iommu/io-pgtable-arm: Implement arm_lpae_unmap_pages()

Implement the unmap_pages() callback for the ARM LPAE io-pgtable
format.

Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>
Suggested-by: Will Deacon <will@kernel.org>
Signed-off-by: Georgi Djakov <quic_c_gdjako@quicinc.com>
Link: https://lore.kernel.org/r/1623850736-389584-11-git-send-email-quic_c_gdjako@quicinc.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index ea66b10..fe8fa0e 100644 (file)
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -46,6 +46,9 @@
 #define ARM_LPAE_PGD_SIZE(d)                                           \
        (sizeof(arm_lpae_iopte) << (d)->pgd_bits)
 
+#define ARM_LPAE_PTES_PER_TABLE(d)                                     \
+       (ARM_LPAE_GRANULE(d) >> ilog2(sizeof(arm_lpae_iopte)))
+
 /*
  * Calculate the index at level l used to map virtual address a using the
  * pagetable in d.
@@ -239,22 +242,19 @@ static void __arm_lpae_sync_pte(arm_lpae_iopte *ptep, int num_entries,
                                   sizeof(*ptep) * num_entries, DMA_TO_DEVICE);
 }
 
-static void __arm_lpae_set_pte(arm_lpae_iopte *ptep, arm_lpae_iopte pte,
-                              int num_entries, struct io_pgtable_cfg *cfg)
+static void __arm_lpae_clear_pte(arm_lpae_iopte *ptep, struct io_pgtable_cfg *cfg)
 {
-       int i;
 
-       for (i = 0; i < num_entries; i++)
-               ptep[i] = pte;
+       *ptep = 0;
 
        if (!cfg->coherent_walk)
-               __arm_lpae_sync_pte(ptep, num_entries, cfg);
+               __arm_lpae_sync_pte(ptep, 1, cfg);
 }
 
 static size_t __arm_lpae_unmap(struct arm_lpae_io_pgtable *data,
                               struct iommu_iotlb_gather *gather,
-                              unsigned long iova, size_t size, int lvl,
-                              arm_lpae_iopte *ptep);
+                              unsigned long iova, size_t size, size_t pgcount,
+                              int lvl, arm_lpae_iopte *ptep);
 
 static void __arm_lpae_init_pte(struct arm_lpae_io_pgtable *data,
                                phys_addr_t paddr, arm_lpae_iopte prot,
@@ -298,7 +298,7 @@ static int arm_lpae_init_pte(struct arm_lpae_io_pgtable *data,
                        size_t sz = ARM_LPAE_BLOCK_SIZE(lvl, data);
 
                        tblp = ptep - ARM_LPAE_LVL_IDX(iova, lvl, data);
-                       if (__arm_lpae_unmap(data, NULL, iova + i * sz, sz,
+                       if (__arm_lpae_unmap(data, NULL, iova + i * sz, sz, 1,
                                             lvl, tblp) != sz) {
                                WARN_ON(1);
                                return -EINVAL;
@@ -526,14 +526,15 @@ static size_t arm_lpae_split_blk_unmap(struct arm_lpae_io_pgtable *data,
                                       struct iommu_iotlb_gather *gather,
                                       unsigned long iova, size_t size,
                                       arm_lpae_iopte blk_pte, int lvl,
-                                      arm_lpae_iopte *ptep)
+                                      arm_lpae_iopte *ptep, size_t pgcount)
 {
        struct io_pgtable_cfg *cfg = &data->iop.cfg;
        arm_lpae_iopte pte, *tablep;
        phys_addr_t blk_paddr;
        size_t tablesz = ARM_LPAE_GRANULE(data);
        size_t split_sz = ARM_LPAE_BLOCK_SIZE(lvl, data);
-       int i, unmap_idx = -1;
+       int ptes_per_table = ARM_LPAE_PTES_PER_TABLE(data);
+       int i, unmap_idx_start = -1, num_entries = 0, max_entries;
 
        if (WARN_ON(lvl == ARM_LPAE_MAX_LEVELS))
                return 0;
@@ -542,15 +543,18 @@ static size_t arm_lpae_split_blk_unmap(struct arm_lpae_io_pgtable *data,
        if (!tablep)
                return 0; /* Bytes unmapped */
 
-       if (size == split_sz)
-               unmap_idx = ARM_LPAE_LVL_IDX(iova, lvl, data);
+       if (size == split_sz) {
+               unmap_idx_start = ARM_LPAE_LVL_IDX(iova, lvl, data);
+               max_entries = ptes_per_table - unmap_idx_start;
+               num_entries = min_t(int, pgcount, max_entries);
+       }
 
        blk_paddr = iopte_to_paddr(blk_pte, data);
        pte = iopte_prot(blk_pte);
 
-       for (i = 0; i < tablesz / sizeof(pte); i++, blk_paddr += split_sz) {
+       for (i = 0; i < ptes_per_table; i++, blk_paddr += split_sz) {
                /* Unmap! */
-               if (i == unmap_idx)
+               if (i >= unmap_idx_start && i < (unmap_idx_start + num_entries))
                        continue;
 
                __arm_lpae_init_pte(data, blk_paddr, pte, lvl, 1, &tablep[i]);
@@ -568,76 +572,92 @@ static size_t arm_lpae_split_blk_unmap(struct arm_lpae_io_pgtable *data,
                        return 0;
 
                tablep = iopte_deref(pte, data);
-       } else if (unmap_idx >= 0) {
-               io_pgtable_tlb_add_page(&data->iop, gather, iova, size);
-               return size;
+       } else if (unmap_idx_start >= 0) {
+               for (i = 0; i < num_entries; i++)
+                       io_pgtable_tlb_add_page(&data->iop, gather, iova + i * size, size);
+
+               return num_entries * size;
        }
 
-       return __arm_lpae_unmap(data, gather, iova, size, lvl, tablep);
+       return __arm_lpae_unmap(data, gather, iova, size, pgcount, lvl, tablep);
 }
 
 static size_t __arm_lpae_unmap(struct arm_lpae_io_pgtable *data,
                               struct iommu_iotlb_gather *gather,
-                              unsigned long iova, size_t size, int lvl,
-                              arm_lpae_iopte *ptep)
+                              unsigned long iova, size_t size, size_t pgcount,
+                              int lvl, arm_lpae_iopte *ptep)
 {
        arm_lpae_iopte pte;
        struct io_pgtable *iop = &data->iop;
+       int i = 0, num_entries, max_entries, unmap_idx_start;
 
        /* Something went horribly wrong and we ran out of page table */
        if (WARN_ON(lvl == ARM_LPAE_MAX_LEVELS))
                return 0;
 
-       ptep += ARM_LPAE_LVL_IDX(iova, lvl, data);
+       unmap_idx_start = ARM_LPAE_LVL_IDX(iova, lvl, data);
+       ptep += unmap_idx_start;
        pte = READ_ONCE(*ptep);
        if (WARN_ON(!pte))
                return 0;
 
        /* If the size matches this level, we're in the right place */
        if (size == ARM_LPAE_BLOCK_SIZE(lvl, data)) {
-               __arm_lpae_set_pte(ptep, 0, 1, &iop->cfg);
-
-               if (!iopte_leaf(pte, lvl, iop->fmt)) {
-                       /* Also flush any partial walks */
-                       io_pgtable_tlb_flush_walk(iop, iova, size,
-                                                 ARM_LPAE_GRANULE(data));
-                       ptep = iopte_deref(pte, data);
-                       __arm_lpae_free_pgtable(data, lvl + 1, ptep);
-               } else if (iop->cfg.quirks & IO_PGTABLE_QUIRK_NON_STRICT) {
-                       /*
-                        * Order the PTE update against queueing the IOVA, to
-                        * guarantee that a flush callback from a different CPU
-                        * has observed it before the TLBIALL can be issued.
-                        */
-                       smp_wmb();
-               } else {
-                       io_pgtable_tlb_add_page(iop, gather, iova, size);
+               max_entries = ARM_LPAE_PTES_PER_TABLE(data) - unmap_idx_start;
+               num_entries = min_t(int, pgcount, max_entries);
+
+               while (i < num_entries) {
+                       pte = READ_ONCE(*ptep);
+                       if (WARN_ON(!pte))
+                               break;
+
+                       __arm_lpae_clear_pte(ptep, &iop->cfg);
+
+                       if (!iopte_leaf(pte, lvl, iop->fmt)) {
+                               /* Also flush any partial walks */
+                               io_pgtable_tlb_flush_walk(iop, iova + i * size, size,
+                                                         ARM_LPAE_GRANULE(data));
+                               __arm_lpae_free_pgtable(data, lvl + 1, iopte_deref(pte, data));
+                       } else if (iop->cfg.quirks & IO_PGTABLE_QUIRK_NON_STRICT) {
+                               /*
+                                * Order the PTE update against queueing the IOVA, to
+                                * guarantee that a flush callback from a different CPU
+                                * has observed it before the TLBIALL can be issued.
+                                */
+                               smp_wmb();
+                       } else {
+                               io_pgtable_tlb_add_page(iop, gather, iova + i * size, size);
+                       }
+
+                       ptep++;
+                       i++;
                }
 
-               return size;
+               return i * size;
        } else if (iopte_leaf(pte, lvl, iop->fmt)) {
                /*
                 * Insert a table at the next level to map the old region,
                 * minus the part we want to unmap
                 */
                return arm_lpae_split_blk_unmap(data, gather, iova, size, pte,
-                                               lvl + 1, ptep);
+                                               lvl + 1, ptep, pgcount);
        }
 
        /* Keep on walkin' */
        ptep = iopte_deref(pte, data);
-       return __arm_lpae_unmap(data, gather, iova, size, lvl + 1, ptep);
+       return __arm_lpae_unmap(data, gather, iova, size, pgcount, lvl + 1, ptep);
 }
 
-static size_t arm_lpae_unmap(struct io_pgtable_ops *ops, unsigned long iova,
-                            size_t size, struct iommu_iotlb_gather *gather)
+static size_t arm_lpae_unmap_pages(struct io_pgtable_ops *ops, unsigned long iova,
+                                  size_t pgsize, size_t pgcount,
+                                  struct iommu_iotlb_gather *gather)
 {
        struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops);
        struct io_pgtable_cfg *cfg = &data->iop.cfg;
        arm_lpae_iopte *ptep = data->pgd;
        long iaext = (s64)iova >> cfg->ias;
 
-       if (WARN_ON(!size || (size & cfg->pgsize_bitmap) != size))
+       if (WARN_ON(!pgsize || (pgsize & cfg->pgsize_bitmap) != pgsize || !pgcount))
                return 0;
 
        if (cfg->quirks & IO_PGTABLE_QUIRK_ARM_TTBR1)
@@ -645,7 +665,14 @@ static size_t arm_lpae_unmap(struct io_pgtable_ops *ops, unsigned long iova,
        if (WARN_ON(iaext))
                return 0;
 
-       return __arm_lpae_unmap(data, gather, iova, size, data->start_level, ptep);
+       return __arm_lpae_unmap(data, gather, iova, pgsize, pgcount,
+                               data->start_level, ptep);
+}
+
+static size_t arm_lpae_unmap(struct io_pgtable_ops *ops, unsigned long iova,
+                            size_t size, struct iommu_iotlb_gather *gather)
+{
+       return arm_lpae_unmap_pages(ops, iova, size, 1, gather);
 }
 
 static phys_addr_t arm_lpae_iova_to_phys(struct io_pgtable_ops *ops,
@@ -761,6 +788,7 @@ arm_lpae_alloc_pgtable(struct io_pgtable_cfg *cfg)
        data->iop.ops = (struct io_pgtable_ops) {
                .map            = arm_lpae_map,
                .unmap          = arm_lpae_unmap,
+               .unmap_pages    = arm_lpae_unmap_pages,
                .iova_to_phys   = arm_lpae_iova_to_phys,
        };