Messages in this thread Patch in this message | | | From | Eric Auger <> | Subject | [PATCH v7 4/7] vfio: allow reserved iova registration | Date | Tue, 19 Apr 2016 17:24:44 +0000 |
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The user is allowed to [un]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 driver allocates its MSIs.
Signed-off-by: Eric Auger <eric.auger@linaro.org> Signed-off-by: Bharat Bhushan <Bharat.Bhushan@freescale.com>
--- v6 -> v7: - use iommu_free_reserved_iova_domain - convey prot attributes downto dma-reserved-iommu iova domain creation - reserved bindings teardown now performed on iommu domain destruction - rename VFIO_DMA_MAP_FLAG_MSI_RESERVED_IOVA into VFIO_DMA_MAP_FLAG_RESERVED_MSI_IOVA - change title - pass the protection attribute to dma-reserved-iommu API
v3 -> v4: - use iommu_alloc/free_reserved_iova_domain exported by dma-reserved-iommu - protect vfio_register_reserved_iova_range implementation with CONFIG_IOMMU_DMA_RESERVED - handle unregistration by user-space and on vfio_iommu_type1 release
v1 -> v2: - set returned value according to alloc_reserved_iova_domain result - free the iova domains in case any error occurs
RFC v1 -> v1: - 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 | 138 +++++++++++++++++++++++++++++++++++++++- include/uapi/linux/vfio.h | 9 ++- 2 files changed, 145 insertions(+), 2 deletions(-)
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index 93c17d9..fa6b8b1 100644 --- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -454,6 +454,27 @@ static void vfio_destroy_reserved(struct vfio_iommu *iommu) iommu_free_reserved_iova_domain(d->domain); } +static int vfio_create_reserved(struct vfio_iommu *iommu, + dma_addr_t iova, size_t size, + int prot, unsigned long order) +{ + struct vfio_domain *d; + int ret = 0; + + list_for_each_entry(d, &iommu->domain_list, next) { + ret = iommu_alloc_reserved_iova_domain(d->domain, iova, + size, prot, order); + if (ret) + break; + } + + if (ret) { + list_for_each_entry(d, &iommu->domain_list, next) + iommu_free_reserved_iova_domain(d->domain); + } + return ret; +} + static void vfio_remove_dma(struct vfio_iommu *iommu, struct vfio_dma *dma) { if (likely(dma->type == VFIO_IOVA_USER)) @@ -705,6 +726,110 @@ 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; + int ret = 0, prot = 0; + struct vfio_dma *dma; + unsigned long order; + uint64_t mask; + + /* 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); + + if (!size || (size | iova) & mask) + return -EINVAL; + + /* Don't allow IOVA address wrap */ + if (iova + size - 1 < iova) + return -EINVAL; + + mutex_lock(&iommu->lock); + + if (vfio_find_dma(iommu, iova, size, VFIO_IOVA_ANY)) { + ret = -EEXIST; + goto unlock; + } + + dma = kzalloc(sizeof(*dma), GFP_KERNEL); + if (!dma) { + ret = -ENOMEM; + goto unlock; + } + + dma->iova = iova; + dma->size = size; + dma->type = VFIO_IOVA_RESERVED; + + if (map->flags & VFIO_DMA_MAP_FLAG_READ) + prot = IOMMU_READ; + if (map->flags & VFIO_DMA_MAP_FLAG_WRITE) + prot |= IOMMU_WRITE; + + ret = vfio_create_reserved(iommu, iova, size, prot, order); + if (ret) + goto free_unlock; + + vfio_link_dma(iommu, dma); + goto unlock; + +free_unlock: + kfree(dma); +unlock: + mutex_unlock(&iommu->lock); + return ret; +} + +static int vfio_unregister_reserved_iova_range(struct vfio_iommu *iommu, + struct vfio_iommu_type1_dma_unmap *unmap) +{ + dma_addr_t iova = unmap->iova; + struct vfio_dma *dma; + size_t size = unmap->size; + uint64_t mask; + unsigned long order; + int ret = -EINVAL; + + /* Verify that none of our __u64 fields overflow */ + if (unmap->size != size || unmap->iova != iova) + return ret; + + order = __ffs(vfio_pgsize_bitmap(iommu)); + mask = ((uint64_t)1 << order) - 1; + + WARN_ON(mask & PAGE_MASK); + + if (!size || (size | iova) & mask) + return ret; + + /* Don't allow IOVA address wrap */ + if (iova + size - 1 < iova) + return ret; + + mutex_lock(&iommu->lock); + + dma = vfio_find_dma(iommu, iova, size, VFIO_IOVA_RESERVED); + + if (dma && (dma->iova == iova) && (dma->size == size)) { + unmap->size = dma->size; + vfio_remove_dma(iommu, dma); + ret = 0; + goto unlock; + } + unmap->size = 0; +unlock: + mutex_unlock(&iommu->lock); + return ret; +} + static int vfio_bus_type(struct device *dev, void *data) { struct bus_type **bus = data; @@ -1074,7 +1199,8 @@ 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_RESERVED_MSI_IOVA; minsz = offsetofend(struct vfio_iommu_type1_dma_map, size); @@ -1084,6 +1210,9 @@ 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_RESERVED_MSI_IOVA) + return vfio_register_reserved_iova_range(iommu, &map); + return vfio_dma_do_map(iommu, &map); } else if (cmd == VFIO_IOMMU_UNMAP_DMA) { @@ -1098,6 +1227,13 @@ static long vfio_iommu_type1_ioctl(void *iommu_data, if (unmap.argsz < minsz || unmap.flags) return -EINVAL; + if (unmap.flags & VFIO_DMA_MAP_FLAG_RESERVED_MSI_IOVA) { + ret = vfio_unregister_reserved_iova_range(iommu, + &unmap); + if (ret) + return ret; + } + ret = vfio_dma_do_unmap(iommu, &unmap); if (ret) return ret; diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h index 255a211..0637f35 100644 --- a/include/uapi/linux/vfio.h +++ b/include/uapi/linux/vfio.h @@ -498,12 +498,18 @@ 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 RESERVED_MSI_IOVA flag is set, the API only aims at registering an + * IOVA region that will be used on some platforms to map the host MSI frames. + * In that specific case, vaddr is ignored. */ 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_RESERVED_MSI_IOVA (1 << 2) __u64 vaddr; /* Process virtual address */ __u64 iova; /* IO virtual address */ __u64 size; /* Size of mapping (bytes) */ @@ -519,7 +525,8 @@ struct vfio_iommu_type1_dma_map { * Caller sets argsz. The actual unmapped size is returned in the size * field. No guarantee is made to the user that arbitrary unmaps of iova * or size different from those used in the original mapping call will - * succeed. + * succeed. A Reserved DMA region must be unmapped with RESERVED_MSI_IOVA + * flag set. */ struct vfio_iommu_type1_dma_unmap { __u32 argsz; -- 1.9.1
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