From: Joerg Roedel <joro@8bytes.org>
To: "Michael S . Tsirkin" <mst@redhat.com>,
Jason Wang <jasowang@redhat.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Jens Axboe <axboe@kernel.dk>,
virtualization@lists.linux-foundation.org,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
iommu@lists.linux-foundation.org, jfehlig@suse.com,
jon.grimm@amd.com, brijesh.singh@amd.com, hch@lst.de,
Joerg Roedel <joro@8bytes.org>
Subject: [PATCH 0/3] Fix virtio-blk issue with SWIOTLB
Date: Thu, 10 Jan 2019 14:44:30 +0100 [thread overview]
Message-ID: <20190110134433.15672-1-joro@8bytes.org> (raw)
Hi,
there is a problem with virtio-blk driven devices when
virtio-ring uses SWIOTLB through the DMA-API. This happens
for example in AMD-SEV enabled guests, where the guest RAM
is mostly encrypted and all emulated DMA has to happen
to/from the SWIOTLB aperture.
The problem is a limitation of the SWIOTLB implementation,
which does not support allocations larger than 256kb. When
the virtio-blk driver tries to read/write a block larger
than that, the allocation of the dma-handle fails and an IO
error is reported.
This patch-set adds a check to the virtio-code whether it
might be using SWIOTLB bounce buffering and limits the
maximum segment size in the virtio-blk driver in this case,
so that it doesn't try to do larger reads/writes.
Please review.
Thanks,
Joerg
Joerg Roedel (3):
swiotlb: Export maximum allocation size
virtio: Introduce virtio_max_dma_size()
virtio-blk: Consider virtio_max_dma_size() for maximum segment size
drivers/block/virtio_blk.c | 10 ++++++----
drivers/virtio/virtio_ring.c | 11 +++++++++++
include/linux/swiotlb.h | 12 ++++++++++++
include/linux/virtio.h | 2 ++
4 files changed, 31 insertions(+), 4 deletions(-)
--
2.17.1
next reply other threads:[~2019-01-10 13:44 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-10 13:44 Joerg Roedel [this message]
2019-01-10 13:44 ` [PATCH 1/3] swiotlb: Export maximum allocation size Joerg Roedel
2019-01-10 17:02 ` Konrad Rzeszutek Wilk
2019-01-11 9:12 ` Joerg Roedel
2019-01-14 20:49 ` Konrad Rzeszutek Wilk
2019-01-14 21:59 ` Michael S. Tsirkin
2019-01-15 13:05 ` Christoph Hellwig
2019-01-10 13:44 ` [PATCH 2/3] virtio: Introduce virtio_max_dma_size() Joerg Roedel
2019-01-10 13:44 ` [PATCH 3/3] virtio-blk: Consider virtio_max_dma_size() for maximum segment size Joerg Roedel
2019-01-10 13:59 ` [PATCH 0/3] Fix virtio-blk issue with SWIOTLB Christoph Hellwig
2019-01-10 14:26 ` Joerg Roedel
2019-01-11 3:29 ` Jason Wang
2019-01-11 9:15 ` Joerg Roedel
2019-01-14 9:41 ` Jason Wang
2019-01-14 9:50 ` Christoph Hellwig
2019-01-14 12:41 ` Jason Wang
2019-01-14 18:20 ` Michael S. Tsirkin
2019-01-14 19:09 ` Singh, Brijesh
2019-01-14 19:12 ` Robin Murphy
2019-01-14 20:22 ` Christoph Hellwig
2019-01-14 20:29 ` Michael S. Tsirkin
2019-01-14 20:19 ` Christoph Hellwig
2019-01-14 20:48 ` Michael S. Tsirkin
2019-01-15 13:09 ` Christoph Hellwig
2019-01-15 8:37 ` Joerg Roedel
2019-01-15 13:20 ` Christoph Hellwig
2019-01-16 14:16 ` Michael S. Tsirkin
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