From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36058) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1asofo-00086E-27 for qemu-devel@nongnu.org; Wed, 20 Apr 2016 05:43:53 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1asofj-0003le-SE for qemu-devel@nongnu.org; Wed, 20 Apr 2016 05:43:52 -0400 Received: from mail-pf0-x22f.google.com ([2607:f8b0:400e:c00::22f]:36265) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1asofj-0003lD-BV for qemu-devel@nongnu.org; Wed, 20 Apr 2016 05:43:47 -0400 Received: by mail-pf0-x22f.google.com with SMTP id e128so16578715pfe.3 for ; Wed, 20 Apr 2016 02:43:47 -0700 (PDT) References: <1459762426-18440-1-git-send-email-aik@ozlabs.ru> <1459762426-18440-17-git-send-email-aik@ozlabs.ru> <20160407011024.GG16485@voom.fritz.box> From: Alexey Kardashevskiy Message-ID: <57174F4D.9010003@ozlabs.ru> Date: Wed, 20 Apr 2016 19:43:41 +1000 MIME-Version: 1.0 In-Reply-To: <20160407011024.GG16485@voom.fritz.box> Content-Type: text/plain; charset=koi8-r; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH qemu v15 16/17] vfio/spapr: Use VFIO_SPAPR_TCE_v2_IOMMU List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: David Gibson Cc: qemu-devel@nongnu.org, qemu-ppc@nongnu.org, Alex Williamson , Alexander Graf 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? :) > >> This should cause no guest visible change in behavior. >> >> Signed-off-by: Alexey Kardashevskiy >> --- >> 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... > >> + 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. > 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" > -- Alexey