Re: [Qemu-devel] [PATCH 2/2] virtio-blk: disable write cache if not negotiated

2012-07-04 Thread Paolo Bonzini
Il 04/07/2012 14:50, Kevin Wolf ha scritto: > Before merging the patches (or actually this patch, I think patch 1 is > fairly independent), Yes, it is. > I'd like to hear more opinions on whether we need > the cache parameter split first Ok, let's discuss it next week on the KVM/QEMU call. Gett

Re: [Qemu-devel] [PATCH 2/2] virtio-blk: disable write cache if not negotiated

2012-07-04 Thread Kevin Wolf
Am 04.07.2012 14:21, schrieb Paolo Bonzini: > Il 04/07/2012 12:16, Kevin Wolf ha scritto: Yes. It doesn't override cache=unsafe though. >> When the guest doesn't support flushes, cache=writeback is equivalent to >> cache=unsafe, so if you want the old behaviour back you can switch to >> cache

Re: [Qemu-devel] [PATCH 2/2] virtio-blk: disable write cache if not negotiated

2012-07-04 Thread Paolo Bonzini
Il 04/07/2012 12:16, Kevin Wolf ha scritto: >> > Yes. It doesn't override cache=unsafe though. > When the guest doesn't support flushes, cache=writeback is equivalent to > cache=unsafe, so if you want the old behaviour back you can switch to > cache=unsafe without additional risks. > > We don't h

Re: [Qemu-devel] [PATCH 2/2] virtio-blk: disable write cache if not negotiated

2012-07-04 Thread Kevin Wolf
Am 03.07.2012 15:51, schrieb Paolo Bonzini: > Il 03/07/2012 15:49, Kevin Wolf ha scritto: >>> If the guest does not support flushes, we should run in writethrough mode. The setting is temporary until the next reset, so that for example the BIOS will run in writethrough mode while Linux wi

Re: [PATCH 2/2] virtio-blk: disable write cache if not negotiated

2012-07-03 Thread Paolo Bonzini
Il 03/07/2012 15:49, Kevin Wolf ha scritto: >> If the guest does not support flushes, we should run in writethrough mode. >> > The setting is temporary until the next reset, so that for example the >> > BIOS will run in writethrough mode while Linux will run with a writeback >> > cache. >> > >> >

Re: [PATCH 2/2] virtio-blk: disable write cache if not negotiated

2012-07-03 Thread Kevin Wolf
Am 03.07.2012 15:20, schrieb Paolo Bonzini: > If the guest does not support flushes, we should run in writethrough mode. > The setting is temporary until the next reset, so that for example the > BIOS will run in writethrough mode while Linux will run with a writeback > cache. > > VIRTIO_BLK_F_FLU

[PATCH 2/2] virtio-blk: disable write cache if not negotiated

2012-07-03 Thread Paolo Bonzini
If the guest does not support flushes, we should run in writethrough mode. The setting is temporary until the next reset, so that for example the BIOS will run in writethrough mode while Linux will run with a writeback cache. VIRTIO_BLK_F_FLUSH has been introduced in Linux 2.6.32 (in 2009) and was