On Wed, Apr 22, 2015 at 07:38:27PM +1000, Alexey Kardashevskiy wrote: > On 04/22/2015 03:53 PM, David Gibson wrote: > >On Sat, Apr 11, 2015 at 01:24:36AM +1000, Alexey Kardashevskiy wrote: > >>This makes use of the new "memory registering" feature. The idea is > >>to provide the userspace ability to notify the host kernel about pages > >>which are going to be used for DMA. Having this information, the host > >>kernel can pin them all once per user process, do locked pages > >>accounting (once) and not spent time on doing that in real time with > >>possible failures which cannot be handled nicely in some cases. > >> > >>This adds a guest RAM memory listener which notifies a VFIO container > >>about memory which needs to be pinned/unpinned. VFIO MMIO regions > >>(i.e. "skip dump" regions) are skipped. > >> > >>The feature is only enabled for SPAPR IOMMU v2. The host kernel changes > >>are required. Since v2 does not need/support VFIO_IOMMU_ENABLE, this does > >>not call it when v2 is detected and enabled. > >> > >>This does not change the guest visible interface. > >> > >>Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru> > > > >Reviewed-by: David Gibson <da...@gibson.dropbear.id.au> > > > >Albeit with some nits described below.
[snip]
> >>+ vfio_ram_do_region(container, section,
> >>VFIO_IOMMU_SPAPR_UNREGISTER_MEMORY);
> >>+}
> >>+
> >>+static const MemoryListener vfio_spapr_ram_memory_listener = {
> >>+ .region_add = vfio_spapr_ram_listener_region_add,
> >>+ .region_del = vfio_spapr_ram_listener_region_del,
> >>+};
> >>+
> >> static void vfio_spapr_listener_release(VFIOContainer *container)
> >> {
> >> memory_listener_unregister(&container->iommu_data.spapr.listener);
> >> }
> >>
> >>-void spapr_memory_listener_register(VFIOContainer *container)
> >>+static void vfio_spapr_listener_release_v2(VFIOContainer *container)
> >>+{
> >>+ memory_listener_unregister(&container->iommu_data.spapr.listener);
> >>+ vfio_spapr_listener_release(container);
> >>+}
> >>+
> >>+int spapr_memory_listener_register(VFIOContainer *container, int ver)
> >> {
> >> container->iommu_data.spapr.listener = vfio_spapr_memory_listener;
> >> container->iommu_data.release = vfio_spapr_listener_release;
> >>-
> >> memory_listener_register(&container->iommu_data.spapr.listener,
> >> container->space->as);
> >>+ if (ver < 2) {
> >>+ return 0;
> >>+ }
> >
> >I wonder if it would make sense to store the IOMMU type value into the
> >VFIOContainer (from non-arch specific code). It would avoid the
> >ad-hoc passing of version here and also allow for some sanity checks.
>
>
> What kind of checks? Cannot think of any which would make sense to do here
> and not in spapr_(pci|rtas)*.c
Well, all I was thinking of was something like
assert(container->iommu_type == SPAPR_TCE_TYPE);
In spapr (or x86) callbacks from the core vfio code to make sure we
haven't somehow gotten here with a Type1 container.
> >>+
> >>+ container->iommu_data.spapr.ramlistener =
> >>vfio_spapr_ram_memory_listener;
> >>+ container->iommu_data.release = vfio_spapr_listener_release_v2;
> >>+ memory_listener_register(&container->iommu_data.spapr.ramlistener,
> >>+ &address_space_memory);
> >>+
> >>+ container->iommu_data.spapr.ram_reg_initialized = true;
> >>+
> >>+ return container->iommu_data.spapr.ram_reg_error;
> >> }
> >>diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
> >>index d0b831c..b5ef446 100644
> >>--- a/include/hw/vfio/vfio-common.h
> >>+++ b/include/hw/vfio/vfio-common.h
> >>@@ -71,6 +71,9 @@ typedef struct VFIOType1 {
> >>
> >> typedef struct VFIOSPAPR {
> >> MemoryListener listener;
> >>+ MemoryListener ramlistener;
> >
> >The names "listener" and "ramlistener" don't exactly give a clear hint
> >as to what the difference between them is. Maybe "register_listener"
> >for the new one since its purpose is to register dma memory.
>
>
> It is listening for RAM changes. If/when we decide to add something else to
> this listener, we won't have to change its name :) Still change?
Ah, I see. I was forgetting that the other listener wasn't really
about RAM (I think an understandable error for a *Memory*Listener).
But actually I'm having trouble thinking of names that are clearly
better than the current ones. So, I guess I don't really care.
>
>
> >I forget
> >what the purpose of the old one is, and so what a better name for it
> >might be.
>
> It is listening on PHB address space for IOMMU table updates and translates
> those to MAP/UNMAP ioctls to VFIO containers.
>
>
>
> >
> >>+ int ram_reg_error;
> >>+ bool ram_reg_initialized;
> >> } VFIOSPAPR;
> >>
> >> typedef struct VFIOContainer {
> >>@@ -156,6 +159,6 @@ extern int vfio_dma_unmap(VFIOContainer *container,
> >> hwaddr iova, ram_addr_t size);
> >> bool vfio_listener_skipped_section(MemoryRegionSection *section);
> >>
> >>-extern void spapr_memory_listener_register(VFIOContainer *container);
> >>+extern int spapr_memory_listener_register(VFIOContainer *container, int
> >>ver);
> >>
> >> #endif /* !HW_VFIO_VFIO_COMMON_H */
> >>diff --git a/trace-events b/trace-events
> >>index 1231ba4..2739140 100644
> >>--- a/trace-events
> >>+++ b/trace-events
> >>@@ -1563,6 +1563,7 @@ vfio_disconnect_container(int fd) "close
> >>container->fd=%d"
> >> vfio_put_group(int fd) "close group->fd=%d"
> >> vfio_get_device(const char * name, unsigned int flags, unsigned int
> >> num_regions, unsigned int num_irqs) "Device %s flags: %u, regions: %u,
> >> irqs: %u"
> >> vfio_put_base_device(int fd) "close vdev->fd=%d"
> >>+vfio_ram_register(int req, uint64_t va, uint64_t size, int ret) "req=%d
> >>va=%"PRIx64" size=%"PRIx64" ret=%d"
> >>
> >> #hw/acpi/memory_hotplug.c
> >> mhp_acpi_invalid_slot_selected(uint32_t slot) "0x%"PRIx32
> >
>
>
--
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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