From: Wendy Liang <wendy.liang@xilinx.com>
To: ohad@wizery.com, bjorn.andersson@linaro.org,
linux-remoteproc@vger.kernel.org, mst@redhat.com,
jasowang@redhat.com, virtualization@lists.linux-foundation.org
Cc: Wendy Liang <jliang@xilinx.com>
Subject: [RFC LINUX PATCH 0/2] Virtio ring works with DMA coherent memory
Date: Tue, 6 Dec 2016 10:21:28 -0800 [thread overview]
Message-ID: <1481048488-1026-1-git-send-email-jliang@xilinx.com> (raw)
RPMsg uses dma_alloc_coherent() to allocate memory to shared with the remote.
In this case, as there is no pages setup in the dma_alloc_coherent(),
we cannot get the physical address back from the virtual address, and thus,
we can set the sg_dma_addr to store the DMA address and mark it already DMA
mapped.
When virtio vring sees the sg_dma_addr is ready set, do not call dma_map_page().
The issue was once discussed here:
http://virtualization.linux-foundation.narkive.com/CfVP32Vy/rfc-0-4-rpmsg-fix-init-of-dma-able-virtqueues
Edgar E. Iglesias (1):
rpmsg: DMA map sgs passed to virtio
Wendy Liang (1):
virtio_ring: Do not call dma_map_page if sg is already mapped.
drivers/rpmsg/virtio_rpmsg_bus.c | 22 +++++++++++++++++++---
drivers/virtio/virtio_ring.c | 6 ++++++
2 files changed, 25 insertions(+), 3 deletions(-)
--
1.9.1
next reply other threads:[~2016-12-06 18:21 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-06 18:21 Wendy Liang [this message]
2016-12-08 3:18 ` [RFC LINUX PATCH 0/2] Virtio ring works with DMA coherent memory Jason Wang
2016-12-08 5:57 ` Jiaying Liang
-- strict thread matches above, loose matches on Subject: below --
2016-12-06 18:08 Wendy Liang
2016-11-22 0:32 Wendy Liang
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