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vfio: allow mapping MSI-X BARs if kernel allows it

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Currently, DPDK will skip mapping some areas (or even an entire BAR)
if MSI-X table happens to be in them but is smaller than page size.

Kernels 4.16+ will allow mapping MSI-X BARs [1], and will report this
as a capability flag. Capability flags themselves are also only
supported since kernel 4.6 [2].

This commit will introduce support for checking VFIO capabilities,
and will use it to check if we are allowed to map BARs with MSI-X
tables in them, along with backwards compatibility for older
kernels, including a workaround for a variable rename in VFIO
region info structure [3].

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/
linux.git/commit/?id=a32295c612c57990d17fb0f41e7134394b2f35f6

[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/
linux.git/commit/?id=c84982adb23bcf3b99b79ca33527cd2625fbe279

[3] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/
linux.git/commit/?id=ff63eb638d63b95e489f976428f1df01391e15e4

Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
This commit is contained in:
Anatoly Burakov 2018-09-20 14:11:13 +01:00 committed by Thomas Monjalon
parent b1621823ea
commit 03ba15ca65
2 changed files with 145 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

132
drivers/bus/pci/linux/pci_vfio.c
View File

@ -415,6 +415,93 @@ pci_vfio_mmap_bar(int vfio_dev_fd, struct mapped_pci_resource *vfio_res,
return 0;
}
/*
* region info may contain capability headers, so we need to keep reallocating
* the memory until we match allocated memory size with argsz.
*/
static int
pci_vfio_get_region_info(int vfio_dev_fd, struct vfio_region_info **info,
int region)
{
struct vfio_region_info *ri;
size_t argsz = sizeof(*ri);
int ret;
ri = malloc(sizeof(*ri));
if (ri == NULL) {
RTE_LOG(ERR, EAL, "Cannot allocate memory for region info\n");
return -1;
}
again:
memset(ri, 0, argsz);
ri->argsz = argsz;
ri->index = region;
ret = ioctl(vfio_dev_fd, VFIO_DEVICE_GET_REGION_INFO, ri);
if (ret < 0) {
free(ri);
return ret;
}
if (ri->argsz != argsz) {
struct vfio_region_info *tmp;
argsz = ri->argsz;
tmp = realloc(ri, argsz);
if (tmp == NULL) {
/* realloc failed but the ri is still there */
free(ri);
RTE_LOG(ERR, EAL, "Cannot reallocate memory for region info\n");
return -1;
}
ri = tmp;
goto again;
}
*info = ri;
return 0;
}
static struct vfio_info_cap_header *
pci_vfio_info_cap(struct vfio_region_info *info, int cap)
{
struct vfio_info_cap_header *h;
size_t offset;
if ((info->flags & RTE_VFIO_INFO_FLAG_CAPS) == 0) {
/* VFIO info does not advertise capabilities */
return NULL;
}
offset = VFIO_CAP_OFFSET(info);
while (offset != 0) {
h = RTE_PTR_ADD(info, offset);
if (h->id == cap)
return h;
offset = h->next;
}
return NULL;
}
static int
pci_vfio_msix_is_mappable(int vfio_dev_fd, int msix_region)
{
struct vfio_region_info *info;
int ret;
ret = pci_vfio_get_region_info(vfio_dev_fd, &info, msix_region);
if (ret < 0)
return -1;
ret = pci_vfio_info_cap(info, RTE_VFIO_CAP_MSIX_MAPPABLE) != NULL;
/* cleanup */
free(info);
return ret;
}
static int
pci_vfio_map_resource_primary(struct rte_pci_device *dev)
{
@ -464,56 +551,75 @@ pci_vfio_map_resource_primary(struct rte_pci_device *dev)
if (ret < 0) {
RTE_LOG(ERR, EAL, " %s cannot get MSI-X BAR number!\n",
pci_addr);
goto err_vfio_dev_fd;
goto err_vfio_res;
}
/* if we found our MSI-X BAR region, check if we can mmap it */
if (vfio_res->msix_table.bar_index != -1) {
int ret = pci_vfio_msix_is_mappable(vfio_dev_fd,
vfio_res->msix_table.bar_index);
if (ret < 0) {
RTE_LOG(ERR, EAL, "Couldn't check if MSI-X BAR is mappable\n");
goto err_vfio_res;
} else if (ret != 0) {
/* we can map it, so we don't care where it is */
RTE_LOG(DEBUG, EAL, "VFIO reports MSI-X BAR as mappable\n");
vfio_res->msix_table.bar_index = -1;
}
}
for (i = 0; i < (int) vfio_res->nb_maps; i++) {
struct vfio_region_info reg = { .argsz = sizeof(reg) };
struct vfio_region_info *reg = NULL;
void *bar_addr;
reg.index = i;
ret = ioctl(vfio_dev_fd, VFIO_DEVICE_GET_REGION_INFO, &reg);
if (ret) {
ret = pci_vfio_get_region_info(vfio_dev_fd, &reg, i);
if (ret < 0) {
RTE_LOG(ERR, EAL, " %s cannot get device region info "
"error %i (%s)\n", pci_addr, errno, strerror(errno));
"error %i (%s)\n", pci_addr, errno,
strerror(errno));
goto err_vfio_res;
}
/* chk for io port region */
ret = pci_vfio_is_ioport_bar(vfio_dev_fd, i);
if (ret < 0)
if (ret < 0) {
free(reg);
goto err_vfio_res;
else if (ret) {
} else if (ret) {
RTE_LOG(INFO, EAL, "Ignore mapping IO port bar(%d)\n",
i);
free(reg);
continue;
}
/* skip non-mmapable BARs */
if ((reg.flags & VFIO_REGION_INFO_FLAG_MMAP) == 0)
if ((reg->flags & VFIO_REGION_INFO_FLAG_MMAP) == 0) {
free(reg);
continue;
}
/* try mapping somewhere close to the end of hugepages */
if (pci_map_addr == NULL)
pci_map_addr = pci_find_max_end_va();
bar_addr = pci_map_addr;
pci_map_addr = RTE_PTR_ADD(bar_addr, (size_t) reg.size);
pci_map_addr = RTE_PTR_ADD(bar_addr, (size_t) reg->size);
maps[i].addr = bar_addr;
maps[i].offset = reg.offset;
maps[i].size = reg.size;
maps[i].offset = reg->offset;
maps[i].size = reg->size;
maps[i].path = NULL; /* vfio doesn't have per-resource paths */
ret = pci_vfio_mmap_bar(vfio_dev_fd, vfio_res, i, 0);
if (ret < 0) {
RTE_LOG(ERR, EAL, " %s mapping BAR%i failed: %s\n",
pci_addr, i, strerror(errno));
free(reg);
goto err_vfio_res;
}
dev->mem_resource[i].addr = maps[i].addr;
free(reg);
}
if (pci_rte_vfio_setup_device(dev, vfio_dev_fd) < 0) {

26
lib/librte_eal/common/include/rte_vfio.h
View File

@ -14,6 +14,8 @@
extern "C" {
#endif
#include <stdint.h>
/*
* determine if VFIO is present on the system
*/
@ -44,6 +46,30 @@ extern "C" {
#define RTE_VFIO_NOIOMMU 8
#endif
/*
* capabilities are only supported on kernel 4.6+. there were also some API
* changes as well, so add a macro to get cap offset.
*/
#ifdef VFIO_REGION_INFO_FLAG_CAPS
#define RTE_VFIO_INFO_FLAG_CAPS VFIO_REGION_INFO_FLAG_CAPS
#define VFIO_CAP_OFFSET(x) (x->cap_offset)
#else
#define RTE_VFIO_INFO_FLAG_CAPS (1 << 3)
#define VFIO_CAP_OFFSET(x) (x->resv)
struct vfio_info_cap_header {
uint16_t id;
uint16_t version;
uint32_t next;
};
#endif
/* kernels 4.16+ can map BAR containing MSI-X table */
#ifdef VFIO_REGION_INFO_CAP_MSIX_MAPPABLE
#define RTE_VFIO_CAP_MSIX_MAPPABLE VFIO_REGION_INFO_CAP_MSIX_MAPPABLE
#else
#define RTE_VFIO_CAP_MSIX_MAPPABLE 3
#endif
#else /* not VFIO_PRESENT */
/* we don't need an actual definition, only pointer is used */