Re: [libvirt] [PATCH 4/5] qemu: Check if PCI passhtrough is available in the host when starting

Check the presence of the selected PCI passthrough option when starting a VM. --- src/qemu/qemu_process.c | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c index dd16f6c..e36ab99 100644 --- a/src/qemu/qemu_process.c +++ b/src/qemu/qemu_process.c @@ -3481,6 +3481,8 @@ int qemuProcessStart(virConnectPtr conn, unsigned int stop_flags; virQEMUDriverConfigPtr cfg; virCapsPtr caps = NULL; + int supportsPassthroughKVM = -1; + int supportsPassthroughVFIO = -1; /* Okay, these are just internal flags, * but doesn't hurt to check */ @@ -3713,6 +3715,45 @@ int qemuProcessStart(virConnectPtr conn, goto cleanup; } + /* assign defaults for hostdev passthrough */ + for (i = 0; i < vm->def->nhostdevs; i++) { + virDomainHostdevDefPtr hostdev = vm->def->hostdevs[i]; + + if (hostdev->mode == VIR_DOMAIN_HOSTDEV_MODE_SUBSYS && + hostdev->source.subsys.type == VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_PCI) { + int *backend = &hostdev->source.subsys.u.pci.backend; + + /* cache host state of passthrough support */ + if (supportsPassthroughKVM == -1 || supportsPassthroughVFIO == -1) { + supportsPassthroughKVM = qemuHostdevHostSupportsPassthroughLegacy(); + supportsPassthroughVFIO = qemuHostdevHostSupportsPassthroughVFIO(); + } + + switch ((virDomainHostdevSubsysPciBackendType) *backend) { + case VIR_DOMAIN_HOSTDEV_PCI_BACKEND_VFIO: + if (!supportsPassthroughVFIO) { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", + _("host doesn't support VFIO PCI passthrough")); + goto cleanup; + } + break; + + case VIR_DOMAIN_HOSTDEV_PCI_BACKEND_DEFAULT: + case VIR_DOMAIN_HOSTDEV_PCI_BACKEND_KVM: + if (!supportsPassthroughKVM) { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", + _("host doesn't support legacy PCI passthrough")); + goto cleanup; + } + + break; + + case VIR_DOMAIN_HOSTDEV_PCI_BACKEND_TYPE_LAST: + break; + } + } + }