2018-07-31 20:28 GMT+09:00 Anatoly Burakov <anatoly.bura...@intel.com>:
> 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.bura...@intel.com>
> ---
>
> Notes:
> v2->v1:
> - Fix pointer in pci_vfio_get_region_info
> - Fix commit message
>
> 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..24f665c20 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, ri);
> + 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
Hi Anatoly,
Please fix the error check for ioctl in pci_vfio_region_info() from
"if (ret)" to "if (ret < 0)"
My environment reported compiler errors with -Werror=maybe-uninitialized).
dpdk/drivers/bus/pci/linux/pci_vfio.c: In function
‘pci_vfio_map_resource_primary’:
dpdk/drivers/bus/pci/linux/pci_vfio.c:612:4: error: ‘reg’ may be used
uninitialized in this function [-Werror=maybe-uninitialized]
free(reg);
^~~~~~~~~
dpdk/drivers/bus/pci/linux/pci_vfio.c:495:2: error: ‘info’ may be used
uninitialized in this function [-Werror=maybe-uninitialized]
free(info);
^~~~~~~~~~
dpdk/drivers/bus/pci/linux/pci_vfio.c:485:27: note: ‘info’ was declared here
struct vfio_region_info *info;
Other code looks good to me.
I tested the updated patch with the above change and confirmed it
could mmap BAR on my ppc64le machine.
Thanks,
Takeshi
