intel_iommu: support passthrough (PT)

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 <peterx@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Liu, Yi L <yi.l.liu@linux.intel.com>
Reviewed-by: Jason Wang <jasowang@redhat.com>
This commit is contained in:
Peter Xu 2017-05-19 11:19:47 +08:00 committed by Michael S. Tsirkin
parent f80c98740e
commit dbaabb25f4
5 changed files with 177 additions and 59 deletions

View File

@ -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
*/
@ -1157,6 +1297,11 @@ static void vtd_context_device_invalidate(IntelIOMMUState *s,
trace_vtd_inv_desc_cc_device(bus_n, VTD_PCI_SLOT(devfn_it),
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
@ -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;
}

View File

@ -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 */

View File

@ -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

View File

@ -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(),
};

View File

@ -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 */
};