The user is allowed to register a reserved IOVA range by using the DMA MAP API and setting the new flag: VFIO_DMA_MAP_FLAG_MSI_RESERVED_IOVA. It provides the base address and the size. This region is stored in the vfio_dma rb tree. At that point the iova range is not mapped to any target address yet. The host kernel will use those iova when needed, typically when the VFIO-PCI device allocates its MSI's.
This patch also handles the destruction of the reserved binding RB-tree and domain's iova_domains. Signed-off-by: Eric Auger <[email protected]> Signed-off-by: Bharat Bhushan <[email protected]> --- - Currently the user is not yet informed about the number of pages to provide RFC v1 -> RFC v2: - takes into account Alex comments, based on [RFC PATCH 1/6] vfio: Add interface for add/del reserved iova region: - use the existing dma map/unmap ioctl interface with a flag to register a reserved IOVA range. A single reserved iova region is allowed. --- drivers/vfio/vfio_iommu_type1.c | 98 ++++++++++++++++++++++++++++++++++++++++- include/uapi/linux/vfio.h | 9 ++++ 2 files changed, 106 insertions(+), 1 deletion(-) diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index 2f085d3..37c7d78 100644 --- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -538,10 +538,40 @@ static void vfio_unmap_unpin(struct vfio_iommu *iommu, struct vfio_dma *dma) vfio_lock_acct(-unlocked); } +/* vfio_unmap_reserved: unmap and free all reserved binding nodes + * for all domains and destroy their iova_domain + * + * @iommu: iommu handle + */ +static void vfio_unmap_reserved(struct vfio_iommu *iommu) +{ + struct vfio_domain *d; + + list_for_each_entry(d, &iommu->domain_list, next) { + struct rb_node *node; + + while ((node = rb_first(&d->reserved_binding_list))) { + struct vfio_reserved_binding *b = + rb_entry(node, + struct vfio_reserved_binding, node); + + while (!kref_put(&b->kref, + vfio_reserved_binding_release)) { + } + } + d->reserved_binding_list = RB_ROOT; + + put_iova_domain(d->reserved_iova_domain); + kfree(d->reserved_iova_domain); + } +} + static void vfio_remove_dma(struct vfio_iommu *iommu, struct vfio_dma *dma) { if (likely(dma->type != VFIO_IOVA_RESERVED)) vfio_unmap_unpin(iommu, dma); + else + vfio_unmap_reserved(iommu); vfio_unlink_dma(iommu, dma); kfree(dma); } @@ -785,6 +815,68 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu, return ret; } +static int vfio_register_reserved_iova_range(struct vfio_iommu *iommu, + struct vfio_iommu_type1_dma_map *map) +{ + dma_addr_t iova = map->iova; + size_t size = map->size; + uint64_t mask; + struct vfio_dma *dma; + int ret = 0; + struct vfio_domain *d; + unsigned long order; + + /* Verify that none of our __u64 fields overflow */ + if (map->size != size || map->iova != iova) + return -EINVAL; + + order = __ffs(vfio_pgsize_bitmap(iommu)); + mask = ((uint64_t)1 << order) - 1; + + WARN_ON(mask & PAGE_MASK); + + /* we currently only support MSI_RESERVED_IOVA */ + if (!(map->flags & VFIO_DMA_MAP_FLAG_MSI_RESERVED_IOVA)) + return -EINVAL; + + if (!size || (size | iova) & mask) + return -EINVAL; + + /* Don't allow IOVA address wrap */ + if (iova + size - 1 < iova) + return -EINVAL; + + mutex_lock(&iommu->lock); + + /* check if the iova domain has not been instantiated already*/ + d = list_first_entry(&iommu->domain_list, + struct vfio_domain, next); + + if (d->reserved_iova_domain || vfio_find_dma(iommu, iova, size)) { + ret = -EEXIST; + goto out; + } + + dma = kzalloc(sizeof(*dma), GFP_KERNEL); + if (!dma) { + ret = -ENOMEM; + goto out; + } + + dma->iova = iova; + dma->size = size; + dma->type = VFIO_IOVA_RESERVED; + + vfio_link_dma(iommu, dma); + + list_for_each_entry(d, &iommu->domain_list, next) + alloc_reserved_iova_domain(d, iova, size, order); + +out: + mutex_unlock(&iommu->lock); + return ret; +} + static int vfio_bus_type(struct device *dev, void *data) { struct bus_type **bus = data; @@ -1297,7 +1389,8 @@ static long vfio_iommu_type1_ioctl(void *iommu_data, } else if (cmd == VFIO_IOMMU_MAP_DMA) { struct vfio_iommu_type1_dma_map map; uint32_t mask = VFIO_DMA_MAP_FLAG_READ | - VFIO_DMA_MAP_FLAG_WRITE; + VFIO_DMA_MAP_FLAG_WRITE | + VFIO_DMA_MAP_FLAG_MSI_RESERVED_IOVA; minsz = offsetofend(struct vfio_iommu_type1_dma_map, size); @@ -1307,6 +1400,9 @@ static long vfio_iommu_type1_ioctl(void *iommu_data, if (map.argsz < minsz || map.flags & ~mask) return -EINVAL; + if (map.flags & VFIO_DMA_MAP_FLAG_MSI_RESERVED_IOVA) + return vfio_register_reserved_iova_range(iommu, &map); + return vfio_dma_do_map(iommu, &map); } else if (cmd == VFIO_IOMMU_UNMAP_DMA) { diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h index 43e183b..982e326 100644 --- a/include/uapi/linux/vfio.h +++ b/include/uapi/linux/vfio.h @@ -411,12 +411,21 @@ struct vfio_iommu_type1_info { * * Map process virtual addresses to IO virtual addresses using the * provided struct vfio_dma_map. Caller sets argsz. READ &/ WRITE required. + * + * In case MSI_RESERVED_IOVA is set, the API only aims at registering an IOVA + * region which will be used on some platforms to map the host MSI frame. + * in that specific case, vaddr and prot are ignored. The requirement for + * provisioning such IOVA range can be checked by calling VFIO_IOMMU_GET_INFO + * with the VFIO_IOMMU_INFO_REQUIRE_MSI_MAP attribute. A single + * MSI_RESERVED_IOVA region can be registered */ struct vfio_iommu_type1_dma_map { __u32 argsz; __u32 flags; #define VFIO_DMA_MAP_FLAG_READ (1 << 0) /* readable from device */ #define VFIO_DMA_MAP_FLAG_WRITE (1 << 1) /* writable from device */ +/* reserved iova for MSI vectors*/ +#define VFIO_DMA_MAP_FLAG_MSI_RESERVED_IOVA (1 << 2) __u64 vaddr; /* Process virtual address */ __u64 iova; /* IO virtual address */ __u64 size; /* Size of mapping (bytes) */ -- 1.9.1
