Re: [PATCH 0/3] virtio-net: inline header support

2012-10-12 Thread Cornelia Huck
On Fri, 12 Oct 2012 09:07:46 +1030 Rusty Russell wrote: > "Michael S. Tsirkin" writes: > > On Thu, Oct 11, 2012 at 10:33:31AM +1030, Rusty Russell wrote: > >> OK. Well, Anthony wants qemu to be robust in this regard, so I am > >> tempted to rework all the qemu drivers to handle arbitrary layout

Re: [PATCH 0/3] virtio-net: inline header support

2012-10-12 Thread Paolo Bonzini
Il 12/10/2012 00:37, Rusty Russell ha scritto: > "Michael S. Tsirkin" writes: >> On Thu, Oct 11, 2012 at 10:33:31AM +1030, Rusty Russell wrote: >>> OK. Well, Anthony wants qemu to be robust in this regard, so I am >>> tempted to rework all the qemu drivers to handle arbitrary layouts. >>> They co

Re: [PATCH 0/3] virtio-net: inline header support

2012-10-11 Thread Rusty Russell
"Michael S. Tsirkin" writes: > On Thu, Oct 11, 2012 at 10:33:31AM +1030, Rusty Russell wrote: >> OK. Well, Anthony wants qemu to be robust in this regard, so I am >> tempted to rework all the qemu drivers to handle arbitrary layouts. >> They could use a good audit anyway. > > I agree here. Still

Re: [PATCH 0/3] virtio-net: inline header support

2012-10-11 Thread Michael S. Tsirkin
On Thu, Oct 11, 2012 at 10:33:31AM +1030, Rusty Russell wrote: > Paolo Bonzini writes: > > Il 09/10/2012 06:59, Rusty Russell ha scritto: > >> Paolo Bonzini writes: > >>> Il 05/10/2012 07:43, Rusty Russell ha scritto: > That's good. But virtio_blk's scsi command is insoluble AFAICT. As I >

Re: [PATCH 0/3] virtio-net: inline header support

2012-10-10 Thread Rusty Russell
Paolo Bonzini writes: > Il 09/10/2012 06:59, Rusty Russell ha scritto: >> Paolo Bonzini writes: >>> Il 05/10/2012 07:43, Rusty Russell ha scritto: That's good. But virtio_blk's scsi command is insoluble AFAICT. As I said to Anthony, the best rules are "always" and "never", so I'd real

Re: [PATCH 0/3] virtio-net: inline header support

2012-10-09 Thread Paolo Bonzini
Il 09/10/2012 06:59, Rusty Russell ha scritto: > Paolo Bonzini writes: >> Il 05/10/2012 07:43, Rusty Russell ha scritto: >>> That's good. But virtio_blk's scsi command is insoluble AFAICT. As I >>> said to Anthony, the best rules are "always" and "never", so I'd really >>> rather not have to gra

Re: [PATCH 0/3] virtio-net: inline header support

2012-10-08 Thread Rusty Russell
Paolo Bonzini writes: > Il 05/10/2012 07:43, Rusty Russell ha scritto: >> That's good. But virtio_blk's scsi command is insoluble AFAICT. As I >> said to Anthony, the best rules are "always" and "never", so I'd really >> rather not have to grandfather that in. > > It is, but we can add a rule th

Re: [PATCH 0/3] virtio-net: inline header support

2012-10-08 Thread Michael S. Tsirkin
On Thu, Oct 04, 2012 at 01:04:56PM +0930, Rusty Russell wrote: > Anthony Liguori writes: > > Rusty Russell writes: > > > >> "Michael S. Tsirkin" writes: > >> > >>> Thinking about Sasha's patches, we can reduce ring usage > >>> for virtio net small packets dramatically if we put > >>> virtio net

Re: [PATCH 0/3] virtio-net: inline header support

2012-10-08 Thread Michael S. Tsirkin
On Wed, Oct 03, 2012 at 04:14:17PM +0930, Rusty Russell wrote: > "Michael S. Tsirkin" writes: > > > Thinking about Sasha's patches, we can reduce ring usage > > for virtio net small packets dramatically if we put > > virtio net header inline with the data. > > This can be done for free in case gu

Re: [PATCH 0/3] virtio-net: inline header support

2012-10-06 Thread Paolo Bonzini
Il 05/10/2012 07:43, Rusty Russell ha scritto: >> > struct virtio_scsi_req_cmd { >> > // Read-only >> > u8 lun[8]; >> > u64 id; >> > u8 task_attr; >> > u8 prio; >> > u8 crn; >> > char cdb[cdb_size]; >> > char dataout[]; >> >

Re: [PATCH 0/3] virtio-net: inline header support

2012-10-05 Thread Rusty Russell
Paolo Bonzini writes: > Il 04/10/2012 14:51, Rusty Russell ha scritto: >> Paolo Bonzini writes: >> >>> Il 04/10/2012 02:11, Rusty Russell ha scritto: >> There's a reason I haven't done this. I really, really dislike "my >> implemention isn't broken" feature bits. We could have an infi

Re: [PATCH 0/3] virtio-net: inline header support

2012-10-05 Thread Paolo Bonzini
Il 04/10/2012 09:44, Rusty Russell ha scritto: > -In particular, no implementation should use the descriptor > -boundaries to determine the size of any header in a request.[footnote: > -The current qemu device implementations mistakenly insist that > -the first descriptor cover the header in these

Re: [PATCH 0/3] virtio-net: inline header support

2012-10-04 Thread Paolo Bonzini
Il 04/10/2012 14:51, Rusty Russell ha scritto: > Paolo Bonzini writes: > >> Il 04/10/2012 02:11, Rusty Russell ha scritto: > There's a reason I haven't done this. I really, really dislike "my > implemention isn't broken" feature bits. We could have an infinite > number of them, for

Re: [PATCH 0/3] virtio-net: inline header support

2012-10-04 Thread Rusty Russell
Paolo Bonzini writes: > Il 04/10/2012 02:11, Rusty Russell ha scritto: >> > > There's a reason I haven't done this. I really, really dislike "my >> > > implemention isn't broken" feature bits. We could have an infinite >> > > number of them, for each bug in each device. >> > >> > However, this

Re: [PATCH 0/3] virtio-net: inline header support

2012-10-04 Thread Rusty Russell
Anthony Liguori writes: >> lguest fix is pending in my queue. lkvm and qemu are broken; lkvm isn't >> ever going to be merged, so I'm not sure what its status is? But I'm >> determined to fix qemu, and hence my torture patch to make sure this >> doesn't creep in again. > > There are even more im

Re: [PATCH 0/3] virtio-net: inline header support

2012-10-04 Thread Paolo Bonzini
Il 04/10/2012 02:11, Rusty Russell ha scritto: > > > There's a reason I haven't done this. I really, really dislike "my > > > implemention isn't broken" feature bits. We could have an infinite > > > number of them, for each bug in each device. > > > > However, this bug affects (almost) all implem

Re: [PATCH 0/3] virtio-net: inline header support

2012-10-03 Thread Rusty Russell
Anthony Liguori writes: > Rusty Russell writes: > >> "Michael S. Tsirkin" writes: >> >> There's a reason I haven't done this. I really, really dislike "my >> implemention isn't broken" feature bits. We could have an infinite >> number of them, for each bug in each device. >> >> So my plan was

Re: [PATCH 0/3] virtio-net: inline header support

2012-10-03 Thread Anthony Liguori
Rusty Russell writes: > Anthony Liguori writes: >> Rusty Russell writes: >> >>> "Michael S. Tsirkin" writes: >>> Thinking about Sasha's patches, we can reduce ring usage for virtio net small packets dramatically if we put virtio net header inline with the data. This can be

Re: [PATCH 0/3] virtio-net: inline header support

2012-10-03 Thread Rusty Russell
Anthony Liguori writes: > Rusty Russell writes: > >> "Michael S. Tsirkin" writes: >> >>> Thinking about Sasha's patches, we can reduce ring usage >>> for virtio net small packets dramatically if we put >>> virtio net header inline with the data. >>> This can be done for free in case guest net st

Re: [PATCH 0/3] virtio-net: inline header support

2012-10-03 Thread Anthony Liguori
Rusty Russell writes: > "Michael S. Tsirkin" writes: > > There's a reason I haven't done this. I really, really dislike "my > implemention isn't broken" feature bits. We could have an infinite > number of them, for each bug in each device. > > So my plan was to tie this assumption to the new P

Re: [PATCH 0/3] virtio-net: inline header support

2012-10-03 Thread Anthony Liguori
Rusty Russell writes: > "Michael S. Tsirkin" writes: > >> Thinking about Sasha's patches, we can reduce ring usage >> for virtio net small packets dramatically if we put >> virtio net header inline with the data. >> This can be done for free in case guest net stack allocated >> extra head room f

Re: [PATCH 0/3] virtio-net: inline header support

2012-10-03 Thread Rusty Russell
Paolo Bonzini writes: > Il 03/10/2012 08:44, Rusty Russell ha scritto: >> There's a reason I haven't done this. I really, really dislike "my >> implemention isn't broken" feature bits. We could have an infinite >> number of them, for each bug in each device. > > However, this bug affects (almos

Re: [PATCH 0/3] virtio-net: inline header support

2012-10-03 Thread Rusty Russell
Rusty Russell writes: > "Michael S. Tsirkin" writes: > >> Thinking about Sasha's patches, we can reduce ring usage >> for virtio net small packets dramatically if we put >> virtio net header inline with the data. >> This can be done for free in case guest net stack allocated >> extra head room f

Re: [PATCH 0/3] virtio-net: inline header support

2012-10-03 Thread Paolo Bonzini
Il 03/10/2012 08:44, Rusty Russell ha scritto: > There's a reason I haven't done this. I really, really dislike "my > implemention isn't broken" feature bits. We could have an infinite > number of them, for each bug in each device. However, this bug affects (almost) all implementations and (almo

Re: [PATCH 0/3] virtio-net: inline header support

2012-10-03 Thread Rusty Russell
"Michael S. Tsirkin" writes: > Thinking about Sasha's patches, we can reduce ring usage > for virtio net small packets dramatically if we put > virtio net header inline with the data. > This can be done for free in case guest net stack allocated > extra head room for the packet, and I don't see >