Re: [Qemu-devel] [2.5 issue] virtio-1 in virtio-net and old vhost

2015-12-04 Thread Michael S. Tsirkin
On Fri, Dec 04, 2015 at 11:15:48AM +0100, Cornelia Huck wrote: > On Fri, 4 Dec 2015 10:06:58 +0800 > Jason Wang wrote: > > > The problem is for pci: without this patch, guest may always see modern > > bar is "disable-modern=false". But with this patch, on an old kernel > > that does not support V

Re: [Qemu-devel] [2.5 issue] virtio-1 in virtio-net and old vhost

2015-12-04 Thread Cornelia Huck
On Fri, 4 Dec 2015 10:06:58 +0800 Jason Wang wrote: > The problem is for pci: without this patch, guest may always see modern > bar is "disable-modern=false". But with this patch, on an old kernel > that does not support VERSION_1, even "disable-modern=false" were > specified, guest can not see m

Re: [Qemu-devel] [2.5 issue] virtio-1 in virtio-net and old vhost

2015-12-03 Thread Jason Wang
On 12/02/2015 06:11 PM, Cornelia Huck wrote: > On Wed, 2 Dec 2015 13:54:09 +0800 > Jason Wang wrote: > >> I wonder instead of rolling back in post_plugged(), maybe we could just >> delay the region setups to post_plugged(). > If this is the saner thing to do for pci, sure. > >> Or just call tra

Re: [Qemu-devel] [2.5 issue] virtio-1 in virtio-net and old vhost

2015-12-02 Thread Michael S. Tsirkin
On Wed, Dec 02, 2015 at 11:11:28AM +0100, Cornelia Huck wrote: > On Wed, 2 Dec 2015 13:54:09 +0800 > Jason Wang wrote: > > > I wonder instead of rolling back in post_plugged(), maybe we could just > > delay the region setups to post_plugged(). > > If this is the saner thing to do for pci, sure.

Re: [Qemu-devel] [2.5 issue] virtio-1 in virtio-net and old vhost

2015-12-02 Thread Cornelia Huck
On Wed, 2 Dec 2015 13:54:09 +0800 Jason Wang wrote: > I wonder instead of rolling back in post_plugged(), maybe we could just > delay the region setups to post_plugged(). If this is the saner thing to do for pci, sure. > Or just call transport > specific device_plugged() after get_features() c

Re: [Qemu-devel] [2.5 issue] virtio-1 in virtio-net and old vhost

2015-12-01 Thread Jason Wang
On 12/01/2015 10:21 PM, Cornelia Huck wrote: > On Tue, 1 Dec 2015 13:10:40 +0100 > Cornelia Huck wrote: > >> On Tue, 1 Dec 2015 11:11:08 +0100 >> Cornelia Huck wrote: >> >>> Some of our test folks tried to run a recent-ish qemu (nearly 2.5) >>> combined with an old host kernel (and a virtio-1 c

Re: [Qemu-devel] [2.5 issue] virtio-1 in virtio-net and old vhost

2015-12-01 Thread Cornelia Huck
On Tue, 1 Dec 2015 13:10:40 +0100 Cornelia Huck wrote: > On Tue, 1 Dec 2015 11:11:08 +0100 > Cornelia Huck wrote: > > > Some of our test folks tried to run a recent-ish qemu (nearly 2.5) > > combined with an old host kernel (and a virtio-1 capable guest). > > > > In that setup, we had the tran

Re: [Qemu-devel] [2.5 issue] virtio-1 in virtio-net and old vhost

2015-12-01 Thread Cornelia Huck
On Tue, 1 Dec 2015 11:11:08 +0100 Cornelia Huck wrote: > Some of our test folks tried to run a recent-ish qemu (nearly 2.5) > combined with an old host kernel (and a virtio-1 capable guest). > > In that setup, we had the transport (in that case, virtio-ccw) > advertise VERSION_1 as it is a revis

[Qemu-devel] [2.5 issue] virtio-1 in virtio-net and old vhost

2015-12-01 Thread Cornelia Huck
Some of our test folks tried to run a recent-ish qemu (nearly 2.5) combined with an old host kernel (and a virtio-1 capable guest). In that setup, we had the transport (in that case, virtio-ccw) advertise VERSION_1 as it is a revision 1 device. However, the old vhost driver did not support virtio-