| Message ID | 1585078359-20124-5-git-send-email-kwankhede@nvidia.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KABIs to support migration for VFIO devices | expand |
On Wed, 25 Mar 2020 01:02:36 +0530 Kirti Wankhede <kwankhede@nvidia.com> wrote: > VFIO_IOMMU_DIRTY_PAGES ioctl performs three operations: > - Start dirty pages tracking while migration is active > - Stop dirty pages tracking. > - Get dirty pages bitmap. Its user space application's responsibility to > copy content of dirty pages from source to destination during migration. > > To prevent DoS attack, memory for bitmap is allocated per vfio_dma > structure. Bitmap size is calculated considering smallest supported page > size. Bitmap is allocated for all vfio_dmas when dirty logging is enabled > > Bitmap is populated for already pinned pages when bitmap is allocated for > a vfio_dma with the smallest supported page size. Update bitmap from > pinning functions when tracking is enabled. When user application queries > bitmap, check if requested page size is same as page size used to > populated bitmap. If it is equal, copy bitmap, but if not equal, return > error. > > Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com> > Reviewed-by: Neo Jia <cjia@nvidia.com> > --- > drivers/vfio/vfio_iommu_type1.c | 265 +++++++++++++++++++++++++++++++++++++++- > 1 file changed, 259 insertions(+), 6 deletions(-) > > diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c > index 70aeab921d0f..27ed069c5053 100644 > --- a/drivers/vfio/vfio_iommu_type1.c > +++ b/drivers/vfio/vfio_iommu_type1.c > @@ -71,6 +71,7 @@ struct vfio_iommu { > unsigned int dma_avail; > bool v2; > bool nesting; > + bool dirty_page_tracking; > }; > > struct vfio_domain { > @@ -91,6 +92,7 @@ struct vfio_dma { > bool lock_cap; /* capable(CAP_IPC_LOCK) */ > struct task_struct *task; > struct rb_root pfn_list; /* Ex-user pinned pfn list */ > + unsigned long *bitmap; > }; > > struct vfio_group { > @@ -125,7 +127,21 @@ struct vfio_regions { > #define IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu) \ > (!list_empty(&iommu->domain_list)) > > +#define DIRTY_BITMAP_BYTES(n) (ALIGN(n, BITS_PER_TYPE(u64)) / BITS_PER_BYTE) > + > +/* > + * Input argument of number of bits to bitmap_set() is unsigned integer, which > + * further casts to signed integer for unaligned multi-bit operation, > + * __bitmap_set(). > + * Then maximum bitmap size supported is 2^31 bits divided by 2^3 bits/byte, > + * that is 2^28 (256 MB) which maps to 2^31 * 2^12 = 2^43 (8TB) on 4K page > + * system. > + */ > +#define DIRTY_BITMAP_PAGES_MAX (uint64_t)(INT_MAX - 1) > +#define DIRTY_BITMAP_SIZE_MAX DIRTY_BITMAP_BYTES(DIRTY_BITMAP_PAGES_MAX) > + > static int put_pfn(unsigned long pfn, int prot); > +static unsigned long vfio_pgsize_bitmap(struct vfio_iommu *iommu); > > /* > * This code handles mapping and unmapping of user data buffers > @@ -175,6 +191,77 @@ static void vfio_unlink_dma(struct vfio_iommu *iommu, struct vfio_dma *old) > rb_erase(&old->node, &iommu->dma_list); > } > > + > +static int vfio_dma_bitmap_alloc(struct vfio_dma *dma, uint64_t pgsize) > +{ > + uint64_t npages = dma->size / pgsize; > + > + if (npages > DIRTY_BITMAP_PAGES_MAX) > + return -EINVAL; > + > + dma->bitmap = kvzalloc(DIRTY_BITMAP_BYTES(npages), GFP_KERNEL); > + if (!dma->bitmap) > + return -ENOMEM; > + > + return 0; > +} > + > +static void vfio_dma_bitmap_free(struct vfio_dma *dma) > +{ > + kfree(dma->bitmap); > + dma->bitmap = NULL; > +} > + > +static void vfio_dma_populate_bitmap(struct vfio_dma *dma, uint64_t pgsize) > +{ > + struct rb_node *p; > + > + if (RB_EMPTY_ROOT(&dma->pfn_list)) > + return; > + > + for (p = rb_first(&dma->pfn_list); p; p = rb_next(p)) { > + struct vfio_pfn *vpfn = rb_entry(p, struct vfio_pfn, node); > + > + bitmap_set(dma->bitmap, (vpfn->iova - dma->iova) / pgsize, 1); > + } > +} > + > +static int vfio_dma_bitmap_alloc_all(struct vfio_iommu *iommu, uint64_t pgsize) > +{ > + struct rb_node *n = rb_first(&iommu->dma_list); > + > + for (; n; n = rb_next(n)) { > + struct vfio_dma *dma = rb_entry(n, struct vfio_dma, node); > + int ret; > + > + ret = vfio_dma_bitmap_alloc(dma, pgsize); > + if (ret) { > + struct rb_node *p = rb_prev(n); > + > + for (; p; p = rb_prev(p)) { > + struct vfio_dma *dma = rb_entry(n, > + struct vfio_dma, node); > + > + vfio_dma_bitmap_free(dma); > + } > + return ret; > + } > + vfio_dma_populate_bitmap(dma, pgsize); > + } > + return 0; > +} > + > +static void vfio_dma_bitmap_free_all(struct vfio_iommu *iommu) > +{ > + struct rb_node *n = rb_first(&iommu->dma_list); > + > + for (; n; n = rb_next(n)) { > + struct vfio_dma *dma = rb_entry(n, struct vfio_dma, node); > + > + vfio_dma_bitmap_free(dma); > + } > +} > + > /* > * Helper Functions for host iova-pfn list > */ > @@ -567,6 +654,18 @@ static int vfio_iommu_type1_pin_pages(void *iommu_data, > vfio_unpin_page_external(dma, iova, do_accounting); > goto pin_unwind; > } > + > + if (iommu->dirty_page_tracking) { > + unsigned long pgshift = > + __ffs(vfio_pgsize_bitmap(iommu)); > + > + /* > + * Bitmap populated with the smallest supported page > + * size > + */ > + bitmap_set(dma->bitmap, > + (vpfn->iova - dma->iova) >> pgshift, 1); > + } > } > > ret = i; > @@ -801,6 +900,7 @@ static void vfio_remove_dma(struct vfio_iommu *iommu, struct vfio_dma *dma) > vfio_unmap_unpin(iommu, dma, true); > vfio_unlink_dma(iommu, dma); > put_task_struct(dma->task); > + vfio_dma_bitmap_free(dma); > kfree(dma); > iommu->dma_avail++; > } > @@ -831,6 +931,56 @@ static unsigned long vfio_pgsize_bitmap(struct vfio_iommu *iommu) > return bitmap; > } > > +static int vfio_iova_dirty_bitmap(struct vfio_iommu *iommu, dma_addr_t iova, > + size_t size, uint64_t pgsize, > + u64 __user *bitmap) > +{ > + struct vfio_dma *dma; > + unsigned long pgshift = __ffs(pgsize); > + unsigned int npages, bitmap_size; > + > + dma = vfio_find_dma(iommu, iova, 1); > + > + if (!dma) > + return -EINVAL; > + > + if (dma->iova != iova || dma->size != size) > + return -EINVAL; > + > + npages = dma->size >> pgshift; > + bitmap_size = DIRTY_BITMAP_BYTES(npages); > + > + /* mark all pages dirty if all pages are pinned and mapped. */ > + if (dma->iommu_mapped) > + bitmap_set(dma->bitmap, 0, npages); > + > + if (copy_to_user((void __user *)bitmap, dma->bitmap, bitmap_size)) > + return -EFAULT; > + > + /* > + * Re-populate bitmap to include all pinned pages which are considered > + * as dirty but exclude pages which are unpinned and pages which are > + * marked dirty by vfio_dma_rw() > + */ > + vfio_dma_populate_bitmap(dma, pgsize); vfio_dma_populate_bitmap() only sets bits, it doesn't clear them. Shouldn't we do a memset() zero before calling this? Thanks, Alex > + return 0; > +} > + > +static int verify_bitmap_size(uint64_t npages, uint64_t bitmap_size) > +{ > + uint64_t bsize; > + > + if (!npages || !bitmap_size || (bitmap_size > DIRTY_BITMAP_SIZE_MAX)) > + return -EINVAL; > + > + bsize = DIRTY_BITMAP_BYTES(npages); > + > + if (bitmap_size < bsize) > + return -EINVAL; > + > + return 0; > +} > + > static int vfio_dma_do_unmap(struct vfio_iommu *iommu, > struct vfio_iommu_type1_dma_unmap *unmap) > { > @@ -1038,16 +1188,16 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu, > unsigned long vaddr = map->vaddr; > size_t size = map->size; > int ret = 0, prot = 0; > - uint64_t mask; > + uint64_t pgsize; > struct vfio_dma *dma; > > /* Verify that none of our __u64 fields overflow */ > if (map->size != size || map->vaddr != vaddr || map->iova != iova) > return -EINVAL; > > - mask = ((uint64_t)1 << __ffs(vfio_pgsize_bitmap(iommu))) - 1; > + pgsize = (uint64_t)1 << __ffs(vfio_pgsize_bitmap(iommu)); > > - WARN_ON(mask & PAGE_MASK); > + WARN_ON((pgsize - 1) & PAGE_MASK); > > /* READ/WRITE from device perspective */ > if (map->flags & VFIO_DMA_MAP_FLAG_WRITE) > @@ -1055,7 +1205,7 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu, > if (map->flags & VFIO_DMA_MAP_FLAG_READ) > prot |= IOMMU_READ; > > - if (!prot || !size || (size | iova | vaddr) & mask) > + if (!prot || !size || (size | iova | vaddr) & (pgsize - 1)) > return -EINVAL; > > /* Don't allow IOVA or virtual address wrap */ > @@ -1130,6 +1280,12 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu, > else > ret = vfio_pin_map_dma(iommu, dma, size); > > + if (!ret && iommu->dirty_page_tracking) { > + ret = vfio_dma_bitmap_alloc(dma, pgsize); > + if (ret) > + vfio_remove_dma(iommu, dma); > + } > + > out_unlock: > mutex_unlock(&iommu->lock); > return ret; > @@ -2278,6 +2434,93 @@ static long vfio_iommu_type1_ioctl(void *iommu_data, > > return copy_to_user((void __user *)arg, &unmap, minsz) ? > -EFAULT : 0; > + } else if (cmd == VFIO_IOMMU_DIRTY_PAGES) { > + struct vfio_iommu_type1_dirty_bitmap dirty; > + uint32_t mask = VFIO_IOMMU_DIRTY_PAGES_FLAG_START | > + VFIO_IOMMU_DIRTY_PAGES_FLAG_STOP | > + VFIO_IOMMU_DIRTY_PAGES_FLAG_GET_BITMAP; > + int ret = 0; > + > + if (!iommu->v2) > + return -EACCES; > + > + minsz = offsetofend(struct vfio_iommu_type1_dirty_bitmap, > + flags); > + > + if (copy_from_user(&dirty, (void __user *)arg, minsz)) > + return -EFAULT; > + > + if (dirty.argsz < minsz || dirty.flags & ~mask) > + return -EINVAL; > + > + /* only one flag should be set at a time */ > + if (__ffs(dirty.flags) != __fls(dirty.flags)) > + return -EINVAL; > + > + if (dirty.flags & VFIO_IOMMU_DIRTY_PAGES_FLAG_START) { > + uint64_t pgsize = 1 << __ffs(vfio_pgsize_bitmap(iommu)); > + > + mutex_lock(&iommu->lock); > + if (!iommu->dirty_page_tracking) { > + ret = vfio_dma_bitmap_alloc_all(iommu, pgsize); > + if (!ret) > + iommu->dirty_page_tracking = true; > + } > + mutex_unlock(&iommu->lock); > + return ret; > + } else if (dirty.flags & VFIO_IOMMU_DIRTY_PAGES_FLAG_STOP) { > + mutex_lock(&iommu->lock); > + if (iommu->dirty_page_tracking) { > + iommu->dirty_page_tracking = false; > + vfio_dma_bitmap_free_all(iommu); > + } > + mutex_unlock(&iommu->lock); > + return 0; > + } else if (dirty.flags & > + VFIO_IOMMU_DIRTY_PAGES_FLAG_GET_BITMAP) { > + struct vfio_iommu_type1_dirty_bitmap_get range; > + unsigned long pgshift; > + size_t data_size = dirty.argsz - minsz; > + uint64_t iommu_pgsize = > + 1 << __ffs(vfio_pgsize_bitmap(iommu)); > + > + if (!data_size || data_size < sizeof(range)) > + return -EINVAL; > + > + if (copy_from_user(&range, (void __user *)(arg + minsz), > + sizeof(range))) > + return -EFAULT; > + > + /* allow only smallest supported pgsize */ > + if (range.bitmap.pgsize != iommu_pgsize) > + return -EINVAL; > + if (range.iova & (iommu_pgsize - 1)) > + return -EINVAL; > + if (!range.size || range.size & (iommu_pgsize - 1)) > + return -EINVAL; > + if (range.iova + range.size < range.iova) > + return -EINVAL; > + if (!access_ok((void __user *)range.bitmap.data, > + range.bitmap.size)) > + return -EINVAL; > + > + pgshift = __ffs(range.bitmap.pgsize); > + ret = verify_bitmap_size(range.size >> pgshift, > + range.bitmap.size); > + if (ret) > + return ret; > + > + mutex_lock(&iommu->lock); > + if (iommu->dirty_page_tracking) > + ret = vfio_iova_dirty_bitmap(iommu, range.iova, > + range.size, range.bitmap.pgsize, > + range.bitmap.data); > + else > + ret = -EINVAL; > + mutex_unlock(&iommu->lock); > + > + return ret; > + } > } > > return -ENOTTY; > @@ -2345,10 +2588,20 @@ static int vfio_iommu_type1_dma_rw_chunk(struct vfio_iommu *iommu, > > vaddr = dma->vaddr + offset; > > - if (write) > + if (write) { > *copied = __copy_to_user((void __user *)vaddr, data, > count) ? 0 : count; > - else > + if (*copied && iommu->dirty_page_tracking) { > + unsigned long pgshift = > + __ffs(vfio_pgsize_bitmap(iommu)); > + /* > + * Bitmap populated with the smallest supported page > + * size > + */ > + bitmap_set(dma->bitmap, offset >> pgshift, > + *copied >> pgshift); > + } > + } else > *copied = __copy_from_user(data, (void __user *)vaddr, > count) ? 0 : count; > if (kthread)
On Tue, 24 Mar 2020 14:37:16 -0600 Alex Williamson <alex.williamson@redhat.com> wrote: > On Wed, 25 Mar 2020 01:02:36 +0530 > Kirti Wankhede <kwankhede@nvidia.com> wrote: > > > VFIO_IOMMU_DIRTY_PAGES ioctl performs three operations: > > - Start dirty pages tracking while migration is active > > - Stop dirty pages tracking. > > - Get dirty pages bitmap. Its user space application's responsibility to > > copy content of dirty pages from source to destination during migration. > > > > To prevent DoS attack, memory for bitmap is allocated per vfio_dma > > structure. Bitmap size is calculated considering smallest supported page > > size. Bitmap is allocated for all vfio_dmas when dirty logging is enabled > > > > Bitmap is populated for already pinned pages when bitmap is allocated for > > a vfio_dma with the smallest supported page size. Update bitmap from > > pinning functions when tracking is enabled. When user application queries > > bitmap, check if requested page size is same as page size used to > > populated bitmap. If it is equal, copy bitmap, but if not equal, return > > error. > > > > Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com> > > Reviewed-by: Neo Jia <cjia@nvidia.com> > > --- > > drivers/vfio/vfio_iommu_type1.c | 265 +++++++++++++++++++++++++++++++++++++++- > > 1 file changed, 259 insertions(+), 6 deletions(-) > > > > diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c > > index 70aeab921d0f..27ed069c5053 100644 > > --- a/drivers/vfio/vfio_iommu_type1.c > > +++ b/drivers/vfio/vfio_iommu_type1.c > > @@ -71,6 +71,7 @@ struct vfio_iommu { > > unsigned int dma_avail; > > bool v2; > > bool nesting; > > + bool dirty_page_tracking; > > }; > > > > struct vfio_domain { > > @@ -91,6 +92,7 @@ struct vfio_dma { > > bool lock_cap; /* capable(CAP_IPC_LOCK) */ > > struct task_struct *task; > > struct rb_root pfn_list; /* Ex-user pinned pfn list */ > > + unsigned long *bitmap; > > }; > > > > struct vfio_group { > > @@ -125,7 +127,21 @@ struct vfio_regions { > > #define IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu) \ > > (!list_empty(&iommu->domain_list)) > > > > +#define DIRTY_BITMAP_BYTES(n) (ALIGN(n, BITS_PER_TYPE(u64)) / BITS_PER_BYTE) > > + > > +/* > > + * Input argument of number of bits to bitmap_set() is unsigned integer, which > > + * further casts to signed integer for unaligned multi-bit operation, > > + * __bitmap_set(). > > + * Then maximum bitmap size supported is 2^31 bits divided by 2^3 bits/byte, > > + * that is 2^28 (256 MB) which maps to 2^31 * 2^12 = 2^43 (8TB) on 4K page > > + * system. > > + */ > > +#define DIRTY_BITMAP_PAGES_MAX (uint64_t)(INT_MAX - 1) > > +#define DIRTY_BITMAP_SIZE_MAX DIRTY_BITMAP_BYTES(DIRTY_BITMAP_PAGES_MAX) > > + > > static int put_pfn(unsigned long pfn, int prot); > > +static unsigned long vfio_pgsize_bitmap(struct vfio_iommu *iommu); > > > > /* > > * This code handles mapping and unmapping of user data buffers > > @@ -175,6 +191,77 @@ static void vfio_unlink_dma(struct vfio_iommu *iommu, struct vfio_dma *old) > > rb_erase(&old->node, &iommu->dma_list); > > } > > > > + > > +static int vfio_dma_bitmap_alloc(struct vfio_dma *dma, uint64_t pgsize) > > +{ > > + uint64_t npages = dma->size / pgsize; > > + > > + if (npages > DIRTY_BITMAP_PAGES_MAX) > > + return -EINVAL; > > + > > + dma->bitmap = kvzalloc(DIRTY_BITMAP_BYTES(npages), GFP_KERNEL); > > + if (!dma->bitmap) > > + return -ENOMEM; > > + > > + return 0; > > +} > > + > > +static void vfio_dma_bitmap_free(struct vfio_dma *dma) > > +{ > > + kfree(dma->bitmap); > > + dma->bitmap = NULL; > > +} > > + > > +static void vfio_dma_populate_bitmap(struct vfio_dma *dma, uint64_t pgsize) > > +{ > > + struct rb_node *p; > > + > > + if (RB_EMPTY_ROOT(&dma->pfn_list)) > > + return; > > + > > + for (p = rb_first(&dma->pfn_list); p; p = rb_next(p)) { > > + struct vfio_pfn *vpfn = rb_entry(p, struct vfio_pfn, node); > > + > > + bitmap_set(dma->bitmap, (vpfn->iova - dma->iova) / pgsize, 1); > > + } > > +} > > + > > +static int vfio_dma_bitmap_alloc_all(struct vfio_iommu *iommu, uint64_t pgsize) > > +{ > > + struct rb_node *n = rb_first(&iommu->dma_list); > > + > > + for (; n; n = rb_next(n)) { > > + struct vfio_dma *dma = rb_entry(n, struct vfio_dma, node); > > + int ret; > > + > > + ret = vfio_dma_bitmap_alloc(dma, pgsize); > > + if (ret) { > > + struct rb_node *p = rb_prev(n); > > + > > + for (; p; p = rb_prev(p)) { > > + struct vfio_dma *dma = rb_entry(n, > > + struct vfio_dma, node); > > + > > + vfio_dma_bitmap_free(dma); > > + } > > + return ret; > > + } > > + vfio_dma_populate_bitmap(dma, pgsize); > > + } > > + return 0; > > +} > > + > > +static void vfio_dma_bitmap_free_all(struct vfio_iommu *iommu) > > +{ > > + struct rb_node *n = rb_first(&iommu->dma_list); > > + > > + for (; n; n = rb_next(n)) { > > + struct vfio_dma *dma = rb_entry(n, struct vfio_dma, node); > > + > > + vfio_dma_bitmap_free(dma); > > + } > > +} > > + > > /* > > * Helper Functions for host iova-pfn list > > */ > > @@ -567,6 +654,18 @@ static int vfio_iommu_type1_pin_pages(void *iommu_data, > > vfio_unpin_page_external(dma, iova, do_accounting); > > goto pin_unwind; > > } > > + > > + if (iommu->dirty_page_tracking) { > > + unsigned long pgshift = > > + __ffs(vfio_pgsize_bitmap(iommu)); > > + > > + /* > > + * Bitmap populated with the smallest supported page > > + * size > > + */ > > + bitmap_set(dma->bitmap, > > + (vpfn->iova - dma->iova) >> pgshift, 1); > > + } > > } > > > > ret = i; > > @@ -801,6 +900,7 @@ static void vfio_remove_dma(struct vfio_iommu *iommu, struct vfio_dma *dma) > > vfio_unmap_unpin(iommu, dma, true); > > vfio_unlink_dma(iommu, dma); > > put_task_struct(dma->task); > > + vfio_dma_bitmap_free(dma); > > kfree(dma); > > iommu->dma_avail++; > > } > > @@ -831,6 +931,56 @@ static unsigned long vfio_pgsize_bitmap(struct vfio_iommu *iommu) > > return bitmap; > > } > > > > +static int vfio_iova_dirty_bitmap(struct vfio_iommu *iommu, dma_addr_t iova, > > + size_t size, uint64_t pgsize, > > + u64 __user *bitmap) > > +{ > > + struct vfio_dma *dma; > > + unsigned long pgshift = __ffs(pgsize); > > + unsigned int npages, bitmap_size; > > + > > + dma = vfio_find_dma(iommu, iova, 1); > > + > > + if (!dma) > > + return -EINVAL; > > + > > + if (dma->iova != iova || dma->size != size) > > + return -EINVAL; > > + > > + npages = dma->size >> pgshift; > > + bitmap_size = DIRTY_BITMAP_BYTES(npages); > > + > > + /* mark all pages dirty if all pages are pinned and mapped. */ > > + if (dma->iommu_mapped) > > + bitmap_set(dma->bitmap, 0, npages); > > + > > + if (copy_to_user((void __user *)bitmap, dma->bitmap, bitmap_size)) > > + return -EFAULT; > > + > > + /* > > + * Re-populate bitmap to include all pinned pages which are considered > > + * as dirty but exclude pages which are unpinned and pages which are > > + * marked dirty by vfio_dma_rw() > > + */ > > + vfio_dma_populate_bitmap(dma, pgsize); > > vfio_dma_populate_bitmap() only sets bits, it doesn't clear them. > Shouldn't we do a memset() zero before calling this? Thanks, Or a bitmap_clear() would be better given we use bitmap_set() above. Thanks, Alex
On 3/25/2020 2:15 AM, Alex Williamson wrote: > On Tue, 24 Mar 2020 14:37:16 -0600 > Alex Williamson <alex.williamson@redhat.com> wrote: > >> On Wed, 25 Mar 2020 01:02:36 +0530 >> Kirti Wankhede <kwankhede@nvidia.com> wrote: >> >>> VFIO_IOMMU_DIRTY_PAGES ioctl performs three operations: >>> - Start dirty pages tracking while migration is active >>> - Stop dirty pages tracking. >>> - Get dirty pages bitmap. Its user space application's responsibility to >>> copy content of dirty pages from source to destination during migration. >>> >>> To prevent DoS attack, memory for bitmap is allocated per vfio_dma >>> structure. Bitmap size is calculated considering smallest supported page >>> size. Bitmap is allocated for all vfio_dmas when dirty logging is enabled >>> >>> Bitmap is populated for already pinned pages when bitmap is allocated for >>> a vfio_dma with the smallest supported page size. Update bitmap from >>> pinning functions when tracking is enabled. When user application queries >>> bitmap, check if requested page size is same as page size used to >>> populated bitmap. If it is equal, copy bitmap, but if not equal, return >>> error. >>> >>> Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com> >>> Reviewed-by: Neo Jia <cjia@nvidia.com> >>> --- >>> drivers/vfio/vfio_iommu_type1.c | 265 +++++++++++++++++++++++++++++++++++++++- >>> 1 file changed, 259 insertions(+), 6 deletions(-) >>> >>> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c >>> index 70aeab921d0f..27ed069c5053 100644 >>> --- a/drivers/vfio/vfio_iommu_type1.c >>> +++ b/drivers/vfio/vfio_iommu_type1.c >>> @@ -71,6 +71,7 @@ struct vfio_iommu { >>> unsigned int dma_avail; >>> bool v2; >>> bool nesting; >>> + bool dirty_page_tracking; >>> }; >>> >>> struct vfio_domain { >>> @@ -91,6 +92,7 @@ struct vfio_dma { >>> bool lock_cap; /* capable(CAP_IPC_LOCK) */ >>> struct task_struct *task; >>> struct rb_root pfn_list; /* Ex-user pinned pfn list */ >>> + unsigned long *bitmap; >>> }; >>> >>> struct vfio_group { >>> @@ -125,7 +127,21 @@ struct vfio_regions { >>> #define IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu) \ >>> (!list_empty(&iommu->domain_list)) >>> >>> +#define DIRTY_BITMAP_BYTES(n) (ALIGN(n, BITS_PER_TYPE(u64)) / BITS_PER_BYTE) >>> + >>> +/* >>> + * Input argument of number of bits to bitmap_set() is unsigned integer, which >>> + * further casts to signed integer for unaligned multi-bit operation, >>> + * __bitmap_set(). >>> + * Then maximum bitmap size supported is 2^31 bits divided by 2^3 bits/byte, >>> + * that is 2^28 (256 MB) which maps to 2^31 * 2^12 = 2^43 (8TB) on 4K page >>> + * system. >>> + */ >>> +#define DIRTY_BITMAP_PAGES_MAX (uint64_t)(INT_MAX - 1) >>> +#define DIRTY_BITMAP_SIZE_MAX DIRTY_BITMAP_BYTES(DIRTY_BITMAP_PAGES_MAX) >>> + >>> static int put_pfn(unsigned long pfn, int prot); >>> +static unsigned long vfio_pgsize_bitmap(struct vfio_iommu *iommu); >>> >>> /* >>> * This code handles mapping and unmapping of user data buffers >>> @@ -175,6 +191,77 @@ static void vfio_unlink_dma(struct vfio_iommu *iommu, struct vfio_dma *old) >>> rb_erase(&old->node, &iommu->dma_list); >>> } >>> >>> + >>> +static int vfio_dma_bitmap_alloc(struct vfio_dma *dma, uint64_t pgsize) >>> +{ >>> + uint64_t npages = dma->size / pgsize; >>> + >>> + if (npages > DIRTY_BITMAP_PAGES_MAX) >>> + return -EINVAL; >>> + >>> + dma->bitmap = kvzalloc(DIRTY_BITMAP_BYTES(npages), GFP_KERNEL); >>> + if (!dma->bitmap) >>> + return -ENOMEM; >>> + >>> + return 0; >>> +} >>> + >>> +static void vfio_dma_bitmap_free(struct vfio_dma *dma) >>> +{ >>> + kfree(dma->bitmap); >>> + dma->bitmap = NULL; >>> +} >>> + >>> +static void vfio_dma_populate_bitmap(struct vfio_dma *dma, uint64_t pgsize) >>> +{ >>> + struct rb_node *p; >>> + >>> + if (RB_EMPTY_ROOT(&dma->pfn_list)) >>> + return; >>> + >>> + for (p = rb_first(&dma->pfn_list); p; p = rb_next(p)) { >>> + struct vfio_pfn *vpfn = rb_entry(p, struct vfio_pfn, node); >>> + >>> + bitmap_set(dma->bitmap, (vpfn->iova - dma->iova) / pgsize, 1); >>> + } >>> +} >>> + >>> +static int vfio_dma_bitmap_alloc_all(struct vfio_iommu *iommu, uint64_t pgsize) >>> +{ >>> + struct rb_node *n = rb_first(&iommu->dma_list); >>> + >>> + for (; n; n = rb_next(n)) { >>> + struct vfio_dma *dma = rb_entry(n, struct vfio_dma, node); >>> + int ret; >>> + >>> + ret = vfio_dma_bitmap_alloc(dma, pgsize); >>> + if (ret) { >>> + struct rb_node *p = rb_prev(n); >>> + >>> + for (; p; p = rb_prev(p)) { >>> + struct vfio_dma *dma = rb_entry(n, >>> + struct vfio_dma, node); >>> + >>> + vfio_dma_bitmap_free(dma); >>> + } >>> + return ret; >>> + } >>> + vfio_dma_populate_bitmap(dma, pgsize); >>> + } >>> + return 0; >>> +} >>> + >>> +static void vfio_dma_bitmap_free_all(struct vfio_iommu *iommu) >>> +{ >>> + struct rb_node *n = rb_first(&iommu->dma_list); >>> + >>> + for (; n; n = rb_next(n)) { >>> + struct vfio_dma *dma = rb_entry(n, struct vfio_dma, node); >>> + >>> + vfio_dma_bitmap_free(dma); >>> + } >>> +} >>> + >>> /* >>> * Helper Functions for host iova-pfn list >>> */ >>> @@ -567,6 +654,18 @@ static int vfio_iommu_type1_pin_pages(void *iommu_data, >>> vfio_unpin_page_external(dma, iova, do_accounting); >>> goto pin_unwind; >>> } >>> + >>> + if (iommu->dirty_page_tracking) { >>> + unsigned long pgshift = >>> + __ffs(vfio_pgsize_bitmap(iommu)); >>> + >>> + /* >>> + * Bitmap populated with the smallest supported page >>> + * size >>> + */ >>> + bitmap_set(dma->bitmap, >>> + (vpfn->iova - dma->iova) >> pgshift, 1); >>> + } >>> } >>> >>> ret = i; >>> @@ -801,6 +900,7 @@ static void vfio_remove_dma(struct vfio_iommu *iommu, struct vfio_dma *dma) >>> vfio_unmap_unpin(iommu, dma, true); >>> vfio_unlink_dma(iommu, dma); >>> put_task_struct(dma->task); >>> + vfio_dma_bitmap_free(dma); >>> kfree(dma); >>> iommu->dma_avail++; >>> } >>> @@ -831,6 +931,56 @@ static unsigned long vfio_pgsize_bitmap(struct vfio_iommu *iommu) >>> return bitmap; >>> } >>> >>> +static int vfio_iova_dirty_bitmap(struct vfio_iommu *iommu, dma_addr_t iova, >>> + size_t size, uint64_t pgsize, >>> + u64 __user *bitmap) >>> +{ >>> + struct vfio_dma *dma; >>> + unsigned long pgshift = __ffs(pgsize); >>> + unsigned int npages, bitmap_size; >>> + >>> + dma = vfio_find_dma(iommu, iova, 1); >>> + >>> + if (!dma) >>> + return -EINVAL; >>> + >>> + if (dma->iova != iova || dma->size != size) >>> + return -EINVAL; >>> + >>> + npages = dma->size >> pgshift; >>> + bitmap_size = DIRTY_BITMAP_BYTES(npages); >>> + >>> + /* mark all pages dirty if all pages are pinned and mapped. */ >>> + if (dma->iommu_mapped) >>> + bitmap_set(dma->bitmap, 0, npages); >>> + >>> + if (copy_to_user((void __user *)bitmap, dma->bitmap, bitmap_size)) >>> + return -EFAULT; >>> + >>> + /* >>> + * Re-populate bitmap to include all pinned pages which are considered >>> + * as dirty but exclude pages which are unpinned and pages which are >>> + * marked dirty by vfio_dma_rw() >>> + */ >>> + vfio_dma_populate_bitmap(dma, pgsize); >> >> vfio_dma_populate_bitmap() only sets bits, it doesn't clear them. >> Shouldn't we do a memset() zero before calling this? Thanks, > > Or a bitmap_clear() would be better given we use bitmap_set() above. > Thanks, > Oh, I missed clearing bitmap. Resending only this patch again. Thanks, Kirti
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index 70aeab921d0f..27ed069c5053 100644 --- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -71,6 +71,7 @@ struct vfio_iommu { unsigned int dma_avail; bool v2; bool nesting; + bool dirty_page_tracking; }; struct vfio_domain { @@ -91,6 +92,7 @@ struct vfio_dma { bool lock_cap; /* capable(CAP_IPC_LOCK) */ struct task_struct *task; struct rb_root pfn_list; /* Ex-user pinned pfn list */ + unsigned long *bitmap; }; struct vfio_group { @@ -125,7 +127,21 @@ struct vfio_regions { #define IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu) \ (!list_empty(&iommu->domain_list)) +#define DIRTY_BITMAP_BYTES(n) (ALIGN(n, BITS_PER_TYPE(u64)) / BITS_PER_BYTE) + +/* + * Input argument of number of bits to bitmap_set() is unsigned integer, which + * further casts to signed integer for unaligned multi-bit operation, + * __bitmap_set(). + * Then maximum bitmap size supported is 2^31 bits divided by 2^3 bits/byte, + * that is 2^28 (256 MB) which maps to 2^31 * 2^12 = 2^43 (8TB) on 4K page + * system. + */ +#define DIRTY_BITMAP_PAGES_MAX (uint64_t)(INT_MAX - 1) +#define DIRTY_BITMAP_SIZE_MAX DIRTY_BITMAP_BYTES(DIRTY_BITMAP_PAGES_MAX) + static int put_pfn(unsigned long pfn, int prot); +static unsigned long vfio_pgsize_bitmap(struct vfio_iommu *iommu); /* * This code handles mapping and unmapping of user data buffers @@ -175,6 +191,77 @@ static void vfio_unlink_dma(struct vfio_iommu *iommu, struct vfio_dma *old) rb_erase(&old->node, &iommu->dma_list); } + +static int vfio_dma_bitmap_alloc(struct vfio_dma *dma, uint64_t pgsize) +{ + uint64_t npages = dma->size / pgsize; + + if (npages > DIRTY_BITMAP_PAGES_MAX) + return -EINVAL; + + dma->bitmap = kvzalloc(DIRTY_BITMAP_BYTES(npages), GFP_KERNEL); + if (!dma->bitmap) + return -ENOMEM; + + return 0; +} + +static void vfio_dma_bitmap_free(struct vfio_dma *dma) +{ + kfree(dma->bitmap); + dma->bitmap = NULL; +} + +static void vfio_dma_populate_bitmap(struct vfio_dma *dma, uint64_t pgsize) +{ + struct rb_node *p; + + if (RB_EMPTY_ROOT(&dma->pfn_list)) + return; + + for (p = rb_first(&dma->pfn_list); p; p = rb_next(p)) { + struct vfio_pfn *vpfn = rb_entry(p, struct vfio_pfn, node); + + bitmap_set(dma->bitmap, (vpfn->iova - dma->iova) / pgsize, 1); + } +} + +static int vfio_dma_bitmap_alloc_all(struct vfio_iommu *iommu, uint64_t pgsize) +{ + struct rb_node *n = rb_first(&iommu->dma_list); + + for (; n; n = rb_next(n)) { + struct vfio_dma *dma = rb_entry(n, struct vfio_dma, node); + int ret; + + ret = vfio_dma_bitmap_alloc(dma, pgsize); + if (ret) { + struct rb_node *p = rb_prev(n); + + for (; p; p = rb_prev(p)) { + struct vfio_dma *dma = rb_entry(n, + struct vfio_dma, node); + + vfio_dma_bitmap_free(dma); + } + return ret; + } + vfio_dma_populate_bitmap(dma, pgsize); + } + return 0; +} + +static void vfio_dma_bitmap_free_all(struct vfio_iommu *iommu) +{ + struct rb_node *n = rb_first(&iommu->dma_list); + + for (; n; n = rb_next(n)) { + struct vfio_dma *dma = rb_entry(n, struct vfio_dma, node); + + vfio_dma_bitmap_free(dma); + } +} + /* * Helper Functions for host iova-pfn list */ @@ -567,6 +654,18 @@ static int vfio_iommu_type1_pin_pages(void *iommu_data, vfio_unpin_page_external(dma, iova, do_accounting); goto pin_unwind; } + + if (iommu->dirty_page_tracking) { + unsigned long pgshift = + __ffs(vfio_pgsize_bitmap(iommu)); + + /* + * Bitmap populated with the smallest supported page + * size + */ + bitmap_set(dma->bitmap, + (vpfn->iova - dma->iova) >> pgshift, 1); + } } ret = i; @@ -801,6 +900,7 @@ static void vfio_remove_dma(struct vfio_iommu *iommu, struct vfio_dma *dma) vfio_unmap_unpin(iommu, dma, true); vfio_unlink_dma(iommu, dma); put_task_struct(dma->task); + vfio_dma_bitmap_free(dma); kfree(dma); iommu->dma_avail++; } @@ -831,6 +931,56 @@ static unsigned long vfio_pgsize_bitmap(struct vfio_iommu *iommu) return bitmap; } +static int vfio_iova_dirty_bitmap(struct vfio_iommu *iommu, dma_addr_t iova, + size_t size, uint64_t pgsize, + u64 __user *bitmap) +{ + struct vfio_dma *dma; + unsigned long pgshift = __ffs(pgsize); + unsigned int npages, bitmap_size; + + dma = vfio_find_dma(iommu, iova, 1); + + if (!dma) + return -EINVAL; + + if (dma->iova != iova || dma->size != size) + return -EINVAL; + + npages = dma->size >> pgshift; + bitmap_size = DIRTY_BITMAP_BYTES(npages); + + /* mark all pages dirty if all pages are pinned and mapped. */ + if (dma->iommu_mapped) + bitmap_set(dma->bitmap, 0, npages); + + if (copy_to_user((void __user *)bitmap, dma->bitmap, bitmap_size)) + return -EFAULT; + + /* + * Re-populate bitmap to include all pinned pages which are considered + * as dirty but exclude pages which are unpinned and pages which are + * marked dirty by vfio_dma_rw() + */ + vfio_dma_populate_bitmap(dma, pgsize); + return 0; +} + +static int verify_bitmap_size(uint64_t npages, uint64_t bitmap_size) +{ + uint64_t bsize; + + if (!npages || !bitmap_size || (bitmap_size > DIRTY_BITMAP_SIZE_MAX)) + return -EINVAL; + + bsize = DIRTY_BITMAP_BYTES(npages); + + if (bitmap_size < bsize) + return -EINVAL; + + return 0; +} + static int vfio_dma_do_unmap(struct vfio_iommu *iommu, struct vfio_iommu_type1_dma_unmap *unmap) { @@ -1038,16 +1188,16 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu, unsigned long vaddr = map->vaddr; size_t size = map->size; int ret = 0, prot = 0; - uint64_t mask; + uint64_t pgsize; struct vfio_dma *dma; /* Verify that none of our __u64 fields overflow */ if (map->size != size || map->vaddr != vaddr || map->iova != iova) return -EINVAL; - mask = ((uint64_t)1 << __ffs(vfio_pgsize_bitmap(iommu))) - 1; + pgsize = (uint64_t)1 << __ffs(vfio_pgsize_bitmap(iommu)); - WARN_ON(mask & PAGE_MASK); + WARN_ON((pgsize - 1) & PAGE_MASK); /* READ/WRITE from device perspective */ if (map->flags & VFIO_DMA_MAP_FLAG_WRITE) @@ -1055,7 +1205,7 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu, if (map->flags & VFIO_DMA_MAP_FLAG_READ) prot |= IOMMU_READ; - if (!prot || !size || (size | iova | vaddr) & mask) + if (!prot || !size || (size | iova | vaddr) & (pgsize - 1)) return -EINVAL; /* Don't allow IOVA or virtual address wrap */ @@ -1130,6 +1280,12 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu, else ret = vfio_pin_map_dma(iommu, dma, size); + if (!ret && iommu->dirty_page_tracking) { + ret = vfio_dma_bitmap_alloc(dma, pgsize); + if (ret) + vfio_remove_dma(iommu, dma); + } + out_unlock: mutex_unlock(&iommu->lock); return ret; @@ -2278,6 +2434,93 @@ static long vfio_iommu_type1_ioctl(void *iommu_data, return copy_to_user((void __user *)arg, &unmap, minsz) ? -EFAULT : 0; + } else if (cmd == VFIO_IOMMU_DIRTY_PAGES) { + struct vfio_iommu_type1_dirty_bitmap dirty; + uint32_t mask = VFIO_IOMMU_DIRTY_PAGES_FLAG_START | + VFIO_IOMMU_DIRTY_PAGES_FLAG_STOP | + VFIO_IOMMU_DIRTY_PAGES_FLAG_GET_BITMAP; + int ret = 0; + + if (!iommu->v2) + return -EACCES; + + minsz = offsetofend(struct vfio_iommu_type1_dirty_bitmap, + flags); + + if (copy_from_user(&dirty, (void __user *)arg, minsz)) + return -EFAULT; + + if (dirty.argsz < minsz || dirty.flags & ~mask) + return -EINVAL; + + /* only one flag should be set at a time */ + if (__ffs(dirty.flags) != __fls(dirty.flags)) + return -EINVAL; + + if (dirty.flags & VFIO_IOMMU_DIRTY_PAGES_FLAG_START) { + uint64_t pgsize = 1 << __ffs(vfio_pgsize_bitmap(iommu)); + + mutex_lock(&iommu->lock); + if (!iommu->dirty_page_tracking) { + ret = vfio_dma_bitmap_alloc_all(iommu, pgsize); + if (!ret) + iommu->dirty_page_tracking = true; + } + mutex_unlock(&iommu->lock); + return ret; + } else if (dirty.flags & VFIO_IOMMU_DIRTY_PAGES_FLAG_STOP) { + mutex_lock(&iommu->lock); + if (iommu->dirty_page_tracking) { + iommu->dirty_page_tracking = false; + vfio_dma_bitmap_free_all(iommu); + } + mutex_unlock(&iommu->lock); + return 0; + } else if (dirty.flags & + VFIO_IOMMU_DIRTY_PAGES_FLAG_GET_BITMAP) { + struct vfio_iommu_type1_dirty_bitmap_get range; + unsigned long pgshift; + size_t data_size = dirty.argsz - minsz; + uint64_t iommu_pgsize = + 1 << __ffs(vfio_pgsize_bitmap(iommu)); + + if (!data_size || data_size < sizeof(range)) + return -EINVAL; + + if (copy_from_user(&range, (void __user *)(arg + minsz), + sizeof(range))) + return -EFAULT; + + /* allow only smallest supported pgsize */ + if (range.bitmap.pgsize != iommu_pgsize) + return -EINVAL; + if (range.iova & (iommu_pgsize - 1)) + return -EINVAL; + if (!range.size || range.size & (iommu_pgsize - 1)) + return -EINVAL; + if (range.iova + range.size < range.iova) + return -EINVAL; + if (!access_ok((void __user *)range.bitmap.data, + range.bitmap.size)) + return -EINVAL; + + pgshift = __ffs(range.bitmap.pgsize); + ret = verify_bitmap_size(range.size >> pgshift, + range.bitmap.size); + if (ret) + return ret; + + mutex_lock(&iommu->lock); + if (iommu->dirty_page_tracking) + ret = vfio_iova_dirty_bitmap(iommu, range.iova, + range.size, range.bitmap.pgsize, + range.bitmap.data); + else + ret = -EINVAL; + mutex_unlock(&iommu->lock); + + return ret; + } } return -ENOTTY; @@ -2345,10 +2588,20 @@ static int vfio_iommu_type1_dma_rw_chunk(struct vfio_iommu *iommu, vaddr = dma->vaddr + offset; - if (write) + if (write) { *copied = __copy_to_user((void __user *)vaddr, data, count) ? 0 : count; - else + if (*copied && iommu->dirty_page_tracking) { + unsigned long pgshift = + __ffs(vfio_pgsize_bitmap(iommu)); + /* + * Bitmap populated with the smallest supported page + * size + */ + bitmap_set(dma->bitmap, offset >> pgshift, + *copied >> pgshift); + } + } else *copied = __copy_from_user(data, (void __user *)vaddr, count) ? 0 : count; if (kthread)