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 BA448212557 for ; Tue, 30 Dec 2025 10:15:50 +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=1767089752; cv=none; b=L0dT6IYXS5MbFCtlYd6NpkC7XLzogMgH65pSoF6lhJKFejd2+rdEbHoJqXfJc610INdiP4KxnHWTk3wR2zmGobCAa49abPrgEkZLgAxegPkesszKlpU9pdH3JePNi+deiuNphVNRbtnjJlV6BJLXvyrCdqTrDkE70osws93DvHc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767089752; c=relaxed/simple; bh=LCt+6pV3SVXX+jVlhPofZ+B+PV2iA9I/7Ha5xrB3hCU=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition; b=St36WZMtz/9pEpuo79Y2iDmEGsM7VnOB6T//K9X5fbLNq4xnCPdqXEbefTbMHin/jg2ssrNKcvdWHVvJZpC1wt+ITr19ip1t0PYFmBbUDaMqw1KzUbMvmICGZHalFeKvUWzyJ4Aqft78Sbd+fi+P/xo4Ws5Kg5J83PY1OCjg4V4= 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=P0yYMVW3; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b=bQ/HbEYj; 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="P0yYMVW3"; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b="bQ/HbEYj" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1767089749; 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; bh=QPeHJm+twCiufdOXqLeCn+SgUmZXimx3Kj8OMbSgWcg=; b=P0yYMVW35jxYgBF3YWX+d5Ks1WvgEpHVbY7hSsHdHk78Zw0WyrCeBBSmS2yyK5oTbRjjF3 I2ThzC+UAqPDYagw+qh9Y0x6x56cCzUJauXeqWrqndmgRCxf/08HSGzrcABR2iQB8QGVxM 4lSXGaXGdADw9gUk4PbTfeYlI1of3DM= Received: from mail-wr1-f70.google.com (mail-wr1-f70.google.com [209.85.221.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-659-44A5UbFqPMW-mHa_C8s4Dg-1; Tue, 30 Dec 2025 05:15:48 -0500 X-MC-Unique: 44A5UbFqPMW-mHa_C8s4Dg-1 X-Mimecast-MFC-AGG-ID: 44A5UbFqPMW-mHa_C8s4Dg_1767089747 Received: by mail-wr1-f70.google.com with SMTP id ffacd0b85a97d-430ffa9fccaso7718805f8f.1 for ; Tue, 30 Dec 2025 02:15:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=google; t=1767089747; x=1767694547; darn=vger.kernel.org; h=content-disposition:mime-version:message-id:subject:cc:to:from:date :from:to:cc:subject:date:message-id:reply-to; bh=QPeHJm+twCiufdOXqLeCn+SgUmZXimx3Kj8OMbSgWcg=; b=bQ/HbEYjNkNw4GOqt29NjfpwNJkMUoztoEvr64Ppr8lbJ3224HO5X8wrOAe+mil+Pz Tz1I0PKlgmqhMtQFmBGBSCLC/Omr1qWBkrAkVME27WwwXQ/vtgA7j1IqAHRWqRWFRl2G /ns5g2z/FMVxRZEozM550fAkUewyL5nAUJj1T5/Z70GbdMjHTHLhG7+DiZfqEvKPctjV KVM6uHGAP0ULWx1FjNINl3cd7Gcx7vwi7I/xJ84jnZygb5VPe50x62PvVKLT60UjIM3v mGBb0I2g9F9gw0qbl+/IdaOhP4baFcH3/2DCOkfKmwfkVjObQk103KmD6GGz0GXvuTFS a/QQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1767089747; x=1767694547; h=content-disposition:mime-version:message-id:subject:cc:to:from:date :x-gm-gg:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=QPeHJm+twCiufdOXqLeCn+SgUmZXimx3Kj8OMbSgWcg=; b=dCf/ekA6xiBhSxj+v22SOpgTgvJ6/6BH8dI2L1Oyn22G8cC7KsQn5YHZAhbH0/HsuO ed9WIVhqPyLM6paj4FaZXPckKdffh7t1FT4SXlInVBL/Svf4/wyakjQl9KmiNi8SE3zI bxJgT65HtEeB3ZxtEYQXEkASj/QREFqphJO/C1YoiGHaGPWpKI2kaxMXPQkkPa6PexQ8 qVINbkcIyj8RyY/AdIXyMnF4yPY6SNlcr3gqFSrcu5PsC5Wbf5PIxPXm4oFoIWX6ha3P pskGfibaDOivlQc5iFwiIEJkYlPaXtE9PXciI+1v4AJjysj2sUOXjW0daIRFhcNTY2eR q1fw== X-Forwarded-Encrypted: i=1; AJvYcCVZcLbXAxWn3vSwwhzZdwsjDzT6StejgHLJu6QW1n4z4WdzIc2ZhEuqNzHjHgqO7xseUZQ=@vger.kernel.org X-Gm-Message-State: AOJu0YyLZXxTvcOhoQV1lP+H8OHsKvx/elqHZivoimoRTv5T8EU5cGm6 dTwkVxnD9ZfDGQnMWPawDpaHWHXK7WSrUxJolRdiOUbTM9F+CjGRR4GuTAFTHWIYa1khBa2tcJU 6mraaD6zNkBbiNaTzGAU1XNdlIqSn+P0C4FXEdoYDAjooIDX+/4Mr7g== X-Gm-Gg: AY/fxX5QpBZVdPLcQBUtIA3A6KlY4aF3Xqz5phrH8gFHFRy2jHNo5dSUiXskMsD73+M viGa7oM77pZtmStNIj9nybMmgWJ3jRV/sd4Cp6p3P82c+tNhoJButPepboxFBF/2ZhkTn1k5Nq7 db4csEuXf9Fj3IGXGgNp/hJ03Q89k2GoD+gls6iaNUWGvviGAGdeLm3jUXBM31On+/TpPDnDuuL HFfuMp1IotJVcGJTJvkuZQV+Jzq6aq4Wn/c8F3NKlQwSWEWU5V89vq6lkD1GUBYv24/d/Z4BlO0 i/4Gu2gd7ZxtQOWzGxyRZoBLPqL9RfGOKeK38GJ8BR1A5mtktojCXV2hBVBamfKoq0gNdXDVPh4 9o1aKQ2HN1Rmm3onmqtbyTsyN+PT2LJNs3Q== X-Received: by 2002:a05:6000:2503:b0:431:a33:d872 with SMTP id ffacd0b85a97d-4324e4c1219mr30005604f8f.8.1767089746604; Tue, 30 Dec 2025 02:15:46 -0800 (PST) X-Google-Smtp-Source: AGHT+IEbvOFHJ91a0TKLxq+k7tMABBS8U1GQCYZPCELRU5Zsc1Gaj+GYCwYcD6RmChYOtX8+5x3fqQ== X-Received: by 2002:a05:6000:2503:b0:431:a33:d872 with SMTP id ffacd0b85a97d-4324e4c1219mr30005566f8f.8.1767089746108; Tue, 30 Dec 2025 02:15:46 -0800 (PST) Received: from redhat.com (IGLD-80-230-31-118.inter.net.il. [80.230.31.118]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-4324e9ba877sm67681523f8f.0.2025.12.30.02.15.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 30 Dec 2025 02:15:45 -0800 (PST) Date: Tue, 30 Dec 2025 05:15:42 -0500 From: "Michael S. Tsirkin" To: linux-kernel@vger.kernel.org Cc: 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 , Stefano Garzarella , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Petr Tesarik , Leon Romanovsky , Jason Gunthorpe , 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: [PATCH RFC 00/13] fix DMA aligment issues around virtio Message-ID: Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Mailer: git-send-email 2.27.0.106.g8ac3dc51b1 X-Mutt-Fcc: =sent Cong Wang reported dma debug warnings with virtio-vsock and proposed a patch, see: https://lore.kernel.org/all/20251228015451.1253271-1-xiyou.wangcong@gmail.com/ however, the issue is more widespread. This is an attempt to fix it systematically. Note: i2c and gio might also be affected, I am still looking into it. Help from maintainers welcome. Early RFC, compile tested only. Sending for early feedback/flames. Cursor/claude used liberally mostly for refactoring, and english. DMA maintainers, could you please confirm the DMA core changes are ok with you? Thanks! Michael S. Tsirkin (13): dma-mapping: add __dma_from_device_align_begin/end docs: dma-api: document __dma_align_begin/end dma-mapping: add DMA_ATTR_CPU_CACHE_CLEAN docs: dma-api: document DMA_ATTR_CPU_CACHE_CLEAN dma-debug: track cache clean flag in entries virtio: add virtqueue_add_inbuf_cache_clean API vsock/virtio: fix DMA alignment for event_list vsock/virtio: use virtqueue_add_inbuf_cache_clean for events virtio_input: fix DMA alignment for evts virtio_scsi: fix DMA cacheline issues for events virtio-rng: fix DMA alignment for data buffer virtio_input: use virtqueue_add_inbuf_cache_clean for events vsock/virtio: reorder fields to reduce struct padding Documentation/core-api/dma-api-howto.rst | 42 +++++++++++++ Documentation/core-api/dma-attributes.rst | 9 +++ drivers/char/hw_random/virtio-rng.c | 2 + drivers/scsi/virtio_scsi.c | 18 ++++-- drivers/virtio/virtio_input.c | 5 +- drivers/virtio/virtio_ring.c | 72 +++++++++++++++++------ include/linux/dma-mapping.h | 17 ++++++ include/linux/virtio.h | 5 ++ kernel/dma/debug.c | 26 ++++++-- net/vmw_vsock/virtio_transport.c | 8 ++- 10 files changed, 172 insertions(+), 32 deletions(-) -- MST