[libvirt] [PATCH] Force FLR on for buggy SR-IOV devices.
Some buggy PCI devices actually support FLR, but
forget to advertise that fact in their PCI config space.
However, Virtual Functions on SR-IOV devices are
*required* to support FLR by the spec, so force has_flr
on if this is a virtual function.
Signed-off-by: Chris Lalancette <clalance(a)redhat.com>
---
src/util/pci.c | 48 ++++++++++++++++++++++++++++++++++++++++++++----
1 files changed, 44 insertions(+), 4 deletions(-)
diff --git a/src/util/pci.c b/src/util/pci.c
index c45b179..41e91af 100644
--- a/src/util/pci.c
+++ b/src/util/pci.c
@@ -183,6 +183,16 @@ pciOpenConfig(pciDevice *dev)
return 0;
}
+static void
+pciCloseConfig(pciDevice *dev)
+{
+ if (!dev)
+ return;
+
+ if (dev->fd >= 0)
+ close(dev->fd);
+}
+
static int
pciRead(pciDevice *dev, unsigned pos, uint8_t *buf, unsigned buflen)
{
@@ -380,11 +390,16 @@ pciFindExtendedCapabilityOffset(pciDevice *dev, unsigned
capability)
return 0;
}
-static unsigned
+/* detects whether this device has FLR. Returns 0 if the device does
+ * not have FLR, 1 if it does, and -1 on error
+ */
+static int
pciDetectFunctionLevelReset(pciDevice *dev)
{
uint32_t caps;
uint8_t pos;
+ char *path;
+ int found;
/* The PCIe Function Level Reset capability allows
* individual device functions to be reset without
@@ -413,6 +428,25 @@ pciDetectFunctionLevelReset(pciDevice *dev)
}
}
+ /* there are some buggy devices that do support FLR, but forget to
+ * advertise that fact in their capabilities. However, FLR is *required*
+ * to be present for virtual functions (VFs), so if we see that this
+ * device is a VF, we just assume FLR works
+ */
+
+ if (virAsprintf(&path, PCI_SYSFS "devices/%s/physfn", dev->name)
< 0) {
+ virReportOOMError();
+ return -1;
+ }
+
+ found = virFileExists(path);
+ VIR_FREE(path);
+ if (found) {
+ VIR_DEBUG("%s %s: buggy device didn't advertise FLR, but is a VF;
forcing flr on",
+ dev->id, dev->name);
+ return 1;
+ }
+
VIR_DEBUG("%s %s: no FLR capability found", dev->id, dev->name);
return 0;
@@ -626,6 +660,8 @@ pciTryPowerManagementReset(pciDevice *dev)
static int
pciInitDevice(pciDevice *dev)
{
+ int flr;
+
if (pciOpenConfig(dev) < 0) {
virReportSystemError(errno,
_("Failed to open config space file
'%s'"),
@@ -635,7 +671,12 @@ pciInitDevice(pciDevice *dev)
dev->pcie_cap_pos = pciFindCapabilityOffset(dev, PCI_CAP_ID_EXP);
dev->pci_pm_cap_pos = pciFindCapabilityOffset(dev, PCI_CAP_ID_PM);
- dev->has_flr = pciDetectFunctionLevelReset(dev);
+ flr = pciDetectFunctionLevelReset(dev);
+ if (flr < 0) {
+ pciCloseConfig(dev);
+ return flr;
+ }
+ dev->has_flr = flr;
dev->has_pm_reset = pciDetectPowerManagementReset(dev);
dev->initted = 1;
return 0;
@@ -1098,8 +1139,7 @@ pciFreeDevice(pciDevice *dev)
if (!dev)
return;
VIR_DEBUG("%s %s: freeing", dev->id, dev->name);
- if (dev->fd >= 0)
- close(dev->fd);
+ pciCloseConfig(dev);
VIR_FREE(dev);
}
--
1.7.1.1