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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: |
Thu, 5 Apr 2012 13:03:14 +0300 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
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.
So I would have organized it differently,
with a bugfix first and the rework on top
(e.g. make life easier if we want to cherry-pick this change
to the stable branch) and there's a bit of
discussion about documentation but I'm prepared to apply
this as is too if you prefer.
For the series:
Acked-by: Michael S. Tsirkin <address@hidden>
> 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).
Reproducible?
> 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.
>
> For a device_add, the 'present' & 'request' bitmaps gets set for
> the slot by qemu, gpe.sts set and SCI interrupt sent. The OSPM
> can simply compare requested state vs power state and send the
> appropriate notify. Same general idea for removal. _STA can be
> formed by looking at the 'present' and 'power' bitmaps, and
> _PS0/3 perform writes to the power register to indicate the virtual
> state. I think this provides a better register ownership model
> (qemu owns present/request, OSPM owns power) and also allows us
> to differentiate between a guest initiated remove and a platform
> (vm manager) initiated remove so we can avoid changing the vm
> state in the former case. I'll try to send a patch for this out
> soon, but let me know if there are any concerns or suggestions for
> a redesign. Thanks,
>
> Alex
>
> ---
>
> Alex Williamson (5):
> acpi_piix4: Fix PCI hotplug race
> acpi_piix4: Remove PCI_RMV_BASE write code
> acpi_piix4: Use pci_get/set_byte
> acpi_piix4: Only allow writes to PCI hotplug eject register
> acpi_piix4: Disallow write to up/down PCI hotplug registers
>
>
> docs/specs/acpi_pci_hotplug.txt | 8 +-
> hw/acpi_piix4.c | 178
> ++++++++++++++++++++-------------------
> 2 files changed, 95 insertions(+), 91 deletions(-)
- Re: [Qemu-devel] [PATCH 2/5] acpi_piix4: Only allow writes to PCI hotplug eject register, (continued)
- Re: [Qemu-devel] [PATCH 2/5] acpi_piix4: Only allow writes to PCI hotplug eject register, Gleb Natapov, 2012/04/05
- Re: [Qemu-devel] [PATCH 2/5] acpi_piix4: Only allow writes to PCI hotplug eject register, Michael S. Tsirkin, 2012/04/05
- Re: [Qemu-devel] [PATCH 2/5] acpi_piix4: Only allow writes to PCI hotplug eject register, Gleb Natapov, 2012/04/05
- Re: [Qemu-devel] [PATCH 2/5] acpi_piix4: Only allow writes to PCI hotplug eject register, Michael S. Tsirkin, 2012/04/05
- Re: [Qemu-devel] [PATCH 2/5] acpi_piix4: Only allow writes to PCI hotplug eject register, Gleb Natapov, 2012/04/05
- Re: [Qemu-devel] [PATCH 2/5] acpi_piix4: Only allow writes to PCI hotplug eject register, Alex Williamson, 2012/04/05
- Re: [Qemu-devel] [PATCH 2/5] acpi_piix4: Only allow writes to PCI hotplug eject register, Michael S. Tsirkin, 2012/04/05
- Re: [Qemu-devel] [PATCH 2/5] acpi_piix4: Only allow writes to PCI hotplug eject register, Alex Williamson, 2012/04/05
[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 <=
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