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Re: [Qemu-devel] [PATCH 0/2] pci: exit path cleanup and fix
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH 0/2] pci: exit path cleanup and fix |
Date: |
Wed, 04 Jul 2012 10:22:53 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:13.0) Gecko/20120605 Thunderbird/13.0 |
Il 04/07/2012 06:39, Alex Williamson ha scritto:
> We've currently got a bug in pci_unregister_device in the ordering of
> calling the driver exit function and unregistering io regions. In
> every driver memory regions are created in the init function and
> destroyed in the exit function. By calling pci_unregister_io_regions
> after the exit function, we're calling memory_region_del_subregion
> with a pointer to a MemoryRegion that has already been destroyed.
>
> It's easy enough to change the ordering, but the exit function is
> currently allowed to fail. Even if we wanted to restore the device
> at that point, we've interrupted the mappings from the guest
> perspective and it seems precarious at best whether an exit function
> can fail and leave a usable device. Fortunately nobody has any
> possibility of actually failing the exit path. Normally I'm a
> proponent of error paths, but allowing an exit to fail is like
> allowing free(3) to fail.
>
> So, firt redefine that exit can't fail, then fix the ordering of
> pci_unregister_device(). If anyone has plans for a failure case in
> the exit path, please speak now. Thanks,
>
> Alex
>
> ---
>
> Alex Williamson (2):
> pci: Unregister BARs before device exit
> pci: convert PCIUnregisterFunc to void
>
>
> hw/ac97.c | 3 +--
> hw/e1000.c | 3 +--
> hw/eepro100.c | 3 +--
> hw/es1370.c | 3 +--
> hw/ide/cmd646.c | 4 +---
> hw/ide/ich.c | 4 +---
> hw/ide/piix.c | 4 +---
> hw/ide/via.c | 4 +---
> hw/intel-hda.c | 3 +--
> hw/ioh3420.c | 8 +++-----
> hw/ivshmem.c | 4 +---
> hw/lsi53c895a.c | 4 +---
> hw/ne2000.c | 3 +--
> hw/pci.c | 11 +++++------
> hw/pci.h | 2 +-
> hw/pci_bridge.c | 3 +--
> hw/pci_bridge.h | 2 +-
> hw/pci_bridge_dev.c | 12 ++++--------
> hw/pcnet-pci.c | 3 +--
> hw/rtl8139.c | 3 +--
> hw/usb/hcd-uhci.c | 3 +--
> hw/virtio-pci.c | 23 +++++++++++------------
> hw/wdt_i6300esb.c | 4 +---
> hw/xio3130_downstream.c | 8 +++-----
> hw/xio3130_upstream.c | 8 +++-----
> 25 files changed, 48 insertions(+), 84 deletions(-)
>
>
The diffstat caught my eye. :)
Reviewed-by: Paolo Bonzini <address@hidden>