From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 8CA294ECFCD for ; Thu, 8 Jan 2026 14:04:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767881073; cv=none; b=OT/pbPEvRsK2KZ0o6o+TgSoewMOqxM/E2xZ/N1j3qMmCHHup3Dtkfg7br54uzxXp6N69sXnU5gZWlndFNxj6+uDdB8FTTHsDacgh1xFAYLGqNKxLRKA5M8JLyRWEWvx4G7w3oEtezP1f5gjfxCyXP8DnX56fG8vEFld/xFHlRr4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767881073; c=relaxed/simple; bh=yXMok8JlOEM2sgAIipul0a74lzFqWXRhO2Aov20FAgc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=fwJvSFbk3RkSNuLA7WMB4lIZlKoblziYy/fYYW+SNp4aEu/h1cXvLzqhorGf7hjr9DZNDIdNiBQFdvJ4uaxWJI/IqwszeCE6LKAM+4vTnVJ1jNUbrDqxLnnDkgex6sAhTGAoQkQmuqnotVpWtA0Hxfe92Y3tQ5pBdRSfiKb+kw0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=UF3RLuvY; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b=shfpwgPb; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="UF3RLuvY"; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b="shfpwgPb" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1767881070; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=FmGHhC+vkdZJgHO0r54G5/mI53k1eZnkbsYL2uSG2DQ=; b=UF3RLuvYJBY5RjSmvxQ6zCy4LCIq1tzeAReT9cIp+jzDXHSIA4JXqYkWxlZ4O1zgbTl154 1nNN9KiuDZU4d9Z1rTKvbwpYKi0chZFPJmensz/7eSzaVYN9ixJ8pZ9NFtaLQOJMHF6Xz0 TDmx7kkamKn+HUBwaJZQ9YpG1X4XqMw= Received: from mail-ej1-f70.google.com (mail-ej1-f70.google.com [209.85.218.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-518-ymHRsDaRONCPBBD8Hc_GKg-1; Thu, 08 Jan 2026 09:04:29 -0500 X-MC-Unique: ymHRsDaRONCPBBD8Hc_GKg-1 X-Mimecast-MFC-AGG-ID: ymHRsDaRONCPBBD8Hc_GKg_1767881068 Received: by mail-ej1-f70.google.com with SMTP id a640c23a62f3a-b771bfe9802so384501266b.1 for ; Thu, 08 Jan 2026 06:04:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=google; t=1767881068; x=1768485868; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=FmGHhC+vkdZJgHO0r54G5/mI53k1eZnkbsYL2uSG2DQ=; b=shfpwgPb9LiNC4RMyXNeaAydM+O4PgXrgayaVFh93s4USaWOAaWjZpVwiy1sXwxVba +joVYqHfHeZAptMJrIAHxN+Il8KeIwX8vLznxxcMIJ1fFQz9JXdXx2vk2a4I/AHdyxva cTYY9/tSUdMp1ijSF6MFKiXUxA6rpdXMRu7eAD38oCh7tocT1ncw0/5GVNMy5MP5ZtPS 5k7qSgFQaTfMXylcEdtmyZ4XyiK+iNaTqnFVtbMaa/dVgCM+4h99Mdg0JkPDzpZltGlK gsh2k9LQwfzbiZtioTg9D9HsFjFqKW67YV/ABUXh53UzuP7Rh+1eYW9ysm1SKRlaoP+9 3Tlw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1767881068; x=1768485868; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=FmGHhC+vkdZJgHO0r54G5/mI53k1eZnkbsYL2uSG2DQ=; b=XZwj/q/QE+4RGWe6z8qG+eaZUNuBYNlSlhm5CUfUKy/Sw3AV3pKCd2qrvYKv8H9irH eZPDOLTqnIXb/RsGXERLy3ICzloWp/Oqrwupt2z9r5rxnBGJiD58yVpyfohffPyv+JHj m6eOlVVyi5PcCLGmms0H29rrxOmFWnU5nPy/7aHYoMZs7Ws7X1gowz0FbmWbAREOddoM fEi9bKvIddVT+gnwWfrwudYKsdv4bKTdIIPHD8TydQ2JQvxLlq3AOsEpmbny8QtrWlwy QVh4//aSUKkZ9msHPYtENnvJu2D/c7I3Y16fZ7ZK9PxgxYjCUKpz7RPR541/T15CFlpO d+HQ== X-Forwarded-Encrypted: i=1; AJvYcCW2h8zgtpJt7aYSgPmCyK/LHZCEf1Y66MbVt6AjeqYhdU9OHNvM/pXjHNA/pkBoyrH7LomAlVc=@vger.kernel.org X-Gm-Message-State: AOJu0Yw2Y5xQX4eEvj3SAdmuPdRrcAh4Jxc1ioKQf7WfAKLPM8RRPQ0B ldyeiSuSDwRZMUgaDR4mjmR0nbUJNv9zJnfZqjwDUQgRHOP03AmdUnjnbSsS6KdJZoaKsnTI50V HtfsMrAt1U+1miZizRj+7sI9VhIGpSxauofl10oGRssrKdR59ZRB0ClJGnQ== X-Gm-Gg: AY/fxX6X6bbM/XerS7Q2mJyyDd0TptkysJuKCsku0m0c1v0PgE5tlppc7jdRT/w7sxU OsHaGwc4SKlvx9haRWW4eriqYvJMb7iHeFjkjvBmjtObvGANoKJXUnrvKy9zu1ste1Vx8V0zgRY DfURIsA201Q6Zt9wTzH4PieH81LF4Ks66o2LRWgK2s87HFKXnEZbJod5h1rhZ9I22IJdW1TCZFB 4ras17cqgSIdC7CX9V/a/O6ookmCFx+zyc0LOZz4H9DzCQtLbcirP3zV1SdZk+FZTCiLQMOah2I 1ZfmR+w+U4PgNFLA469qUORli4O/UcJvu2LfrtZ6Qv9r9+a4qIIuy4kwArkyNytHJWNOrvCVZnq 6rF43It8ZlpBu8eZO X-Received: by 2002:a17:907:3da6:b0:b7d:11ae:4006 with SMTP id a640c23a62f3a-b8444fd6743mr637892866b.52.1767881067706; Thu, 08 Jan 2026 06:04:27 -0800 (PST) X-Google-Smtp-Source: AGHT+IGgw/BdfC1kapmuRYU6+l1S1c4vqL+ygT6gHm7yV/BgYYGWFixI2eOd8lpv0XHKoQQX3Zl7xQ== X-Received: by 2002:a17:907:3da6:b0:b7d:11ae:4006 with SMTP id a640c23a62f3a-b8444fd6743mr637888166b.52.1767881067171; Thu, 08 Jan 2026 06:04:27 -0800 (PST) Received: from sgarzare-redhat ([193.207.223.215]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-b842a564284sm830039366b.62.2026.01.08.06.04.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 08 Jan 2026 06:04:26 -0800 (PST) Date: Thu, 8 Jan 2026 15:04:07 +0100 From: Stefano Garzarella To: "Michael S. Tsirkin" Cc: linux-kernel@vger.kernel.org, Cong Wang , Jonathan Corbet , Olivia Mackall , Herbert Xu , Jason Wang , Paolo Bonzini , Stefan Hajnoczi , Eugenio =?utf-8?B?UMOpcmV6?= , "James E.J. Bottomley" , "Martin K. Petersen" , Gerd Hoffmann , Xuan Zhuo , Marek Szyprowski , Robin Murphy , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Petr Tesarik , Leon Romanovsky , Jason Gunthorpe , Bartosz Golaszewski , linux-doc@vger.kernel.org, linux-crypto@vger.kernel.org, virtualization@lists.linux.dev, linux-scsi@vger.kernel.org, iommu@lists.linux.dev, kvm@vger.kernel.org, netdev@vger.kernel.org Subject: Re: [PATCH v2 07/15] vsock/virtio: fix DMA alignment for event_list Message-ID: References: Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: On Mon, Jan 05, 2026 at 03:23:17AM -0500, Michael S. Tsirkin wrote: >On non-cache-coherent platforms, when a structure contains a buffer >used for DMA alongside fields that the CPU writes to, cacheline sharing >can cause data corruption. > >The event_list array is used for DMA_FROM_DEVICE operations via >virtqueue_add_inbuf(). The adjacent event_run and guest_cid fields are >written by the CPU while the buffer is available, so mapped for the >device. If these share cachelines with event_list, CPU writes can >corrupt DMA data. > >Add __dma_from_device_group_begin()/end() annotations to ensure event_list >is isolated in its own cachelines. > >Signed-off-by: Michael S. Tsirkin >--- > net/vmw_vsock/virtio_transport.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > >diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c >index 8c867023a2e5..bb94baadfd8b 100644 >--- a/net/vmw_vsock/virtio_transport.c >+++ b/net/vmw_vsock/virtio_transport.c >@@ -17,6 +17,7 @@ > #include > #include > #include >+#include > #include > #include > #include >@@ -59,8 +60,9 @@ struct virtio_vsock { > */ > struct mutex event_lock; > bool event_run; >+ __dma_from_device_group_begin(); > struct virtio_vsock_event event_list[8]; >- >+ __dma_from_device_group_end(); Can we keep the blank line before `guest_cid` so that the comment before this section makes sense? (regarding the lock required to access these fields) Thanks, Stefano > u32 guest_cid; > bool seqpacket_allow; > >-- >MST >