On Wed, 2010-05-19 at 22:34 -0700, Chris Wright wrote: Yes, it should be. Oh good, I meant to look, but obviously forgot. Fixed. Done. We could certainly open the file and pass an fd, but I don't know how to let qemu make use of it after it's been spawned, so I reverted to existing behavior here. Thanks, Alex

This allows libvirt to open the PCI device sysfs config file prior to dropping privileges so qemu can access the full config space. Without this, a de-privileged qemu can only access the first 64 bytes of config space. Signed-off-by: Alex Williamson <alex.williamson(a)redhat.com&gt; --- v2: - fix qemuargs, two separate args (thanks Chris) - don't hardcode pci segment - error message of open() fail src/qemu/qemu_conf.c | 89 +++++++++++++++++++++++++++++++++++++++++++++++- src/qemu/qemu_conf.h | 8 ++++ src/qemu/qemu_driver.c | 2 + 3 files changed, 95 insertions(+), 4 deletions(-) diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c index d7bc798..24c360e 100644 --- a/src/qemu/qemu_conf.c +++ b/src/qemu/qemu_conf.c @@ -1345,6 +1345,48 @@ fail: return -1; } +void qemudParsePCIDeviceStrs(const char *qemu, unsigned long long *flags) +{ + const char *const qemuarg[] = { qemu, "-device", "pci-assign,?", NULL }; + const char *const qemuenv[] = { "LC_ALL=C", NULL }; + pid_t child; + int status; + int newstderr = -1; + + if (virExec(qemuarg, qemuenv, NULL, + &child, -1, NULL, &newstderr, VIR_EXEC_CLEAR_CAPS) < 0) + return; + + char *pciassign = NULL; + enum { MAX_PCI_OUTPUT_SIZE = 1024*4 }; + int len = virFileReadLimFD(newstderr, MAX_PCI_OUTPUT_SIZE, &pciassign); + if (len < 0) { + virReportSystemError(errno, + _("Unable to read %s pci-assign device output"), + qemu); + goto cleanup; + } + + if (strstr(pciassign, "pci-assign.configfd")) + *flags |= QEMUD_CMD_FLAG_PCI_CONFIGFD; + +cleanup: + VIR_FREE(pciassign); + close(newstderr); +rewait: + if (waitpid(child, &status, 0) != child) { + if (errno == EINTR) + goto rewait; + + VIR_ERROR(_("Unexpected exit status from qemu %d pid %lu"), + WEXITSTATUS(status), (unsigned long)child); + } + if (WEXITSTATUS(status) != 0) { + VIR_WARN("Unexpected exit status '%d', qemu probably failed", + WEXITSTATUS(status)); + } +} + int qemudExtractVersionInfo(const char *qemu, unsigned int *retversion, unsigned long long *retflags) { @@ -1378,6 +1420,9 @@ int qemudExtractVersionInfo(const char *qemu, &version, &is_kvm, &kvm_version) == -1) goto cleanup2; + if (flags & QEMUD_CMD_FLAG_DEVICE) + qemudParsePCIDeviceStrs(qemu, &flags); + if (retversion) *retversion = version; if (retflags) @@ -2887,8 +2932,33 @@ error: } +int +qemudOpenPCIConfig(virDomainHostdevDefPtr dev) +{ + char *path = NULL; + int configfd = -1; + + if (virAsprintf(&path, "/sys/bus/pci/devices/%04x:%02x:%02x.%01x/config", + dev->source.subsys.u.pci.domain, + dev->source.subsys.u.pci.bus, + dev->source.subsys.u.pci.slot, + dev->source.subsys.u.pci.function) < 0) { + virReportOOMError(); + return -1; + } + + configfd = open(path, O_RDWR, 0); + + if (configfd < 0) + virReportSystemError(errno, _("Failed opening %s"), path); + + VIR_FREE(path); + + return configfd; +} + char * -qemuBuildPCIHostdevDevStr(virDomainHostdevDefPtr dev) +qemuBuildPCIHostdevDevStr(virDomainHostdevDefPtr dev, int configfd) { virBuffer buf = VIR_BUFFER_INITIALIZER; @@ -2898,6 +2968,8 @@ qemuBuildPCIHostdevDevStr(virDomainHostdevDefPtr dev) dev->source.subsys.u.pci.slot, dev->source.subsys.u.pci.function); virBufferVSprintf(&buf, ",id=%s", dev->info.alias); + if (configfd >= 0) + virBufferVSprintf(&buf, ",configfd=%d", configfd); if (qemuBuildDeviceAddressStr(&buf, &dev->info) < 0) goto error; @@ -4600,8 +4672,21 @@ int qemudBuildCommandLine(virConnectPtr conn, if (hostdev->mode == VIR_DOMAIN_HOSTDEV_MODE_SUBSYS && hostdev->source.subsys.type == VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_PCI) { if (qemuCmdFlags & QEMUD_CMD_FLAG_DEVICE) { + int configfd = -1; + if (qemuCmdFlags & QEMUD_CMD_FLAG_PCI_CONFIGFD) { + configfd = qemudOpenPCIConfig(hostdev); + + if (configfd >= 0) { + if (VIR_REALLOC_N(*vmfds, (*nvmfds)+1) < 0) { + close(configfd); + goto no_memory; + } + + (*vmfds)[(*nvmfds)++] = configfd; + } + } ADD_ARG_LIT("-device"); - if (!(devstr = qemuBuildPCIHostdevDevStr(hostdev))) + if (!(devstr = qemuBuildPCIHostdevDevStr(hostdev, configfd))) goto error; ADD_ARG(devstr); } else if (qemuCmdFlags & QEMUD_CMD_FLAG_PCIDEVICE) { diff --git a/src/qemu/qemu_conf.h b/src/qemu/qemu_conf.h index a101e47..64fab60 100644 --- a/src/qemu/qemu_conf.h +++ b/src/qemu/qemu_conf.h @@ -88,6 +88,7 @@ enum qemud_cmd_flags { QEMUD_CMD_FLAG_NO_HPET = (1LL << 33), /* -no-hpet flag is supported */ QEMUD_CMD_FLAG_NO_KVM_PIT = (1LL << 34), /* -no-kvm-pit-reinjection supported */ QEMUD_CMD_FLAG_TDF = (1LL << 35), /* -tdf flag (user-mode pit catchup) */ + QEMUD_CMD_FLAG_PCI_CONFIGFD = (1LL << 36), /* pci-assign.configfd */ }; /* Main driver state */ @@ -190,6 +191,9 @@ int qemudParseHelpStr (const char *qemu, unsigned int *is_kvm, unsigned int *kvm_version); +void qemudParsePCIDeviceStrs (const char *qemu, + unsigned long long *qemuCmdFlags); + int qemudBuildCommandLine (virConnectPtr conn, struct qemud_driver *driver, virDomainDefPtr def, @@ -242,7 +246,9 @@ char * qemuBuildSoundDevStr(virDomainSoundDefPtr sound); /* Legacy, pre device support */ char * qemuBuildPCIHostdevPCIDevStr(virDomainHostdevDefPtr dev); /* Current, best practice */ -char * qemuBuildPCIHostdevDevStr(virDomainHostdevDefPtr dev); +char * qemuBuildPCIHostdevDevStr(virDomainHostdevDefPtr dev, int configfd); + +int qemudOpenPCIConfig(virDomainHostdevDefPtr dev); /* Current, best practice */ char * qemuBuildChrChardevStr(virDomainChrDefPtr dev); diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index dd5bd24..219a973 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -7567,7 +7567,7 @@ static int qemudDomainAttachHostPciDevice(struct qemud_driver *driver, if (qemuDomainPCIAddressEnsureAddr(priv->pciaddrs, &hostdev->info) < 0) goto error; - if (!(devstr = qemuBuildPCIHostdevDevStr(hostdev))) + if (!(devstr = qemuBuildPCIHostdevDevStr(hostdev, -1))) goto error; }