From: Wendy Liang <wendy.liang@xilinx.com>
To: jasowang@redhat.com, mst@redhat.com,
virtualization@lists.linux-foundation.org, ohad@wizery.com,
bjorn.andersson@linaro.org, linux-remoteproc@vger.kernel.org
Cc: Wendy Liang <jliang@xilinx.com>
Subject: [PATCH 0/2] Virtio ring works with DMA coherent memory
Date: Wed, 7 Dec 2016 22:59:11 -0800 [thread overview]
Message-ID: <1481180353-11139-1-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:[~2016-12-08 6:59 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-08 6:59 Wendy Liang [this message]
2016-12-08 6:59 ` [PATCH 1/2] virtio_ring: Do not call dma_map_page if sg is already mapped Wendy Liang
2016-12-08 16:46 ` Michael S. Tsirkin
2016-12-08 16:46 ` Michael S. Tsirkin
2016-12-09 18:19 ` Wendy Liang
2016-12-09 18:19 ` Wendy Liang
2016-12-08 6:59 ` [PATCH 2/2] rpmsg: DMA map sgs passed to virtio Wendy Liang
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