libvirt/tests/qemuxml2argvdata/hostdev-scsi-vhost-scsi-pcie.xml

<domain type='kvm'>
  <name>QEMUGuest2</name>
  <uuid>c7a5fdbd-edaf-9466-926a-d65c16db1809</uuid>
  <memory unit='KiB'>219100</memory>
  <currentMemory unit='KiB'>219100</currentMemory>
  <vcpu placement='static'>1</vcpu>
  <os>
    <type arch='x86_64' machine='pc-q35-2.7'>hvm</type>
    <boot dev='hd'/>
  </os>
  <clock offset='utc'/>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>destroy</on_crash>
  <devices>
    <emulator>/usr/bin/qemu-system-x86_64</emulator>
    <controller type='usb' index='0' model='none'/>
    <hostdev mode='subsystem' type='scsi_host' managed='no'>
      <source protocol='vhost' wwpn='naa.5123456789abcde0'/>
    </hostdev>
    <memballoon model='none'/>
  </devices>
</domain>
qemu: assign correct type of PCI address for vhost-scsi when using pcie-root Commit 10c73bf1 fixed a bug that I had introduced back in commit 70249927 - if a vhost-scsi device had no manually assigned PCI address, one wouldn't be assigned automatically. There was a slight problem with the logic of the fix though - in the case of domains with pcie-root (e.g. those with a q35 machinetype), qemuDomainDeviceCalculatePCIConnectFlags() will attempt to determine if the host-side PCI device is Express or legacy by examining sysfs based on the host-side PCI address stored in hostdev->source.subsys.u.pci.addr, but that part of the union is only valid for PCI hostdevs, not for SCSI hostdevs. So we end up trying to read sysfs for some probably-non-existent device, which fails, and the function virPCIDeviceIsPCIExpress() returns failure (-1). By coincidence, the return value is being examined as a boolean, and since -1 is true, we still end up assigning the vhost-scsi device to an Express slot, but that is just by chance (and could fail in the case that the gibberish in the "hostside PCI address" was the address of a real device that happened to be legacy PCI). Since (according to Paolo Bonzini) vhost-scsi devices appear just like virtio-scsi devices in the guest, they should follow the same rules as virtio devices when deciding whether they should be placed in an Express or a legacy slot. That's accomplished in this patch by returning early with virtioFlags, rather than erroneously using hostdev->source.subsys.u.pci.addr. It also adds a test case for PCIe to assure it doesn't get broken in the future. 2017-12-15 16:42:35 +00:00			`<domain type='kvm'>`
			`<name>QEMUGuest2</name>`
			`<uuid>c7a5fdbd-edaf-9466-926a-d65c16db1809</uuid>`
			`<memory unit='KiB'>219100</memory>`
			`<currentMemory unit='KiB'>219100</currentMemory>`
			`<vcpu placement='static'>1</vcpu>`
			`<os>`
			`<type arch='x86_64' machine='pc-q35-2.7'>hvm</type>`
			`<boot dev='hd'/>`
			`</os>`
			`<clock offset='utc'/>`
			`<on_poweroff>destroy</on_poweroff>`
			`<on_reboot>restart</on_reboot>`
			`<on_crash>destroy</on_crash>`
			`<devices>`
			`<emulator>/usr/bin/qemu-system-x86_64</emulator>`
			`<controller type='usb' index='0' model='none'/>`
			`<hostdev mode='subsystem' type='scsi_host' managed='no'>`
			`<source protocol='vhost' wwpn='naa.5123456789abcde0'/>`
			`</hostdev>`
			`<memballoon model='none'/>`
			`</devices>`
			`</domain>`