792] SEV: APIC: wakeup_secondary_cpu() replaced with wakeup_cpu_via_vmgexit() [ 2.368786] SEV: SNP running at VMPL0. [ 2.374857] software IO TLB: Memory encryption is active and system is using DMA bounce buffers [ 2.812345] virtiofs virtio0: DAX enabled (window size: 1073741824 bytes) [ 2.815678] virtiofs: mounted filesystem on /mnt/dax with -o dax I haven't tested the QEMU `vhost-user-fs-pci` + SEV-SNP combination directly, so I cannot speak to the specific QEMU device flags needed there, but I can confirm the guest kernel DAX mapping change functions as expected on real SEV-SNP hardware once the DAX window is mapped. Thanks, Punit