Re: [RESEND PATCH v3] hotplug: add device per func in ACPI DSDT tables

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, May 09, 2012 at 03:24:52PM +0800, Amos Kong wrote:
> Boot up a Linux VM with 8 pci block devices which
> are the 8 functions in one pci slot.
> | # qemu-kvm ...
> | -drive file=images/u0,if=none,id=drv0,format=qcow2,cache=none \
> | -device virtio-blk-pci,drive=drv0,id=v0,multifunction=on,addr=0x03.0 \
> | ....
> | -drive file=images/u7,if=none,id=drv7,format=qcow2,cache=none \
> | -device virtio-blk-pci,drive=drv7,id=v7,multifunction=on,addr=0x03.7 \
> 
> Check devices in guest.
> | vm)# ls /dev/vd*
> |    vda vdb vdc vde vdf vdg vdh
> | vm)# lspci |grep block
> | 00:03.0 SCSI storage controller: Red Hat, Inc Virtio block device
> |    ...
> | 00:03.7 SCSI storage controller: Red Hat, Inc Virtio block device
> |
> 
> Func1~7 still exist in guest after hot-removing the whole slot
> through qemu monitor.
> | vm)# lspci |grep block    (00:03.0 disappeared)
> | 00:03.1 SCSI storage controller: Red Hat, Inc Virtio block device (rev ff)
> |    ...
> | 00:03.7 SCSI storage controller: Red Hat, Inc Virtio block device (rev ff)
> | vm)# ls /dev/vd*          (vda disappeared)
> |    vdb vdc vde vdf vdg vdh
> | vm)# mkfs /dev/vdb
> |    INFO: task mkfs.ext2:1784 blocked for more than 120 seconds. (task hung)
> 
> 
> Currently only func0 is defined in ACPI DSDT table
> of seabios, and only hot-adding func0 would cause
> a ACPI event for notification. Other funcs except
> func0 wouldn't be registered in linux pci driver.
> (we can only found func0 in slot->funcs list of
> pci driver).

Isn't this what your patch 'PCI: Can continually add funcs after adding
func0' addresses?
If yes it's commit f382a086f3129edc152b8044b69ccc6682e637bb in 3.4.
So let's class the problematic behaviour guest bug and avoid workarounds
in bios?

-- 
MST