[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v2][RFC] libxl: Add AHCI support for upstream qemu
On Tue, 19 May 2015, Fabio Fantoni wrote: > Il 19/05/2015 12:40, Wei Liu ha scritto: > > On Mon, May 18, 2015 at 07:22:01PM +0200, Fabio Fantoni wrote: > > > Il 18/05/2015 17:53, Wei Liu ha scritto: > > > > On Thu, May 14, 2015 at 01:11:13PM +0200, Fabio Fantoni wrote: > > > > > Usage: > > > > > ahci=0|1 (default=0) > > > > > > > > > > If enabled adds ich9 disk controller in ahci mode and uses it with > > > > > upstream qemu to emulate disks instead of ide. > > > > Is ICH9 available in our default setup? > > > > > > > > Why do we not always enable AHCI? > > > ahci seems require ich9 controller (default in q35 but not in older used > > > by > > > xen), I think that change it ide->ahci automatically for all cases may > > > causes problems, probably in save/restore and more probably in windows <=7 > > > without pv where change ide<->ahci require a registry change for not have > > > blue screen. > > > > > I guess we now have a QEMU with Q35. But migrating from previous > > previous versions will indeed need to be taken care of. > > This patch don't add q35 cipset support but only ich9 ahci disk controller in > older and only cipset supported in xen. This is pretty nice actually, thanks for the patch! > Time ago I tried to add q35 support in xen but I had some problems I was > unable to solves and nobody helped me. > Q35 have newer ich9 ahci disk controller as default, on older cipset must be > added (done in this patch). > qemu, kvm ovmf already support q35, xen need changes at least in hvmloader > (that I'm probably unable to do) and libxl (that I started time ago without > good result), Add ahci support and switch all qemu parameters in libxl to new > -device is a good start also for future q35 support (are both part needed > based on my old q35 tests on xen) Yeah, going q35 opens a whole new can of worms. I think that adding the ich9 chipset to the existing machine is a good compromise. > > > > > > > It doesn't support cdroms which still use ide (cdroms will use > > > > > "-device > > > > > ide-cd" as new qemu parameters) > > > > > Ahci requires new qemu parameters but for now other emulated disks > > > > > cases > > > > > remains with old ones because automatic bus selection seems bugged in > > > > > qemu using new parameters. (I'll retry) > > > > > > > > > Buggy as in? Have you reported to QEMU upstream? > > > Already reported long time ago in xen-devel and qemu-devel, the only reply > > > from qemu-devel was to use fixed bus and is what I did in v2 of this > > > patch. > > > Can someone tell me if can be a problem fixed bus? > > > > > I don't have enough knowledge on this. Maybe Anthony and Stefano have > > more insight. Let me get this straight: cdrom still works but goes via ide. In addition AHCI disks can be attached. Seems good to me. Have you tested Windows? If this works with Windows too, I would expose an ahci option (default=off) in the config file. If ahci=on, then all disks could be exposed via ahci. Does this seem sensible? In a couple of releases, if it works well, we could make ahci=on the default. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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