On 11/07/2013 12:10 PM, Laine Stump wrote: > This resolves: > > https://bugzilla.redhat.com/show_bug.cgi?id=1025397 > > When libvirt creates the list of an SRIOV Physical Function's (PF) > Virtual Functions (VF), it assumes that the order of "virtfn*" links > returned by readdir() from the PF's sysfs directory is already in the > correct order. Experience has shown that this is not always the case. > > This results in 1) incorrect assumptions made by consumers of the > output of the virt_functions list of virsh nodedev-dumpxml, and 2) > setting MAC address and vlan tag on the wrong VF (since libvirt uses > netlink to set mac address and vlan tag, netlink requires the VF#, and > the function virPCIGetVirtualFunctionIndex() returns the wrong index > due to the improperly ordered VF list). See the bugzilla report for an > example of this improper behavior. > > The solution provided by this patch is for virPCIGetVirtualFunctions > to first gather all the "virtfn*" names from the PFs sysfs directory, > then allocate a virtual_functions array large enough to hold all > entries, and finally to create a device entry for each virtfn* name > and place it into the virtual_functions array at the proper index > (based on interpreting the value following "virtfn" in the name). > > Checks are introduced to ensure that 1) the virtfn list given in sysfs > is not sparse (ie, there are no indexes larger than the length of the > list), and that no two virtfn* entries decode to the same index. > --- > > Difference from V1: Based on jtomko's review, truncate trailing NULLs > in virtual_functions array, and actually check for NULLs in the middle > (a sparse array) and generate an error in that case, as we already > claimed to do in the commit message. > > (Sorry for the lack of inter-diff, but the only changes from V1 are > the addition of the lines starting with "truncate any trailing nulls" > and continuing until the next VIR_DEBUG.) > > src/util/virpci.c | 115 > ++++++++++++++++++++++++++++++++++++++++++------------ > 1 file changed, 90 insertions(+), 25 deletions(-) > > diff --git a/src/util/virpci.c b/src/util/virpci.c > index 148631f..f744c8b 100644 > --- a/src/util/virpci.c > +++ b/src/util/virpci.c > @@ -2379,6 +2379,8 @@ virPCIGetPhysicalFunction(const char *vf_sysfs_path, > return ret; > } > > +static const char *virtfnPrefix = "virtfn"; > + > /* > * Returns virtual functions of a physical function > */ > @@ -2393,6 +2395,8 @@ virPCIGetVirtualFunctions(const char *sysfs_path, > struct dirent *entry = NULL; > char *device_link = NULL; > char errbuf[64]; > + char **virtfnNames = NULL; > + size_t nVirtfnNames = 0; > > VIR_DEBUG("Attempting to get SR IOV virtual functions for device" > "with sysfs path '%s'", sysfs_path); > @@ -2411,51 +2415,112 @@ virPCIGetVirtualFunctions(const char *sysfs_path, > > while ((entry = readdir(dir))) { > if (STRPREFIX(entry->d_name, "virtfn")) { > - virPCIDeviceAddress *config_addr = NULL; > + char *tempName; > > - if (virBuildPath(&device_link, sysfs_path, entry->d_name) == -1) > { > - virReportOOMError(); > + /* save these to sort into virtual_functions array */ > + if (VIR_STRDUP(tempName, entry->d_name) < 0) > + goto error; > + if (VIR_APPEND_ELEMENT(virtfnNames, nVirtfnNames, tempName) < 0) > { > + VIR_FREE(tempName); > goto error; > } > + } > + }
Wouldn't it be easier to just count the entries beginning with "virtfn" and
then go from 0 to n? (This would need a special return value for
virPCIGetDeviceAddressFromSysfsLink if the link does not exist, if the entries
in the directory can truly be sparse, or a virtfn-poorly-chosen-name appears)
>
> - VIR_DEBUG("Number of virtual functions: %d",
> - *num_virtual_functions);
> + /* pre-allocate because we will be filling in out of order */
> + if (nVirtfnNames && VIR_ALLOC_N(*virtual_functions, nVirtfnNames) < 0)
> + goto error;
> + *num_virtual_functions = nVirtfnNames;
>
> - if (virPCIGetDeviceAddressFromSysfsLink(device_link,
> - &config_addr) !=
> - SRIOV_FOUND) {
> - VIR_WARN("Failed to get SRIOV function from device "
> - "link '%s'", device_link);
> - VIR_FREE(device_link);
> - continue;
> - }
> + for (i = 0; i < nVirtfnNames; i++) {
> + virPCIDeviceAddress *config_addr = NULL;
> + unsigned int virtfnIndex;
>
> - if (VIR_REALLOC_N(*virtual_functions,
> - *num_virtual_functions + 1) < 0) {
> - VIR_FREE(config_addr);
> - goto error;
> - }
> + if (virBuildPath(&device_link, sysfs_path, virtfnNames[i]) < 0) {
> + virReportOOMError();
> + goto error;
> + }
> +
> + if (virStrToLong_ui(virtfnNames[i] + strlen(virtfnPrefix),
> + 0, 10, &virtfnIndex) < 0) {
> + virReportError(VIR_ERR_INTERNAL_ERROR,
> + _("Invalid virtual function link name '%s' "
> + "in physical function directory '%s'"),
> + virtfnNames[i], sysfs_path);
> + goto error;
> + }
This rejects "virtfn-poor-name-choice" (which is fine by me, it's really a
poor choice).
> +
> + if (virtfnIndex >= nVirtfnNames) {
> + virReportError(VIR_ERR_INTERNAL_ERROR,
> + _("Virtual function link name '%s' larger than "
> + "total count of virtual functions %zu "
> + "in physical function directory '%s'"),
> + virtfnNames[i], nVirtfnNames, sysfs_path);
> + goto error;
> + }
> +
> + if ((*virtual_functions)[virtfnIndex]) {
> + virReportError(VIR_ERR_INTERNAL_ERROR,
> + _("Virtual function link name '%s' "
> + "generates duplicate index %zu "
> + "in physical function directory '%s'"),
> + virtfnNames[i], nVirtfnNames, sysfs_path);
> + goto error;
> + }
Can there really be two entries in a directory with the same name?
>
> - (*virtual_functions)[*num_virtual_functions] = config_addr;
> - (*num_virtual_functions)++;
> + if (virPCIGetDeviceAddressFromSysfsLink(device_link, &config_addr) !=
> + SRIOV_FOUND) {
This also ignores OOM errors.
> + VIR_WARN("Failed to get SRIOV function from device link '%s'",
> + device_link);
> VIR_FREE(device_link);
> + continue;
> }
> +
> + VIR_DEBUG("Found virtual function %d", virtfnIndex);
> + (*virtual_functions)[virtfnIndex] = config_addr;
> + VIR_FREE(device_link);
> }
> + /* truncate any trailing nulls due to files having names starting
> + * with "virtfn" which weren't actually a link to a virtual
> + * function.
> + */
> + while (*num_virtual_functions &&
> + !(*virtual_functions)[(*num_virtual_functions) - 1])
> + (*num_virtual_functions)--;
> +
> + /* failure of realloc when shrinking is safe */
> + ignore_value(VIR_REALLOC_N(*virtual_functions, *num_virtual_functions));
> +
This treats contiguous missing entries at the end differently than the missing
ones at the beginning, are the virtfns with larger indexes less important? :)
> + /* if there are any NULLs left in the array, fail and log an error
> + * - the virtual function array cannot be sparse.
> + */
> + for (i = 0; i < *num_virtual_functions; i++) {
> + if (!(*virtual_functions)[*num_virtual_functions]) {
> + virReportError(VIR_ERR_INTERNAL_ERROR,
> + _("Missing virtual function link for VF %zu "
> + "in physical function directory '%s'"),
> + i, sysfs_path);
In other words, virPCIGetDeviceAddressFromSysfsLink failed. If we really need
to ignore entries that aren't a symlink with a PCI address, the array has to
be sparse and we need to fix all the users :(
> + goto error;
> + }
> + }
> +
> + VIR_DEBUG("Number of virtual functions: %d", *num_virtual_functions);
Jan
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