[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [PATCH V2 2/4] intel-iommu: drop VTDBus
From: |
Peter Xu |
Subject: |
Re: [PATCH V2 2/4] intel-iommu: drop VTDBus |
Date: |
Fri, 22 Apr 2022 08:55:59 -0400 |
On Fri, Apr 22, 2022 at 02:26:11PM +0800, Jason Wang wrote:
> On Fri, Apr 22, 2022 at 9:17 AM Peter Xu <peterx@redhat.com> wrote:
> >
> > Hi, Jason,
> >
> > Mostly good to me, just a few nitpicks below.
> >
> > On Mon, Mar 21, 2022 at 01:54:27PM +0800, Jason Wang wrote:
> > > We introduce VTDBus structure as an intermediate step for searching
> > > the address space. This works well with SID based matching/lookup. But
> > > when we want to support SID plus PASID based address space lookup,
> > > this intermediate steps turns out to be a burden. So the patch simply
> > > drops the VTDBus structure and use the PCIBus and devfn as the key for
> > > the g_hash_table(). This simplifies the codes and the future PASID
> > > extension.
> > >
> > > To prevent being slower for past vtd_find_as_from_bus_num() callers, a
> > > vtd_as cache indexed by the bus number is introduced to store the last
> > > recent search result of a vtd_as belongs to a specific bus.
> > >
> > > Signed-off-by: Jason Wang <jasowang@redhat.com>
> > > ---
> > > hw/i386/intel_iommu.c | 238 +++++++++++++++++-----------------
> > > include/hw/i386/intel_iommu.h | 11 +-
> > > 2 files changed, 123 insertions(+), 126 deletions(-)
> > >
> > > diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
> > > index 90964b201c..5851a17d0e 100644
> > > --- a/hw/i386/intel_iommu.c
> > > +++ b/hw/i386/intel_iommu.c
> > > @@ -61,6 +61,16 @@
> > > }
> > > \
> > > }
> > >
> > > +/*
> > > + * PCI bus number (or SID) is not reliable since the device is usaully
> > > + * initalized before guest can configure the PCI bridge
> > > + * (SECONDARY_BUS_NUMBER).
> > > + */
> > > +struct vtd_as_key {
> > > + PCIBus *bus;
> > > + uint8_t devfn;
> > > +};
> > > +
> > > static void vtd_address_space_refresh_all(IntelIOMMUState *s);
> > > static void vtd_address_space_unmap(VTDAddressSpace *as, IOMMUNotifier
> > > *n);
> > >
> > > @@ -210,6 +220,31 @@ static guint vtd_uint64_hash(gconstpointer v)
> > > return (guint)*(const uint64_t *)v;
> > > }
> > >
> > > +static gboolean vtd_as_equal(gconstpointer v1, gconstpointer v2)
> > > +{
> > > + const struct vtd_as_key *key1 = v1;
> > > + const struct vtd_as_key *key2 = v2;
> > > +
> > > + return (key1->bus == key2->bus) && (key1->devfn == key2->devfn);
> > > +}
> > > +
> > > +static inline uint16_t vtd_make_source_id(uint8_t bus_num, uint8_t devfn)
> > > +{
> > > + return ((bus_num & 0xffUL) << 8) | (devfn & 0xffUL);
> > > +}
> >
> > Nit: we could directly drop this one and use PCI_BUILD_BDF().
>
> Will fix.
>
> >
> > > +
> > > +/*
> > > + * Note that we use pointer to PCIBus as the key, so hashing/shifting
> > > + * based on the pointer value is intended.
> >
> > Thanks for the comment; that helps.
> >
> > Should we also mention that this hash is not the only interface to identify
> > two vtd_as*, say, even if on a 32bit system we got last 24 bits collapsed
> > on two vtd_as* pointers, we can still have vtd_as_equal() to guard us?
>
> Ok. let me add that in the next version.
>
> >
> > > + */
> > > +static guint vtd_as_hash(gconstpointer v)
> > > +{
> > > + const struct vtd_as_key *key = v;
> > > + guint value = (guint)(uintptr_t)key->bus;
> > > +
> > > + return (guint)(value << 8 | key->devfn);
> > > +}
> > > +
> > > static gboolean vtd_hash_remove_by_domain(gpointer key, gpointer value,
> > > gpointer user_data)
> > > {
> > > @@ -248,22 +283,14 @@ static gboolean vtd_hash_remove_by_page(gpointer
> > > key, gpointer value,
> > > static void vtd_reset_context_cache_locked(IntelIOMMUState *s)
> > > {
> > > VTDAddressSpace *vtd_as;
> > > - VTDBus *vtd_bus;
> > > - GHashTableIter bus_it;
> > > - uint32_t devfn_it;
> > > + GHashTableIter as_it;
> > >
> > > trace_vtd_context_cache_reset();
> > >
> > > - g_hash_table_iter_init(&bus_it, s->vtd_as_by_busptr);
> > > + g_hash_table_iter_init(&as_it, s->vtd_as);
> > >
> > > - while (g_hash_table_iter_next (&bus_it, NULL, (void**)&vtd_bus)) {
> > > - for (devfn_it = 0; devfn_it < PCI_DEVFN_MAX; ++devfn_it) {
> > > - vtd_as = vtd_bus->dev_as[devfn_it];
> > > - if (!vtd_as) {
> > > - continue;
> > > - }
> > > - vtd_as->context_cache_entry.context_cache_gen = 0;
> > > - }
> > > + while (g_hash_table_iter_next (&as_it, NULL, (void**)&vtd_as)) {
> > > + vtd_as->context_cache_entry.context_cache_gen = 0;
> > > }
> > > s->context_cache_gen = 1;
> > > }
> > > @@ -993,32 +1020,6 @@ static bool vtd_slpte_nonzero_rsvd(uint64_t slpte,
> > > uint32_t level)
> > > return slpte & rsvd_mask;
> > > }
> > >
> > > -/* 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];
> > > - GHashTableIter iter;
> > > -
> > > - if (vtd_bus) {
> > > - return vtd_bus;
> > > - }
> > > -
> > > - /*
> > > - * Iterate over the registered buses to find the one which
> > > - * currently holds this bus number and update the bus_num
> > > - * lookup table.
> > > - */
> > > - 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 NULL;
> > > -}
> > > -
> > > /* 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.
> > > */
> > > @@ -1634,24 +1635,13 @@ static bool
> > > vtd_switch_address_space(VTDAddressSpace *as)
> > >
> > > static void vtd_switch_address_space_all(IntelIOMMUState *s)
> > > {
> > > + VTDAddressSpace *vtd_as;
> > > 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 < 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);
> > > + g_hash_table_iter_init(&iter, s->vtd_as);
> > > + while (g_hash_table_iter_next(&iter, NULL, (void **)&vtd_as)) {
> > > + vtd_switch_address_space(vtd_as);
> > > + }
> > > }
> > >
> > > static const bool vtd_qualified_faults[] = {
> > > @@ -1688,18 +1678,39 @@ static inline bool vtd_is_interrupt_addr(hwaddr
> > > addr)
> > > return VTD_INTERRUPT_ADDR_FIRST <= addr && addr <=
> > > VTD_INTERRUPT_ADDR_LAST;
> > > }
> > >
> > > +static gboolean vtd_find_as_by_sid(gpointer key, gpointer value,
> > > + gpointer user_data)
> > > +{
> > > + struct vtd_as_key *as_key = (struct vtd_as_key *)key;
> > > + uint16_t target_sid = *(uint16_t *)user_data;
> > > + uint16_t sid = vtd_make_source_id(pci_bus_num(as_key->bus),
> > > + as_key->devfn);
> > > + return sid == target_sid;
> > > +}
> > > +
> > > +static VTDAddressSpace *vtd_get_as_by_sid(IntelIOMMUState *s, uint16_t
> > > sid)
> > > +{
> > > + uint8_t bus_num = sid >> 8;
> >
> > PCI_BUS_NUM(sid)?
>
> Will do.
>
> >
> > > + VTDAddressSpace *vtd_as = s->vtd_as_cache[bus_num];
> > > +
> > > + if (vtd_as &&
> > > + (sid == vtd_make_source_id(pci_bus_num(vtd_as->bus),
> > > + vtd_as->devfn))) {
> > > + return vtd_as;
> > > + }
> > > +
> > > + vtd_as = g_hash_table_find(s->vtd_as, vtd_find_as_by_sid, &sid);
> > > + s->vtd_as_cache[bus_num] = vtd_as;
> > > +
> > > + return vtd_as;
> > > +}
> > > +
> > > 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)];
> > > + vtd_as = vtd_get_as_by_sid(s, source_id);
> > > if (!vtd_as) {
> > > goto out;
> > > }
> > > @@ -1907,11 +1918,10 @@ static void
> > > vtd_context_device_invalidate(IntelIOMMUState *s,
> > > uint16_t source_id,
> > > uint16_t func_mask)
> > > {
> > > + GHashTableIter as_it;
> > > uint16_t mask;
> > > - VTDBus *vtd_bus;
> > > VTDAddressSpace *vtd_as;
> > > uint8_t bus_n, devfn;
> > > - uint16_t devfn_it;
> > >
> > > trace_vtd_inv_desc_cc_devices(source_id, func_mask);
> > >
> > > @@ -1934,32 +1944,31 @@ static void
> > > vtd_context_device_invalidate(IntelIOMMUState *s,
> > > mask = ~mask;
> > >
> > > bus_n = VTD_SID_TO_BUS(source_id);
> > > - vtd_bus = vtd_find_as_from_bus_num(s, bus_n);
> > > - if (vtd_bus) {
> > > - devfn = VTD_SID_TO_DEVFN(source_id);
> > > - for (devfn_it = 0; devfn_it < PCI_DEVFN_MAX; ++devfn_it) {
> > > - vtd_as = vtd_bus->dev_as[devfn_it];
> > > - if (vtd_as && ((devfn_it & mask) == (devfn & mask))) {
> > > - trace_vtd_inv_desc_cc_device(bus_n,
> > > VTD_PCI_SLOT(devfn_it),
> > > - VTD_PCI_FUNC(devfn_it));
> > > - vtd_iommu_lock(s);
> > > - vtd_as->context_cache_entry.context_cache_gen = 0;
> > > - vtd_iommu_unlock(s);
> > > - /*
> > > - * 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, resync the shadow page table.
> > > - * This won't bring bad even if we have no such
> > > - * notifier registered - the IOMMU notification
> > > - * framework will skip MAP notifications if that
> > > - * happened.
> > > - */
> > > - vtd_sync_shadow_page_table(vtd_as);
> > > - }
> > > + devfn = VTD_SID_TO_DEVFN(source_id);
> > > +
> > > + g_hash_table_iter_init(&as_it, s->vtd_as);
> > > + while (g_hash_table_iter_next(&as_it, NULL, (void**)&vtd_as)) {
> > > + if ((pci_bus_num(vtd_as->bus) == bus_n) &&
> > > + (vtd_as->devfn & mask) == (devfn & mask)) {
> > > + trace_vtd_inv_desc_cc_device(bus_n,
> > > VTD_PCI_SLOT(vtd_as->devfn),
> > > + VTD_PCI_FUNC(vtd_as->devfn));
> > > + vtd_iommu_lock(s);
> > > + vtd_as->context_cache_entry.context_cache_gen = 0;
> > > + vtd_iommu_unlock(s);
> > > + /*
> > > + * 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, resync the shadow page table.
> > > + * This won't bring bad even if we have no such
> > > + * notifier registered - the IOMMU notification
> > > + * framework will skip MAP notifications if that
> > > + * happened.
> > > + */
> > > + vtd_sync_shadow_page_table(vtd_as);
> > > }
> > > }
> > > }
> > > @@ -2473,18 +2482,13 @@ static bool
> > > vtd_process_device_iotlb_desc(IntelIOMMUState *s,
> > > {
> > > VTDAddressSpace *vtd_dev_as;
> > > IOMMUTLBEvent event;
> > > - struct VTDBus *vtd_bus;
> > > hwaddr addr;
> > > uint64_t sz;
> > > uint16_t sid;
> > > - uint8_t devfn;
> > > bool size;
> > > - uint8_t bus_num;
> > >
> > > addr = VTD_INV_DESC_DEVICE_IOTLB_ADDR(inv_desc->hi);
> > > sid = VTD_INV_DESC_DEVICE_IOTLB_SID(inv_desc->lo);
> > > - devfn = sid & 0xff;
> > > - bus_num = sid >> 8;
> > > size = VTD_INV_DESC_DEVICE_IOTLB_SIZE(inv_desc->hi);
> > >
> > > if ((inv_desc->lo & VTD_INV_DESC_DEVICE_IOTLB_RSVD_LO) ||
> > > @@ -2495,12 +2499,11 @@ static bool
> > > vtd_process_device_iotlb_desc(IntelIOMMUState *s,
> > > return false;
> > > }
> > >
> > > - vtd_bus = vtd_find_as_from_bus_num(s, bus_num);
> > > - if (!vtd_bus) {
> > > - goto done;
> > > - }
> > > -
> > > - vtd_dev_as = vtd_bus->dev_as[devfn];
> > > + /*
> > > + * Using sid is OK since the guest should have finished the
> > > + * initialization of both the bus and device.
> > > + */
> > > + vtd_dev_as = vtd_get_as_by_sid(s, sid);
> > > if (!vtd_dev_as) {
> > > goto done;
> > > }
> > > @@ -3426,27 +3429,27 @@ static const MemoryRegionOps vtd_mem_ir_ops = {
> > >
> > > VTDAddressSpace *vtd_find_add_as(IntelIOMMUState *s, PCIBus *bus, int
> > > devfn)
> > > {
> > > - uintptr_t key = (uintptr_t)bus;
> > > - VTDBus *vtd_bus = g_hash_table_lookup(s->vtd_as_by_busptr, &key);
> > > + /*
> > > + * We can't simply use sid here since the bus number might not be
> > > + * initialized by the guest.
> > > + */
> > > + struct vtd_as_key key = {
> > > + .bus = bus,
> > > + .devfn = devfn,
> > > + };
> > > VTDAddressSpace *vtd_dev_as;
> > > char name[128];
> > >
> > > - if (!vtd_bus) {
> > > - uintptr_t *new_key = g_malloc(sizeof(*new_key));
> > > - *new_key = (uintptr_t)bus;
> > > - /* No corresponding free() */
> > > - vtd_bus = g_malloc0(sizeof(VTDBus) + sizeof(VTDAddressSpace *) *
> > > \
> > > - PCI_DEVFN_MAX);
> > > - vtd_bus->bus = bus;
> > > - g_hash_table_insert(s->vtd_as_by_busptr, new_key, vtd_bus);
> > > - }
> > > + vtd_dev_as = g_hash_table_lookup(s->vtd_as, &key);
> > > + if (!vtd_dev_as) {
> > > + struct vtd_as_key *new_key = g_malloc(sizeof(*new_key));
> > >
> > > - vtd_dev_as = vtd_bus->dev_as[devfn];
> > > + new_key->bus = bus;
> > > + new_key->devfn = devfn;
> > >
> > > - if (!vtd_dev_as) {
> > > snprintf(name, sizeof(name), "vtd-%02x.%x", PCI_SLOT(devfn),
> > > PCI_FUNC(devfn));
> > > - vtd_bus->dev_as[devfn] = vtd_dev_as =
> > > g_malloc0(sizeof(VTDAddressSpace));
> > > + vtd_dev_as = g_malloc0(sizeof(VTDAddressSpace));
> > >
> > > vtd_dev_as->bus = bus;
> > > vtd_dev_as->devfn = (uint8_t)devfn;
> > > @@ -3502,6 +3505,8 @@ VTDAddressSpace *vtd_find_add_as(IntelIOMMUState
> > > *s, PCIBus *bus, int devfn)
> > > &vtd_dev_as->nodmar, 0);
> > >
> > > vtd_switch_address_space(vtd_dev_as);
> > > +
> > > + g_hash_table_insert(s->vtd_as, new_key, vtd_dev_as);
> > > }
> > > return vtd_dev_as;
> > > }
> > > @@ -3875,7 +3880,6 @@ static void vtd_realize(DeviceState *dev, Error
> > > **errp)
> > >
> > > QLIST_INIT(&s->vtd_as_with_notifiers);
> > > qemu_mutex_init(&s->iommu_lock);
> > > - memset(s->vtd_as_by_bus_num, 0, sizeof(s->vtd_as_by_bus_num));
> > > memory_region_init_io(&s->csrmem, OBJECT(s), &vtd_mem_ops, s,
> > > "intel_iommu", DMAR_REG_SIZE);
> > >
> > > @@ -3897,8 +3901,8 @@ static void vtd_realize(DeviceState *dev, Error
> > > **errp)
> > > /* No corresponding destroy */
> > > s->iotlb = g_hash_table_new_full(vtd_uint64_hash, vtd_uint64_equal,
> > > g_free, g_free);
> > > - s->vtd_as_by_busptr = g_hash_table_new_full(vtd_uint64_hash,
> > > vtd_uint64_equal,
> > > - g_free, g_free);
> > > + s->vtd_as = g_hash_table_new_full(vtd_as_hash, vtd_as_equal,
> > > + g_free, g_free);
> > > vtd_init(s);
> > > sysbus_mmio_map(SYS_BUS_DEVICE(s), 0, Q35_HOST_BRIDGE_IOMMU_ADDR);
> > > pci_setup_iommu(bus, vtd_host_dma_iommu, dev);
> > > diff --git a/include/hw/i386/intel_iommu.h b/include/hw/i386/intel_iommu.h
> > > index 3b5ac869db..fa1bed353c 100644
> > > --- a/include/hw/i386/intel_iommu.h
> > > +++ b/include/hw/i386/intel_iommu.h
> > > @@ -58,7 +58,6 @@ typedef struct VTDContextEntry VTDContextEntry;
> > > typedef struct VTDContextCacheEntry VTDContextCacheEntry;
> > > typedef struct VTDAddressSpace VTDAddressSpace;
> > > typedef struct VTDIOTLBEntry VTDIOTLBEntry;
> > > -typedef struct VTDBus VTDBus;
> > > typedef union VTD_IR_TableEntry VTD_IR_TableEntry;
> > > typedef union VTD_IR_MSIAddress VTD_IR_MSIAddress;
> > > typedef struct VTDPASIDDirEntry VTDPASIDDirEntry;
> > > @@ -111,12 +110,6 @@ struct VTDAddressSpace {
> > > IOVATree *iova_tree; /* Traces mapped IOVA ranges */
> > > };
> > >
> > > -struct VTDBus {
> > > - PCIBus* bus; /* A reference to the bus to provide
> > > translation for */
> > > - /* A table of VTDAddressSpace objects indexed by devfn */
> > > - VTDAddressSpace *dev_as[];
> > > -};
> > > -
> > > struct VTDIOTLBEntry {
> > > uint64_t gfn;
> > > uint16_t domain_id;
> > > @@ -253,8 +246,8 @@ struct IntelIOMMUState {
> > > uint32_t context_cache_gen; /* Should be in [1,MAX] */
> > > GHashTable *iotlb; /* IOTLB */
> > >
> > > - GHashTable *vtd_as_by_busptr; /* VTDBus objects indexed by PCIBus*
> > > reference */
> > > - VTDBus *vtd_as_by_bus_num[VTD_PCI_BUS_MAX]; /* VTDBus objects
> > > indexed by bus number */
> > > + GHashTable *vtd_as; /* VTD address space indexed by
> > > source id*/
> >
> > It's not indexed by source ID but vtd_as_key?
>
> Right, let me fix that.
>
> >
> > Meanwhile how about renaming it to vtd_address_spaces? Since we use vtd_as
> > as the name for VTDAddressSpace* in most code paths, so imho it'll be
> > easier to identify the two.
>
> Ok.
If with all above nitpicks fixed, please feel free to add:
Reviewed-by: Peter Xu <peterx@redhat.com>
Thanks!
--
Peter Xu