--- v6
+++ v7
@@ -1,105 +1,260 @@
-The iommu_free_table helper release memory it is using (the TCE table and
-@it_map) and release the iommu_table struct as well. We might not want
-the very last step as we store iommu_table in parent structures.
+TCE tables might get too big in case of 4K IOMMU pages and DDW enabled
+on huge guests (hundreds of GB of RAM) so the kernel might be unable to
+allocate contiguous chunk of physical memory to store the TCE table.
+
+To address this, POWER8 CPU (actually, IODA2) supports multi-level TCE tables,
+up to 5 levels which splits the table into a tree of smaller subtables.
+
+This adds multi-level TCE tables support to pnv_pci_ioda2_create_table()
+and pnv_pci_ioda2_free_table() callbacks.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
- arch/powerpc/include/asm/iommu.h | 1 +
- arch/powerpc/kernel/iommu.c | 57 ++++++++++++++++++++++++----------------
- 2 files changed, 35 insertions(+), 23 deletions(-)
+ arch/powerpc/include/asm/iommu.h | 2 +
+ arch/powerpc/platforms/powernv/pci-ioda.c | 128 ++++++++++++++++++++++++------
+ arch/powerpc/platforms/powernv/pci.c | 19 +++++
+ 3 files changed, 123 insertions(+), 26 deletions(-)
diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
-index 6af22a4..fd118ea 100644
+index 8ed4648..1e0d907 100644
--- a/arch/powerpc/include/asm/iommu.h
+++ b/arch/powerpc/include/asm/iommu.h
-@@ -125,6 +125,7 @@ static inline void *get_iommu_table_base(struct device *dev)
-
- extern struct iommu_table *iommu_table_alloc(int node);
- /* Frees table for an individual device node */
-+extern void iommu_reset_table(struct iommu_table *tbl, const char *node_name);
- extern void iommu_free_table(struct iommu_table *tbl, const char *node_name);
-
- /* Initializes an iommu_table based in values set in the passed-in
-diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
-index 2856a4a..3500bd0 100644
---- a/arch/powerpc/kernel/iommu.c
-+++ b/arch/powerpc/kernel/iommu.c
-@@ -721,24 +721,46 @@ struct iommu_table *iommu_table_alloc(int node)
- return &table_group->tables[0];
- }
-
-+void iommu_reset_table(struct iommu_table *tbl, const char *node_name)
+@@ -90,6 +90,8 @@ struct iommu_pool {
+ struct iommu_table {
+ unsigned long it_busno; /* Bus number this table belongs to */
+ unsigned long it_size; /* Size of iommu table in entries */
++ unsigned long it_indirect_levels;
++ unsigned long it_level_size;
+ unsigned long it_offset; /* Offset into global table */
+ unsigned long it_base; /* mapped address of tce table */
+ unsigned long it_index; /* which iommu table this is */
+diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
+index 64b7cfe..74e119c 100644
+--- a/arch/powerpc/platforms/powernv/pci-ioda.c
++++ b/arch/powerpc/platforms/powernv/pci-ioda.c
+@@ -47,6 +47,10 @@
+ #include "powernv.h"
+ #include "pci.h"
+
++#define POWERNV_IOMMU_DEFAULT_LEVELS 1
++#define POWERNV_IOMMU_MAX_LEVELS 5
++#define ROUND_UP(x, n) (((x) + (n) - 1u) & ~((n) - 1u))
++
+ static void pe_level_printk(const struct pnv_ioda_pe *pe, const char *level,
+ const char *fmt, ...)
+ {
+@@ -1339,16 +1343,82 @@ static void pnv_pci_ioda_setup_dma_pe(struct pnv_phb *phb,
+ __free_pages(tce_mem, get_order(TCE32_TABLE_SIZE * segs));
+ }
+
++static void pnv_free_tce_table(unsigned long addr, unsigned size,
++ unsigned level)
+{
-+ if (!tbl)
-+ return;
-+
-+ if (tbl->it_map) {
-+ unsigned long bitmap_sz;
-+ unsigned int order;
-+
-+ /*
-+ * In case we have reserved the first bit, we should not emit
-+ * the warning below.
-+ */
-+ if (tbl->it_offset == 0)
-+ clear_bit(0, tbl->it_map);
-+
-+ /* verify that table contains no entries */
-+ if (!bitmap_empty(tbl->it_map, tbl->it_size))
-+ pr_warn("%s: Unexpected TCEs for %s\n", __func__,
-+ node_name);
-+
-+ /* calculate bitmap size in bytes */
-+ bitmap_sz = BITS_TO_LONGS(tbl->it_size) * sizeof(unsigned long);
-+
-+ /* free bitmap */
-+ order = get_order(bitmap_sz);
-+ free_pages((unsigned long) tbl->it_map, order);
-+ }
-+
-+ memset(tbl, 0, sizeof(*tbl));
++ addr &= ~(TCE_PCI_READ | TCE_PCI_WRITE);
++
++ if (level) {
++ long i;
++ u64 *tmp = (u64 *) addr;
++
++ for (i = 0; i < size; ++i) {
++ unsigned long hpa = be64_to_cpu(tmp[i]);
++
++ if (!(hpa & (TCE_PCI_READ | TCE_PCI_WRITE)))
++ continue;
++
++ pnv_free_tce_table((unsigned long) __va(hpa),
++ size, level - 1);
++ }
++ }
++
++ free_pages(addr, get_order(size << 3));
+}
+
- void iommu_free_table(struct iommu_table *tbl, const char *node_name)
- {
-- unsigned long bitmap_sz;
-- unsigned int order;
- struct iommu_table_group *table_group = tbl->it_group;
-
-- if (!tbl || !tbl->it_map) {
-- printk(KERN_ERR "%s: expected TCE map for %s\n", __func__,
-- node_name);
-+ if (!tbl)
++static __be64 *pnv_alloc_tce_table(int nid,
++ unsigned shift, unsigned levels, unsigned long *left)
++{
++ struct page *tce_mem = NULL;
++ __be64 *addr, *tmp;
++ unsigned order = max_t(unsigned, shift, PAGE_SHIFT) - PAGE_SHIFT;
++ unsigned long chunk = 1UL << shift, i;
++
++ tce_mem = alloc_pages_node(nid, GFP_KERNEL, order);
++ if (!tce_mem) {
++ pr_err("Failed to allocate a TCE memory\n");
++ return NULL;
++ }
++
++ if (!*left)
++ return NULL;
++
++ addr = page_address(tce_mem);
++ memset(addr, 0, chunk);
++
++ --levels;
++ if (!levels) {
++ /* This is last level, actual TCEs */
++ *left -= min(*left, chunk);
++ return addr;
++ }
++
++ for (i = 0; i < (chunk >> 3); ++i) {
++ /* We allocated required TCEs, mark the rest "page fault" */
++ if (!*left) {
++ addr[i] = cpu_to_be64(0);
++ continue;
++ }
++
++ tmp = pnv_alloc_tce_table(nid, shift, levels, left);
++ addr[i] = cpu_to_be64(__pa(tmp) |
++ TCE_PCI_READ | TCE_PCI_WRITE);
++ }
++
++ return addr;
++}
++
+ static long pnv_pci_ioda2_create_table(struct pnv_ioda_pe *pe,
+- __u32 page_shift, __u64 window_size,
++ __u32 page_shift, __u64 window_size, __u32 levels,
+ struct iommu_table *tbl)
+ {
+ int nid = pe->phb->hose->node;
+- struct page *tce_mem = NULL;
+ void *addr;
+- unsigned long tce_table_size;
+- int64_t rc;
+- unsigned order;
++ unsigned long tce_table_size, left;
++ unsigned shift;
++
++ if (!levels || (levels > POWERNV_IOMMU_MAX_LEVELS))
++ return -EINVAL;
+
+ if ((window_size > memory_hotplug_max()) || !is_power_of_2(window_size))
+ return -EINVAL;
+@@ -1357,16 +1427,19 @@ static long pnv_pci_ioda2_create_table(struct pnv_ioda_pe *pe,
+ tce_table_size = max(0x1000UL, tce_table_size);
+
+ /* Allocate TCE table */
+- order = get_order(tce_table_size);
++ shift = ROUND_UP(ilog2(window_size) - page_shift, levels) / levels;
++ shift += 3;
++ shift = max_t(unsigned, shift, IOMMU_PAGE_SHIFT_4K);
++ pr_info("Creating TCE table %08llx, %d levels, TCE table size = %lx\n",
++ window_size, levels, 1UL << shift);
+
+- tce_mem = alloc_pages_node(nid, GFP_KERNEL, order);
+- if (!tce_mem) {
+- pr_err("Failed to allocate a TCE memory, order=%d\n", order);
+- rc = -ENOMEM;
+- goto fail;
+- }
+- addr = page_address(tce_mem);
+- memset(addr, 0, tce_table_size);
++ tbl->it_level_size = 1ULL << (shift - 3);
++ left = tce_table_size;
++ addr = pnv_alloc_tce_table(nid, shift, levels, &left);
++ if (!addr)
++ return -ENOMEM;
++
++ tbl->it_indirect_levels = levels - 1;
+
+ /* Setup linux iommu table */
+ pnv_pci_setup_iommu_table(tbl, addr, tce_table_size, 0,
+@@ -1375,20 +1448,18 @@ static long pnv_pci_ioda2_create_table(struct pnv_ioda_pe *pe,
+ tbl->it_ops = &pnv_ioda2_iommu_ops;
+
+ return 0;
+-fail:
+- if (tce_mem)
+- __free_pages(tce_mem, get_order(tce_table_size));
+-
+- return rc;
+ }
+
+ static void pnv_pci_free_table(struct iommu_table *tbl)
+ {
++ const unsigned size = tbl->it_indirect_levels ?
++ tbl->it_level_size : tbl->it_size;
++
+ if (!tbl->it_size)
return;
-- }
-
-- /*
-- * In case we have reserved the first bit, we should not emit
-- * the warning below.
-- */
-- if (tbl->it_offset == 0)
-- clear_bit(0, tbl->it_map);
-+ iommu_reset_table(tbl, node_name);
-
- #ifdef CONFIG_IOMMU_API
- if (table_group->group) {
-@@ -747,17 +769,6 @@ void iommu_free_table(struct iommu_table *tbl, const char *node_name)
- }
- #endif
-
-- /* verify that table contains no entries */
-- if (!bitmap_empty(tbl->it_map, tbl->it_size))
-- pr_warn("%s: Unexpected TCEs for %s\n", __func__, node_name);
--
-- /* calculate bitmap size in bytes */
-- bitmap_sz = BITS_TO_LONGS(tbl->it_size) * sizeof(unsigned long);
--
-- /* free bitmap */
-- order = get_order(bitmap_sz);
-- free_pages((unsigned long) tbl->it_map, order);
--
- /* free table */
- kfree(table_group);
+
+- free_pages(tbl->it_base, get_order(tbl->it_size << 3));
+- memset(tbl, 0, sizeof(struct iommu_table));
++ pnv_free_tce_table(tbl->it_base, size, tbl->it_indirect_levels);
++ iommu_reset_table(tbl, "ioda2");
+ }
+
+ static long pnv_pci_ioda2_set_window(struct pnv_ioda_pe *pe,
+@@ -1397,12 +1468,15 @@ static long pnv_pci_ioda2_set_window(struct pnv_ioda_pe *pe,
+ struct pnv_phb *phb = pe->phb;
+ const __be64 *swinvp;
+ int64_t rc;
++ const unsigned size = tbl->it_indirect_levels ?
++ tbl->it_level_size : tbl->it_size;
+ const __u64 start_addr = tbl->it_offset << tbl->it_page_shift;
+ const __u64 win_size = tbl->it_size << tbl->it_page_shift;
+
+- pe_info(pe, "Setting up window at %llx..%llx pagesize=0x%x tablesize=0x%lx\n",
++ pe_info(pe, "Setting up window at %llx..%llx pagesize=0x%x tablesize=0x%lx levels=%d levelsize=%x\n",
+ start_addr, start_addr + win_size - 1,
+- 1UL << tbl->it_page_shift, tbl->it_size << 3);
++ 1UL << tbl->it_page_shift, tbl->it_size,
++ tbl->it_indirect_levels + 1, tbl->it_level_size);
+
+ pe->table_group.tables[0] = *tbl;
+ tbl = &pe->table_group.tables[0];
+@@ -1413,8 +1487,9 @@ static long pnv_pci_ioda2_set_window(struct pnv_ioda_pe *pe,
+ * shifted by 1 bit for 32-bits DMA space.
+ */
+ rc = opal_pci_map_pe_dma_window(phb->opal_id, pe->pe_number,
+- pe->pe_number << 1, 1, __pa(tbl->it_base),
+- tbl->it_size << 3, 1ULL << tbl->it_page_shift);
++ pe->pe_number << 1, tbl->it_indirect_levels + 1,
++ __pa(tbl->it_base),
++ size << 3, 1ULL << tbl->it_page_shift);
+ if (rc) {
+ pe_err(pe, "Failed to configure TCE table, err %ld\n", rc);
+ goto fail;
+@@ -1530,7 +1605,8 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
+ end);
+
+ rc = pnv_pci_ioda2_create_table(pe, IOMMU_PAGE_SHIFT_4K,
+- phb->ioda.m32_pci_base, tbl);
++ phb->ioda.m32_pci_base,
++ POWERNV_IOMMU_DEFAULT_LEVELS, tbl);
+ if (rc) {
+ pe_err(pe, "Failed to create 32-bit TCE table, err %ld", rc);
+ return;
+diff --git a/arch/powerpc/platforms/powernv/pci.c b/arch/powerpc/platforms/powernv/pci.c
+index a9797dd..e734e37 100644
+--- a/arch/powerpc/platforms/powernv/pci.c
++++ b/arch/powerpc/platforms/powernv/pci.c
+@@ -592,6 +592,25 @@ struct pci_ops pnv_pci_ops = {
+ static __be64 *pnv_tce(struct iommu_table *tbl, long index)
+ {
+ __be64 *tmp = ((__be64 *)tbl->it_base);
++ int level = tbl->it_indirect_levels;
++ const long shift = ilog2(tbl->it_level_size);
++ unsigned long mask = (tbl->it_level_size - 1) << (level * shift);
++
++ if (index >= tbl->it_size)
++ return NULL;
++
++ while (level) {
++ int n = (index & mask) >> (level * shift);
++ unsigned long tce = be64_to_cpu(tmp[n]);
++
++ if (!(tce & (TCE_PCI_READ | TCE_PCI_WRITE)))
++ return NULL;
++
++ tmp = __va(tce & ~(TCE_PCI_READ | TCE_PCI_WRITE));
++ index &= ~mask;
++ mask >>= shift;
++ --level;
++ }
+
+ return tmp + index;
}
--
2.0.0