This patch adds the function that reassigns page-aligned memory
resources to device, to linux.
I created this patch for xen's dom0 linux. It is useful when we assign
I/O device to HVM domain using pci passthrough, because page-aligned
memory resource is required for pci passthrough. But I heard it is
also useful for KVM. So I submit it to linux-pci ML.
On many system, BIOS assigns memory resources to the device and
enables it. So my patch disables the device, and releases memory
resources. Then it assigns page-aligned memory resource to the device.
To reassign page-aligned memory resources to device, please add boot
parameters of linux as follows.
reassigndev=00:1d.7,01:00.0
reassigndev= Specifies device to reassign page-aligned
memory resources. PCI-PCI bridge can be
specified, if resource windows need to be
expanded.
You can easily improve the way of specifying device to reassign,
changing the code of reassigndev.c.
Thanks,
--
Yuji Shimada
Signed-off-by: Yuji Shimada <shimada-yxb@xxxxxxxxxxxxxxx>
diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
index e1ca425..202d3d2 100644
--- a/drivers/pci/Kconfig
+++ b/drivers/pci/Kconfig
@@ -32,6 +32,20 @@ config PCI_LEGACY
option serves to include/exclude only a few drivers that are
still using this API.
+config PCI_REASSIGN
+ bool "Enable reassign page-aligned memory resources to device"
+ depends on PCI
+ default y
+ help
+ Say Y here if you want to reassign page-aligned memory resources to
+ the device. And add boot parameters of linux as follows.
+
+ reassigndev=00:1d.7,01:00.0
+
+ "reassigndev=" specifies devices to reassign page-aligned memory
+ resources. PCI-PCI bridge can be specified, if resource windows need
+ to be expanded.
+
config PCI_DEBUG
bool "PCI Debugging"
depends on PCI && DEBUG_KERNEL
diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile
index af3bfe2..50c6b35 100644
--- a/drivers/pci/Makefile
+++ b/drivers/pci/Makefile
@@ -6,6 +6,7 @@ obj-y += access.o bus.o probe.o remove.o pci.o quirks.o slot.o \
pci-driver.o search.o pci-sysfs.o rom.o setup-res.o \
irq.o
obj-$(CONFIG_PROC_FS) += proc.o
+obj-$(CONFIG_PCI_REASSIGN) += reassigndev.o
# Build PCI Express stuff if needed
obj-$(CONFIG_PCIEPORTBUS) += pcie/
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 9de87e9..4b51f3f 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -171,4 +171,11 @@ static inline int pci_ari_enabled(struct pci_dev *dev)
return dev->ari_enabled;
}
+#ifdef CONFIG_PCI_REASSIGN
+extern int is_reassigndev(struct pci_dev *dev);
+#else
+#define is_reassigndev(dev) 0
+#endif
+extern void pci_disable_bridge_window(struct pci_dev *dev);
+
#endif /* DRIVERS_PCI_H */
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 96cf8ec..af2ae0e 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -31,6 +31,53 @@ EXPORT_SYMBOL(pci_pci_problems);
int pcie_mch_quirk;
EXPORT_SYMBOL(pcie_mch_quirk);
+/*
+ * This quirk function disables the device and releases resources
+ * which is specified by kernel's boot parameter 'reassigndev'.
+ * Later on, kernel will assign page-aligned memory resource back
+ * to that device.
+ */
+static void __devinit quirk_release_resources(struct pci_dev *dev)
+{
+ int i;
+ struct resource *r;
+
+ if (is_reassigndev(dev)) {
+ if (dev->hdr_type == PCI_HEADER_TYPE_NORMAL &&
+ (dev->class >> 8) == PCI_CLASS_BRIDGE_HOST) {
+ /* PCI Host Bridge isn't a target device */
+ return;
+ }
+ printk(KERN_INFO
+ "PCI: Disable device and release resources [%s].\n",
+ pci_name(dev));
+ pci_disable_device(dev);
+
+ for (i=0; i < PCI_NUM_RESOURCES; i++) {
+ r = &dev->resource[i];
+ if (!(r->flags & IORESOURCE_MEM))
+ continue;
+
+ r->end = r->end - r->start;
+ r->start = 0;
+
+ if (i < PCI_BRIDGE_RESOURCES) {
+ pci_update_resource(dev, r, i);
+ }
+ }
+ /* need to disable bridge's resource window,
+ * to make kernel enable to reassign new resource
+ * window later on.
+ */
+ if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE &&
+ (dev->class >> 8) == PCI_CLASS_BRIDGE_PCI) {
+ pci_disable_bridge_window(dev);
+ }
+ return;
+ }
+}
+DECLARE_PCI_FIXUP_HEADER(PCI_ANY_ID, PCI_ANY_ID, quirk_release_resources);
+
#ifdef CONFIG_PCI_QUIRKS
/* The Mellanox Tavor device gives false positive parity errors
* Mark this device with a broken_parity_status, to allow
diff --git a/drivers/pci/reassigndev.c b/drivers/pci/reassigndev.c
new file mode 100644
index 0000000..ea19481
--- /dev/null
+++ b/drivers/pci/reassigndev.c
@@ -0,0 +1,80 @@
+/*
+ * Copyright (c) 2008, NEC Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place - Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+#include <linux/kernel.h>
+#include <linux/pci.h>
+#include <linux/string.h>
+#include "pci.h"
+
+
+#define REASSIGNDEV_PARAM_MAX (2048)
+#define TOKEN_MAX (12) /* "SSSS:BB:DD.F" length is 12 */
+
+static char param_reassigndev[REASSIGNDEV_PARAM_MAX] = {0};
+
+static int __init reassigndev_setup(char *str)
+{
+ strncpy(param_reassigndev, str, REASSIGNDEV_PARAM_MAX);
+ param_reassigndev[REASSIGNDEV_PARAM_MAX - 1] = '\0';
+ return 1;
+}
+__setup("reassigndev=", reassigndev_setup);
+
+int is_reassigndev(struct pci_dev *dev)
+{
+ char dev_str[TOKEN_MAX+1];
+ int seg, bus, slot, func;
+ int len;
+ char *p, *next_str;
+
+ p = param_reassigndev;
+ for (; p; p = next_str + 1) {
+ next_str = strpbrk(p, ",");
+ if (next_str) {
+ len = next_str - p;
+ } else {
+ len = strlen(p);
+ }
+ if (len > 0 && len <= TOKEN_MAX) {
+ strncpy(dev_str, p, len);
+ *(dev_str + len) = '\0';
+
+ if (sscanf(dev_str, "%x:%x:%x.%x",
+ &seg, &bus, &slot, &func) != 4) {
+ if (sscanf(dev_str, "%x:%x.%x",
+ &bus, &slot, &func) == 3) {
+ seg = 0;
+ } else {
+ /* failed to scan strings */
+ seg = -1;
+ bus = -1;
+ }
+ }
+ if (seg == pci_domain_nr(dev->bus) &&
+ bus == dev->bus->number &&
+ slot == PCI_SLOT(dev->devfn) &&
+ func == PCI_FUNC(dev->devfn)) {
+ /* It's a target device */
+ return 1;
+ }
+ }
+ if (!next_str)
+ break;
+ }
+
+ return 0;
+}
diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index ea979f2..96c0b3e 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -25,6 +25,7 @@
#include <linux/ioport.h>
#include <linux/cache.h>
#include <linux/slab.h>
+#include "pci.h"
static void pbus_assign_resources_sorted(struct pci_bus *bus)
@@ -343,6 +344,7 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask, unsigned long
list_for_each_entry(dev, &bus->devices, bus_list) {
int i;
+ int reassign = is_reassigndev(dev);
for (i = 0; i < PCI_NUM_RESOURCES; i++) {
struct resource *r = &dev->resource[i];
@@ -351,6 +353,8 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask, unsigned long
if (r->parent || (r->flags & mask) != type)
continue;
r_size = resource_size(r);
+ if (reassign)
+ r_size = ALIGN(r_size, PAGE_SIZE);
/* For bridges size != alignment */
align = resource_alignment(r);
order = __ffs(align) - 20;
diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c
index 2dbd96c..111e5d2 100644
--- a/drivers/pci/setup-res.c
+++ b/drivers/pci/setup-res.c
@@ -122,17 +122,35 @@ int pci_claim_resource(struct pci_dev *dev, int resource)
return err;
}
+void pci_disable_bridge_window(struct pci_dev *dev)
+{
+ dev_dbg(&dev->dev, "Disable bridge window\n");
+
+ /* MMIO Base/Limit */
+ pci_write_config_dword(dev, PCI_MEMORY_BASE, 0x0000fff0);
+
+ /* Prefetchable MMIO Base/Limit */
+ pci_write_config_dword(dev, PCI_PREF_LIMIT_UPPER32, 0);
+ pci_write_config_dword(dev, PCI_PREF_MEMORY_BASE, 0x0000fff0);
+ pci_write_config_dword(dev, PCI_PREF_BASE_UPPER32, 0xffffffff);
+}
+
int pci_assign_resource(struct pci_dev *dev, int resno)
{
struct pci_bus *bus = dev->bus;
struct resource *res = dev->resource + resno;
resource_size_t size, min, align;
int ret;
+ int reassigndev = is_reassigndev(dev);
size = resource_size(res);
min = (res->flags & IORESOURCE_IO) ? PCIBIOS_MIN_IO : PCIBIOS_MIN_MEM;
align = resource_alignment(res);
+ if ((reassigndev) &&
+ (res->flags & IORESOURCE_MEM)) {
+ align = ALIGN(align, PAGE_SIZE);
+ }
if (!align) {
dev_err(&dev->dev, "BAR %d: can't allocate resource (bogus "
"alignment) %pR flags %#lx\n",
@@ -162,6 +180,11 @@ int pci_assign_resource(struct pci_dev *dev, int resno)
} else {
res->flags &= ~IORESOURCE_STARTALIGN;
if (resno < PCI_BRIDGE_RESOURCES)
+ if (reassigndev)
+ dev_dbg(&dev->dev, "BAR %d: assign resource "
+ "[%#llx - %#llx\n", resno,
+ (unsigned long long)res->start,
+ (unsigned long long)res->end);
pci_update_resource(dev, res, resno);
}
--
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