On 2022/10/28 14:14, Jason Wang wrote:
We introduce VTDBus structure as an intermediate step for searching
the address space. This works well with SID based matching/lookup. But
when we want to support SID plus PASID based address space lookup,
this intermediate steps turns out to be a burden. So the patch simply
drops the VTDBus structure and use the PCIBus and devfn as the key for
the g_hash_table(). This simplifies the codes and the future PASID
extension.
just a nit.
in this way, all vtd_as'es are in the single hash table. will it become
a bottle-neck for searching? Especially with patch 4/4 in this serial.
sid has 16 bits, pasid has 20 bits, so at most there will be 2^36 entries
in the hash table.
To prevent being slower for past vtd_find_as_from_bus_num() callers, a
vtd_as cache indexed by the bus number is introduced to store the last
recent search result of a vtd_as belongs to a specific bus.
Reviewed-by: Peter Xu <pet...@redhat.com>
Signed-off-by: Jason Wang <jasow...@redhat.com>
---
Changes since V2:
- use PCI_BUILD_BDF() instead of vtd_make_source_id()
- Tweak the comments above vtd_as_hash()
- use PCI_BUS_NUM() instead of open coding
- rename vtd_as to vtd_address_spaces
---
hw/i386/intel_iommu.c | 234 +++++++++++++++++-----------------
include/hw/i386/intel_iommu.h | 11 +-
2 files changed, 118 insertions(+), 127 deletions(-)
diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index 271de995be..9fe5a222eb 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -61,6 +61,16 @@
}
\
}
+/*
+ * PCI bus number (or SID) is not reliable since the device is usaully
+ * initalized before guest can configure the PCI bridge
+ * (SECONDARY_BUS_NUMBER).
+ */
+struct vtd_as_key {
+ PCIBus *bus;
+ uint8_t devfn;
+};
+
static void vtd_address_space_refresh_all(IntelIOMMUState *s);
static void vtd_address_space_unmap(VTDAddressSpace *as, IOMMUNotifier *n);
@@ -210,6 +220,27 @@ static guint vtd_uint64_hash(gconstpointer v)
return (guint)*(const uint64_t *)v;
}
+static gboolean vtd_as_equal(gconstpointer v1, gconstpointer v2)
+{
+ const struct vtd_as_key *key1 = v1;
+ const struct vtd_as_key *key2 = v2;
+
+ return (key1->bus == key2->bus) && (key1->devfn == key2->devfn);
+}
+
+/*
+ * Note that we use pointer to PCIBus as the key, so hashing/shifting
+ * based on the pointer value is intended. Note that we deal with
+ * collisions through vtd_as_equal().
+ */
+static guint vtd_as_hash(gconstpointer v)
+{
+ const struct vtd_as_key *key = v;
+ guint value = (guint)(uintptr_t)key->bus;
+
+ return (guint)(value << 8 | key->devfn);
+}
+
static gboolean vtd_hash_remove_by_domain(gpointer key, gpointer value,
gpointer user_data)
{
@@ -248,22 +279,14 @@ static gboolean vtd_hash_remove_by_page(gpointer key,
gpointer value,
static void vtd_reset_context_cache_locked(IntelIOMMUState *s)
{
VTDAddressSpace *vtd_as;
- VTDBus *vtd_bus;
- GHashTableIter bus_it;
- uint32_t devfn_it;
+ GHashTableIter as_it;
trace_vtd_context_cache_reset();
- g_hash_table_iter_init(&bus_it, s->vtd_as_by_busptr);
+ g_hash_table_iter_init(&as_it, s->vtd_address_spaces);
- while (g_hash_table_iter_next (&bus_it, NULL, (void**)&vtd_bus)) {
- for (devfn_it = 0; devfn_it < PCI_DEVFN_MAX; ++devfn_it) {
- vtd_as = vtd_bus->dev_as[devfn_it];
- if (!vtd_as) {
- continue;
- }
- vtd_as->context_cache_entry.context_cache_gen = 0;
- }
+ while (g_hash_table_iter_next (&as_it, NULL, (void**)&vtd_as)) {
+ vtd_as->context_cache_entry.context_cache_gen = 0;
}
s->context_cache_gen = 1;
}
@@ -993,32 +1016,6 @@ static bool vtd_slpte_nonzero_rsvd(uint64_t slpte,
uint32_t level)
return slpte & rsvd_mask;
}
-/* Find the VTD address space associated with a given bus number */
-static VTDBus *vtd_find_as_from_bus_num(IntelIOMMUState *s, uint8_t bus_num)
-{
- VTDBus *vtd_bus = s->vtd_as_by_bus_num[bus_num];
- GHashTableIter iter;
-
- if (vtd_bus) {
- return vtd_bus;
- }
-
- /*
- * Iterate over the registered buses to find the one which
- * currently holds this bus number and update the bus_num
- * lookup table.
- */
- g_hash_table_iter_init(&iter, s->vtd_as_by_busptr);
- while (g_hash_table_iter_next(&iter, NULL, (void **)&vtd_bus)) {
- if (pci_bus_num(vtd_bus->bus) == bus_num) {
- s->vtd_as_by_bus_num[bus_num] = vtd_bus;
- return vtd_bus;
- }
- }
-
- return NULL;
-}
-
/* Given the @iova, get relevant @slptep. @slpte_level will be the last level
* of the translation, can be used for deciding the size of large page.
*/
@@ -1632,24 +1629,13 @@ static bool vtd_switch_address_space(VTDAddressSpace
*as)
static void vtd_switch_address_space_all(IntelIOMMUState *s)
{
+ VTDAddressSpace *vtd_as;
GHashTableIter iter;
- VTDBus *vtd_bus;
- int i;
-
- g_hash_table_iter_init(&iter, s->vtd_as_by_busptr);
- while (g_hash_table_iter_next(&iter, NULL, (void **)&vtd_bus)) {
- for (i = 0; i < PCI_DEVFN_MAX; i++) {
- if (!vtd_bus->dev_as[i]) {
- continue;
- }
- vtd_switch_address_space(vtd_bus->dev_as[i]);
- }
- }
-}
-static inline uint16_t vtd_make_source_id(uint8_t bus_num, uint8_t devfn)
-{
- return ((bus_num & 0xffUL) << 8) | (devfn & 0xffUL);
+ g_hash_table_iter_init(&iter, s->vtd_address_spaces);
+ while (g_hash_table_iter_next(&iter, NULL, (void **)&vtd_as)) {
+ vtd_switch_address_space(vtd_as);
+ }
}
static const bool vtd_qualified_faults[] = {
@@ -1686,18 +1672,37 @@ static inline bool vtd_is_interrupt_addr(hwaddr addr)
return VTD_INTERRUPT_ADDR_FIRST <= addr && addr <=
VTD_INTERRUPT_ADDR_LAST;
}
+static gboolean vtd_find_as_by_sid(gpointer key, gpointer value,
+ gpointer user_data)
+{
+ struct vtd_as_key *as_key = (struct vtd_as_key *)key;
+ uint16_t target_sid = *(uint16_t *)user_data;
+ uint16_t sid = PCI_BUILD_BDF(pci_bus_num(as_key->bus), as_key->devfn);
+ return sid == target_sid;
this is a check instead of find. how about vtd_as_check_sid()?
+}
+
+static VTDAddressSpace *vtd_get_as_by_sid(IntelIOMMUState *s, uint16_t sid)
+{
+ uint8_t bus_num = PCI_BUS_NUM(sid);
+ VTDAddressSpace *vtd_as = s->vtd_as_cache[bus_num];
+
+ if (vtd_as &&
+ (sid == PCI_BUILD_BDF(pci_bus_num(vtd_as->bus), vtd_as->devfn))) {
this checks sid as well. not sure if it can share the above helper.:-)
Besides the above nits, this patch looks good to me.
Reviewed-by: Yi Liu <yi.l....@intel.com>
+ return vtd_as;
+ }
+
+ vtd_as = g_hash_table_find(s->vtd_address_spaces, vtd_find_as_by_sid,
&sid);
+ s->vtd_as_cache[bus_num] = vtd_as;
+
+ return vtd_as;
+}
+
static void vtd_pt_enable_fast_path(IntelIOMMUState *s, uint16_t source_id)
{
- VTDBus *vtd_bus;
VTDAddressSpace *vtd_as;
bool success = false;
- vtd_bus = vtd_find_as_from_bus_num(s, VTD_SID_TO_BUS(source_id));
- if (!vtd_bus) {
- goto out;
- }
-
- vtd_as = vtd_bus->dev_as[VTD_SID_TO_DEVFN(source_id)];
+ vtd_as = vtd_get_as_by_sid(s, source_id);
if (!vtd_as) {
goto out;
}
@@ -1733,7 +1738,7 @@ static bool vtd_do_iommu_translate(VTDAddressSpace
*vtd_as, PCIBus *bus,
VTDContextCacheEntry *cc_entry;
uint64_t slpte, page_mask;
uint32_t level;
- uint16_t source_id = vtd_make_source_id(bus_num, devfn);
+ uint16_t source_id = PCI_BUILD_BDF(bus_num, devfn);
int ret_fr;
bool is_fpd_set = false;
bool reads = true;
@@ -1905,11 +1910,10 @@ static void
vtd_context_device_invalidate(IntelIOMMUState *s,
uint16_t source_id,
uint16_t func_mask)
{
+ GHashTableIter as_it;
uint16_t mask;
- VTDBus *vtd_bus;
VTDAddressSpace *vtd_as;
uint8_t bus_n, devfn;
- uint16_t devfn_it;
trace_vtd_inv_desc_cc_devices(source_id, func_mask);
@@ -1932,32 +1936,31 @@ static void vtd_context_device_invalidate(IntelIOMMUState *s,
mask = ~mask;
bus_n = VTD_SID_TO_BUS(source_id);
- vtd_bus = vtd_find_as_from_bus_num(s, bus_n);
- if (vtd_bus) {
- devfn = VTD_SID_TO_DEVFN(source_id);
- for (devfn_it = 0; devfn_it < PCI_DEVFN_MAX; ++devfn_it) {
- vtd_as = vtd_bus->dev_as[devfn_it];
- if (vtd_as && ((devfn_it & mask) == (devfn & mask))) {
- trace_vtd_inv_desc_cc_device(bus_n, VTD_PCI_SLOT(devfn_it),
- VTD_PCI_FUNC(devfn_it));
- vtd_iommu_lock(s);
- vtd_as->context_cache_entry.context_cache_gen = 0;
- vtd_iommu_unlock(s);
- /*
- * Do switch address space when needed, in case if the
- * device passthrough bit is switched.
- */
- vtd_switch_address_space(vtd_as);
- /*
- * So a device is moving out of (or moving into) a
- * domain, resync the shadow page table.
- * This won't bring bad even if we have no such
- * notifier registered - the IOMMU notification
- * framework will skip MAP notifications if that
- * happened.
- */
- vtd_sync_shadow_page_table(vtd_as);
- }
+ devfn = VTD_SID_TO_DEVFN(source_id);
+
+ g_hash_table_iter_init(&as_it, s->vtd_address_spaces);
+ while (g_hash_table_iter_next(&as_it, NULL, (void**)&vtd_as)) {
+ if ((pci_bus_num(vtd_as->bus) == bus_n) &&
+ (vtd_as->devfn & mask) == (devfn & mask)) {
+ trace_vtd_inv_desc_cc_device(bus_n, VTD_PCI_SLOT(vtd_as->devfn),
+ VTD_PCI_FUNC(vtd_as->devfn));
+ vtd_iommu_lock(s);
+ vtd_as->context_cache_entry.context_cache_gen = 0;
+ vtd_iommu_unlock(s);
+ /*
+ * Do switch address space when needed, in case if the
+ * device passthrough bit is switched.
+ */
+ vtd_switch_address_space(vtd_as);
+ /*
+ * So a device is moving out of (or moving into) a
+ * domain, resync the shadow page table.
+ * This won't bring bad even if we have no such
+ * notifier registered - the IOMMU notification
+ * framework will skip MAP notifications if that
+ * happened.
+ */
+ vtd_sync_shadow_page_table(vtd_as);
}
}
}
@@ -2473,18 +2476,13 @@ static bool
vtd_process_device_iotlb_desc(IntelIOMMUState *s,
{
VTDAddressSpace *vtd_dev_as;
IOMMUTLBEvent event;
- struct VTDBus *vtd_bus;
hwaddr addr;
uint64_t sz;
uint16_t sid;
- uint8_t devfn;
bool size;
- uint8_t bus_num;
addr = VTD_INV_DESC_DEVICE_IOTLB_ADDR(inv_desc->hi);
sid = VTD_INV_DESC_DEVICE_IOTLB_SID(inv_desc->lo);
- devfn = sid & 0xff;
- bus_num = sid >> 8;
size = VTD_INV_DESC_DEVICE_IOTLB_SIZE(inv_desc->hi);
if ((inv_desc->lo & VTD_INV_DESC_DEVICE_IOTLB_RSVD_LO) ||
@@ -2495,12 +2493,11 @@ static bool
vtd_process_device_iotlb_desc(IntelIOMMUState *s,
return false;
}
- vtd_bus = vtd_find_as_from_bus_num(s, bus_num);
- if (!vtd_bus) {
- goto done;
- }
-
- vtd_dev_as = vtd_bus->dev_as[devfn];
+ /*
+ * Using sid is OK since the guest should have finished the
+ * initialization of both the bus and device.
+ */
+ vtd_dev_as = vtd_get_as_by_sid(s, sid);
if (!vtd_dev_as) {
goto done;
}
@@ -3427,27 +3424,27 @@ static const MemoryRegionOps vtd_mem_ir_ops = {
VTDAddressSpace *vtd_find_add_as(IntelIOMMUState *s, PCIBus *bus, int devfn)
{
- uintptr_t key = (uintptr_t)bus;
- VTDBus *vtd_bus = g_hash_table_lookup(s->vtd_as_by_busptr, &key);
+ /*
+ * We can't simply use sid here since the bus number might not be
+ * initialized by the guest.
+ */
+ struct vtd_as_key key = {
+ .bus = bus,
+ .devfn = devfn,
+ };
VTDAddressSpace *vtd_dev_as;
char name[128];
- if (!vtd_bus) {
- uintptr_t *new_key = g_malloc(sizeof(*new_key));
- *new_key = (uintptr_t)bus;
- /* No corresponding free() */
- vtd_bus = g_malloc0(sizeof(VTDBus) + sizeof(VTDAddressSpace *) * \
- PCI_DEVFN_MAX);
- vtd_bus->bus = bus;
- g_hash_table_insert(s->vtd_as_by_busptr, new_key, vtd_bus);
- }
+ vtd_dev_as = g_hash_table_lookup(s->vtd_address_spaces, &key);
+ if (!vtd_dev_as) {
+ struct vtd_as_key *new_key = g_malloc(sizeof(*new_key));
- vtd_dev_as = vtd_bus->dev_as[devfn];
+ new_key->bus = bus;
+ new_key->devfn = devfn;
- if (!vtd_dev_as) {
snprintf(name, sizeof(name), "vtd-%02x.%x", PCI_SLOT(devfn),
PCI_FUNC(devfn));
- vtd_bus->dev_as[devfn] = vtd_dev_as = g_new0(VTDAddressSpace, 1);
+ vtd_dev_as = g_new0(VTDAddressSpace, 1);
vtd_dev_as->bus = bus;
vtd_dev_as->devfn = (uint8_t)devfn;
@@ -3503,6 +3500,8 @@ VTDAddressSpace *vtd_find_add_as(IntelIOMMUState *s,
PCIBus *bus, int devfn)
&vtd_dev_as->nodmar, 0);
vtd_switch_address_space(vtd_dev_as);
+
+ g_hash_table_insert(s->vtd_address_spaces, new_key, vtd_dev_as);
}
return vtd_dev_as;
}
@@ -3881,7 +3880,6 @@ static void vtd_realize(DeviceState *dev, Error **errp)
QLIST_INIT(&s->vtd_as_with_notifiers);
qemu_mutex_init(&s->iommu_lock);
- memset(s->vtd_as_by_bus_num, 0, sizeof(s->vtd_as_by_bus_num));
memory_region_init_io(&s->csrmem, OBJECT(s), &vtd_mem_ops, s,
"intel_iommu", DMAR_REG_SIZE);
@@ -3903,8 +3901,8 @@ static void vtd_realize(DeviceState *dev, Error **errp)
/* No corresponding destroy */
s->iotlb = g_hash_table_new_full(vtd_uint64_hash, vtd_uint64_equal,
g_free, g_free);
- s->vtd_as_by_busptr = g_hash_table_new_full(vtd_uint64_hash,
vtd_uint64_equal,
- g_free, g_free);
+ s->vtd_address_spaces = g_hash_table_new_full(vtd_as_hash, vtd_as_equal,
+ g_free, g_free);
vtd_init(s);
sysbus_mmio_map(SYS_BUS_DEVICE(s), 0, Q35_HOST_BRIDGE_IOMMU_ADDR);
pci_setup_iommu(bus, vtd_host_dma_iommu, dev);
diff --git a/include/hw/i386/intel_iommu.h b/include/hw/i386/intel_iommu.h
index 67653b0f9b..e49fff2a6c 100644
--- a/include/hw/i386/intel_iommu.h
+++ b/include/hw/i386/intel_iommu.h
@@ -58,7 +58,6 @@ typedef struct VTDContextEntry VTDContextEntry;
typedef struct VTDContextCacheEntry VTDContextCacheEntry;
typedef struct VTDAddressSpace VTDAddressSpace;
typedef struct VTDIOTLBEntry VTDIOTLBEntry;
-typedef struct VTDBus VTDBus;
typedef union VTD_IR_TableEntry VTD_IR_TableEntry;
typedef union VTD_IR_MSIAddress VTD_IR_MSIAddress;
typedef struct VTDPASIDDirEntry VTDPASIDDirEntry;
@@ -111,12 +110,6 @@ struct VTDAddressSpace {
IOVATree *iova_tree; /* Traces mapped IOVA ranges */
};
-struct VTDBus {
- PCIBus* bus; /* A reference to the bus to provide
translation for */
- /* A table of VTDAddressSpace objects indexed by devfn */
- VTDAddressSpace *dev_as[];
-};
-
struct VTDIOTLBEntry {
uint64_t gfn;
uint16_t domain_id;
@@ -253,8 +246,8 @@ struct IntelIOMMUState {
uint32_t context_cache_gen; /* Should be in [1,MAX] */
GHashTable *iotlb; /* IOTLB */
- GHashTable *vtd_as_by_busptr; /* VTDBus objects indexed by PCIBus* reference */
- VTDBus *vtd_as_by_bus_num[VTD_PCI_BUS_MAX]; /* VTDBus objects indexed by
bus number */
+ GHashTable *vtd_address_spaces; /* VTD address spaces */
+ VTDAddressSpace *vtd_as_cache[VTD_PCI_BUS_MAX]; /* VTD address space cache
*/
/* list of registered notifiers */
QLIST_HEAD(, VTDAddressSpace) vtd_as_with_notifiers;
--
Regards,
Yi Liu
