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-rw-r--r--drivers/pci/hotplug/pcihp_slot.c4
-rw-r--r--drivers/pci/pci.c6
-rw-r--r--drivers/pci/probe.c59
-rw-r--r--drivers/pci/xen-pcifront.c5
4 files changed, 46 insertions, 28 deletions
diff --git a/drivers/pci/hotplug/pcihp_slot.c b/drivers/pci/hotplug/pcihp_slot.c
index 753b21aaea6..3ffd9c1acc0 100644
--- a/drivers/pci/hotplug/pcihp_slot.c
+++ b/drivers/pci/hotplug/pcihp_slot.c
@@ -169,7 +169,9 @@ void pci_configure_slot(struct pci_dev *dev)
(dev->class >> 8) == PCI_CLASS_BRIDGE_PCI)))
return;
- pcie_bus_configure_settings(dev->bus, dev->bus->self->pcie_mpss);
+ if (dev->bus && dev->bus->self)
+ pcie_bus_configure_settings(dev->bus,
+ dev->bus->self->pcie_mpss);
memset(&hpp, 0, sizeof(hpp));
ret = pci_get_hp_params(dev, &hpp);
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 0ce67423a0a..e9651f0a881 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -77,7 +77,7 @@ unsigned long pci_cardbus_mem_size = DEFAULT_CARDBUS_MEM_SIZE;
unsigned long pci_hotplug_io_size = DEFAULT_HOTPLUG_IO_SIZE;
unsigned long pci_hotplug_mem_size = DEFAULT_HOTPLUG_MEM_SIZE;
-enum pcie_bus_config_types pcie_bus_config = PCIE_BUS_PERFORMANCE;
+enum pcie_bus_config_types pcie_bus_config = PCIE_BUS_TUNE_OFF;
/*
* The default CLS is used if arch didn't set CLS explicitly and not
@@ -3568,10 +3568,14 @@ static int __init pci_setup(char *str)
pci_hotplug_io_size = memparse(str + 9, &str);
} else if (!strncmp(str, "hpmemsize=", 10)) {
pci_hotplug_mem_size = memparse(str + 10, &str);
+ } else if (!strncmp(str, "pcie_bus_tune_off", 17)) {
+ pcie_bus_config = PCIE_BUS_TUNE_OFF;
} else if (!strncmp(str, "pcie_bus_safe", 13)) {
pcie_bus_config = PCIE_BUS_SAFE;
} else if (!strncmp(str, "pcie_bus_perf", 13)) {
pcie_bus_config = PCIE_BUS_PERFORMANCE;
+ } else if (!strncmp(str, "pcie_bus_peer2peer", 18)) {
+ pcie_bus_config = PCIE_BUS_PEER2PEER;
} else {
printk(KERN_ERR "PCI: Unknown option `%s'\n",
str);
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 8473727b29f..6ab6bd3df4b 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1351,7 +1351,8 @@ static int pcie_find_smpss(struct pci_dev *dev, void *data)
* will occur as normal.
*/
if (dev->is_hotplug_bridge && (!list_is_singular(&dev->bus->devices) ||
- dev->bus->self->pcie_type != PCI_EXP_TYPE_ROOT_PORT))
+ (dev->bus->self &&
+ dev->bus->self->pcie_type != PCI_EXP_TYPE_ROOT_PORT)))
*smpss = 0;
if (*smpss > dev->pcie_mpss)
@@ -1396,34 +1397,37 @@ static void pcie_write_mps(struct pci_dev *dev, int mps)
static void pcie_write_mrrs(struct pci_dev *dev, int mps)
{
- int rc, mrrs;
+ int rc, mrrs, dev_mpss;
- if (pcie_bus_config == PCIE_BUS_PERFORMANCE) {
- int dev_mpss = 128 << dev->pcie_mpss;
+ /* In the "safe" case, do not configure the MRRS. There appear to be
+ * issues with setting MRRS to 0 on a number of devices.
+ */
- /* For Max performance, the MRRS must be set to the largest
- * supported value. However, it cannot be configured larger
- * than the MPS the device or the bus can support. This assumes
- * that the largest MRRS available on the device cannot be
- * smaller than the device MPSS.
- */
- mrrs = mps < dev_mpss ? mps : dev_mpss;
- } else
- /* In the "safe" case, configure the MRRS for fairness on the
- * bus by making all devices have the same size
- */
- mrrs = mps;
+ if (pcie_bus_config != PCIE_BUS_PERFORMANCE)
+ return;
+ dev_mpss = 128 << dev->pcie_mpss;
+
+ /* For Max performance, the MRRS must be set to the largest supported
+ * value. However, it cannot be configured larger than the MPS the
+ * device or the bus can support. This assumes that the largest MRRS
+ * available on the device cannot be smaller than the device MPSS.
+ */
+ mrrs = min(mps, dev_mpss);
/* MRRS is a R/W register. Invalid values can be written, but a
- * subsiquent read will verify if the value is acceptable or not.
+ * subsequent read will verify if the value is acceptable or not.
* If the MRRS value provided is not acceptable (e.g., too large),
* shrink the value until it is acceptable to the HW.
*/
while (mrrs != pcie_get_readrq(dev) && mrrs >= 128) {
+ dev_warn(&dev->dev, "Attempting to modify the PCI-E MRRS value"
+ " to %d. If any issues are encountered, please try "
+ "running with pci=pcie_bus_safe\n", mrrs);
rc = pcie_set_readrq(dev, mrrs);
if (rc)
- dev_err(&dev->dev, "Failed attempting to set the MRRS\n");
+ dev_err(&dev->dev,
+ "Failed attempting to set the MRRS\n");
mrrs /= 2;
}
@@ -1436,13 +1440,13 @@ static int pcie_bus_configure_set(struct pci_dev *dev, void *data)
if (!pci_is_pcie(dev))
return 0;
- dev_info(&dev->dev, "Dev MPS %d MPSS %d MRRS %d\n",
+ dev_dbg(&dev->dev, "Dev MPS %d MPSS %d MRRS %d\n",
pcie_get_mps(dev), 128<<dev->pcie_mpss, pcie_get_readrq(dev));
pcie_write_mps(dev, mps);
pcie_write_mrrs(dev, mps);
- dev_info(&dev->dev, "Dev MPS %d MPSS %d MRRS %d\n",
+ dev_dbg(&dev->dev, "Dev MPS %d MPSS %d MRRS %d\n",
pcie_get_mps(dev), 128<<dev->pcie_mpss, pcie_get_readrq(dev));
return 0;
@@ -1454,15 +1458,24 @@ static int pcie_bus_configure_set(struct pci_dev *dev, void *data)
*/
void pcie_bus_configure_settings(struct pci_bus *bus, u8 mpss)
{
- u8 smpss = mpss;
+ u8 smpss;
- if (!bus->self)
+ if (!pci_is_pcie(bus->self))
return;
- if (!pci_is_pcie(bus->self))
+ if (pcie_bus_config == PCIE_BUS_TUNE_OFF)
return;
+ /* FIXME - Peer to peer DMA is possible, though the endpoint would need
+ * to be aware to the MPS of the destination. To work around this,
+ * simply force the MPS of the entire system to the smallest possible.
+ */
+ if (pcie_bus_config == PCIE_BUS_PEER2PEER)
+ smpss = 0;
+
if (pcie_bus_config == PCIE_BUS_SAFE) {
+ smpss = mpss;
+
pcie_find_smpss(bus->self, &smpss);
pci_walk_bus(bus, pcie_find_smpss, &smpss);
}
diff --git a/drivers/pci/xen-pcifront.c b/drivers/pci/xen-pcifront.c
index 6fa215a3861..90832a95599 100644
--- a/drivers/pci/xen-pcifront.c
+++ b/drivers/pci/xen-pcifront.c
@@ -400,9 +400,8 @@ static int pcifront_claim_resource(struct pci_dev *dev, void *data)
dev_info(&pdev->xdev->dev, "claiming resource %s/%d\n",
pci_name(dev), i);
if (pci_claim_resource(dev, i)) {
- dev_err(&pdev->xdev->dev, "Could not claim "
- "resource %s/%d! Device offline. Try "
- "giving less than 4GB to domain.\n",
+ dev_err(&pdev->xdev->dev, "Could not claim resource %s/%d! "
+ "Device offline. Try using e820_host=1 in the guest config.\n",
pci_name(dev), i);
}
}
generated by cgit v1.2.3-70-g09d2 (git 2.51.2) at 2025-11-04 05:17:39 +0000