On Tue, Feb 07, 2017 at 04:28:17PM +0800, Peter Xu wrote: > The default replay() don't work for VT-d since vt-d will have a huge > default memory region which covers address range 0-(2^64-1). This will > normally consumes a lot of time (which looks like a dead loop). > > The solution is simple - we don't walk over all the regions. Instead, we > jump over the regions when we found that the page directories are empty. > It'll greatly reduce the time to walk the whole region. > > To achieve this, we provided a page walk helper to do that, invoking > corresponding hook function when we found an page we are interested in. > vtd_page_walk_level() is the core logic for the page walking. It's > interface is designed to suite further use case, e.g., to invalidate a > range of addresses. > > Reviewed-by: Jason Wang > Signed-off-by: Peter Xu For small values of reviewed: Reviewed-by: David Gibson The concept is sensible and there's nothing obviously wrong. But, I'm not familiar enough with the VT-d page table format to check the code in detail. > --- > hw/i386/intel_iommu.c | 182 ++++++++++++++++++++++++++++++++++++++++++++++++-- > hw/i386/trace-events | 7 ++ > include/exec/memory.h | 2 + > 3 files changed, 186 insertions(+), 5 deletions(-) > > diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c > index 22d8226..f8d5713 100644 > --- a/hw/i386/intel_iommu.c > +++ b/hw/i386/intel_iommu.c > @@ -595,6 +595,22 @@ static inline uint32_t vtd_get_agaw_from_context_entry(VTDContextEntry *ce) > return 30 + (ce->hi & VTD_CONTEXT_ENTRY_AW) * 9; > } > > +static inline uint64_t vtd_iova_limit(VTDContextEntry *ce) > +{ > + uint32_t ce_agaw = vtd_get_agaw_from_context_entry(ce); > + return 1ULL << MIN(ce_agaw, VTD_MGAW); > +} > + > +/* Return true if IOVA passes range check, otherwise false. */ > +static inline bool vtd_iova_range_check(uint64_t iova, VTDContextEntry *ce) > +{ > + /* > + * Check if @iova is above 2^X-1, where X is the minimum of MGAW > + * in CAP_REG and AW in context-entry. > + */ > + return !(iova & ~(vtd_iova_limit(ce) - 1)); > +} > + > static const uint64_t vtd_paging_entry_rsvd_field[] = { > [0] = ~0ULL, > /* For not large page */ > @@ -630,13 +646,9 @@ static int vtd_iova_to_slpte(VTDContextEntry *ce, uint64_t iova, bool is_write, > uint32_t level = vtd_get_level_from_context_entry(ce); > uint32_t offset; > uint64_t slpte; > - uint32_t ce_agaw = vtd_get_agaw_from_context_entry(ce); > uint64_t access_right_check; > > - /* Check if @iova is above 2^X-1, where X is the minimum of MGAW > - * in CAP_REG and AW in context-entry. > - */ > - if (iova & ~((1ULL << MIN(ce_agaw, VTD_MGAW)) - 1)) { > + if (!vtd_iova_range_check(iova, ce)) { > VTD_DPRINTF(GENERAL, "error: iova 0x%"PRIx64 " exceeds limits", iova); > return -VTD_FR_ADDR_BEYOND_MGAW; > } > @@ -684,6 +696,134 @@ static int vtd_iova_to_slpte(VTDContextEntry *ce, uint64_t iova, bool is_write, > } > } > > +typedef int (*vtd_page_walk_hook)(IOMMUTLBEntry *entry, void *private); > + > +/** > + * vtd_page_walk_level - walk over specific level for IOVA range > + * > + * @addr: base GPA addr to start the walk > + * @start: IOVA range start address > + * @end: IOVA range end address (start <= addr < end) > + * @hook_fn: hook func to be called when detected page > + * @private: private data to be passed into hook func > + * @read: whether parent level has read permission > + * @write: whether parent level has write permission > + * @notify_unmap: whether we should notify invalid entries > + */ > +static int vtd_page_walk_level(dma_addr_t addr, uint64_t start, > + uint64_t end, vtd_page_walk_hook hook_fn, > + void *private, uint32_t level, > + bool read, bool write, bool notify_unmap) > +{ > + bool read_cur, write_cur, entry_valid; > + uint32_t offset; > + uint64_t slpte; > + uint64_t subpage_size, subpage_mask; > + IOMMUTLBEntry entry; > + uint64_t iova = start; > + uint64_t iova_next; > + int ret = 0; > + > + trace_vtd_page_walk_level(addr, level, start, end); > + > + subpage_size = 1ULL << vtd_slpt_level_shift(level); > + subpage_mask = vtd_slpt_level_page_mask(level); > + > + while (iova < end) { > + iova_next = (iova & subpage_mask) + subpage_size; > + > + offset = vtd_iova_level_offset(iova, level); > + slpte = vtd_get_slpte(addr, offset); > + > + if (slpte == (uint64_t)-1) { > + trace_vtd_page_walk_skip_read(iova, iova_next); > + goto next; > + } > + > + if (vtd_slpte_nonzero_rsvd(slpte, level)) { > + trace_vtd_page_walk_skip_reserve(iova, iova_next); > + goto next; > + } > + > + /* Permissions are stacked with parents' */ > + read_cur = read && (slpte & VTD_SL_R); > + write_cur = write && (slpte & VTD_SL_W); > + > + /* > + * As long as we have either read/write permission, this is a > + * valid entry. The rule works for both page entries and page > + * table entries. > + */ > + entry_valid = read_cur | write_cur; > + > + if (vtd_is_last_slpte(slpte, level)) { > + entry.target_as = &address_space_memory; > + entry.iova = iova & subpage_mask; > + /* NOTE: this is only meaningful if entry_valid == true */ > + entry.translated_addr = vtd_get_slpte_addr(slpte); > + entry.addr_mask = ~subpage_mask; > + entry.perm = IOMMU_ACCESS_FLAG(read_cur, write_cur); > + if (!entry_valid && !notify_unmap) { > + trace_vtd_page_walk_skip_perm(iova, iova_next); > + goto next; > + } > + trace_vtd_page_walk_one(level, entry.iova, entry.translated_addr, > + entry.addr_mask, entry.perm); > + if (hook_fn) { > + ret = hook_fn(&entry, private); > + if (ret < 0) { > + return ret; > + } > + } > + } else { > + if (!entry_valid) { > + trace_vtd_page_walk_skip_perm(iova, iova_next); > + goto next; > + } > + ret = vtd_page_walk_level(vtd_get_slpte_addr(slpte), iova, > + MIN(iova_next, end), hook_fn, private, > + level - 1, read_cur, write_cur, > + notify_unmap); > + if (ret < 0) { > + return ret; > + } > + } > + > +next: > + iova = iova_next; > + } > + > + return 0; > +} > + > +/** > + * vtd_page_walk - walk specific IOVA range, and call the hook > + * > + * @ce: context entry to walk upon > + * @start: IOVA address to start the walk > + * @end: IOVA range end address (start <= addr < end) > + * @hook_fn: the hook that to be called for each detected area > + * @private: private data for the hook function > + */ > +static int vtd_page_walk(VTDContextEntry *ce, uint64_t start, uint64_t end, > + vtd_page_walk_hook hook_fn, void *private) > +{ > + dma_addr_t addr = vtd_get_slpt_base_from_context(ce); > + uint32_t level = vtd_get_level_from_context_entry(ce); > + > + if (!vtd_iova_range_check(start, ce)) { > + return -VTD_FR_ADDR_BEYOND_MGAW; > + } > + > + if (!vtd_iova_range_check(end, ce)) { > + /* Fix end so that it reaches the maximum */ > + end = vtd_iova_limit(ce); > + } > + > + return vtd_page_walk_level(addr, start, end, hook_fn, private, > + level, true, true, false); > +} > + > /* Map a device to its corresponding domain (context-entry) */ > static int vtd_dev_to_context_entry(IntelIOMMUState *s, uint8_t bus_num, > uint8_t devfn, VTDContextEntry *ce) > @@ -2402,6 +2542,37 @@ VTDAddressSpace *vtd_find_add_as(IntelIOMMUState *s, PCIBus *bus, int devfn) > return vtd_dev_as; > } > > +static int vtd_replay_hook(IOMMUTLBEntry *entry, void *private) > +{ > + memory_region_notify_one((IOMMUNotifier *)private, entry); > + return 0; > +} > + > +static void vtd_iommu_replay(MemoryRegion *mr, IOMMUNotifier *n) > +{ > + VTDAddressSpace *vtd_as = container_of(mr, VTDAddressSpace, iommu); > + IntelIOMMUState *s = vtd_as->iommu_state; > + uint8_t bus_n = pci_bus_num(vtd_as->bus); > + VTDContextEntry ce; > + > + if (vtd_dev_to_context_entry(s, bus_n, vtd_as->devfn, &ce) == 0) { > + /* > + * Scanned a valid context entry, walk over the pages and > + * notify when needed. > + */ > + trace_vtd_replay_ce_valid(bus_n, PCI_SLOT(vtd_as->devfn), > + PCI_FUNC(vtd_as->devfn), > + VTD_CONTEXT_ENTRY_DID(ce.hi), > + ce.hi, ce.lo); > + vtd_page_walk(&ce, 0, ~0ULL, vtd_replay_hook, (void *)n); > + } else { > + trace_vtd_replay_ce_invalid(bus_n, PCI_SLOT(vtd_as->devfn), > + PCI_FUNC(vtd_as->devfn)); > + } > + > + return; > +} > + > /* Do the initialization. It will also be called when reset, so pay > * attention when adding new initialization stuff. > */ > @@ -2416,6 +2587,7 @@ static void vtd_init(IntelIOMMUState *s) > > s->iommu_ops.translate = vtd_iommu_translate; > s->iommu_ops.notify_flag_changed = vtd_iommu_notify_flag_changed; > + s->iommu_ops.replay = vtd_iommu_replay; > s->root = 0; > s->root_extended = false; > s->dmar_enabled = false; > diff --git a/hw/i386/trace-events b/hw/i386/trace-events > index 88ad5e4..463db0d 100644 > --- a/hw/i386/trace-events > +++ b/hw/i386/trace-events > @@ -30,6 +30,13 @@ vtd_iotlb_cc_hit(uint8_t bus, uint8_t devfn, uint64_t high, uint64_t low, uint32 > vtd_iotlb_cc_update(uint8_t bus, uint8_t devfn, uint64_t high, uint64_t low, uint32_t gen1, uint32_t gen2) "IOTLB context update bus 0x%"PRIx8" devfn 0x%"PRIx8" high 0x%"PRIx64" low 0x%"PRIx64" gen %"PRIu32" -> gen %"PRIu32 > vtd_iotlb_reset(const char *reason) "IOTLB reset (reason: %s)" > vtd_fault_disabled(void) "Fault processing disabled for context entry" > +vtd_replay_ce_valid(uint8_t bus, uint8_t dev, uint8_t fn, uint16_t domain, uint64_t hi, uint64_t lo) "replay valid context device %02"PRIx8":%02"PRIx8".%02"PRIx8" domain 0x%"PRIx16" hi 0x%"PRIx64" lo 0x%"PRIx64 > +vtd_replay_ce_invalid(uint8_t bus, uint8_t dev, uint8_t fn) "replay invalid context device %02"PRIx8":%02"PRIx8".%02"PRIx8 > +vtd_page_walk_level(uint64_t addr, uint32_t level, uint64_t start, uint64_t end) "walk (base=0x%"PRIx64", level=%"PRIu32") iova range 0x%"PRIx64" - 0x%"PRIx64 > +vtd_page_walk_one(uint32_t level, uint64_t iova, uint64_t gpa, uint64_t mask, int perm) "detected page level 0x%"PRIx32" iova 0x%"PRIx64" -> gpa 0x%"PRIx64" mask 0x%"PRIx64" perm %d" > +vtd_page_walk_skip_read(uint64_t iova, uint64_t next) "Page walk skip iova 0x%"PRIx64" - 0x%"PRIx64" due to unable to read" > +vtd_page_walk_skip_perm(uint64_t iova, uint64_t next) "Page walk skip iova 0x%"PRIx64" - 0x%"PRIx64" due to perm empty" > +vtd_page_walk_skip_reserve(uint64_t iova, uint64_t next) "Page walk skip iova 0x%"PRIx64" - 0x%"PRIx64" due to rsrv set" > > # 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/include/exec/memory.h b/include/exec/memory.h > index 30b2a74..267f399 100644 > --- a/include/exec/memory.h > +++ b/include/exec/memory.h > @@ -55,6 +55,8 @@ typedef enum { > IOMMU_RW = 3, > } IOMMUAccessFlags; > > +#define IOMMU_ACCESS_FLAG(r, w) (((r) ? IOMMU_RO : 0) | ((w) ? IOMMU_WO : 0)) > + > struct IOMMUTLBEntry { > AddressSpace *target_as; > hwaddr iova; -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson