From 32a9a682bef2f6fce7026bd94d1ce20028b0e52d Mon Sep 17 00:00:00 2001 From: Yuji Shimada Date: Mon, 16 Mar 2009 17:13:39 +0900 Subject: PCI: allow assignment of memory resources with a specified alignment 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: [@][:]:.[; ...] Specifies alignment and device to reassign aligned memory resources. If 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 Reviewed-by: Yu Zhao Signed-off-by: Yuji Shimada Signed-off-by: Jesse Barnes --- drivers/pci/pci.c | 120 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 120 insertions(+) (limited to 'drivers/pci/pci.c') diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 8310dc2f943..a35a8b2ba63 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -20,6 +20,8 @@ #include #include #include /* isa_dma_bridge_buggy */ +#include +#include #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); -- cgit v1.2.3