Currently, DPDK will skip mapping some areas (or even an entire BAR)
if MSI-X happens to be in it but is smaller than page address.
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.bura...@intel.com>
---
drivers/bus/pci/linux/pci_vfio.c | 127 ++++++++++++++++++++---
lib/librte_eal/common/include/rte_vfio.h | 26 +++++
2 files changed, 140 insertions(+), 13 deletions(-)
diff --git a/drivers/bus/pci/linux/pci_vfio.c b/drivers/bus/pci/linux/pci_vfio.c
index 686386d6a..e7765ee11 100644
--- a/drivers/bus/pci/linux/pci_vfio.c
+++ b/drivers/bus/pci/linux/pci_vfio.c
@@ -415,6 +415,88 @@ 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, info);
+ if (ret) {
+ free(ri);
+ return ret;
+ }
+ if (ri->argsz != argsz) {
+ argsz = ri->argsz;
+ ri = realloc(ri, argsz);
+
+ if (ri == NULL) {
+ RTE_LOG(ERR, EAL, "Cannot reallocate memory for region
info\n");
+ return -1;
+ }
+ 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 +546,75 @@ 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;
void *bar_addr;
- reg.index = i;
-
- ret = ioctl(vfio_dev_fd, VFIO_DEVICE_GET_REGION_INFO, ®);
- if (ret) {
+ ret = pci_vfio_get_region_info(vfio_dev_fd, ®, 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) {
diff --git a/lib/librte_eal/common/include/rte_vfio.h
b/lib/librte_eal/common/include/rte_vfio.h
index 5ca13fcce..f6617e004 100644
--- a/lib/librte_eal/common/include/rte_vfio.h
+++ b/lib/librte_eal/common/include/rte_vfio.h
@@ -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 */
--
2.17.1
