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Re: [Qemu-ppc] [PATCH qemu v15 16/17] vfio/spapr: Use VFIO_SPAPR_TCE_v2_
From: |
David Gibson |
Subject: |
Re: [Qemu-ppc] [PATCH qemu v15 16/17] vfio/spapr: Use VFIO_SPAPR_TCE_v2_IOMMU |
Date: |
Thu, 21 Apr 2016 14:03:59 +1000 |
User-agent: |
Mutt/1.5.24 (2015-08-30) |
On Wed, Apr 20, 2016 at 07:43:41PM +1000, Alexey Kardashevskiy wrote:
> On 04/07/2016 11:10 AM, David Gibson wrote:
> >Subject doesn't seem quite right, since you added at least minimal
> >support for the SPAPRv2 IOMMU in the prereg patch.
> >
> >On Mon, Apr 04, 2016 at 07:33:45PM +1000, Alexey Kardashevskiy wrote:
> >>New VFIO_SPAPR_TCE_v2_IOMMU type supports dynamic DMA window management.
> >>This adds ability to VFIO common code to dynamically allocate/remove
> >>DMA windows in the host kernel when new VFIO container is added/removed.
> >>
> >>This adds VFIO_IOMMU_SPAPR_TCE_CREATE ioctl to vfio_listener_region_add
> >>and adds just created IOMMU into the host IOMMU list; the opposite
> >>action is taken in vfio_listener_region_del.
> >>
> >>When creating a new window, this uses euristic to decide on the TCE table
> >>levels number.
> >
> >"heuristic" has an 'h' (yes, English spelling is stupid[0]).
> >
> >[0] The historical reasons for that are kind of fascinating, though.
>
> Tried googling, could not spot quickly the reasoning, any hints what to
> google for? Or just a link with an explanation? :)
That wasn't a comment about heuristic specifically, but english
spelling in general. I got most of the fascinating stuff I've seen
from:
http://www.amazon.com/Spell-Out-Enthralling-Extraordinary-Spelling/dp/1250056128/ref=la_B000AP940C_1_5/189-2461131-2789630?s=books&ie=UTF8&qid=1461211129&sr=1-5
> >>This should cause no guest visible change in behavior.
> >>
> >>Signed-off-by: Alexey Kardashevskiy <address@hidden>
> >>---
> >>Changes:
> >>v14:
> >>* new to the series
> >>
> >>---
> >>TODO:
> >>* export levels to PHB
> >>---
> >> hw/vfio/common.c | 115
> >> ++++++++++++++++++++++++++++++++++++++++++++++++++-----
> >> trace-events | 2 +
> >> 2 files changed, 107 insertions(+), 10 deletions(-)
> >>
> >>diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> >>index 5e5b77c..57a51df 100644
> >>--- a/hw/vfio/common.c
> >>+++ b/hw/vfio/common.c
> >>@@ -279,6 +279,14 @@ static int vfio_host_win_add(VFIOContainer *container,
> >> return 0;
> >> }
> >>
> >>+static void vfio_host_win_del(VFIOContainer *container, hwaddr min_iova)
> >>+{
> >>+ VFIOHostDMAWindow *hostwin = vfio_host_win_lookup(container, min_iova,
> >>1);
> >>+
> >>+ g_assert(hostwin);
> >>+ QLIST_REMOVE(hostwin, hiommu_next);
> >>+}
> >>+
> >> static bool vfio_listener_skipped_section(MemoryRegionSection *section)
> >> {
> >> return (!memory_region_is_ram(section->mr) &&
> >>@@ -392,6 +400,63 @@ static void vfio_listener_region_add(MemoryListener
> >>*listener,
> >> }
> >> end = int128_get64(llend);
> >>
> >>+ if (container->iommu_type == VFIO_SPAPR_TCE_v2_IOMMU) {
> >
> >I think the "add region" path could do with being split out into a
> >different function - vfio_listener_region_add() is getting pretty
> >huge.
>
> It is big but not huge and I am trying to avoid having functions with
> "spapr" in their names in common.c as once they appear, we will start having
> a discussion if they should move to a separate file and if they do, then may
> be some other code should too, etc...
I don't think it needs to be a "spapr" named function. The spapr
backend is the only one to support it for now, but other iommus could
support dynamic windows in future (for example, if I ever get time to
implement the "type2" converged interface I was thinking about, I'd
look to include that).
> >>+ unsigned entries, pages, pagesize = qemu_real_host_page_size;
> >>+ struct vfio_iommu_spapr_tce_create create = { .argsz =
> >>sizeof(create) };
> >>+
> >>+ trace_vfio_listener_region_add_iommu(iova, end - 1);
> >>+ if (section->mr->iommu_ops) {
> >>+ pagesize = section->mr->iommu_ops->get_page_sizes(section->mr);
> >
> >Since you're querying the guest IOMMU here, I assume pagesize is
> >supposed to represent *guest* IOMMU pagesizes, in which case it should
> >default to TARGET_PAGE_SIZE, instead of qemu_real_host_page_size.
> >(didn't you already have a function which implemented that fallback?)
>
> Yes, will use the helper.
>
>
> >>+ }
> >>+ /*
> >>+ * FIXME: For VFIO iommu types which have KVM acceleration to
> >>+ * avoid bouncing all map/unmaps through qemu this way, this
> >>+ * would be the right place to wire that up (tell the KVM
> >>+ * device emulation the VFIO iommu handles to use).
> >>+ */
> >>+ create.window_size = int128_get64(section->size);
> >>+ create.page_shift = ctz64(pagesize);
> >>+ /*
> >>+ * SPAPR host supports multilevel TCE tables, there is some
> >>+ * euristic to decide how many levels we want for our table:
> >
> >s/some euristic/a heuristic/
> >
> >>+ * 0..64 = 1; 65..4096 = 2; 4097..262144 = 3; 262145.. = 4
> >>+ */
> >>+ entries = create.window_size >> create.page_shift;
> >>+ pages = (entries * sizeof(uint64_t)) / getpagesize();
> >>+ create.levels = ctz64(pow2ceil(pages) - 1) / 6 + 1;
> >>+
> >>+ if (vfio_host_win_lookup(container, create.start_addr,
> >>+ create.start_addr + create.window_size -
> >>1)) {
> >>+ goto fail;
> >
> >Hmm.. if you successfully look up a host window, it seems to me you
> >shouldn't fail, but in fact don't even need to create a new window
> >(the removal path gets harder though, because you need to check if any
> >guest window requires that host window).
>
>
> At the moment if the window is there, it is failure in the environment I am
> testing it in. And, having a host kernel which cannot allocate and map
> windows randomly, it is unlikely that I'll have a setup where this spot
> won't mean that something went wrong. x86 case needs lot more than this
> anyway.
Hm, I suppose so.
>
>
> >Requiring that the host windows exactly match the guest windows is
> >probably ok for a first version - except that in that case any overlap
> >should cause a failure, not just a complete inclusion.
>
> Yes, for now this should fail too, I'll fix it.
>
>
> >
> >>+ }
> >>+
> >>+ ret = ioctl(container->fd, VFIO_IOMMU_SPAPR_TCE_CREATE, &create);
> >>+ if (ret) {
> >>+ error_report("Failed to create a window, ret = %d (%m)", ret);
> >>+ goto fail;
> >>+ }
> >>+
> >>+ if (create.start_addr != section->offset_within_address_space) {
> >>+ struct vfio_iommu_spapr_tce_remove remove = {
> >>+ .argsz = sizeof(remove),
> >>+ .start_addr = create.start_addr
> >>+ };
> >>+ error_report("Host doesn't support DMA window at
> >>%"HWADDR_PRIx", must be %"PRIx64,
> >>+ section->offset_within_address_space,
> >>+ create.start_addr);
> >>+ ioctl(container->fd, VFIO_IOMMU_SPAPR_TCE_REMOVE, &remove);
> >>+ ret = -EINVAL;
> >>+ goto fail;
> >>+ }
> >>+ trace_vfio_spapr_create_window(create.page_shift,
> >>+ create.window_size,
> >>+ create.start_addr);
> >>+
> >>+ vfio_host_win_add(container, create.start_addr,
> >>+ create.start_addr + create.window_size - 1,
> >>+ 1ULL << create.page_shift);
> >>+ }
> >>+
> >> if (!vfio_host_win_lookup(container, iova, end - 1)) {
> >> error_report("vfio: IOMMU container %p can't map guest IOVA
> >> region"
> >> " 0x%"HWADDR_PRIx"..0x%"HWADDR_PRIx,
> >>@@ -525,6 +590,22 @@ static void vfio_listener_region_del(MemoryListener
> >>*listener,
> >> container, iova, end - iova, ret);
> >> }
> >>
> >>+ if (container->iommu_type == VFIO_SPAPR_TCE_v2_IOMMU) {
> >>+ struct vfio_iommu_spapr_tce_remove remove = {
> >>+ .argsz = sizeof(remove),
> >>+ .start_addr = section->offset_within_address_space,
> >>+ };
> >>+ ret = ioctl(container->fd, VFIO_IOMMU_SPAPR_TCE_REMOVE, &remove);
> >>+ if (ret) {
> >>+ error_report("Failed to remove window at %"PRIx64,
> >>+ remove.start_addr);
> >>+ }
> >>+
> >>+ vfio_host_win_del(container, section->offset_within_address_space);
> >>+
> >>+ trace_vfio_spapr_remove_window(remove.start_addr);
> >>+ }
> >>+
> >> if (iommu && iommu->iommu_ops && iommu->iommu_ops->vfio_stop) {
> >> iommu->iommu_ops->vfio_stop(section->mr);
> >> }
> >>@@ -915,11 +996,6 @@ static int vfio_connect_container(VFIOGroup *group,
> >>AddressSpace *as)
> >> }
> >> }
> >>
> >>- /*
> >>- * This only considers the host IOMMU's 32-bit window. At
> >>- * some point we need to add support for the optional 64-bit
> >>- * window and dynamic windows
> >>- */
> >> info.argsz = sizeof(info);
> >> ret = ioctl(fd, VFIO_IOMMU_SPAPR_TCE_GET_INFO, &info);
> >> if (ret) {
> >>@@ -928,11 +1004,30 @@ static int vfio_connect_container(VFIOGroup *group,
> >>AddressSpace *as)
> >> goto listener_release_exit;
> >> }
> >>
> >>- /* The default table uses 4K pages */
> >>- vfio_host_win_add(container, info.dma32_window_start,
> >>- info.dma32_window_start +
> >>- info.dma32_window_size - 1,
> >>- 0x1000);
> >>+ if (v2) {
> >>+ /*
> >>+ * There is a default window in just created container.
> >>+ * To make region_add/del simpler, we better remove this
> >>+ * window now and let those iommu_listener callbacks
> >>+ * create/remove them when needed.
> >>+ */
> >>+ struct vfio_iommu_spapr_tce_remove remove = {
> >>+ .argsz = sizeof(remove),
> >>+ .start_addr = info.dma32_window_start,
> >>+ };
> >>+ ret = ioctl(fd, VFIO_IOMMU_SPAPR_TCE_REMOVE, &remove);
> >>+ if (ret) {
> >>+ error_report("vfio: VFIO_IOMMU_SPAPR_TCE_REMOVE failed:
> >>%m");
> >>+ ret = -errno;
> >>+ goto free_container_exit;
> >>+ }
> >>+ } else {
> >>+ /* The default table uses 4K pages */
> >>+ vfio_host_win_add(container, info.dma32_window_start,
> >>+ info.dma32_window_start +
> >>+ info.dma32_window_size - 1,
> >>+ 0x1000);
> >>+ }
> >> } else {
> >> error_report("vfio: No available IOMMU models");
> >> ret = -EINVAL;
> >>diff --git a/trace-events b/trace-events
> >>index 23ca0b9..5c651fa 100644
> >>--- a/trace-events
> >>+++ b/trace-events
> >>@@ -1738,6 +1738,8 @@ vfio_region_finalize(const char *name, int index)
> >>"Device %s, region %d"
> >> vfio_region_mmaps_set_enabled(const char *name, bool enabled) "Region %s
> >> mmaps enabled: %d"
> >> vfio_ram_register(uint64_t va, uint64_t size, int ret) "va=%"PRIx64"
> >> size=%"PRIx64" ret=%d"
> >> vfio_ram_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
> >>
> >> # hw/vfio/platform.c
> >> vfio_platform_base_device_init(char *name, int groupid) "%s belongs to
> >> group #%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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- [Qemu-ppc] [PATCH qemu v15 13/17] vfio: Add host side DMA window capabilities, (continued)
- [Qemu-ppc] [PATCH qemu v15 13/17] vfio: Add host side DMA window capabilities, Alexey Kardashevskiy, 2016/04/04
- [Qemu-ppc] [PATCH qemu v15 14/17] spapr_iommu, vfio, memory: Notify IOMMU about starting/stopping being used by VFIO, Alexey Kardashevskiy, 2016/04/04
- Re: [Qemu-ppc] [PATCH qemu v15 14/17] spapr_iommu, vfio, memory: Notify IOMMU about starting/stopping being used by VFIO, David Gibson, 2016/04/06
- Re: [Qemu-ppc] [PATCH qemu v15 14/17] spapr_iommu, vfio, memory: Notify IOMMU about starting/stopping being used by VFIO, Alexey Kardashevskiy, 2016/04/20
- Re: [Qemu-ppc] [PATCH qemu v15 14/17] spapr_iommu, vfio, memory: Notify IOMMU about starting/stopping being used by VFIO, David Gibson, 2016/04/21
- Re: [Qemu-ppc] [PATCH qemu v15 14/17] spapr_iommu, vfio, memory: Notify IOMMU about starting/stopping being used by VFIO, Alexey Kardashevskiy, 2016/04/21
[Qemu-ppc] [PATCH qemu v15 16/17] vfio/spapr: Use VFIO_SPAPR_TCE_v2_IOMMU, Alexey Kardashevskiy, 2016/04/04
[Qemu-ppc] [PATCH qemu v15 08/17] spapr_iommu: Add root memory region, Alexey Kardashevskiy, 2016/04/04
[Qemu-ppc] [PATCH qemu v15 17/17] spapr_pci/spapr_pci_vfio: Support Dynamic DMA Windows (DDW), Alexey Kardashevskiy, 2016/04/04