Here is a revised version that works for both UIO and VFIO. The config access is property of device not the I/O model.
From: Stephen Hemminger <step...@networkplumber.org> Subject: [PATCH 1/4] pci: allow access to PCI config space Some drivers need ability to access PCI config (for example for power management). This adds an abstraction to do this; only implemented on Linux, but should be possible on BSD. Signed-off-by: Stephen Hemminger <stephen at networkplumber.org> --- lib/librte_eal/common/include/rte_pci.h | 29 +++++++++++++++++++++++++++++ lib/librte_eal/linuxapp/eal/eal_pci.c | 15 +++++++++++++++ lib/librte_eal/linuxapp/eal/eal_pci_uio.c | 10 ++++++++++ 3 files changed, 54 insertions(+) Index: dpdk/lib/librte_eal/common/include/rte_pci.h =================================================================== --- dpdk.orig/lib/librte_eal/common/include/rte_pci.h 2015-02-10 15:58:53.915744256 -0800 +++ dpdk/lib/librte_eal/common/include/rte_pci.h 2015-02-10 15:58:53.911744221 -0800 @@ -152,6 +152,7 @@ uint16_t max_vfs; /**< sriov enable if not zero */ int numa_node; /**< NUMA node connection */ struct rte_devargs *devargs; /**< Device user arguments */ + int config_fd; /**< PCI config access */ }; /** Any PCI device identifier (vendor, device, ...) */ @@ -304,6 +305,34 @@ */ void rte_eal_pci_unregister(struct rte_pci_driver *driver); +/** + * Read PCI config space. + * + * @param device + * A pointer to a rte_pci_device structure describing the device + * to use + * @param buf + * A data buffer where the bytes should be read into + * @param size + * The length of the data buffer. + */ +int rte_eal_pci_read_config(const struct rte_pci_device *device, + void *buf, size_t len, off_t offset); + +/** + * Write PCI config space. + * + * @param device + * A pointer to a rte_pci_device structure describing the device + * to use + * @param buf + * A data buffer containing the bytes should be written + * @param size + * The length of the data buffer. + */ +int rte_eal_pci_write_config(const struct rte_pci_device *device, + const void *buf, size_t len, off_t offset); + #ifdef __cplusplus } #endif Index: dpdk/lib/librte_eal/linuxapp/eal/eal_pci.c =================================================================== --- dpdk.orig/lib/librte_eal/linuxapp/eal/eal_pci.c 2015-02-10 15:58:53.915744256 -0800 +++ dpdk/lib/librte_eal/linuxapp/eal/eal_pci.c 2015-02-10 15:59:46.564201569 -0800 @@ -34,6 +34,7 @@ #include <string.h> #include <dirent.h> #include <sys/mman.h> +#include <sys/fcntl.h> #include <rte_log.h> #include <rte_pci.h> @@ -233,6 +234,7 @@ dev->addr.bus = bus; dev->addr.devid = devid; dev->addr.function = function; + dev->config_fd = -1; /* get vendor id */ snprintf(filename, sizeof(filename), "%s/vendor", dirname); @@ -498,6 +500,26 @@ #endif static int +pci_config_open(struct rte_pci_device *dev) +{ + struct rte_pci_addr *loc = &dev->addr; + char filename[PATH_MAX]; + + /* Open fd for access to PCI config */ + snprintf(filename, sizeof(filename), + SYSFS_PCI_DEVICES "/" PCI_PRI_FMT "/config", + loc->domain, loc->bus, loc->devid, loc->function); + dev->config_fd = open(filename, O_RDWR); + if (dev->config_fd < 0) { + RTE_LOG(ERR, EAL, "%s(): cannot open %s: %s\n", + __func__, filename, strerror(errno)); + return -1; + } + + return 0; +} + +static int pci_map_device(struct rte_pci_device *dev) { int ret, mapped = 0; @@ -518,7 +540,8 @@ if (ret != 0) return ret; } - return 0; + + return pci_config_open(dev); } /* @@ -595,6 +618,20 @@ return 1; } +/* Read PCI config space. */ +int rte_eal_pci_read_config(const struct rte_pci_device *device, + void *buf, size_t len, off_t offset) +{ + return pread(device->config_fd, buf, len, offset); +} + +/* Write PCI config space. */ +int rte_eal_pci_write_config(const struct rte_pci_device *device, + const void *buf, size_t len, off_t offset) +{ + return pwrite(device->config_fd, buf, len, offset); +} + /* Init the PCI EAL subsystem */ int rte_eal_pci_init(void)