Re: [PATCH 2/3] virtio_ring: Support DMA APIs

2015-10-27 Thread Andy Lutomirski
On Tue, Oct 27, 2015 at 7:21 PM, Joerg Roedel wrote: > On Tue, Oct 27, 2015 at 07:13:56PM -0700, Andy Lutomirski wrote: >> On Tue, Oct 27, 2015 at 7:06 PM, Joerg Roedel wrote: >> > Hi Andy, >> > >> > On Tue, Oct 27, 2015 at 06:17:09PM -0700, Andy Lutomirski wrote: >> >> From: Andy Lutomirski >>

Re: [PATCH 2/3] virtio_ring: Support DMA APIs

2015-10-27 Thread Andy Lutomirski
On Tue, Oct 27, 2015 at 7:27 PM, Christian Borntraeger wrote: > Am 28.10.2015 um 10:17 schrieb Andy Lutomirski: > @@ -423,27 +522,42 @@ EXPORT_SYMBOL_GPL(virtqueue_kick); >> >> static void detach_buf(struct vring_virtqueue *vq, unsigned int head) >> { >> - unsigned int i; >> + unsigned i

Re: [PATCH 2/3] virtio_ring: Support DMA APIs

2015-10-27 Thread Christian Borntraeger
Am 28.10.2015 um 10:17 schrieb Andy Lutomirski: @@ -423,27 +522,42 @@ EXPORT_SYMBOL_GPL(virtqueue_kick); > > 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

Re: [PATCH 2/3] virtio_ring: Support DMA APIs

2015-10-27 Thread Joerg Roedel
On Tue, Oct 27, 2015 at 07:13:56PM -0700, Andy Lutomirski wrote: > On Tue, Oct 27, 2015 at 7:06 PM, Joerg Roedel wrote: > > Hi Andy, > > > > On Tue, Oct 27, 2015 at 06:17:09PM -0700, Andy Lutomirski wrote: > >> From: Andy Lutomirski > >> > >> virtio_ring currently sends the device (usually a hype

Re: [PATCH 2/3] virtio_ring: Support DMA APIs

2015-10-27 Thread Andy Lutomirski
On Tue, Oct 27, 2015 at 7:06 PM, Joerg Roedel wrote: > Hi Andy, > > On Tue, Oct 27, 2015 at 06:17:09PM -0700, Andy Lutomirski wrote: >> From: Andy Lutomirski >> >> virtio_ring currently sends the device (usually a hypervisor) >> physical addresses of its I/O buffers. This is okay when DMA >> add

Re: [PATCH 2/3] virtio_ring: Support DMA APIs

2015-10-27 Thread Joerg Roedel
Hi Andy, On Tue, Oct 27, 2015 at 06:17:09PM -0700, Andy Lutomirski wrote: > From: Andy Lutomirski > > 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'

[PATCH 2/3] virtio_ring: Support DMA APIs

2015-10-27 Thread Andy Lutomirski
From: Andy Lutomirski 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