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.
> ---
> 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.
> 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?
> +}
> +
> 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? And won't you also need notifications
of groups/regions being removed?
> +#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).
> + 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"
--
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
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