Re: [Qemu-devel] [Issues] PCI hotplug does not work well on pc platform?

[Liu, Jing2]

Hi Igor,

Thanks for your reply!

On 2/5/2019 11:47 PM, Igor Mammedov wrote:
> On Wed, 30 Jan 2019 21:02:10 +0800
> "Liu, Jing2" <address@hidden> wrote:
>
> > Hi everyone,
> >
> > I have two questions.
> > 1. PCI hotplug on pci.0 must manually rescan in guest. The ACPI hotplug
> > handler sends the GPE event to guest but it seems guest doesn't receive
> > it? I tried to open ACPI debug level/layer to 0xffffffff, in order to
> > see if there is any message after device_add in monitor, but no message
> > comes out until I manually rescan. Also tried printk in
> > acpi_ev_gpe_xrupt_handler() and acpi_ev_sci_xrupt_handler(). No output
> > in dmesg.
> > (I'm sure that CONFIG_HOTPLUG_PCI_PCIE=y, CONFIG_HOTPLUG_PCI_CPCI=y,
> > CONFIG_HOTPLUG_PCI=y, CONFIG_HOTPLUG_PCI_ACPI=y)
> >
> > Whether this is a kind of design or a known issue? Does guest receive
> > the request, where can I find the
> does it work with known to work kernels (RHEL7)?
>
> Also sharing used QEMU version and command line could help.
Is there any key config of kernel in guest, besides those I listed above?

I used guest kernel v4.18 and qemu upstream v3.1.0
Command line:
sudo /home/xxx/qemu/x86_64-softmmu/qemu-system-x86_64  \
-machine pc,accel=kvm,kernel_irqchip -cpu host -m 1G,slots=2,maxmem=10G \
-nographic -no-user-config -nodefaults -vga none \
-drive file=/home/xxx/image/clear-24690-kvm.img,if=virtio,format=raw \
 -smp sockets=1,cpus=4,cores=2,maxcpus=8 \
-device virtio-serial-pci,id=virtio-serial0,disable-modern,addr=0x5 \
-monitor tcp:0.0.0.0:5000,nowait,server \
-chardev stdio,id=charconsole0 -device 
virtconsole,chardev=charconsole0,id=console0  \
-kernel /home/xxx/linux-stable/arch/x86/boot/bzImage \
-append 'root=/dev/vda3 rw rootfstype=ext4 data=ordered 
rcupdate.rcu_expedited=1 pci=lastbus=0 pci=realloc=on tsc=reliable 
no_timer_check reboot=t noapictimer console=hvc0 iommu=off  panic=1 
initcall_debug acpi.debug_layer=0x40000 acpi.debug_level=4 ' \
-device pci-bridge,bus=pci.0,id=br1,chassis_nr=1,shpc=on,addr=6  \

> > 2. I want to try hotplugging on pci-bridge on pc platform, using shpc. I
> > set shpc=on, but when I do device_add, qemu still calls
> > acpi_pcihp_device_plug_cb? Why it does not call pci_bridge_dev_hotplug_cb?
> > (CONFIG_HOTPLUG_PCI_SHPC=y)
>
> try to disable ACPI hotplug for bridges
>   -global PIIX4_PM.acpi-pci-hotplug-with-bridge-support=off
I'll try it!

Thanks!
Jing
>