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Re: [Qemu-devel] [PATCH qemu v14 17/18] vfio/spapr: Use VFIO_SPAPR_TCE_v
From: |
David Gibson |
Subject: |
Re: [Qemu-devel] [PATCH qemu v14 17/18] vfio/spapr: Use VFIO_SPAPR_TCE_v2_IOMMU |
Date: |
Tue, 22 Mar 2016 16:14:49 +1100 |
User-agent: |
Mutt/1.5.24 (2015-08-30) |
On Mon, Mar 21, 2016 at 06:47:05PM +1100, 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.
>
> 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 | 108
> ++++++++++++++++++++++++++++++++++++++++++++++++++++---
> trace-events | 2 ++
> 2 files changed, 105 insertions(+), 5 deletions(-)
>
> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> index 4e873b7..421d6eb 100644
> --- a/hw/vfio/common.c
> +++ b/hw/vfio/common.c
> @@ -279,6 +279,14 @@ static int vfio_host_iommu_add(VFIOContainer *container,
> return 0;
> }
>
> +static void vfio_host_iommu_del(VFIOContainer *container, hwaddr min_iova)
> +{
> + VFIOHostIOMMU *hiommu = vfio_host_iommu_lookup(container, min_iova,
> 0x1000);
The hard-coded 0x1000 looks dubious..
> + g_assert(hiommu);
> + QLIST_REMOVE(hiommu, hiommu_next);
> +}
> +
> static bool vfio_listener_skipped_section(MemoryRegionSection *section)
> {
> return (!memory_region_is_ram(section->mr) &&
> @@ -392,6 +400,61 @@ static void vfio_listener_region_add(MemoryListener
> *listener,
> }
> end = int128_get64(llend);
>
> + if (container->iommu_type == VFIO_SPAPR_TCE_v2_IOMMU) {
I think this would be clearer split out into a helper function,
vfio_create_host_window() or something.
> + unsigned entries, pages;
> + struct vfio_iommu_spapr_tce_create create = { .argsz =
> sizeof(create) };
> +
> + g_assert(section->mr->iommu_ops);
> + g_assert(memory_region_is_iommu(section->mr));
I don't think you need these asserts. AFAICT the same logic should
work if a RAM MR was added directly to PCI address space - this would
create the new host window, then the existing code for adding a RAM MR
would map that block of RAM statically into the new window.
> + trace_vfio_listener_region_add_iommu(iova, end - 1);
> + /*
> + * 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 = memory_region_size(section->mr);
> + create.page_shift =
> + ctz64(section->mr->iommu_ops->get_page_sizes(section->mr));
Ah.. except that I guess you'd need to fall back to host page size
here to handle a RAM MR.
> + /*
> + * SPAPR host supports multilevel TCE tables, there is some
> + * euristic to decide how many levels we want for our table:
> + * 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;
> +
> + 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 ||
> + vfio_host_iommu_lookup(container, create.start_addr,
> + create.start_addr + create.window_size -
> 1)) {
Under what circumstances can this trigger? Is the kernel ioctl
allowed to return a different window start address than the one
requested?
The second check looks very strange - if it returns true doesn't that
mean you *do* have host window which can accomodate this guest region,
which is what you want?
> + 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_iommu_add(container, create.start_addr,
> + create.start_addr + create.window_size - 1,
> + 1ULL << create.page_shift);
> + }
> +
> if (!vfio_host_iommu_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 +588,22 @@ 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_iommu_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);
> }
> @@ -928,11 +1007,30 @@ static int vfio_connect_container(VFIOGroup *group,
> AddressSpace *as)
> goto listener_release_exit;
> }
>
> - /* The default table uses 4K pages */
> - vfio_host_iommu_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_iommu_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 cc619e1..f2b75a3 100644
> --- a/trace-events
> +++ b/trace-events
> @@ -1736,6 +1736,8 @@ 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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- Re: [Qemu-devel] [PATCH qemu v14 03/18] spapr_pci: Move DMA window enablement to a helper, (continued)
[Qemu-devel] [PATCH qemu v14 08/18] spapr_iommu: Migrate full state, Alexey Kardashevskiy, 2016/03/21
[Qemu-devel] [PATCH qemu v14 14/18] spapr_pci: Add and export DMA resetting helper, Alexey Kardashevskiy, 2016/03/21
[Qemu-devel] [PATCH qemu v14 15/18] vfio: Add host side IOMMU capabilities, Alexey Kardashevskiy, 2016/03/21
[Qemu-devel] [PATCH qemu v14 17/18] vfio/spapr: Use VFIO_SPAPR_TCE_v2_IOMMU, Alexey Kardashevskiy, 2016/03/21
- Re: [Qemu-devel] [PATCH qemu v14 17/18] vfio/spapr: Use VFIO_SPAPR_TCE_v2_IOMMU,
David Gibson <=
- Re: [Qemu-devel] [PATCH qemu v14 17/18] vfio/spapr: Use VFIO_SPAPR_TCE_v2_IOMMU, Alexey Kardashevskiy, 2016/03/22
- Re: [Qemu-devel] [PATCH qemu v14 17/18] vfio/spapr: Use VFIO_SPAPR_TCE_v2_IOMMU, David Gibson, 2016/03/22
- Re: [Qemu-devel] [PATCH qemu v14 17/18] vfio/spapr: Use VFIO_SPAPR_TCE_v2_IOMMU, Alexey Kardashevskiy, 2016/03/22
- Re: [Qemu-devel] [PATCH qemu v14 17/18] vfio/spapr: Use VFIO_SPAPR_TCE_v2_IOMMU, David Gibson, 2016/03/22
- Re: [Qemu-devel] [PATCH qemu v14 17/18] vfio/spapr: Use VFIO_SPAPR_TCE_v2_IOMMU, Alexey Kardashevskiy, 2016/03/22
- Re: [Qemu-devel] [PATCH qemu v14 17/18] vfio/spapr: Use VFIO_SPAPR_TCE_v2_IOMMU, David Gibson, 2016/03/23
- Re: [Qemu-devel] [PATCH qemu v14 17/18] vfio/spapr: Use VFIO_SPAPR_TCE_v2_IOMMU, Alexey Kardashevskiy, 2016/03/23
- Re: [Qemu-devel] [PATCH qemu v14 17/18] vfio/spapr: Use VFIO_SPAPR_TCE_v2_IOMMU, Alexey Kardashevskiy, 2016/03/24
- Re: [Qemu-devel] [PATCH qemu v14 17/18] vfio/spapr: Use VFIO_SPAPR_TCE_v2_IOMMU, David Gibson, 2016/03/29
- Re: [Qemu-devel] [PATCH qemu v14 17/18] vfio/spapr: Use VFIO_SPAPR_TCE_v2_IOMMU, Alexey Kardashevskiy, 2016/03/29