From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 EDFD040F8E8 for ; Thu, 8 Jan 2026 14:18:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767881908; cv=none; b=FrAiMQI/dLWFcLYVWDgf2md+ZKbA6rGRDGmmdslpzSf/bSHMtxkmXp8qoQUFGfIx85tQikLmgonyXUIYPIaS30QQegswtHdI6joPhO/pcAt7ClFPtHrpXUeiL/oOcSOy+Ny87JOM49n5P8UPtpldKKlF98k0dhETtt91BwAB8dQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767881908; c=relaxed/simple; bh=SJZE4KTbW/+usatKP1Sr4PPUbIQlx0UuUvCG+8I8T1A=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Ls3nxnUJyESdrGT7T92/SXVdC+r+oYBFZoV/kawkMKotVkU0BAx01n8z+f8BSzxgSHOI/7vGjG6hxBXzNLnWZIHHwV12QdC3sVhRNBN5pIyAyySl/WHgKUAC8rH8+QMcgexX3FWXJ1QVjWKwLz/B2UCcHEA/8R0tSpoXmtmfOGU= 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=R3wFfw2A; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b=JC7gymIB; arc=none smtp.client-ip=170.10.129.124 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="R3wFfw2A"; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b="JC7gymIB" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1767881906; 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=rqZiGHlphsIXyTZBYYB1RUSRDC4SlQ7PgnKFPfthJ9A=; b=R3wFfw2ApP7SxgdllfSlk6Xr+mhi7oYYZcbmMIjmw1iabWKHleyN1zTXPTfqz5F+1B71u+ trFMeqMvQD5sOnW6N8WIqkuB9xsjXW5myFh4/Z8gnQU4aFc6LmZ3gGj1//PVyqIQdO874e NdQSWOClviM6Qrt68NZf050vLdies4o= 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-169-hMA5W8MHNt-KBMKIDeN7DQ-1; Thu, 08 Jan 2026 09:18:25 -0500 X-MC-Unique: hMA5W8MHNt-KBMKIDeN7DQ-1 X-Mimecast-MFC-AGG-ID: hMA5W8MHNt-KBMKIDeN7DQ_1767881904 Received: by mail-ej1-f70.google.com with SMTP id a640c23a62f3a-b7387d9bbb2so218789066b.0 for ; Thu, 08 Jan 2026 06:18:24 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=google; t=1767881904; x=1768486704; 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=rqZiGHlphsIXyTZBYYB1RUSRDC4SlQ7PgnKFPfthJ9A=; b=JC7gymIBcxw/OfysV7sn+9xCEjaiOlZZ2Karv2EGjt7Br17mK6QduTkk8Pfc6XC3xq h0MDzXa08eyZOWQQzhqyBoM47HzUGT+8E8El24O5Th9PM437FB9OEtaD2AnQmm+Oobcy dMXFPNxAOxEVsZze9JRT8tH1k7IlNqdWBUo5y8ukWQ/xsziWlP9NJnHNL87T4Y6/IfD2 6DaGSuE0H1yqdQZrwftzB/Ok/AvI0z0CkFCWhPt4Jbl2w6wSXTZWYht48b/sVh1r7SSB RlerkxeIm8yfGt6Yn5oqI6mUob7y3Xs83nKbUKJ6FYmysoIM/Sm/Xve1j32jD2WUUWng OwOQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1767881904; x=1768486704; 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=rqZiGHlphsIXyTZBYYB1RUSRDC4SlQ7PgnKFPfthJ9A=; b=ZsmwCFV7fj0mSf/FFO+zxEyjMKztPqrywG4pDDa3A4LO03b1QGeXEgj8aUXMi24KjJ 7C9ijsbRySKgWxzMgWMOh7+vroZpcongBuZ594YaxoqjHFZPbjsuHb1ZYIWiA85CoRu/ JASvqUMYgGsQaUIgM9iO99Ix5uZv4K6Y9u8fk+cAh5v+OQcmdbNMc+/KxKt+kH+U6fcl dhG2gcZ8UtjCj1ApxhYw/mZMUvUGkQv3Yak90HOvbD994mfEFsQUC05ZPxrz7qz8G2Fa g0X9NeNGKmKyEaEHZdePGzM6hIumR+5VpZPqmJasdA614iUqSOtN7HiHxgWER/uQg3A5 SV6g== X-Forwarded-Encrypted: i=1; AJvYcCWd5Rp09j8e8E2QitQDOlZ8EuEHVaF+1xMblCjPhVen43RrsdbQWeZxxaCo0lR1HGB57xWYqxFxB048WcM=@vger.kernel.org X-Gm-Message-State: AOJu0Yyrjsp+ciHi4tpo8rZpCDrdo2xNoAsNahysjESXqzC1TRMBaCwP J4808J7UH2g/ATzGlcwVCOzE8Z+1m+vifTze39+szkbJpVXPH4FIQqzZPExDtB8/CMlt8VirC+F 8Y3EJjj2d5LaQVIeFXHe4h5QF/3fzaMMJVYBEQAUkDXMjxqEABUZf6qU3ERZ+twjsrQ== X-Gm-Gg: AY/fxX4F0SyXbc+aR1/trvKDpE1vCCIw3ydt4Cj4lZE/1ZyKomUnBxlTBBh4lZXReMT hm/03LkI8v/WZrr/NdykCwMwYE69xwYWx6WfzoePt7emDQc0Ct30va7+zY7UEtQUlByn7fANkmd U1MNOmTBuWnl7Z3GUSLgqpvtEwQt8bOc+rNbjiq75fef5OkC4j4I5L59+to6YAXdnOrruzqM+xX FxXWEXd7va3tJmETf+e1VZAoG1RSqTk3Spx6lBPqgnq23inMGYBumG6CajMngj2zMeKgb6VS6Mp 3dFBWrj0+m91hrctIEEW8e03lwcpSYfv0PxeZBDxL2sQtzsK5fl4+Ic1dKJWjHW1QVoDGoY+plv 9Q6jKokBCopKrTC4h X-Received: by 2002:a17:907:2d07:b0:b84:1fc7:944b with SMTP id a640c23a62f3a-b8445066498mr627907666b.58.1767881903672; Thu, 08 Jan 2026 06:18:23 -0800 (PST) X-Google-Smtp-Source: AGHT+IH3Dxa4w6bRkF+MtZ8LKCNuWLpqie07t2Imxvb7EeEx+3jZGwolIwvKYG0CWJg5J8bgXET92Q== X-Received: by 2002:a17:907:2d07:b0:b84:1fc7:944b with SMTP id a640c23a62f3a-b8445066498mr627904166b.58.1767881902999; Thu, 08 Jan 2026 06:18:22 -0800 (PST) Received: from sgarzare-redhat ([193.207.223.215]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-b842a22ff58sm817309166b.6.2026.01.08.06.18.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 08 Jan 2026 06:18:22 -0800 (PST) Date: Thu, 8 Jan 2026 15:18:13 +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: <20260108090639-mutt-send-email-mst@kernel.org> Precedence: bulk X-Mailing-List: linux-crypto@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: <20260108090639-mutt-send-email-mst@kernel.org> On Thu, Jan 08, 2026 at 09:07:53AM -0500, Michael S. Tsirkin wrote: >On Thu, Jan 08, 2026 at 03:04:07PM +0100, Stefano Garzarella wrote: >> 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 > >A follow up patch re-introduces it, so I don't think it matters? Yes, I saw it later. Of course I don't want you to resend the whole series just for this. So if you have to resend the series for other reasons, I would avoid removing the line here because I don't see any value on removing it and add back later. In both cases: Acked-by: Stefano Garzarella > >> > u32 guest_cid; >> > bool seqpacket_allow; >> > >> > -- >> > MST >> > >