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Re: [Qemu-devel] [PATCH 0/5] PCI hotplug fixes/cleanup
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [PATCH 0/5] PCI hotplug fixes/cleanup |
Date: |
Sun, 8 Apr 2012 22:48:02 +0300 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Sun, Apr 08, 2012 at 03:45:38PM -0300, Marcelo Tosatti wrote:
> On Sun, Apr 08, 2012 at 10:15:26AM +0300, Michael S. Tsirkin wrote:
> > On Sun, Apr 08, 2012 at 02:13:00AM -0300, Marcelo Tosatti wrote:
> > > On Wed, Apr 04, 2012 at 11:51:00PM -0600, Alex Williamson wrote:
> > > > We've been batting this one back and forth. This series includes
> > > > several of the cleanups and specification clarifications from my
> > > > series awhile back. Patch 5 is my proposed alternative to
> > > > Michael's PCI hotplug race fix. Since that version I added slot
> > > > present tracking so we can be a little more strategic about which
> > > > slots we ask the guest to check. The approach for that path is
> > > > described in the commit log. I tested hotplug on both Linux an
> > > > Windows guests (XP + 2k8), intentionally trying to do back to back
> > > > device_add and device_del to get a race, but couldn't (I did
> > > > however get a glibc double free that seems unrelated to this
> > > > series).
> > > >
> > > > Long term I'd like to deprecate the up/down PCI hotplug interface
> > > > and move to a new model. I think perhaps we should define 3 new
> > > > registers:
> > > >
> > > > 1) Device present in slot bitmap (foundation already in 5/5 here)
> > > > 2) Virtual slot power state bitmap
> > > > 3) Requested slot date bitmap
> > > >
> > > > With these we should be able to do proper _STA, _PS0, and _PS3.
> > > > We'd maintain the eject register for _EJ0, but deprecate up/down.
> > >
> > > What problem are you trying to address by doing so?
> > >
> > > What is the need for power control? Clearly there is no advantage in
> > > powering down a virtual device.
> >
> > There probably are for an assigned device?
>
> Can't these use native PCI PM?
I haven't looked at PM closely but I think to support D3-cold
you remove power from the host component. I think this means that
we need host PCI bridge support.
--
MST
- [Qemu-devel] [PATCH 5/5] acpi_piix4: Fix PCI hotplug race, (continued)
- [Qemu-devel] [PATCH 5/5] acpi_piix4: Fix PCI hotplug race, Alex Williamson, 2012/04/05
- [Qemu-devel] [PATCH 4/5] acpi_piix4: Remove PCI_RMV_BASE write code, Alex Williamson, 2012/04/05
- Re: [Qemu-devel] [PATCH 0/5] PCI hotplug fixes/cleanup, Michael S. Tsirkin, 2012/04/05
- Re: [Qemu-devel] [PATCH 0/5] PCI hotplug fixes/cleanup, Gleb Natapov, 2012/04/05
- Re: [Qemu-devel] [PATCH 0/5] PCI hotplug fixes/cleanup, Michael S. Tsirkin, 2012/04/05
- Re: [Qemu-devel] [PATCH 0/5] PCI hotplug fixes/cleanup, Marcelo Tosatti, 2012/04/08
- Re: [Qemu-devel] [PATCH 0/5] PCI hotplug fixes/cleanup, Michael S. Tsirkin, 2012/04/08
- Re: [Qemu-devel] [PATCH 0/5] PCI hotplug fixes/cleanup, Marcelo Tosatti, 2012/04/08
- Re: [Qemu-devel] [PATCH 0/5] PCI hotplug fixes/cleanup,
Michael S. Tsirkin <=
- Re: [Qemu-devel] [PATCH 0/5] PCI hotplug fixes/cleanup, Gleb Natapov, 2012/04/09
- Re: [Qemu-devel] [PATCH 0/5] PCI hotplug fixes/cleanup, Michael S. Tsirkin, 2012/04/09
- Re: [Qemu-devel] [PATCH 0/5] PCI hotplug fixes/cleanup, Alex Williamson, 2012/04/10
- Re: [Qemu-devel] [PATCH 0/5] PCI hotplug fixes/cleanup, Michael S. Tsirkin, 2012/04/10
- Re: [Qemu-devel] [PATCH 0/5] PCI hotplug fixes/cleanup, Alex Williamson, 2012/04/10
- Re: [Qemu-devel] [PATCH 0/5] PCI hotplug fixes/cleanup, Michael S. Tsirkin, 2012/04/10
- Re: [Qemu-devel] [PATCH 0/5] PCI hotplug fixes/cleanup, Alex Williamson, 2012/04/10
- Re: [Qemu-devel] [PATCH 0/5] PCI hotplug fixes/cleanup, Michael S. Tsirkin, 2012/04/11
- Re: [Qemu-devel] [PATCH 0/5] PCI hotplug fixes/cleanup, Alex Williamson, 2012/04/12
- Re: [Qemu-devel] [PATCH 0/5] PCI hotplug fixes/cleanup, Michael S. Tsirkin, 2012/04/12