Re: [Qemu-devel] QEMU: PCI bus name on PowerPC platforms

[Alexey Kardashevskiy <aik@ozlabs.ru>]

On 03/05/2014 09:42 PM, Hong-Hua.Yin@freescale.com wrote:
> Hi Gibson,
> 
> I noticed your patch http://git.qemu.org/?p=qemu.git;a=commitdiff;h=89dfd6e1
> and have some question about PCI bus name on PowerPC.
> 
> When I use libvirt to start VM on PowerPC platforms, it failed as below: 
> # virsh start sdk
> error: Failed to start domain sdk
> error: internal error: early end of file from monitor: possible problem:
> qemu-system-ppc: -device piix3-usb-uhci,id=usb,bus=pci,addr=0x1: Bus 'pci' not found



I just tried current upstresm QEMU and it handles bus=pci fine, it prints
an error on bus=pci.0 so I am confused - what qemu are you trying?

I am adding our libvirt developer Li, she might help with this.


> Exactly it should be 'pci.0' according to the default qdev core logic.
> 
> But currently in libvirt it only recognize PCI bus name as 'pci.0' on x86_64/i686 Arch.
> -------------------------------------------------------------------
> libvirt/src/qemu/qemu_capabilities.c
>     /* Currently only x86_64 and i686 support PCI-multibus. */
>     if (qemuCaps->arch == VIR_ARCH_X86_64 ||
>         qemuCaps->arch == VIR_ARCH_I686) {
>         virQEMUCapsSet(qemuCaps, QEMU_CAPS_PCI_MULTIBUS);
> 
> libvirt/src/qemu/qemu_capabilities.h:
>     QEMU_CAPS_PCI_MULTIBUS       = 52, /* bus=pci.0 vs bus=pci */
> -------------------------------------------------------------------
>
> Looking at 'info qtree' output it seems "pseries" is the only PPC machine type 
> using "pci" (out of those we managed to run):
> 
> $ ./ppc64-softmmu/qemu-system-ppc64 -M ?
> Supported machines are:
> virtex-ml507         Xilinx Virtex ML507 reference design
> pseries              pSeries Logical Partition (PAPR compliant) (default)
> prep                 PowerPC PREP platform
> bamboo               bamboo
> ref405ep             ref405ep
> taihu                taihu
> mpc8544ds            mpc8544ds
> g3beige              Heathrow based PowerMAC
> mac99                Mac99 based PowerMAC
> ppce500              generic paravirt e500 platform
> none                 empty machine
> 
> 1) virtex-ml507
> 2) pseries
> Warning: Disabling some instructions which are not emulated by TCG (0x0, 0x4)
>     bus: pci
> 3) prep
>     bus: pci.0
> 4) bamboo
>     bus: pci.0
> 5) ref405ep
> qemu-system-ppc64: Could not load PowerPC BIOS 'ppc405_rom.bin'
> 6) taihu
> qemu-system-ppc64: Could not load PowerPC BIOS 'ppc405_rom.bin'
> 7) mpc8544ds
>     bus: pci.0
> 8) g3beige
>     bus: pci.0
> 9) mac99
>     bus: pci.0
> 10) ppce500
>     bus: pci.0
> 
> 
> Could pseries also use 'pci.0' as PCI bus name? 
> If yes, could we set QEMU_CAPS_PCI_MULTIBUS in libvirt for all the 
> PowerPC platforms? Otherwise, we need detect the machine to fix this issue.
> 
> The discussion in libvirt mailing list is here:
> https://www.redhat.com/archives/libvir-list/2014-March/msg00228.html
> 
> I think we need reach an agreement in QEMU and then work on libvirt.
	>
> Best Regards,
> Olivia
> 


-- 
Alexey