From 1f871c5e6b0f30644a60a81a6a7aadb3afb030ac Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Fri, 15 Jun 2018 14:57:16 +0100 Subject: exec.c: Handle IOMMUs in address_space_translate_for_iotlb() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Reviewed-by: Alex BennĂ©e Message-id: 20180604152941.20374-5-peter.maydell@linaro.org --- exec.c | 135 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 133 insertions(+), 2 deletions(-) (limited to 'exec.c') diff --git a/exec.c b/exec.c index ecdf192994..ebadc0e302 100644 --- a/exec.c +++ b/exec.c @@ -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(¬ifier->n, + tcg_iommu_unmap_notify, + IOMMU_NOTIFIER_UNMAP, + 0, + HWADDR_MAX, + iommu_idx); + memory_region_register_iommu_notifier(notifier->mr, ¬ifier->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, ¬ifier->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 } -- cgit v1.2.3