On Mon, 16 May 2016 14:52:41 +1000
Alexey Kardashevskiy <a...@ozlabs.ru> wrote:
> On 05/14/2016 08:26 AM, Alex Williamson wrote:
> > On Wed, 4 May 2016 16:52:30 +1000
> > Alexey Kardashevskiy <a...@ozlabs.ru> 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 heuristic to decide on the TCE table
> >> levels number.
> >>
> >> This should cause no guest visible change in behavior.
> >>
> >> Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru>
> >> ---
> >> Changes:
> >> v16:
> >> * used memory_region_iommu_get_page_sizes() in vfio_listener_region_add()
> >> * enforced no intersections between windows
> >>
> >> v14:
> >> * new to the series
> >> ---
> >> hw/vfio/common.c | 133
> >> ++++++++++++++++++++++++++++++++++++++++++++++++++-----
> >> trace-events | 2 +
> >> 2 files changed, 125 insertions(+), 10 deletions(-)
> >>
> >> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> >> index 03daf88..bd2dee8 100644
> >> --- a/hw/vfio/common.c
> >> +++ b/hw/vfio/common.c
> >> @@ -240,6 +240,18 @@ static int vfio_dma_map(VFIOContainer *container,
> >> hwaddr iova,
> >> return -errno;
> >> }
> >>
> >> +static bool range_contains(hwaddr start, hwaddr end, hwaddr addr)
> >> +{
> >> + return start <= addr && addr <= end;
> >> +}
> >
> > a) If you want a "range_foo" function then put it in range.h
> > b) I suspect there are already range.h functions that can do this.
> >
> >> +
> >> +static bool vfio_host_win_intersects(VFIOHostDMAWindow *hostwin,
> >> + hwaddr min_iova, hwaddr max_iova)
> >> +{
> >> + return range_contains(hostwin->min_iova, hostwin->min_iova, min_iova)
> >> ||
> >> + range_contains(min_iova, max_iova, hostwin->min_iova);
> >> +}
> >
> > How is this different than ranges_overlap()?
> >> +
> >> static VFIOHostDMAWindow *vfio_host_win_lookup(VFIOContainer *container,
> >> hwaddr min_iova, hwaddr
> >> max_iova)
> >> {
> >> @@ -279,6 +291,14 @@ 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);
> >
> > Handle the error please.
>
> Will this be enough?
>
> if (!hostwin) {
> error_report("%s: Cannot delete missing window at %"HWADDR_PRIx,
> __func__, min_iova);
> return;
> }
Better. I was really thinking to return error to the caller, but if
the caller has no return path, perhaps this is as good as we can do.
Expect that I will push back on any assert() calls added to vfio.
> >> + QLIST_REMOVE(hostwin, hostwin_next);
> >> +}
> >> +
> >> static bool vfio_listener_skipped_section(MemoryRegionSection *section)
> >> {
> >> return (!memory_region_is_ram(section->mr) &&
> >> @@ -392,6 +412,69 @@ static void vfio_listener_region_add(MemoryListener
> >> *listener,
> >> }
> >> end = int128_get64(int128_sub(llend, int128_one()));
> >>
> >> + if (container->iommu_type == VFIO_SPAPR_TCE_v2_IOMMU) {
> >> + VFIOHostDMAWindow *hostwin;
> >> + unsigned pagesizes =
> >> memory_region_iommu_get_page_sizes(section->mr);
> >> + unsigned pagesize = (hwaddr)1 << ctz64(pagesizes);
> >> + unsigned entries, pages;
> >> + struct vfio_iommu_spapr_tce_create create = { .argsz =
> >> sizeof(create) };
> >> +
> >> + trace_vfio_listener_region_add_iommu(iova, end);
> >> + /*
> >> + * 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
> >> + * heuristic 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 = MAX((entries * sizeof(uint64_t)) / getpagesize(), 1);
> >> + pages = MAX(pow2ceil(pages) - 1, 1); /* Round up */
> >> + create.levels = ctz64(pages) / 6 + 1;
> >> +
> >> + /* For now intersections are not allowed, we may relax this later
> >> */
> >> + QLIST_FOREACH(hostwin, &container->hostwin_list, hostwin_next) {
> >> + if (vfio_host_win_intersects(hostwin,
> >> + section->offset_within_address_space,
> >> + section->offset_within_address_space +
> >> + create.window_size - 1)) {
> >> + goto fail;
> >> + }
> >> + }
> >> +
> >> + 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);
> >> + }
> >
> > This is a function on its own, split it out and why not stop pretending
> > prereg is some sort of generic interface and let's just make a spapr
> > support file.
>
>
> Yet another new file - spapr.c, or rename prereg.c to spapr.c and add this
> stuff there?
prereg.c is already spapr specific, so I'd rename it and potentially
add this to it.
> Also, what bits? I'd keep VFIOHostDMAWindow business in here and moved
> vfio_iommu_spapr_tce_create and ioctl to the new place, will this be ok?
> Thanks.
VFIOHostDMAWindow is actually generic, so keeping it here makes sense.
> >> +
> >> if (!vfio_host_win_lookup(container, iova, end)) {
> >> error_report("vfio: IOMMU container %p can't map guest IOVA
> >> region"
> >> " 0x%"HWADDR_PRIx"..0x%"HWADDR_PRIx,
> >> @@ -566,6 +649,22 @@ static void vfio_listener_region_del(MemoryListener
> >> *listener,
> >> container, iova, int128_get64(llsize), 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);
> >> + }
> >
> > This would be in that spapr file too.
> >
> >> +
> >> if (iommu && iommu->iommu_ops && iommu->iommu_ops->vfio_stop) {
> >> iommu->iommu_ops->vfio_stop(section->mr);
> >> }
> >> @@ -957,11 +1056,6 @@ 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) {
> >> @@ -970,11 +1064,30 @@ 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 d0d8615..b5419de 100644
> >> --- a/trace-events
> >> +++ b/trace-events
> >> @@ -1739,6 +1739,8 @@ 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"
> >
>
>
