From: Christoph Hellwig <hch@lst.de>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Joerg Roedel <joro@8bytes.org>, Jason Wang <jasowang@redhat.com>,
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 <jroedel@suse.de>
Subject: Re: [PATCH 1/3] swiotlb: Export maximum allocation size
Date: Tue, 15 Jan 2019 14:05:36 +0100 [thread overview]
Message-ID: <20190115130536.GA28364@lst.de> (raw)
In-Reply-To: <20190114165800-mutt-send-email-mst@kernel.org>
On Mon, Jan 14, 2019 at 04:59:27PM -0500, Michael S. Tsirkin wrote:
> On Mon, Jan 14, 2019 at 03:49:07PM -0500, Konrad Rzeszutek Wilk wrote:
> > On Fri, Jan 11, 2019 at 10:12:31AM +0100, Joerg Roedel wrote:
> > > On Thu, Jan 10, 2019 at 12:02:05PM -0500, Konrad Rzeszutek Wilk wrote:
> > > > Why not use swiotlb_nr_tbl ? That is how drivers/gpu/drm use to figure if they
> > > > need to limit the size of pages.
> > >
> > > That function just exports the overall size of the swiotlb aperture, no?
> > > What I need here is the maximum size for a single mapping.
> >
> > Yes. The other drivers just assumed that if there is SWIOTLB they would use
> > the smaller size by default (as in they knew the limitation).
> >
> > But I agree it would be better to have something smarter - and also convert the
> > DRM drivers to piggy back on this.
> >
> > Or alternatively we could make SWIOTLB handle bigger sizes..
>
>
> Just a thought: is it a good idea to teach blk_queue_max_segment_size
> to get the dma size? This will help us find other devices
> possibly missing this check.
Yes, we should. Both the existing DMA size communicated through dma_params
which is set by the driver, and this new DMA-ops exposed one which needs
to be added. I'm working on some preliminary patches for the first part,
as I think I introduced a bug related to that in the SCSI layer in 5.0..
next prev parent reply other threads:[~2019-01-15 13:05 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-10 13:44 [PATCH 0/3] Fix virtio-blk issue with SWIOTLB Joerg Roedel
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 [this message]
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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