On 25/08/17 16:21, David Gibson wrote: > On Thu, Jul 20, 2017 at 05:22:30PM +1000, Alexey Kardashevskiy wrote: >> This implements a notification for a new IOMMU group attached to >> sPAPR's logical IO bus (LIOBN) to enable in-kernel TCE acceleration. >> >> This extends the TYPE_SPAPR_IOMMU_MEMORY_REGION class with a get_fd() >> callback which returns KVM fd associated with LIOBN, the notifier uses it >> to establish link between LIOBN and IOMMU group in the KVM. >> >> Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru> >> --- >> >> The practical reason for adding get_fd() as a callback is avoiding static >> linking to spapt_tce_get_fd(): hw/vfio/spapr.c compiles when >> CONFIG_SOFTMMU=y to avoid multiple "ifdef PSERIES"'s in the rest >> of VFIO code but hw/ppc/spapr_iommu.c (where spapt_tce_get_fd() besides) >> compiles only when CONFIG_PSERIES=y. > > Ok. Nonetheless I don't think the get_fd() method is a good idea. > First, it's basically an abstraction violation, exposing the region's > internal fd. Second, it's a method which only plausibly has one > implementation which is rarely sensible. > > What this comes down to is that the guest IOMMU mechanism needs > information about host vfio groups mapped - for an optimization in > this case. > > So what would make sense to me is to put an "add_vfio_group" method > into IOMMUMemoryRegionClass (or even MemoryRegionClass). In most > cases that will be NULL (== no-op). For the spapr IOMMU region, it > will (attempt to) connect the host group to the guest liobn.
Like this? IOMMUMemoryRegionClass::add_vfio_group_kvm(int kvm_device_fd, int groupfd); It is just cleaner to keep kvm_device_fd and its ioclts() in the same place but ok. > >> --- >> include/hw/ppc/spapr.h | 15 +++++++++++++++ >> include/hw/vfio/vfio-common.h | 2 ++ >> hw/ppc/spapr_iommu.c | 10 ++++++++++ >> hw/vfio/common.c | 10 ++++++++++ >> hw/vfio/spapr.c | 39 +++++++++++++++++++++++++++++++++++++++ >> hw/vfio/trace-events | 1 + >> 6 files changed, 77 insertions(+) >> >> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h >> index 2a303a705c..c1d37e6356 100644 >> --- a/include/hw/ppc/spapr.h >> +++ b/include/hw/ppc/spapr.h >> @@ -591,6 +591,7 @@ void spapr_load_rtas(sPAPRMachineState *spapr, void >> *fdt, hwaddr addr); >> #define RTAS_EVENT_SCAN_RATE 1 >> >> typedef struct sPAPRTCETable sPAPRTCETable; >> +typedef struct sPAPRIOMMUMemoryRegionClass sPAPRIOMMUMemoryRegionClass; >> >> #define TYPE_SPAPR_TCE_TABLE "spapr-tce-table" >> #define SPAPR_TCE_TABLE(obj) \ >> @@ -599,6 +600,12 @@ typedef struct sPAPRTCETable sPAPRTCETable; >> #define TYPE_SPAPR_IOMMU_MEMORY_REGION "spapr-iommu-memory-region" >> #define SPAPR_IOMMU_MEMORY_REGION(obj) \ >> OBJECT_CHECK(IOMMUMemoryRegion, (obj), >> TYPE_SPAPR_IOMMU_MEMORY_REGION) >> +#define SPAPR_IOMMU_MEMORY_REGION_GET_CLASS(obj) \ >> + OBJECT_GET_CLASS(sPAPRIOMMUMemoryRegionClass, obj, \ >> + TYPE_SPAPR_IOMMU_MEMORY_REGION) >> +#define SPAPR_IOMMU_MEMORY_REGION_CLASS(klass) \ >> + OBJECT_CLASS_CHECK(sPAPRIOMMUMemoryRegionClass, klass, \ >> + TYPE_SPAPR_IOMMU_MEMORY_REGION) >> >> struct sPAPRTCETable { >> DeviceState parent; >> @@ -618,6 +625,14 @@ struct sPAPRTCETable { >> QLIST_ENTRY(sPAPRTCETable) list; >> }; >> >> +struct sPAPRIOMMUMemoryRegionClass { >> + /* private */ >> + IOMMUMemoryRegionClass parent_class; >> + >> + /* public */ >> + int (*get_fd)(IOMMUMemoryRegion *iommu_mr); >> +}; >> + >> sPAPRTCETable *spapr_tce_find_by_liobn(target_ulong liobn); > > To make sure I'm understanding correctly: the MR subclass here is > representing a guest-side property, yes? It means that on the guest > side the IOMMU mappings are managed by the PAPR {GET,PUT}_TCE > interface. I do not understand the question, sorry. MR is a QEMU thing, only QEMU devices use these MRs as MRs. >> struct sPAPREventLogEntry { >> diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h >> index f3a2ac9fee..d245d3cecc 100644 >> --- a/include/hw/vfio/vfio-common.h >> +++ b/include/hw/vfio/vfio-common.h >> @@ -177,6 +177,8 @@ extern const MemoryListener vfio_prereg_listener; >> int vfio_spapr_create_window(VFIOContainer *container, >> MemoryRegionSection *section, >> hwaddr *pgsize); >> +int vfio_spapr_notify_kvm(int vfio_kvm_device_fd, int groupfd, >> + IOMMUMemoryRegion *iommumr); >> int vfio_spapr_remove_window(VFIOContainer *container, >> hwaddr offset_within_address_space); >> >> diff --git a/hw/ppc/spapr_iommu.c b/hw/ppc/spapr_iommu.c >> index 307dc3021e..82fca61a75 100644 >> --- a/hw/ppc/spapr_iommu.c >> +++ b/hw/ppc/spapr_iommu.c >> @@ -171,6 +171,13 @@ static void >> spapr_tce_notify_flag_changed(IOMMUMemoryRegion *iommu, >> } >> } >> >> +static int spapr_tce_get_fd(IOMMUMemoryRegion *iommu_mr) >> +{ >> + sPAPRTCETable *tcet = container_of(iommu_mr, sPAPRTCETable, iommu); >> + >> + return tcet->fd; > > Does this have a well defined value if there's no KVM? It is -1 in TCG, any other value is undefined. > >> +} >> + >> static int spapr_tce_table_post_load(void *opaque, int version_id) >> { >> sPAPRTCETable *tcet = SPAPR_TCE_TABLE(opaque); >> @@ -631,16 +638,19 @@ static TypeInfo spapr_tce_table_info = { >> static void spapr_iommu_memory_region_class_init(ObjectClass *klass, void >> *data) >> { >> IOMMUMemoryRegionClass *imrc = IOMMU_MEMORY_REGION_CLASS(klass); >> + sPAPRIOMMUMemoryRegionClass *simrc = >> SPAPR_IOMMU_MEMORY_REGION_CLASS(klass); >> >> imrc->translate = spapr_tce_translate_iommu; >> imrc->get_min_page_size = spapr_tce_get_min_page_size; >> imrc->notify_flag_changed = spapr_tce_notify_flag_changed; >> + simrc->get_fd = spapr_tce_get_fd; >> } >> >> static const TypeInfo spapr_iommu_memory_region_info = { >> .parent = TYPE_IOMMU_MEMORY_REGION, >> .name = TYPE_SPAPR_IOMMU_MEMORY_REGION, >> .class_init = spapr_iommu_memory_region_class_init, >> + .class_size = sizeof(sPAPRIOMMUMemoryRegionClass), >> }; >> >> static void register_types(void) >> diff --git a/hw/vfio/common.c b/hw/vfio/common.c >> index 7b2924c0ef..92f1f88ae8 100644 >> --- a/hw/vfio/common.c >> +++ b/hw/vfio/common.c >> @@ -454,6 +454,16 @@ static void vfio_listener_region_add(MemoryListener >> *listener, >> goto fail; >> } >> >> +#ifdef CONFIG_KVM >> + if (kvm_enabled()) { >> + VFIOGroup *group; >> + >> + QLIST_FOREACH(group, &container->group_list, container_next) { >> + vfio_spapr_notify_kvm(vfio_kvm_device_fd, group->fd, >> + IOMMU_MEMORY_REGION(section->mr)); >> + } >> + } > > So, here you're informing the region of the groups when the region is > mapped in. But don't you similarly need to notify if a group is added > to an existing address space? It is either in VFIO for ages (forever? in vfio_connect_container()), or I did not understand the question... > And won't you also need notifications > of groups/regions being removed? Same comment. vfio_disconnect_container()? > >> +#endif >> vfio_host_win_add(container, section->offset_within_address_space, >> section->offset_within_address_space + >> int128_get64(section->size) - 1, pgsize); >> diff --git a/hw/vfio/spapr.c b/hw/vfio/spapr.c >> index 32fd6a9b54..2b9af75c03 100644 >> --- a/hw/vfio/spapr.c >> +++ b/hw/vfio/spapr.c >> @@ -15,8 +15,12 @@ >> >> #include "hw/vfio/vfio-common.h" >> #include "hw/hw.h" >> +#include "hw/ppc/spapr.h" >> #include "qemu/error-report.h" >> #include "trace.h" >> +#ifdef CONFIG_KVM >> +#include "linux/kvm.h" >> +#endif >> >> static bool vfio_prereg_listener_skipped_section(MemoryRegionSection >> *section) >> { >> @@ -188,6 +192,41 @@ int vfio_spapr_create_window(VFIOContainer *container, >> return 0; >> } >> >> +int vfio_spapr_notify_kvm(int vfio_kvm_device_fd, int groupfd, >> + IOMMUMemoryRegion *iommu_mr) >> +{ >> +#ifdef CONFIG_KVM >> + struct kvm_vfio_spapr_tce param = { >> + .groupfd = groupfd, >> + }; >> + struct kvm_device_attr attr = { >> + .group = KVM_DEV_VFIO_GROUP, >> + .attr = KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE, >> + .addr = (uint64_t)(unsigned long)¶m, >> + }; >> + IOMMUMemoryRegion *spapr_iommu_mr = SPAPR_IOMMU_MEMORY_REGION(iommu_mr); > > This will assert if you have a non-spapr guest IOMMU on a ppc host > (e.g. emulating an x86 with VT-d under TCG). Sure but this should not execute when TCG, hence "_kvm" in "vfio_spapr_notify_kvm". > >> + sPAPRIOMMUMemoryRegionClass *simrc = >> + SPAPR_IOMMU_MEMORY_REGION_GET_CLASS(spapr_iommu_mr); >> + >> + if (!simrc->get_fd) { >> + error_report("vfio: No get_fd defined for IOMMU MR"); >> + return -EFAULT; >> + } >> + >> + param.tablefd = simrc->get_fd(spapr_iommu_mr); >> + >> + if (param.tablefd != -1) { >> + if (ioctl(vfio_kvm_device_fd, KVM_SET_DEVICE_ATTR, &attr)) { >> + error_report("vfio: failed to setup fd %d for a group with fd >> %d: %s", >> + param.tablefd, param.groupfd, strerror(errno)); >> + return -errno; >> + } >> + } >> + trace_vfio_spapr_notify_kvm(groupfd, param.tablefd); >> +#endif >> + return 0; >> +} >> + >> int vfio_spapr_remove_window(VFIOContainer *container, >> hwaddr offset_within_address_space) >> { >> diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events >> index 2561c6d31a..084a92f7c2 100644 >> --- a/hw/vfio/trace-events >> +++ b/hw/vfio/trace-events >> @@ -123,3 +123,4 @@ vfio_prereg_register(uint64_t va, uint64_t size, int >> ret) "va=%"PRIx64" size=%"P >> vfio_prereg_unregister(uint64_t va, uint64_t size, int ret) "va=%"PRIx64" >> size=%"PRIx64" ret=%d" >> vfio_spapr_create_window(int ps, uint64_t ws, uint64_t off) "pageshift=0x%x >> winsize=0x%"PRIx64" offset=0x%"PRIx64 >> vfio_spapr_remove_window(uint64_t off) "offset=%"PRIx64 >> +vfio_spapr_notify_kvm(int groupfd, int tablefd) "Attached groupfd %d to >> liobn fd %d" > -- Alexey
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