exec.c: Handle IOMMUs in address_space_translate_for_iotlb()

Currently we don't support board configurations that put an IOMMU
in the path of the CPU's memory transactions, and instead just
assert() if the memory region fonud in address_space_translate_for_iotlb()
is an IOMMUMemoryRegion.

Remove this limitation by having the function handle IOMMUs.
This is mostly straightforward, but we must make sure we have
a notifier registered for every IOMMU that a transaction has
passed through, so that we can flush the TLB appropriately
when any of the IOMMUs change their mappings.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-id: 20180604152941.20374-5-peter.maydell@linaro.org
This commit is contained in:
Peter Maydell 2018-06-15 14:57:16 +01:00
parent 2c91bcf273
commit 1f871c5e6b
4 changed files with 140 additions and 4 deletions

View File

@ -632,7 +632,8 @@ void tlb_set_page_with_attrs(CPUState *cpu, target_ulong vaddr,
}
sz = size;
section = address_space_translate_for_iotlb(cpu, asidx, paddr, &xlat, &sz);
section = address_space_translate_for_iotlb(cpu, asidx, paddr, &xlat, &sz,
attrs, &prot);
assert(sz >= TARGET_PAGE_SIZE);
tlb_debug("vaddr=" TARGET_FMT_lx " paddr=0x" TARGET_FMT_plx

135
exec.c
View File

@ -653,18 +653,144 @@ MemoryRegion *flatview_translate(FlatView *fv, hwaddr addr, hwaddr *xlat,
return mr;
}
typedef struct TCGIOMMUNotifier {
IOMMUNotifier n;
MemoryRegion *mr;
CPUState *cpu;
int iommu_idx;
bool active;
} TCGIOMMUNotifier;
static void tcg_iommu_unmap_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
{
TCGIOMMUNotifier *notifier = container_of(n, TCGIOMMUNotifier, n);
if (!notifier->active) {
return;
}
tlb_flush(notifier->cpu);
notifier->active = false;
/* We leave the notifier struct on the list to avoid reallocating it later.
* Generally the number of IOMMUs a CPU deals with will be small.
* In any case we can't unregister the iommu notifier from a notify
* callback.
*/
}
static void tcg_register_iommu_notifier(CPUState *cpu,
IOMMUMemoryRegion *iommu_mr,
int iommu_idx)
{
/* Make sure this CPU has an IOMMU notifier registered for this
* IOMMU/IOMMU index combination, so that we can flush its TLB
* when the IOMMU tells us the mappings we've cached have changed.
*/
MemoryRegion *mr = MEMORY_REGION(iommu_mr);
TCGIOMMUNotifier *notifier;
int i;
for (i = 0; i < cpu->iommu_notifiers->len; i++) {
notifier = &g_array_index(cpu->iommu_notifiers, TCGIOMMUNotifier, i);
if (notifier->mr == mr && notifier->iommu_idx == iommu_idx) {
break;
}
}
if (i == cpu->iommu_notifiers->len) {
/* Not found, add a new entry at the end of the array */
cpu->iommu_notifiers = g_array_set_size(cpu->iommu_notifiers, i + 1);
notifier = &g_array_index(cpu->iommu_notifiers, TCGIOMMUNotifier, i);
notifier->mr = mr;
notifier->iommu_idx = iommu_idx;
notifier->cpu = cpu;
/* Rather than trying to register interest in the specific part
* of the iommu's address space that we've accessed and then
* expand it later as subsequent accesses touch more of it, we
* just register interest in the whole thing, on the assumption
* that iommu reconfiguration will be rare.
*/
iommu_notifier_init(&notifier->n,
tcg_iommu_unmap_notify,
IOMMU_NOTIFIER_UNMAP,
0,
HWADDR_MAX,
iommu_idx);
memory_region_register_iommu_notifier(notifier->mr, &notifier->n);
}
if (!notifier->active) {
notifier->active = true;
}
}
static void tcg_iommu_free_notifier_list(CPUState *cpu)
{
/* Destroy the CPU's notifier list */
int i;
TCGIOMMUNotifier *notifier;
for (i = 0; i < cpu->iommu_notifiers->len; i++) {
notifier = &g_array_index(cpu->iommu_notifiers, TCGIOMMUNotifier, i);
memory_region_unregister_iommu_notifier(notifier->mr, &notifier->n);
}
g_array_free(cpu->iommu_notifiers, true);
}
/* Called from RCU critical section */
MemoryRegionSection *
address_space_translate_for_iotlb(CPUState *cpu, int asidx, hwaddr addr,
hwaddr *xlat, hwaddr *plen)
hwaddr *xlat, hwaddr *plen,
MemTxAttrs attrs, int *prot)
{
MemoryRegionSection *section;
IOMMUMemoryRegion *iommu_mr;
IOMMUMemoryRegionClass *imrc;
IOMMUTLBEntry iotlb;
int iommu_idx;
AddressSpaceDispatch *d = atomic_rcu_read(&cpu->cpu_ases[asidx].memory_dispatch);
section = address_space_translate_internal(d, addr, xlat, plen, false);
for (;;) {
section = address_space_translate_internal(d, addr, &addr, plen, false);
iommu_mr = memory_region_get_iommu(section->mr);
if (!iommu_mr) {
break;
}
imrc = memory_region_get_iommu_class_nocheck(iommu_mr);
iommu_idx = imrc->attrs_to_index(iommu_mr, attrs);
tcg_register_iommu_notifier(cpu, iommu_mr, iommu_idx);
/* We need all the permissions, so pass IOMMU_NONE so the IOMMU
* doesn't short-cut its translation table walk.
*/
iotlb = imrc->translate(iommu_mr, addr, IOMMU_NONE, iommu_idx);
addr = ((iotlb.translated_addr & ~iotlb.addr_mask)
| (addr & iotlb.addr_mask));
/* Update the caller's prot bits to remove permissions the IOMMU
* is giving us a failure response for. If we get down to no
* permissions left at all we can give up now.
*/
if (!(iotlb.perm & IOMMU_RO)) {
*prot &= ~(PAGE_READ | PAGE_EXEC);
}
if (!(iotlb.perm & IOMMU_WO)) {
*prot &= ~PAGE_WRITE;
}
if (!*prot) {
goto translate_fail;
}
d = flatview_to_dispatch(address_space_to_flatview(iotlb.target_as));
}
assert(!memory_region_is_iommu(section->mr));
*xlat = addr;
return section;
translate_fail:
return &d->map.sections[PHYS_SECTION_UNASSIGNED];
}
#endif
@ -823,6 +949,9 @@ void cpu_exec_unrealizefn(CPUState *cpu)
if (qdev_get_vmsd(DEVICE(cpu)) == NULL) {
vmstate_unregister(NULL, &vmstate_cpu_common, cpu);
}
#ifndef CONFIG_USER_ONLY
tcg_iommu_free_notifier_list(cpu);
#endif
}
Property cpu_common_props[] = {
@ -870,6 +999,8 @@ void cpu_exec_realizefn(CPUState *cpu, Error **errp)
if (cc->vmsd != NULL) {
vmstate_register(NULL, cpu->cpu_index, cc->vmsd, cpu);
}
cpu->iommu_notifiers = g_array_new(false, true, sizeof(TCGIOMMUNotifier));
#endif
}

View File

@ -478,7 +478,8 @@ void tb_flush_jmp_cache(CPUState *cpu, target_ulong addr);
MemoryRegionSection *
address_space_translate_for_iotlb(CPUState *cpu, int asidx, hwaddr addr,
hwaddr *xlat, hwaddr *plen);
hwaddr *xlat, hwaddr *plen,
MemTxAttrs attrs, int *prot);
hwaddr memory_region_section_get_iotlb(CPUState *cpu,
MemoryRegionSection *section,
target_ulong vaddr,

View File

@ -429,6 +429,9 @@ struct CPUState {
uint16_t pending_tlb_flush;
int hvf_fd;
/* track IOMMUs whose translations we've cached in the TCG TLB */
GArray *iommu_notifiers;
};
QTAILQ_HEAD(CPUTailQ, CPUState);