From: Christoph Hellwig <hch@infradead.org>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>,
Maxime Coquelin <maxime.coquelin@redhat.com>,
jasowang@redhat.com, xuanzhuo@linux.alibaba.com,
xieyongji@bytedance.com, axboe@kernel.dk,
gregkh@linuxfoundation.org, brauner@kernel.org,
lstoakes@gmail.com, virtualization@lists.linux.dev,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
david.marchand@redhat.com
Subject: Re: [PATCH] vduse: implement DMA sync callbacks
Date: Fri, 23 Feb 2024 00:03:01 -0800 [thread overview]
Message-ID: <ZdhRNeJRo1UaZt2F@infradead.org> (raw)
In-Reply-To: <20240222152541-mutt-send-email-mst@kernel.org>
On Thu, Feb 22, 2024 at 03:29:10PM -0500, Michael S. Tsirkin wrote:
> In a sense ... but on the other hand, the "fake DMA" metaphor seems to
> work surprisingly well, like in this instance - internal bounce buffer
> looks a bit like non-coherent DMA. A way to make this all prettier
> would I guess be to actually wrap all of DMA with virtio wrappers which
> would all go if () dma_... else vduse_...; or something to this end. A
> lot of work for sure, and is it really worth it? if the only crazy
> driver is vduse I'd maybe rather keep the crazy hacks local there ...
Well, vduse is the only driver that does this hack - we had a few more
and we got rid of it. It basically is the only thing preventing us
from doing direct calls into the iommu code and compile out dma_ops
entirely for non-Xen builds on the common architectures.
So yes, I'd really like to see it gone rather sooner than later.
prev parent reply other threads:[~2024-02-23 8:03 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-19 17:06 [PATCH] vduse: implement DMA sync callbacks Maxime Coquelin
2024-02-20 9:01 ` Christoph Hellwig
2024-02-21 8:47 ` Maxime Coquelin
2024-02-22 20:29 ` Michael S. Tsirkin
2024-02-23 8:03 ` Christoph Hellwig [this message]
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