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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