From: Tomer Tayar <tta...@habana.ai>

On devices with virtual device memory (Gaudi2 onwards), user can provide
an offset within an allocated device memory from which he wants to
export a dma-buf object.
The offset value is verified by driver, but it is not taken into
consideration when the importer driver maps the dma-buf and the SG table
it prepared.
Add the missing offset handling.

Signed-off-by: Tomer Tayar <tta...@habana.ai>
Reviewed-by: Oded Gabbay <ogab...@kernel.org>
Signed-off-by: Oded Gabbay <ogab...@kernel.org>
---
 drivers/accel/habanalabs/common/habanalabs.h |  3 +
 drivers/accel/habanalabs/common/memory.c     | 75 +++++++++++---------
 2 files changed, 43 insertions(+), 35 deletions(-)

diff --git a/drivers/accel/habanalabs/common/habanalabs.h 
b/drivers/accel/habanalabs/common/habanalabs.h
index 43e682cdeb75..874ae76cbd78 100644
--- a/drivers/accel/habanalabs/common/habanalabs.h
+++ b/drivers/accel/habanalabs/common/habanalabs.h
@@ -1811,6 +1811,8 @@ struct hl_cs_counters_atomic {
  * @phys_pg_pack: pointer to physical page pack if the dma-buf was exported
  *                where virtual memory is supported.
  * @memhash_hnode: pointer to the memhash node. this object holds the export 
count.
+ * @offset: the offset into the buffer from which the memory is exported.
+ *          Relevant only if virtual memory is supported and phys_pg_pack is 
being used.
  * device_phys_addr: physical address of the device's memory. Relevant only
  *                   if phys_pg_pack is NULL (dma-buf was exported from 
address).
  *                   The total size can be taken from the dmabuf object.
@@ -1820,6 +1822,7 @@ struct hl_dmabuf_priv {
        struct hl_ctx                   *ctx;
        struct hl_vm_phys_pg_pack       *phys_pg_pack;
        struct hl_vm_hash_node          *memhash_hnode;
+       u64                             offset;
        u64                             device_phys_addr;
 };
 
diff --git a/drivers/accel/habanalabs/common/memory.c 
b/drivers/accel/habanalabs/common/memory.c
index dc5ff3e74c39..00e73b5573be 100644
--- a/drivers/accel/habanalabs/common/memory.c
+++ b/drivers/accel/habanalabs/common/memory.c
@@ -1532,11 +1532,11 @@ static int set_dma_sg(struct scatterlist *sg, u64 
bar_address, u64 chunk_size,
 }
 
 static struct sg_table *alloc_sgt_from_device_pages(struct hl_device *hdev, 
u64 *pages, u64 npages,
-                                               u64 page_size, u64 
exported_size,
+                                               u64 page_size, u64 
exported_size, u64 offset,
                                                struct device *dev, enum 
dma_data_direction dir)
 {
        u64 dma_max_seg_size, curr_page, size, chunk_size, left_size_to_export, 
left_size_in_page,
-               left_size_in_dma_seg, device_address, bar_address;
+               left_size_in_dma_seg, device_address, bar_address, start_page;
        struct asic_fixed_properties *prop = &hdev->asic_prop;
        struct scatterlist *sg;
        unsigned int nents, i;
@@ -1557,11 +1557,20 @@ static struct sg_table 
*alloc_sgt_from_device_pages(struct hl_device *hdev, u64
        if (!sgt)
                return ERR_PTR(-ENOMEM);
 
+       /* Use the offset to move to the actual first page that is exported */
+       for (start_page = 0 ; start_page < npages ; ++start_page) {
+               if (offset < page_size)
+                       break;
+
+               /* The offset value was validated so there can't be an 
underflow */
+               offset -= page_size;
+       }
+
        /* Calculate the required number of entries for the SG table */
-       curr_page = 0;
+       curr_page = start_page;
        nents = 1;
        left_size_to_export = exported_size;
-       left_size_in_page = page_size;
+       left_size_in_page = page_size - offset;
        left_size_in_dma_seg = dma_max_seg_size;
        next_sg_entry = false;
 
@@ -1599,10 +1608,10 @@ static struct sg_table 
*alloc_sgt_from_device_pages(struct hl_device *hdev, u64
                goto err_free_sgt;
 
        /* Prepare the SG table entries */
-       curr_page = 0;
-       device_address = pages[curr_page];
+       curr_page = start_page;
+       device_address = pages[curr_page] + offset;
        left_size_to_export = exported_size;
-       left_size_in_page = page_size;
+       left_size_in_page = page_size - offset;
        left_size_in_dma_seg = dma_max_seg_size;
        next_sg_entry = false;
 
@@ -1708,7 +1717,7 @@ static int hl_dmabuf_attach(struct dma_buf *dmabuf,
 static struct sg_table *hl_map_dmabuf(struct dma_buf_attachment *attachment,
                                        enum dma_data_direction dir)
 {
-       u64 *pages, npages, page_size, exported_size;
+       u64 *pages, npages, page_size, exported_size, offset;
        struct dma_buf *dma_buf = attachment->dmabuf;
        struct hl_vm_phys_pg_pack *phys_pg_pack;
        struct hl_dmabuf_priv *hl_dmabuf;
@@ -1723,6 +1732,7 @@ static struct sg_table *hl_map_dmabuf(struct 
dma_buf_attachment *attachment,
        hl_dmabuf = dma_buf->priv;
        hdev = hl_dmabuf->ctx->hdev;
        exported_size = hl_dmabuf->dmabuf->size;
+       offset = hl_dmabuf->offset;
        phys_pg_pack = hl_dmabuf->phys_pg_pack;
 
        if (phys_pg_pack) {
@@ -1735,7 +1745,7 @@ static struct sg_table *hl_map_dmabuf(struct 
dma_buf_attachment *attachment,
                page_size = hl_dmabuf->dmabuf->size;
        }
 
-       sgt = alloc_sgt_from_device_pages(hdev, pages, npages, page_size, 
exported_size,
+       sgt = alloc_sgt_from_device_pages(hdev, pages, npages, page_size, 
exported_size, offset,
                                                attachment->dev, dir);
        if (IS_ERR(sgt))
                dev_err(hdev->dev, "failed (%ld) to initialize sgt for 
dmabuf\n", PTR_ERR(sgt));
@@ -1881,12 +1891,12 @@ static int export_dmabuf(struct hl_ctx *ctx,
        return rc;
 }
 
-static int validate_export_params_common(struct hl_device *hdev, u64 
device_addr, u64 size)
+static int validate_export_params_common(struct hl_device *hdev, u64 addr, u64 
size, u64 offset)
 {
-       if (!PAGE_ALIGNED(device_addr)) {
+       if (!PAGE_ALIGNED(addr)) {
                dev_dbg(hdev->dev,
                        "exported device memory address 0x%llx should be 
aligned to PAGE_SIZE 0x%lx\n",
-                       device_addr, PAGE_SIZE);
+                       addr, PAGE_SIZE);
                return -EINVAL;
        }
 
@@ -1897,6 +1907,13 @@ static int validate_export_params_common(struct 
hl_device *hdev, u64 device_addr
                return -EINVAL;
        }
 
+       if (!PAGE_ALIGNED(offset)) {
+               dev_dbg(hdev->dev,
+                       "exported device memory offset %llu should be a 
multiple of PAGE_SIZE %lu\n",
+                       offset, PAGE_SIZE);
+               return -EINVAL;
+       }
+
        return 0;
 }
 
@@ -1906,13 +1923,13 @@ static int validate_export_params_no_mmu(struct 
hl_device *hdev, u64 device_addr
        u64 bar_address;
        int rc;
 
-       rc = validate_export_params_common(hdev, device_addr, size);
+       rc = validate_export_params_common(hdev, device_addr, size, 0);
        if (rc)
                return rc;
 
        if (device_addr < prop->dram_user_base_address ||
-                               (device_addr + size) > prop->dram_end_address ||
-                               (device_addr + size) < device_addr) {
+                       (device_addr + size) > prop->dram_end_address ||
+                       (device_addr + size) < device_addr) {
                dev_dbg(hdev->dev,
                        "DRAM memory range 0x%llx (+0x%llx) is outside of DRAM 
boundaries\n",
                        device_addr, size);
@@ -1939,36 +1956,26 @@ static int validate_export_params(struct hl_device 
*hdev, u64 device_addr, u64 s
        u64 bar_address;
        int i, rc;
 
-       rc = validate_export_params_common(hdev, device_addr, size);
+       rc = validate_export_params_common(hdev, device_addr, size, offset);
        if (rc)
                return rc;
 
-       if (!PAGE_ALIGNED(offset)) {
-               dev_dbg(hdev->dev,
-                       "exported device memory offset %llu should be a 
multiple of PAGE_SIZE %lu\n",
-                       offset, PAGE_SIZE);
-               return -EINVAL;
-       }
-
        if ((offset + size) > phys_pg_pack->total_size) {
                dev_dbg(hdev->dev, "offset %#llx and size %#llx exceed total 
map size %#llx\n",
-                               offset, size, phys_pg_pack->total_size);
+                       offset, size, phys_pg_pack->total_size);
                return -EINVAL;
        }
 
        for (i = 0 ; i < phys_pg_pack->npages ; i++) {
-
                bar_address = hdev->dram_pci_bar_start +
-                                       (phys_pg_pack->pages[i] - 
prop->dram_base_address);
+                               (phys_pg_pack->pages[i] - 
prop->dram_base_address);
 
                if ((bar_address + phys_pg_pack->page_size) >
                                (hdev->dram_pci_bar_start + 
prop->dram_pci_bar_size) ||
                                (bar_address + phys_pg_pack->page_size) < 
bar_address) {
                        dev_dbg(hdev->dev,
                                "DRAM memory range 0x%llx (+0x%x) is outside of 
PCI BAR boundaries\n",
-                                       phys_pg_pack->pages[i],
-                                       phys_pg_pack->page_size);
-
+                               phys_pg_pack->pages[i], 
phys_pg_pack->page_size);
                        return -EINVAL;
                }
        }
@@ -2024,7 +2031,6 @@ static int export_dmabuf_from_addr(struct hl_ctx *ctx, 
u64 addr, u64 size, u64 o
        struct asic_fixed_properties *prop;
        struct hl_dmabuf_priv *hl_dmabuf;
        struct hl_device *hdev;
-       u64 export_addr;
        int rc;
 
        hdev = ctx->hdev;
@@ -2036,8 +2042,6 @@ static int export_dmabuf_from_addr(struct hl_ctx *ctx, 
u64 addr, u64 size, u64 o
                return -EINVAL;
        }
 
-       export_addr = addr + offset;
-
        hl_dmabuf = kzalloc(sizeof(*hl_dmabuf), GFP_KERNEL);
        if (!hl_dmabuf)
                return -ENOMEM;
@@ -2053,18 +2057,19 @@ static int export_dmabuf_from_addr(struct hl_ctx *ctx, 
u64 addr, u64 size, u64 o
                        rc = PTR_ERR(phys_pg_pack);
                        goto dec_memhash_export_cnt;
                }
-               rc = validate_export_params(hdev, export_addr, size, offset, 
phys_pg_pack);
+               rc = validate_export_params(hdev, addr, size, offset, 
phys_pg_pack);
                if (rc)
                        goto dec_memhash_export_cnt;
 
                hl_dmabuf->phys_pg_pack = phys_pg_pack;
                hl_dmabuf->memhash_hnode = hnode;
+               hl_dmabuf->offset = offset;
        } else {
-               rc = validate_export_params_no_mmu(hdev, export_addr, size);
+               rc = validate_export_params_no_mmu(hdev, addr, size);
                if (rc)
                        goto err_free_dmabuf_wrapper;
 
-               hl_dmabuf->device_phys_addr = export_addr;
+               hl_dmabuf->device_phys_addr = addr;
        }
 
        rc = export_dmabuf(ctx, hl_dmabuf, size, flags, dmabuf_fd);
-- 
2.34.1

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