On 28/08/17 14:20, Alexey Kardashevskiy wrote: > 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>
Ping?
>>> ---
>>>
>>> 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".
>
--
Alexey
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