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Groups > linux.kernel > #1259720
| From | Andy Lutomirski <luto@amacapital.net> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v4 2/6] virtio_ring: Support DMA APIs |
| Date | 2015-10-30 20:00 +0100 |
| Message-ID | <qpn46-WF-21@gated-at.bofh.it> (permalink) |
| References | <qp6wh-7Kj-3@gated-at.bofh.it> <qp6wi-7Kj-21@gated-at.bofh.it> <qpgFj-5Eg-5@gated-at.bofh.it> <qpgFk-5Eg-31@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Fri, Oct 30, 2015 at 5:05 AM, Christian Borntraeger
<borntraeger@de.ibm.com> wrote:
> Am 30.10.2015 um 13:01 schrieb Cornelia Huck:
>> On Thu, 29 Oct 2015 18:09:47 -0700
>> Andy Lutomirski <luto@kernel.org> wrote:
>>
>>> virtio_ring currently sends the device (usually a hypervisor)
>>> physical addresses of its I/O buffers. This is okay when DMA
>>> addresses and physical addresses are the same thing, but this isn't
>>> always the case. For example, this never works on Xen guests, and
>>> it is likely to fail if a physical "virtio" device ever ends up
>>> behind an IOMMU or swiotlb.
>>>
>>> The immediate use case for me is to enable virtio on Xen guests.
>>> For that to work, we need vring to support DMA address translation
>>> as well as a corresponding change to virtio_pci or to another
>>> driver.
>>>
>>> With this patch, if enabled, virtfs survives kmemleak and
>>> CONFIG_DMA_API_DEBUG.
>>>
>>> Signed-off-by: Andy Lutomirski <luto@kernel.org>
>>> ---
>>> drivers/virtio/Kconfig | 2 +-
>>> drivers/virtio/virtio_ring.c | 190 +++++++++++++++++++++++++++++++--------
>>> tools/virtio/linux/dma-mapping.h | 17 ++++
>>> 3 files changed, 172 insertions(+), 37 deletions(-)
>>> create mode 100644 tools/virtio/linux/dma-mapping.h
>>
>>> static void detach_buf(struct vring_virtqueue *vq, unsigned int head)
>>> {
>>> - unsigned int i;
>>> + unsigned int i, j;
>>> + u16 nextflag = cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_NEXT);
>>>
>>> /* Clear data ptr. */
>>> - vq->data[head] = NULL;
>>> + vq->desc_state[head].data = NULL;
>>>
>>> - /* Put back on free list: find end */
>>> + /* Put back on free list: unmap first-level descriptors and find end */
>>> i = head;
>>>
>>> - /* Free the indirect table */
>>> - if (vq->vring.desc[i].flags & cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_INDIRECT))
>>> - kfree(phys_to_virt(virtio64_to_cpu(vq->vq.vdev, vq->vring.desc[i].addr)));
>>> -
>>> - while (vq->vring.desc[i].flags & cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_NEXT)) {
>>> + while (vq->vring.desc[i].flags & nextflag) {
>>> + vring_unmap_one(vq, &vq->vring.desc[i]);
>>> i = virtio16_to_cpu(vq->vq.vdev, vq->vring.desc[i].next);
>>> vq->vq.num_free++;
>>> }
>>>
>>> + vring_unmap_one(vq, &vq->vring.desc[i]);
>>> vq->vring.desc[i].next = cpu_to_virtio16(vq->vq.vdev, vq->free_head);
>>> vq->free_head = head;
>>> +
>>> /* Plus final descriptor */
>>> vq->vq.num_free++;
>>> +
>>> + /* Free the indirect table, if any, now that it's unmapped. */
>>> + if (vq->desc_state[head].indir_desc) {
>>> + struct vring_desc *indir_desc = vq->desc_state[head].indir_desc;
>>> + u32 len = vq->vring.desc[head].len;
>>
>> This one needs to be virtio32_to_cpu(...) as well.
>
> Yes, just did the exact same change
> diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> index f269e1c..f2249df 100644
> --- a/drivers/virtio/virtio_ring.c
> +++ b/drivers/virtio/virtio_ring.c
> @@ -556,7 +556,7 @@ static void detach_buf(struct vring_virtqueue *vq, unsigned int head)
> /* Free the indirect table, if any, now that it's unmapped. */
> if (vq->desc_state[head].indir_desc) {
> struct vring_desc *indir_desc = vq->desc_state[head].indir_desc;
> - u32 len = vq->vring.desc[head].len;
> + u32 len = virtio32_to_cpu(vq->vq.vdev, vq->vring.desc[head].len);
>
> BUG_ON(!(vq->vring.desc[head].flags &
> cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_INDIRECT)));
>
>
> now it boots.
Thanks! I applied this to my tree. I won't send a new version quite
yet, though, to reduce inbox load.
--Andy
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Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
[PATCH v4 0/6] virtio core DMA API conversion Andy Lutomirski <luto@kernel.org> - 2015-10-30 02:20 +0100
[PATCH v4 6/6] virtio_pci: Use the DMA API Andy Lutomirski <luto@kernel.org> - 2015-10-30 02:20 +0100
Re: [PATCH v4 0/6] virtio core DMA API conversion Andy Lutomirski <luto@amacapital.net> - 2015-10-30 02:20 +0100
[PATCH v4 5/6] virtio_mmio: Use the DMA API Andy Lutomirski <luto@kernel.org> - 2015-10-30 02:20 +0100
[PATCH v4 3/6] virtio_pci: Use the DMA API Andy Lutomirski <luto@kernel.org> - 2015-10-30 02:20 +0100
[PATCH v4 4/6] virtio: Add improved queue allocation API Andy Lutomirski <luto@kernel.org> - 2015-10-30 02:20 +0100
[PATCH v4 2/6] virtio_ring: Support DMA APIs Andy Lutomirski <luto@kernel.org> - 2015-10-30 02:20 +0100
Re: [PATCH v4 2/6] virtio_ring: Support DMA APIs Cornelia Huck <cornelia.huck@de.ibm.com> - 2015-10-30 13:10 +0100
Re: [PATCH v4 2/6] virtio_ring: Support DMA APIs Christian Borntraeger <borntraeger@de.ibm.com> - 2015-10-30 13:10 +0100
Re: [PATCH v4 2/6] virtio_ring: Support DMA APIs Andy Lutomirski <luto@amacapital.net> - 2015-10-30 20:00 +0100
Re: [PATCH v4 0/6] virtio core DMA API conversion Christian Borntraeger <borntraeger@de.ibm.com> - 2015-10-30 11:00 +0100
Re: [PATCH v4 0/6] virtio core DMA API conversion "Michael S. Tsirkin" <mst@redhat.com> - 2015-11-09 13:20 +0100
Re: [PATCH v4 0/6] virtio core DMA API conversion Paolo Bonzini <pbonzini@redhat.com> - 2015-11-09 13:30 +0100
Re: [PATCH v4 0/6] virtio core DMA API conversion Benjamin Herrenschmidt <benh@kernel.crashing.org> - 2015-11-10 00:30 +0100
Re: [PATCH v4 0/6] virtio core DMA API conversion Andy Lutomirski <luto@amacapital.net> - 2015-11-10 01:50 +0100
Re: [PATCH v4 0/6] virtio core DMA API conversion Andy Lutomirski <luto@amacapital.net> - 2015-11-10 03:20 +0100
Re: [PATCH v4 0/6] virtio core DMA API conversion Benjamin Herrenschmidt <benh@kernel.crashing.org> - 2015-11-10 06:30 +0100
Re: [PATCH v4 0/6] virtio core DMA API conversion Andy Lutomirski <luto@amacapital.net> - 2015-11-10 06:40 +0100
Re: [PATCH v4 0/6] virtio core DMA API conversion Benjamin Herrenschmidt <benh@kernel.crashing.org> - 2015-11-10 11:40 +0100
Re: [PATCH v4 0/6] virtio core DMA API conversion "Michael S. Tsirkin" <mst@redhat.com> - 2015-11-10 13:50 +0100
Re: [PATCH v4 0/6] virtio core DMA API conversion Benjamin Herrenschmidt <benh@kernel.crashing.org> - 2015-11-10 21:40 +0100
Re: [PATCH v4 0/6] virtio core DMA API conversion Andy Lutomirski <luto@amacapital.net> - 2015-11-10 20:00 +0100
Re: [PATCH v4 0/6] virtio core DMA API conversion Benjamin Herrenschmidt <benh@kernel.crashing.org> - 2015-11-10 23:30 +0100
Re: [PATCH v4 0/6] virtio core DMA API conversion Andy Lutomirski <luto@amacapital.net> - 2015-11-11 00:50 +0100
Re: [PATCH v4 0/6] virtio core DMA API conversion Benjamin Herrenschmidt <benh@kernel.crashing.org> - 2015-11-11 01:50 +0100
Re: [PATCH v4 0/6] virtio core DMA API conversion Andy Lutomirski <luto@amacapital.net> - 2015-11-11 05:50 +0100
Re: [PATCH v4 0/6] virtio core DMA API conversion Benjamin Herrenschmidt <benh@kernel.crashing.org> - 2015-11-11 06:10 +0100
Re: [PATCH v4 0/6] virtio core DMA API conversion Andy Lutomirski <luto@amacapital.net> - 2015-11-10 06:40 +0100
Re: [PATCH v4 0/6] virtio core DMA API conversion Benjamin Herrenschmidt <benh@kernel.crashing.org> - 2015-11-10 07:30 +0100
Re: [PATCH v4 0/6] virtio core DMA API conversion Jan Kiszka <jan.kiszka@siemens.com> - 2015-11-10 09:20 +0100
Re: [PATCH v4 0/6] virtio core DMA API conversion Benjamin Herrenschmidt <benh@kernel.crashing.org> - 2015-11-10 04:10 +0100
Re: [PATCH v4 0/6] virtio core DMA API conversion Knut Omang <knut.omang@oracle.com> - 2015-11-10 10:50 +0100
Re: [PATCH v4 0/6] virtio core DMA API conversion Benjamin Herrenschmidt <benh@kernel.crashing.org> - 2015-11-10 11:50 +0100
Re: [PATCH v4 0/6] virtio core DMA API conversion Joerg Roedel <jroedel@suse.de> - 2015-11-10 11:30 +0100
Re: [PATCH v4 0/6] virtio core DMA API conversion Benjamin Herrenschmidt <benh@kernel.crashing.org> - 2015-11-10 20:40 +0100
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