From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59785) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aiFGj-0007z7-Jj for qemu-devel@nongnu.org; Tue, 22 Mar 2016 01:54:19 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aiFGh-0006Hr-B9 for qemu-devel@nongnu.org; Tue, 22 Mar 2016 01:54:17 -0400 Received: from mail-pf0-x243.google.com ([2607:f8b0:400e:c00::243]:33351) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aiFGf-0006Hf-TZ for qemu-devel@nongnu.org; Tue, 22 Mar 2016 01:54:15 -0400 Received: by mail-pf0-x243.google.com with SMTP id x3so33890878pfb.0 for ; Mon, 21 Mar 2016 22:54:13 -0700 (PDT) References: <1458546426-26222-1-git-send-email-aik@ozlabs.ru> <1458546426-26222-18-git-send-email-aik@ozlabs.ru> <20160322051449.GG23586@voom.redhat.com> From: Alexey Kardashevskiy Message-ID: <56F0DDFF.7050308@ozlabs.ru> Date: Tue, 22 Mar 2016 16:54:07 +1100 MIME-Version: 1.0 In-Reply-To: <20160322051449.GG23586@voom.redhat.com> Content-Type: text/plain; charset=koi8-r; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH qemu v14 17/18] vfio/spapr: Use VFIO_SPAPR_TCE_v2_IOMMU List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: David Gibson Cc: Alex Williamson , qemu-ppc@nongnu.org, qemu-devel@nongnu.org On 03/22/2016 04:14 PM, David Gibson wrote: > 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 >> --- >> 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.. Well, that's the minimal page size... > >> + 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. It is rather vfio_spapr_create_host_window() and we were avoiding xxx_spapr_xxx so far. I'd cut-n-paste the SPAPR PCI AS listener to a separate file but this usually triggers more discussion and never ends well. >> + 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. In what configuration/machine can we do that on SPAPR? >> + 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. Can you give an example of such RAM MR being added to PCI AS on SPAPR? >> + /* >> + * 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? You already asked this some time ago :) The userspace cannot request address, the host kernel returns one. > 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? This should not happen, this is what this check is for. Can make it assert() or something like this. > >> + 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" > -- Alexey