[Qemu-devel] [PULL 43/49] intel_iommu: large page support

["Michael S. Tsirkin" <mst@redhat.com>]

From: Jason Wang <jasowang@redhat.com>

Current intel_iommu only supports 4K page which may not be sufficient
to cover guest working set. This patch tries to enable 2M and 1G mapping
for intel_iommu. This is also useful for future device IOTLB
implementation to have a better hit rate.

Major work is adding a page mask field on IOTLB entry to make it
support large page. And also use the slpte level as key to do IOTLB
lookup. MAMV was increased to 18 to support direct invalidation for 1G
mapping.

Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/i386/intel_iommu_internal.h |  6 ++--
 include/hw/i386/intel_iommu.h  |  1 +
 hw/i386/intel_iommu.c          | 76 ++++++++++++++++++++++++++++++------------
 3 files changed, 59 insertions(+), 24 deletions(-)

diff --git a/hw/i386/intel_iommu_internal.h b/hw/i386/intel_iommu_internal.h
index ba288ab..e5f514c 100644
--- a/hw/i386/intel_iommu_internal.h
+++ b/hw/i386/intel_iommu_internal.h
@@ -113,6 +113,7 @@
 
 /* The shift of source_id in the key of IOTLB hash table */
 #define VTD_IOTLB_SID_SHIFT         36
+#define VTD_IOTLB_LVL_SHIFT         44
 #define VTD_IOTLB_MAX_SIZE          1024    /* Max size of the hash table */
 
 /* IOTLB_REG */
@@ -185,9 +186,10 @@
 #define VTD_CAP_ND                  (((VTD_DOMAIN_ID_SHIFT - 4) / 2) & 7ULL)
 #define VTD_MGAW                    39  /* Maximum Guest Address Width */
 #define VTD_CAP_MGAW                (((VTD_MGAW - 1) & 0x3fULL) << 16)
-#define VTD_MAMV                    9ULL
+#define VTD_MAMV                    18ULL
 #define VTD_CAP_MAMV                (VTD_MAMV << 48)
 #define VTD_CAP_PSI                 (1ULL << 39)
+#define VTD_CAP_SLLPS               ((1ULL << 34) | (1ULL << 35))
 
 /* Supported Adjusted Guest Address Widths */
 #define VTD_CAP_SAGAW_SHIFT         8
@@ -320,7 +322,7 @@ typedef struct VTDInvDesc VTDInvDesc;
 /* Information about page-selective IOTLB invalidate */
 struct VTDIOTLBPageInvInfo {
     uint16_t domain_id;
-    uint64_t gfn;
+    uint64_t addr;
     uint8_t mask;
 };
 typedef struct VTDIOTLBPageInvInfo VTDIOTLBPageInvInfo;
diff --git a/include/hw/i386/intel_iommu.h b/include/hw/i386/intel_iommu.h
index 5dbadb7..b024ffa 100644
--- a/include/hw/i386/intel_iommu.h
+++ b/include/hw/i386/intel_iommu.h
@@ -83,6 +83,7 @@ struct VTDIOTLBEntry {
     uint64_t gfn;
     uint16_t domain_id;
     uint64_t slpte;
+    uint64_t mask;
     bool read_flags;
     bool write_flags;
 };
diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index c25b1fd..347718f 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -153,14 +153,27 @@ static gboolean vtd_hash_remove_by_domain(gpointer key, gpointer value,
     return entry->domain_id == domain_id;
 }
 
+/* The shift of an addr for a certain level of paging structure */
+static inline uint32_t vtd_slpt_level_shift(uint32_t level)
+{
+    return VTD_PAGE_SHIFT_4K + (level - 1) * VTD_SL_LEVEL_BITS;
+}
+
+static inline uint64_t vtd_slpt_level_page_mask(uint32_t level)
+{
+    return ~((1ULL << vtd_slpt_level_shift(level)) - 1);
+}
+
 static gboolean vtd_hash_remove_by_page(gpointer key, gpointer value,
                                         gpointer user_data)
 {
     VTDIOTLBEntry *entry = (VTDIOTLBEntry *)value;
     VTDIOTLBPageInvInfo *info = (VTDIOTLBPageInvInfo *)user_data;
-    uint64_t gfn = info->gfn & info->mask;
+    uint64_t gfn = (info->addr >> VTD_PAGE_SHIFT_4K) & info->mask;
+    uint64_t gfn_tlb = (info->addr & entry->mask) >> VTD_PAGE_SHIFT_4K;
     return (entry->domain_id == info->domain_id) &&
-            ((entry->gfn & info->mask) == gfn);
+            (((entry->gfn & info->mask) == gfn) ||
+             (entry->gfn == gfn_tlb));
 }
 
 /* Reset all the gen of VTDAddressSpace to zero and set the gen of
@@ -194,24 +207,46 @@ static void vtd_reset_iotlb(IntelIOMMUState *s)
     g_hash_table_remove_all(s->iotlb);
 }
 
+static uint64_t vtd_get_iotlb_key(uint64_t gfn, uint8_t source_id,
+                                  uint32_t level)
+{
+    return gfn | ((uint64_t)(source_id) << VTD_IOTLB_SID_SHIFT) |
+           ((uint64_t)(level) << VTD_IOTLB_LVL_SHIFT);
+}
+
+static uint64_t vtd_get_iotlb_gfn(hwaddr addr, uint32_t level)
+{
+    return (addr & vtd_slpt_level_page_mask(level)) >> VTD_PAGE_SHIFT_4K;
+}
+
 static VTDIOTLBEntry *vtd_lookup_iotlb(IntelIOMMUState *s, uint16_t source_id,
                                        hwaddr addr)
 {
+    VTDIOTLBEntry *entry;
     uint64_t key;
+    int level;
+
+    for (level = VTD_SL_PT_LEVEL; level < VTD_SL_PML4_LEVEL; level++) {
+        key = vtd_get_iotlb_key(vtd_get_iotlb_gfn(addr, level),
+                                source_id, level);
+        entry = g_hash_table_lookup(s->iotlb, &key);
+        if (entry) {
+            goto out;
+        }
+    }
 
-    key = (addr >> VTD_PAGE_SHIFT_4K) |
-           ((uint64_t)(source_id) << VTD_IOTLB_SID_SHIFT);
-    return g_hash_table_lookup(s->iotlb, &key);
-
+out:
+    return entry;
 }
 
 static void vtd_update_iotlb(IntelIOMMUState *s, uint16_t source_id,
                              uint16_t domain_id, hwaddr addr, uint64_t slpte,
-                             bool read_flags, bool write_flags)
+                             bool read_flags, bool write_flags,
+                             uint32_t level)
 {
     VTDIOTLBEntry *entry = g_malloc(sizeof(*entry));
     uint64_t *key = g_malloc(sizeof(*key));
-    uint64_t gfn = addr >> VTD_PAGE_SHIFT_4K;
+    uint64_t gfn = vtd_get_iotlb_gfn(addr, level);
 
     VTD_DPRINTF(CACHE, "update iotlb sid 0x%"PRIx16 " gpa 0x%"PRIx64
                 " slpte 0x%"PRIx64 " did 0x%"PRIx16, source_id, addr, slpte,
@@ -226,7 +261,8 @@ static void vtd_update_iotlb(IntelIOMMUState *s, uint16_t source_id,
     entry->slpte = slpte;
     entry->read_flags = read_flags;
     entry->write_flags = write_flags;
-    *key = gfn | ((uint64_t)(source_id) << VTD_IOTLB_SID_SHIFT);
+    entry->mask = vtd_slpt_level_page_mask(level);
+    *key = vtd_get_iotlb_key(gfn, source_id, level);
     g_hash_table_replace(s->iotlb, key, entry);
 }
 
@@ -501,12 +537,6 @@ static inline dma_addr_t vtd_get_slpt_base_from_context(VTDContextEntry *ce)
     return ce->lo & VTD_CONTEXT_ENTRY_SLPTPTR;
 }
 
-/* The shift of an addr for a certain level of paging structure */
-static inline uint32_t vtd_slpt_level_shift(uint32_t level)
-{
-    return VTD_PAGE_SHIFT_4K + (level - 1) * VTD_SL_LEVEL_BITS;
-}
-
 static inline uint64_t vtd_get_slpte_addr(uint64_t slpte)
 {
     return slpte & VTD_SL_PT_BASE_ADDR_MASK;
@@ -762,7 +792,7 @@ static void vtd_do_iommu_translate(VTDAddressSpace *vtd_as, PCIBus *bus,
     VTDContextEntry ce;
     uint8_t bus_num = pci_bus_num(bus);
     VTDContextCacheEntry *cc_entry = &vtd_as->context_cache_entry;
-    uint64_t slpte;
+    uint64_t slpte, page_mask;
     uint32_t level;
     uint16_t source_id = vtd_make_source_id(bus_num, devfn);
     int ret_fr;
@@ -802,6 +832,7 @@ static void vtd_do_iommu_translate(VTDAddressSpace *vtd_as, PCIBus *bus,
         slpte = iotlb_entry->slpte;
         reads = iotlb_entry->read_flags;
         writes = iotlb_entry->write_flags;
+        page_mask = iotlb_entry->mask;
         goto out;
     }
     /* Try to fetch context-entry from cache first */
@@ -848,12 +879,13 @@ static void vtd_do_iommu_translate(VTDAddressSpace *vtd_as, PCIBus *bus,
         return;
     }
 
+    page_mask = vtd_slpt_level_page_mask(level);
     vtd_update_iotlb(s, source_id, VTD_CONTEXT_ENTRY_DID(ce.hi), addr, slpte,
-                     reads, writes);
+                     reads, writes, level);
 out:
-    entry->iova = addr & VTD_PAGE_MASK_4K;
-    entry->translated_addr = vtd_get_slpte_addr(slpte) & VTD_PAGE_MASK_4K;
-    entry->addr_mask = ~VTD_PAGE_MASK_4K;
+    entry->iova = addr & page_mask;
+    entry->translated_addr = vtd_get_slpte_addr(slpte) & page_mask;
+    entry->addr_mask = ~page_mask;
     entry->perm = (writes ? 2 : 0) + (reads ? 1 : 0);
 }
 
@@ -991,7 +1023,7 @@ static void vtd_iotlb_page_invalidate(IntelIOMMUState *s, uint16_t domain_id,
 
     assert(am <= VTD_MAMV);
     info.domain_id = domain_id;
-    info.gfn = addr >> VTD_PAGE_SHIFT_4K;
+    info.addr = addr;
     info.mask = ~((1 << am) - 1);
     g_hash_table_foreach_remove(s->iotlb, vtd_hash_remove_by_page, &info);
 }
@@ -1917,7 +1949,7 @@ static void vtd_init(IntelIOMMUState *s)
     s->iq_last_desc_type = VTD_INV_DESC_NONE;
     s->next_frcd_reg = 0;
     s->cap = VTD_CAP_FRO | VTD_CAP_NFR | VTD_CAP_ND | VTD_CAP_MGAW |
-             VTD_CAP_SAGAW | VTD_CAP_MAMV | VTD_CAP_PSI;
+             VTD_CAP_SAGAW | VTD_CAP_MAMV | VTD_CAP_PSI | VTD_CAP_SLLPS;
     s->ecap = VTD_ECAP_QI | VTD_ECAP_IRO;
 
     vtd_reset_context_cache(s);
-- 
MST