Hardware support for VT-d device passthrough. Although current Linux can
live with iommu=pt even without this, but this is faster than when using
software passthrough.
Signed-off-by: Peter Xu <pet...@redhat.com>
---
hw/i386/intel_iommu.c | 231 ++++++++++++++++++++++++++++++-----------
hw/i386/intel_iommu_internal.h | 1 +
hw/i386/trace-events | 2 +
hw/i386/x86-iommu.c | 1 +
include/hw/i386/x86-iommu.h | 1 +
5 files changed, 177 insertions(+), 59 deletions(-)
diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index aac2cc7..15610b9 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -613,6 +613,11 @@ static inline bool vtd_ce_type_check(X86IOMMUState
*x86_iommu,
return false;
}
break;
+ case VTD_CONTEXT_TT_PASS_THROUGH:
+ if (!x86_iommu->pt_supported) {
+ return false;
+ }
+ break;
default:
/* Unknwon type */
return false;
@@ -660,6 +665,29 @@ static bool vtd_slpte_nonzero_rsvd(uint64_t slpte,
uint32_t level)
}
}
+/* 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];
+ if (!vtd_bus) {
+ /*
+ * Iterate over the registered buses to find the one which
+ * currently hold this bus number, and update the bus_num
+ * lookup table:
+ */
+ GHashTableIter iter;
+
+ 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 vtd_bus;
+}
+
/* 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.
*/
@@ -906,6 +934,91 @@ static int vtd_dev_to_context_entry(IntelIOMMUState *s,
uint8_t bus_num,
return 0;
}
+/*
+ * Fetch translation type for specific device. Returns <0 if error
+ * happens, otherwise return the shifted type to check against
+ * VTD_CONTEXT_TT_*.
+ */
+static int vtd_dev_get_trans_type(VTDAddressSpace *as)
+{
+ IntelIOMMUState *s;
+ VTDContextEntry ce;
+ int ret;
+
+ s = as->iommu_state;
+
+ ret = vtd_dev_to_context_entry(s, pci_bus_num(as->bus),
+ as->devfn, &ce);
+ if (ret) {
+ return ret;
+ }
+
+ return vtd_ce_get_type(&ce);
+}
+
+static bool vtd_dev_pt_enabled(VTDAddressSpace *as)
+{
+ int ret;
+
+ assert(as);
+
+ ret = vtd_dev_get_trans_type(as);
+ if (ret < 0) {
+ /*
+ * Possibly failed to parse the context entry for some reason
+ * (e.g., during init, or any guest configuration errors on
+ * context entries). We should assume PT not enabled for
+ * safety.
+ */
+ return false;
+ }
+
+ return ret == VTD_CONTEXT_TT_PASS_THROUGH;
+}
+
+/* Return whether the device is using IOMMU translation. */
+static bool vtd_switch_address_space(VTDAddressSpace *as)
+{
+ bool use_iommu;
+
+ assert(as);
+
+ use_iommu = as->iommu_state->dmar_enabled & !vtd_dev_pt_enabled(as);
+
+ trace_vtd_switch_address_space(pci_bus_num(as->bus),
+ VTD_PCI_SLOT(as->devfn),
+ VTD_PCI_FUNC(as->devfn),
+ use_iommu);
+
+ /* Turn off first then on the other */
+ if (use_iommu) {
+ memory_region_set_enabled(&as->sys_alias, false);
+ memory_region_set_enabled(&as->iommu, true);
+ } else {
+ memory_region_set_enabled(&as->iommu, false);
+ memory_region_set_enabled(&as->sys_alias, true);
+ }
+
+ return use_iommu;
+}
+
+static void vtd_switch_address_space_all(IntelIOMMUState *s)
+{
+ 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 < X86_IOMMU_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);
@@ -943,6 +1056,31 @@ static inline bool vtd_is_interrupt_addr(hwaddr addr)
return VTD_INTERRUPT_ADDR_FIRST <= addr && addr <= VTD_INTERRUPT_ADDR_LAST;
}
+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)];
+ if (!vtd_as) {
+ goto out;
+ }
+
+ if (vtd_switch_address_space(vtd_as) == false) {
+ /* We switched off IOMMU region successfully. */
+ success = true;
+ }
+
+out:
+ trace_vtd_pt_enable_fast_path(source_id, success);
+}
+
/* Map dev to context-entry then do a paging-structures walk to do a iommu
* translation.
*
@@ -1014,6 +1152,30 @@ static void vtd_do_iommu_translate(VTDAddressSpace
*vtd_as, PCIBus *bus,
cc_entry->context_cache_gen = s->context_cache_gen;
}
+ /*
+ * We don't need to translate for pass-through context entries.
+ * Also, let's ignore IOTLB caching as well for PT devices.
+ */
+ if (vtd_ce_get_type(&ce) == VTD_CONTEXT_TT_PASS_THROUGH) {
+ entry->translated_addr = entry->iova;
+ entry->addr_mask = VTD_PAGE_SIZE - 1;
+ entry->perm = IOMMU_RW;
+ trace_vtd_translate_pt(source_id, entry->iova);
+
+ /*
+ * When this happens, it means firstly caching-mode is not
+ * enabled, and this is the first passthrough translation for
+ * the device. Let's enable the fast path for passthrough.
+ *
+ * When passthrough is disabled again for the device, we can
+ * capture it via the context entry invalidation, then the
+ * IOMMU region can be swapped back.
+ */
+ vtd_pt_enable_fast_path(s, source_id);
+
+ return;
+ }
+
ret_fr = vtd_iova_to_slpte(&ce, addr, is_write, &slpte, &level,
&reads, &writes);
if (ret_fr) {
@@ -1083,6 +1245,7 @@ static void vtd_context_global_invalidate(IntelIOMMUState
*s)
if (s->context_cache_gen == VTD_CONTEXT_CACHE_GEN_MAX) {
vtd_reset_context_cache(s);
}
+ vtd_switch_address_space_all(s);
/*
* From VT-d spec 6.5.2.1, a global context entry invalidation
* should be followed by a IOTLB global invalidation, so we should
@@ -1093,29 +1256,6 @@ static void
vtd_context_global_invalidate(IntelIOMMUState *s)
vtd_iommu_replay_all(s);
}
-
-/* Find the VTD address space currently 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];
- if (!vtd_bus) {
- /* Iterate over the registered buses to find the one
- * which currently hold this bus number, and update the bus_num lookup
table:
- */
- GHashTableIter iter;
-
- 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 vtd_bus;
-}
-
/* Do a context-cache device-selective invalidation.
* @func_mask: FM field after shifting
*/
@@ -1158,6 +1298,11 @@ static void
vtd_context_device_invalidate(IntelIOMMUState *s,
VTD_PCI_FUNC(devfn_it));
vtd_as->context_cache_entry.context_cache_gen = 0;
/*
+ * 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, a replay() suites here to notify all the
* IOMMU_NOTIFIER_MAP registers about this change.
@@ -1389,42 +1534,6 @@ static void vtd_handle_gcmd_sirtp(IntelIOMMUState *s)
vtd_set_clear_mask_long(s, DMAR_GSTS_REG, 0, VTD_GSTS_IRTPS);
}
-static void vtd_switch_address_space(VTDAddressSpace *as)
-{
- assert(as);
-
- trace_vtd_switch_address_space(pci_bus_num(as->bus),
- VTD_PCI_SLOT(as->devfn),
- VTD_PCI_FUNC(as->devfn),
- as->iommu_state->dmar_enabled);
-
- /* Turn off first then on the other */
- if (as->iommu_state->dmar_enabled) {
- memory_region_set_enabled(&as->sys_alias, false);
- memory_region_set_enabled(&as->iommu, true);
- } else {
- memory_region_set_enabled(&as->iommu, false);
- memory_region_set_enabled(&as->sys_alias, true);
- }
-}
-
-static void vtd_switch_address_space_all(IntelIOMMUState *s)
-{
- 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 < X86_IOMMU_PCI_DEVFN_MAX; i++) {
- if (!vtd_bus->dev_as[i]) {
- continue;
- }
- vtd_switch_address_space(vtd_bus->dev_as[i]);
- }
- }
-}
-
/* Handle Translation Enable/Disable */
static void vtd_handle_gcmd_te(IntelIOMMUState *s, bool en)
{
@@ -2872,6 +2981,10 @@ static void vtd_init(IntelIOMMUState *s)
s->ecap |= VTD_ECAP_DT;
}
+ if (x86_iommu->pt_supported) {
+ s->ecap |= VTD_ECAP_PT;
+ }
+
if (s->caching_mode) {
s->cap |= VTD_CAP_CM;
}
diff --git a/hw/i386/intel_iommu_internal.h b/hw/i386/intel_iommu_internal.h
index 29d6707..0e73a65 100644
--- a/hw/i386/intel_iommu_internal.h
+++ b/hw/i386/intel_iommu_internal.h
@@ -187,6 +187,7 @@
/* Interrupt Remapping support */
#define VTD_ECAP_IR (1ULL << 3)
#define VTD_ECAP_EIM (1ULL << 4)
+#define VTD_ECAP_PT (1ULL << 6)
#define VTD_ECAP_MHMV (15ULL << 20)
/* CAP_REG */
diff --git a/hw/i386/trace-events b/hw/i386/trace-events
index 04a6980..72556da 100644
--- a/hw/i386/trace-events
+++ b/hw/i386/trace-events
@@ -38,6 +38,8 @@ vtd_page_walk_skip_perm(uint64_t iova, uint64_t next) "Page
walk skip iova 0x%"P
vtd_page_walk_skip_reserve(uint64_t iova, uint64_t next) "Page walk skip iova
0x%"PRIx64" - 0x%"PRIx64" due to rsrv set"
vtd_switch_address_space(uint8_t bus, uint8_t slot, uint8_t fn, bool on)
"Device %02x:%02x.%x switching address space (iommu enabled=%d)"
vtd_as_unmap_whole(uint8_t bus, uint8_t slot, uint8_t fn, uint64_t iova,
uint64_t size) "Device %02x:%02x.%x start 0x%"PRIx64" size 0x%"PRIx64
+vtd_translate_pt(uint16_t sid, uint64_t addr) "source id 0x%"PRIu16", iova
0x%"PRIx64
+vtd_pt_enable_fast_path(uint16_t sid, bool success) "sid 0x%"PRIu16" %d"
# hw/i386/amd_iommu.c
amdvi_evntlog_fail(uint64_t addr, uint32_t head) "error: fail to write at addr
0x%"PRIx64" + offset 0x%"PRIx32
diff --git a/hw/i386/x86-iommu.c b/hw/i386/x86-iommu.c
index 02b8825..293caf8 100644
--- a/hw/i386/x86-iommu.c
+++ b/hw/i386/x86-iommu.c
@@ -91,6 +91,7 @@ static void x86_iommu_realize(DeviceState *dev, Error **errp)
static Property x86_iommu_properties[] = {
DEFINE_PROP_BOOL("intremap", X86IOMMUState, intr_supported, false),
DEFINE_PROP_BOOL("device-iotlb", X86IOMMUState, dt_supported, false),
+ DEFINE_PROP_BOOL("pt", X86IOMMUState, pt_supported, true),
DEFINE_PROP_END_OF_LIST(),
};
diff --git a/include/hw/i386/x86-iommu.h b/include/hw/i386/x86-iommu.h
index 361c07c..ef89c0c 100644
--- a/include/hw/i386/x86-iommu.h
+++ b/include/hw/i386/x86-iommu.h
@@ -74,6 +74,7 @@ struct X86IOMMUState {
SysBusDevice busdev;
bool intr_supported; /* Whether vIOMMU supports IR */
bool dt_supported; /* Whether vIOMMU supports DT */
+ bool pt_supported; /* Whether vIOMMU supports pass-through */
IommuType type; /* IOMMU type - AMD/Intel */
QLIST_HEAD(, IEC_Notifier) iec_notifiers; /* IEC notify list */
};
--
2.7.4
