To simplify future patches dealing with this code, simplify and refactor some conditions to switch statements. --- src/qemu/qemu_command.c | 27 ++++++++++++++++++--------- src/qemu/qemu_hotplug.c | 27 ++++++++++++++++----------- 2 files changed, 34 insertions(+), 20 deletions(-) diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c index e976466..ecf26cc 100644 --- a/src/qemu/qemu_command.c +++ b/src/qemu/qemu_command.c @@ -5485,14 +5485,25 @@ qemuBuildPCIHostdevDevStr(virDomainDefPtr def, { virBuffer buf = VIR_BUFFER_INITIALIZER; - if (dev->source.subsys.u.pci.backend - == VIR_DOMAIN_HOSTDEV_PCI_BACKEND_VFIO) { - virBufferAddLit(&buf, "vfio-pci"); - } else { + switch ((virDomainHostdevSubsysPciBackendType) + dev->source.subsys.u.pci.backend) { + case VIR_DOMAIN_HOSTDEV_PCI_BACKEND_DEFAULT: + case VIR_DOMAIN_HOSTDEV_PCI_BACKEND_KVM: virBufferAddLit(&buf, "pci-assign"); if (configfd && *configfd) virBufferAsprintf(&buf, ",configfd=%s", configfd); + break; + + case VIR_DOMAIN_HOSTDEV_PCI_BACKEND_VFIO: + virBufferAddLit(&buf, "vfio-pci"); + break; + + case VIR_DOMAIN_HOSTDEV_PCI_BACKEND_TYPE_LAST: + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("PCI passhthrough type needs to be specified")); + break; } + virBufferAsprintf(&buf, ",host=%.2x:%.2x.%.1x", dev->source.subsys.u.pci.addr.bus, dev->source.subsys.u.pci.addr.slot, @@ -9232,7 +9243,6 @@ qemuBuildCommandLine(virConnectPtr conn, VIR_FREE(devstr); } - /* Add host passthrough hardware */ for (i = 0; i < def->nhostdevs; i++) { virDomainHostdevDefPtr hostdev = def->hostdevs[i]; @@ -9305,9 +9315,9 @@ qemuBuildCommandLine(virConnectPtr conn, /* PCI */ 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; - if (hostdev->source.subsys.u.pci.backend - == VIR_DOMAIN_HOSTDEV_PCI_BACKEND_VFIO) { + if (backend == VIR_DOMAIN_HOSTDEV_PCI_BACKEND_VFIO) { if (!virQEMUCapsGet(qemuCaps, QEMU_CAPS_DEVICE_VFIO_PCI)) { virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", _("VFIO PCI device assignment is not " @@ -9321,8 +9331,7 @@ qemuBuildCommandLine(virConnectPtr conn, if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_DEVICE)) { char *configfd_name = NULL; - if ((hostdev->source.subsys.u.pci.backend - != VIR_DOMAIN_HOSTDEV_PCI_BACKEND_VFIO) && + if ((backend != VIR_DOMAIN_HOSTDEV_PCI_BACKEND_VFIO) && virQEMUCapsGet(qemuCaps, QEMU_CAPS_PCI_CONFIGFD)) { int configfd = qemuOpenPCIConfig(hostdev); diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c index 818c726..ae2cbc0 100644 --- a/src/qemu/qemu_hotplug.c +++ b/src/qemu/qemu_hotplug.c @@ -1134,6 +1134,7 @@ int qemuDomainAttachHostPciDevice(virQEMUDriverPtr driver, int configfd = -1; char *configfd_name = NULL; bool releaseaddr = false; + int *backend = &hostdev->source.subsys.u.pci.backend; if (VIR_REALLOC_N(vm->def->hostdevs, vm->def->nhostdevs + 1) < 0) return -1; @@ -1142,10 +1143,8 @@ int qemuDomainAttachHostPciDevice(virQEMUDriverPtr driver, &hostdev, 1) < 0) return -1; - if (hostdev->source.subsys.u.pci.backend - == VIR_DOMAIN_HOSTDEV_PCI_BACKEND_VFIO) { - unsigned long long memKB; - + switch ((virDomainHostdevSubsysPciBackendType) *backend) { + case VIR_DOMAIN_HOSTDEV_PCI_BACKEND_VFIO: if (!virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_DEVICE_VFIO_PCI)) { virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", _("VFIO PCI device assignment is not " @@ -1157,11 +1156,18 @@ int qemuDomainAttachHostPciDevice(virQEMUDriverPtr driver, * In this case, the guest's memory may already be locked, but it * doesn't hurt to "change" the limit to the same value. */ - vm->def->hostdevs[vm->def->nhostdevs++] = hostdev; - memKB = vm->def->mem.hard_limit ? - vm->def->mem.hard_limit : vm->def->mem.max_balloon + 1024 * 1024; - virProcessSetMaxMemLock(vm->pid, memKB); - vm->def->hostdevs[vm->def->nhostdevs--] = NULL; + if (vm->def->mem.hard_limit) + virProcessSetMaxMemLock(vm->pid, vm->def->mem.hard_limit); + else + virProcessSetMaxMemLock(vm->pid, + vm->def->mem.max_balloon + (1024 * 1024)); + + break; + + case VIR_DOMAIN_HOSTDEV_PCI_BACKEND_DEFAULT: + case VIR_DOMAIN_HOSTDEV_PCI_BACKEND_KVM: + case VIR_DOMAIN_HOSTDEV_PCI_BACKEND_TYPE_LAST: + break; } if (virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_DEVICE)) { @@ -1170,8 +1176,7 @@ int qemuDomainAttachHostPciDevice(virQEMUDriverPtr driver, if (qemuDomainPCIAddressEnsureAddr(priv->pciaddrs, hostdev->info) < 0) goto error; releaseaddr = true; - if ((hostdev->source.subsys.u.pci.backend - != VIR_DOMAIN_HOSTDEV_PCI_BACKEND_VFIO) && + if ((*backend != VIR_DOMAIN_HOSTDEV_PCI_BACKEND_VFIO) && virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_PCI_CONFIGFD)) { configfd = qemuOpenPCIConfig(hostdev); if (configfd >= 0) { -- 1.8.3.2

On 10/07/13 15:57, Laine Stump wrote: I started adding this on multiple places earlier. I don't know if there's a official strategy, but I tend to prefer it as I was bitten a few times by adding a new enum value and missed a few switches where I actually should handle those. That's why I'm adding the typecasts where possible. Yes, the _TYPE_LAST will never happen here. I usually leave out any action on the _TYPE_LAST variants, but in this particular case, patch 3/3 changes the default and code in this function shouldn't ever be reached with _DEFAULT any more. danpb suggested adding this error. That would be a ideal global solution. Unfortunately as the SOMETypeFromString macroed functions return -1 on failure almost all variables holding the value got by this functions are declared as int rather than the appropriate enum value. To avoid the need for a separate intermediate variable we tend to declare the holding vars as int. I think that the benefits of the compiler warning in case you add a new variable on places you might have forgotten outweigh a few occurences of unused type in the code. ... Peter

On 10/04/2013 08:55 AM, Peter Krempa wrote: If you're concerned about name length, you could probably remove the "Passthrough" and it would still make sense... Was this all that was suggested? At any rate it's a good start even if there are other checks that can be added later. These should be checked once at the top of the function and their return values cached. You know my opinion on these typecasts :-) (but don't let that stop you). In the case of DEFAULT, we don't want to require support for legacy PCI passthrough, we instead want to make sure that one or the other of the methods is supported on the current host. So DEFAULT should have a separate case that says "if (!(supportsPassthroughKVM || supportsPassthroughVFIO) { error }" In one case you're calling this very near to a call to qemuPrepareHostdevPCIDevices(), in the other very near to a call to qemuPrepareHostDevices, which itself calls qemuPrepareHostdevPCIDevices(); I think this check should be made inside qemuPrepareHostdevPCIDevices() so that the higher level code isn't polluted with the detail.

Prefer using VFIO (if available) to the legacy KVM device passthrough. With this patch a PCI passthrough device without the driver configured will be started with VFIO if it's available on the host. If not legacy KVM passthrough is checked and error is reported if it's not available. --- docs/formatdomain.html.in | 9 ++++----- src/conf/domain_conf.h | 2 +- src/qemu/qemu_command.c | 3 ++- src/qemu/qemu_hostdev.c | 21 +++++++++++++++++++-- src/qemu/qemu_hostdev.h | 3 ++- src/qemu/qemu_hotplug.c | 2 +- src/qemu/qemu_process.c | 15 ++++++++------- tests/qemuxml2argvtest.c | 11 +++++++++++ 8 files changed, 48 insertions(+), 18 deletions(-) diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in index 3689399..6f3f7cf 100644 --- a/docs/formatdomain.html.in +++ b/docs/formatdomain.html.in @@ -2755,11 +2755,10 @@ backend, which is compatible with UEFI SecureBoot) or "kvm" (for the legacy device assignment handled directly by the KVM kernel module)<span class="since">Since 1.0.5 (QEMU and KVM - only, requires kernel 3.6 or newer)</span>. Currently, "kvm" - is the default used by libvirt when not explicitly provided, - but since the two are functionally equivalent, this default - could be changed in the future with no impact to domains that - don't specify anything. + only, requires kernel 3.6 or newer)</span>. The default, when + the driver name is not explicitly specified, is to check wether + VFIO is available and use it if it's the case. If VFIO is not + available, the legacy "kvm" assignment is attempted. </dd> <dt><code>readonly</code></dt> <dd>Indicates that the device is readonly, only supported by SCSI host diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h index f20a916..6b825d8 100644 --- a/src/conf/domain_conf.h +++ b/src/conf/domain_conf.h @@ -399,7 +399,7 @@ enum virDomainHostdevSubsysType { /* the backend driver used for PCI hostdev devices */ typedef enum { - VIR_DOMAIN_HOSTDEV_PCI_BACKEND_DEFAULT, /* currently kvm, could change */ + VIR_DOMAIN_HOSTDEV_PCI_BACKEND_DEFAULT, /* detect automaticaly, prefer VFIO */ VIR_DOMAIN_HOSTDEV_PCI_BACKEND_KVM, /* force legacy kvm style */ VIR_DOMAIN_HOSTDEV_PCI_BACKEND_VFIO, /* force vfio */ diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c index ecf26cc..a4742fa 100644 --- a/src/qemu/qemu_command.c +++ b/src/qemu/qemu_command.c @@ -5487,7 +5487,6 @@ qemuBuildPCIHostdevDevStr(virDomainDefPtr def, switch ((virDomainHostdevSubsysPciBackendType) dev->source.subsys.u.pci.backend) { - case VIR_DOMAIN_HOSTDEV_PCI_BACKEND_DEFAULT: case VIR_DOMAIN_HOSTDEV_PCI_BACKEND_KVM: virBufferAddLit(&buf, "pci-assign"); if (configfd && *configfd) @@ -5498,6 +5497,8 @@ qemuBuildPCIHostdevDevStr(virDomainDefPtr def, virBufferAddLit(&buf, "vfio-pci"); break; + + case VIR_DOMAIN_HOSTDEV_PCI_BACKEND_DEFAULT: case VIR_DOMAIN_HOSTDEV_PCI_BACKEND_TYPE_LAST: virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("PCI passhthrough type needs to be specified")); diff --git a/src/qemu/qemu_hostdev.c b/src/qemu/qemu_hostdev.c index dbbc2b4..ad408d8 100644 --- a/src/qemu/qemu_hostdev.c +++ b/src/qemu/qemu_hostdev.c @@ -1366,7 +1366,8 @@ qemuHostdevHostSupportsPassthroughLegacy(void) bool qemuHostdevHostVerifySupport(virDomainHostdevDefPtr *hostdevs, - size_t nhostdevs) + size_t nhostdevs, + virQEMUCapsPtr qemuCaps) { int supportsPassthroughKVM = -1; int supportsPassthroughVFIO = -1; @@ -1387,6 +1388,23 @@ qemuHostdevHostVerifySupport(virDomainHostdevDefPtr *hostdevs, } switch ((virDomainHostdevSubsysPciBackendType) *backend) { + case VIR_DOMAIN_HOSTDEV_PCI_BACKEND_DEFAULT: + if (supportsPassthroughVFIO && + virQEMUCapsGet(qemuCaps, QEMU_CAPS_DEVICE_VFIO_PCI)) { + *backend = VIR_DOMAIN_HOSTDEV_PCI_BACKEND_VFIO; + } else if (supportsPassthroughKVM && + (virQEMUCapsGet(qemuCaps, QEMU_CAPS_PCIDEVICE) || + virQEMUCapsGet(qemuCaps, QEMU_CAPS_DEVICE))) { + *backend = VIR_DOMAIN_HOSTDEV_PCI_BACKEND_KVM; + } else { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", + _("host doesn't support passthrough of " + "host PCI devices")); + return false; + } + + break; + case VIR_DOMAIN_HOSTDEV_PCI_BACKEND_VFIO: if (!supportsPassthroughVFIO) { virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", @@ -1395,7 +1413,6 @@ qemuHostdevHostVerifySupport(virDomainHostdevDefPtr *hostdevs, } break; - case VIR_DOMAIN_HOSTDEV_PCI_BACKEND_DEFAULT: case VIR_DOMAIN_HOSTDEV_PCI_BACKEND_KVM: if (!supportsPassthroughKVM) { virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", diff --git a/src/qemu/qemu_hostdev.h b/src/qemu/qemu_hostdev.h index 6d88830..afe67a5 100644 --- a/src/qemu/qemu_hostdev.h +++ b/src/qemu/qemu_hostdev.h @@ -70,7 +70,8 @@ int qemuDomainHostdevNetConfigRestore(virDomainHostdevDefPtr hostdev, char *stateDir); bool qemuHostdevHostVerifySupport(virDomainHostdevDefPtr *hostdevs, - size_t nhostdevs); + size_t nhostdevs, + virQEMUCapsPtr qemuCaps); #endif /* __QEMU_HOSTDEV_H__ */ diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c index c72fdc3..0bbbf6e 100644 --- a/src/qemu/qemu_hotplug.c +++ b/src/qemu/qemu_hotplug.c @@ -1144,7 +1144,7 @@ int qemuDomainAttachHostPciDevice(virQEMUDriverPtr driver, return -1; /* verify the availability of passthrough support */ - if (!qemuHostdevHostVerifySupport(&hostdev, 1)) + if (!qemuHostdevHostVerifySupport(&hostdev, 1, priv->qemuCaps)) goto error; switch ((virDomainHostdevSubsysPciBackendType) *backend) { diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c index 4aa9582..64d9326 100644 --- a/src/qemu/qemu_process.c +++ b/src/qemu/qemu_process.c @@ -3567,9 +3567,16 @@ int qemuProcessStart(virConnectPtr conn, goto cleanup; } + VIR_DEBUG("Determining emulator version"); + virObjectUnref(priv->qemuCaps); + if (!(priv->qemuCaps = virQEMUCapsCacheLookupCopy(driver->qemuCapsCache, + vm->def->emulator))) + goto cleanup; + /* check and assign device assignment settings */ if (!qemuHostdevHostVerifySupport(vm->def->hostdevs, - vm->def->nhostdevs)) + vm->def->nhostdevs, + priv->qemuCaps)) goto cleanup; /* network devices must be "prepared" before hostdevs, because @@ -3664,12 +3671,6 @@ int qemuProcessStart(virConnectPtr conn, } } - VIR_DEBUG("Determining emulator version"); - virObjectUnref(priv->qemuCaps); - if (!(priv->qemuCaps = virQEMUCapsCacheLookupCopy(driver->qemuCapsCache, - vm->def->emulator))) - goto cleanup; - if (!qemuValidateCpuMax(vm->def, priv->qemuCaps)) goto cleanup; diff --git a/tests/qemuxml2argvtest.c b/tests/qemuxml2argvtest.c index 38319e5..6fe8c6a 100644 --- a/tests/qemuxml2argvtest.c +++ b/tests/qemuxml2argvtest.c @@ -98,6 +98,7 @@ static int testCompareXMLToArgvFiles(const char *xml, virConnectPtr conn; char *log = NULL; virCommandPtr cmd = NULL; + size_t i; if (!(conn = virGetConnect())) goto out; @@ -154,6 +155,16 @@ static int testCompareXMLToArgvFiles(const char *xml, if (qemuAssignDeviceAliases(vmdef, extraFlags) < 0) goto out; + for (i = 0; i < vmdef->nhostdevs; i++) { + virDomainHostdevDefPtr hostdev = vmdef->hostdevs[i]; + + if (hostdev->mode == VIR_DOMAIN_HOSTDEV_MODE_SUBSYS && + hostdev->source.subsys.type == VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_PCI && + hostdev->source.subsys.u.pci.backend == VIR_DOMAIN_HOSTDEV_PCI_BACKEND_DEFAULT) { + hostdev->source.subsys.u.pci.backend = VIR_DOMAIN_HOSTDEV_PCI_BACKEND_KVM; + } + } + if (!(cmd = qemuBuildCommandLine(conn, &driver, vmdef, &monitor_chr, (flags & FLAG_JSON), extraFlags, migrateFrom, migrateFd, NULL, -- 1.8.3.2

On 10/07/13 16:19, Laine Stump wrote: ... We can't call the detection code in the test suite as we could get different results on different environments. This just "simulates" that legacy passthrough was selected instead of leaving the default so that: a) the command line generator doesn't error out as it now won't work with _DEFAULT b) the test results won't have to be changed to cope with a change to VFIO. Peter