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PCI: allow assignment of memory resources with a specified alignment

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This patch allows memory resources to be assigned with a specified
alignment at boot-time or run-time. The patch is useful when we use PCI
pass-through, because page-aligned memory resources are required to
securely share PCI resources with guest drivers.

If you want to assign the resource at boot time, please set
"pci=resource_alignment=" boot parameter.

This is format of "pci=resource_alignment=" boot parameter:

        [<order of align>@][<domain>:]<bus>:<slot>.<func>[; ...]
                Specifies alignment and device to reassign
                aligned memory resources.
                If <order of align> is not specified, PAGE_SIZE is
                used as alignment.
                PCI-PCI bridge can be specified, if resource
                windows need to be expanded.

This is example:

        pci=resource_alignment=20@07:00.0;18@0f:00.0;00:1d.7

If you want to assign the resource at run-time, please set
"/sys/bus/pci/resource_alignment" file, and hot-remove the device and
hot-add the device.  For this purpose, fakephp or PCI hotplug interfaces
can be used.

The format of "/sys/bus/pci/resource_alignment" file is the same with
boot parameter. You can use "," instead of ";".

For example:

        # cd /sys/bus/pci
        # echo -n 20@12:00.0 > resource_alignment
        # echo 1 > devices/0000:12:00.0/remove
        # echo 1 > rescan

Reviewed-by: Alex Chiang <achiang@hp.com>
Reviewed-by: Yu Zhao <yu.zhao@intel.com>
Signed-off-by: Yuji Shimada <shimada-yxb@necst.nec.co.jp>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
This commit is contained in:
Yuji Shimada 2009-03-16 17:13:39 +09:00 committed by Jesse Barnes
parent 1c8d7b0a56
commit 32a9a682be
5 changed files with 210 additions and 0 deletions
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9
Documentation/kernel-parameters.txt
View File

@ -1760,6 +1760,15 @@ and is between 256 and 4096 characters. It is defined in the file
cbmemsize=nn[KMG] The fixed amount of bus space which is
reserved for the CardBus bridge's memory
window. The default value is 64 megabytes.
resource_alignment=
Format:
[<order of align>@][<domain>:]<bus>:<slot>.<func>[; ...]
Specifies alignment and device to reassign
aligned memory resources.
If <order of align> is not specified,
PAGE_SIZE is used as alignment.
PCI-PCI bridge can be specified, if resource
windows need to be expanded.
pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
Management.

120
drivers/pci/pci.c
View File

@ -20,6 +20,8 @@
#include <linux/pm_wakeup.h>
#include <linux/interrupt.h>
#include <asm/dma.h> /* isa_dma_bridge_buggy */
#include <linux/device.h>
#include <asm/setup.h>
#include "pci.h"
unsigned int pci_pm_d3_delay = PCI_PM_D3_WAIT;
@ -2370,6 +2372,121 @@ int pci_resource_bar(struct pci_dev *dev, int resno, enum pci_bar_type *type)
return 0;
}
#define RESOURCE_ALIGNMENT_PARAM_SIZE COMMAND_LINE_SIZE
static char resource_alignment_param[RESOURCE_ALIGNMENT_PARAM_SIZE] = {0};
spinlock_t resource_alignment_lock = SPIN_LOCK_UNLOCKED;
/**
* pci_specified_resource_alignment - get resource alignment specified by user.
* @dev: the PCI device to get
*
* RETURNS: Resource alignment if it is specified.
* Zero if it is not specified.
*/
resource_size_t pci_specified_resource_alignment(struct pci_dev *dev)
{
int seg, bus, slot, func, align_order, count;
resource_size_t align = 0;
char *p;
spin_lock(&resource_alignment_lock);
p = resource_alignment_param;
while (*p) {
count = 0;
if (sscanf(p, "%d%n", &align_order, &count) == 1 &&
p[count] == '@') {
p += count + 1;
} else {
align_order = -1;
}
if (sscanf(p, "%x:%x:%x.%x%n",
&seg, &bus, &slot, &func, &count) != 4) {
seg = 0;
if (sscanf(p, "%x:%x.%x%n",
&bus, &slot, &func, &count) != 3) {
/* Invalid format */
printk(KERN_ERR "PCI: Can't parse resource_alignment parameter: %s\n",
p);
break;
}
}
p += count;
if (seg == pci_domain_nr(dev->bus) &&
bus == dev->bus->number &&
slot == PCI_SLOT(dev->devfn) &&
func == PCI_FUNC(dev->devfn)) {
if (align_order == -1) {
align = PAGE_SIZE;
} else {
align = 1 << align_order;
}
/* Found */
break;
}
if (*p != ';' && *p != ',') {
/* End of param or invalid format */
break;
}
p++;
}
spin_unlock(&resource_alignment_lock);
return align;
}
/**
* pci_is_reassigndev - check if specified PCI is target device to reassign
* @dev: the PCI device to check
*
* RETURNS: non-zero for PCI device is a target device to reassign,
* or zero is not.
*/
int pci_is_reassigndev(struct pci_dev *dev)
{
return (pci_specified_resource_alignment(dev) != 0);
}
ssize_t pci_set_resource_alignment_param(const char *buf, size_t count)
{
if (count > RESOURCE_ALIGNMENT_PARAM_SIZE - 1)
count = RESOURCE_ALIGNMENT_PARAM_SIZE - 1;
spin_lock(&resource_alignment_lock);
strncpy(resource_alignment_param, buf, count);
resource_alignment_param[count] = '\0';
spin_unlock(&resource_alignment_lock);
return count;
}
ssize_t pci_get_resource_alignment_param(char *buf, size_t size)
{
size_t count;
spin_lock(&resource_alignment_lock);
count = snprintf(buf, size, "%s", resource_alignment_param);
spin_unlock(&resource_alignment_lock);
return count;
}
static ssize_t pci_resource_alignment_show(struct bus_type *bus, char *buf)
{
return pci_get_resource_alignment_param(buf, PAGE_SIZE);
}
static ssize_t pci_resource_alignment_store(struct bus_type *bus,
const char *buf, size_t count)
{
return pci_set_resource_alignment_param(buf, count);
}
BUS_ATTR(resource_alignment, 0644, pci_resource_alignment_show,
pci_resource_alignment_store);
static int __init pci_resource_alignment_sysfs_init(void)
{
return bus_create_file(&pci_bus_type,
&bus_attr_resource_alignment);
}
late_initcall(pci_resource_alignment_sysfs_init);
static void __devinit pci_no_domains(void)
{
#ifdef CONFIG_PCI_DOMAINS
@ -2418,6 +2535,9 @@ static int __init pci_setup(char *str)
pci_cardbus_io_size = memparse(str + 9, &str);
} else if (!strncmp(str, "cbmemsize=", 10)) {
pci_cardbus_mem_size = memparse(str + 10, &str);
} else if (!strncmp(str, "resource_alignment=", 19)) {
pci_set_resource_alignment_param(str + 19,
strlen(str + 19));
} else {
printk(KERN_ERR "PCI: Unknown option `%s'\n",
str);

6
drivers/pci/pci.h
View File

@ -195,4 +195,10 @@ static inline int pci_ari_enabled(struct pci_bus *bus)
return bus->self && bus->self->ari_enabled;
}
#ifdef CONFIG_PCI_QUIRKS
extern int pci_is_reassigndev(struct pci_dev *dev);
resource_size_t pci_specified_resource_alignment(struct pci_dev *dev);
extern void pci_disable_bridge_window(struct pci_dev *dev);
#endif
#endif /* DRIVERS_PCI_H */

60
drivers/pci/quirks.c
View File

@ -24,6 +24,7 @@
#include <linux/kallsyms.h>
#include <linux/dmi.h>
#include <linux/pci-aspm.h>
#include <linux/ioport.h>
#include "pci.h"
int isa_dma_bridge_buggy;
@ -34,6 +35,65 @@ int pcie_mch_quirk;
EXPORT_SYMBOL(pcie_mch_quirk);
#ifdef CONFIG_PCI_QUIRKS
/*
* This quirk function disables the device and releases resources
* which is specified by kernel's boot parameter 'pci=resource_alignment='.
* It also rounds up size to specified alignment.
* Later on, the kernel will assign page-aligned memory resource back
* to that device.
*/
static void __devinit quirk_resource_alignment(struct pci_dev *dev)
{
int i;
struct resource *r;
resource_size_t align, size;
if (!pci_is_reassigndev(dev))
return;
if (dev->hdr_type == PCI_HEADER_TYPE_NORMAL &&
(dev->class >> 8) == PCI_CLASS_BRIDGE_HOST) {
dev_warn(&dev->dev,
"Can't reassign resources to host bridge.\n");
return;
}
dev_info(&dev->dev, "Disabling device and release resources.\n");
pci_disable_device(dev);
align = pci_specified_resource_alignment(dev);
for (i=0; i < PCI_BRIDGE_RESOURCES; i++) {
r = &dev->resource[i];
if (!(r->flags & IORESOURCE_MEM))
continue;
size = resource_size(r);
if (size < align) {
size = align;
dev_info(&dev->dev,
"Rounding up size of resource #%d to %#llx.\n",
i, (unsigned long long)size);
}
r->end = size - 1;
r->start = 0;
}
/* Need to disable bridge's resource window,
* to enable the kernel to reassign new resource
* window later on.
*/
if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE &&
(dev->class >> 8) == PCI_CLASS_BRIDGE_PCI) {
for (i = PCI_BRIDGE_RESOURCES; i < PCI_NUM_RESOURCES; i++) {
r = &dev->resource[i];
if (!(r->flags & IORESOURCE_MEM))
continue;
r->end = resource_size(r) - 1;
r->start = 0;
}
pci_disable_bridge_window(dev);
}
}
DECLARE_PCI_FIXUP_HEADER(PCI_ANY_ID, PCI_ANY_ID, quirk_resource_alignment);
/* The Mellanox Tavor device gives false positive parity errors
* Mark this device with a broken_parity_status, to allow
* PCI scanning code to "skip" this now blacklisted device.

15
drivers/pci/setup-res.c
View File

@ -120,6 +120,21 @@ int pci_claim_resource(struct pci_dev *dev, int resource)
return err;
}
#ifdef CONFIG_PCI_QUIRKS
void pci_disable_bridge_window(struct pci_dev *dev)
{
dev_dbg(&dev->dev, "Disabling 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);
}
#endif /* CONFIG_PCI_QUIRKS */
int pci_assign_resource(struct pci_dev *dev, int resno)
{
struct pci_bus *bus = dev->bus;