From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E0D40C5519F for ; Wed, 18 Nov 2020 11:41:14 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7101E2225B for ; Wed, 18 Nov 2020 11:41:14 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7101E2225B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id A570C6E3F7; Wed, 18 Nov 2020 11:41:13 +0000 (UTC) Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by gabe.freedesktop.org (Postfix) with ESMTPS id 394A86E3F7 for ; Wed, 18 Nov 2020 11:41:12 +0000 (UTC) IronPort-SDR: xWsae5LGdI6nTmHWi/U3cC29L+xoxkOYV2h5oWPd4djIy8WYOSOUHwqYQBVxbIwR+pXeeoSBCI c6rPahIsOr5w== X-IronPort-AV: E=McAfee;i="6000,8403,9808"; a="171199396" X-IronPort-AV: E=Sophos;i="5.77,486,1596524400"; d="scan'208";a="171199396" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Nov 2020 03:41:11 -0800 IronPort-SDR: lNrPFYt/iHCYT4A9oX8IWtw+Oga978/eAnhLmcOhnWw1NbNPhrwaLJvJBr+WOa5BmNkiHnKz3t A9og1kXALiHw== X-IronPort-AV: E=Sophos;i="5.77,486,1596524400"; d="scan'208";a="476311634" Received: from smcintyr-mobl1.ger.corp.intel.com (HELO localhost) ([10.252.19.232]) by orsmga004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Nov 2020 03:41:09 -0800 MIME-Version: 1.0 In-Reply-To: <20201117110132.22267-8-chris@chris-wilson.co.uk> References: <20201117110132.22267-1-chris@chris-wilson.co.uk> <20201117110132.22267-8-chris@chris-wilson.co.uk> From: Joonas Lahtinen To: Chris Wilson , intel-gfx@lists.freedesktop.org, Umesh Nerlige Ramappa , Lionel Landwerlin Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Message-ID: <160569966633.4294.16743669061444949073@jlahtine-mobl.ger.corp.intel.com> User-Agent: alot/0.8.1 Date: Wed, 18 Nov 2020 13:41:06 +0200 Subject: Re: [Intel-gfx] [PATCH 8/8] drm/i915/perf: Map OA buffer to user space for gen12 performance query X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Piotr Maciejewski , Chris Wilson Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" + Umesh, Lionel Do we have a link to the userspace changes and IGT tests? Those are absolutely needed before we can do a final review and merge. We should really test and review the kernel and userspace changes together to make sure that we're coming up with a solid uAPI. Regards, Joonas Quoting Chris Wilson (2020-11-17 13:01:32) > From: Umesh Nerlige Ramappa > > i915 used to support time based sampling mode which is good for overall > system monitoring, but is not enough for query mode used to measure a > single draw call or dispatch. Gen9-Gen11 are using current i915 perf > implementation for query, but Gen12+ requires a new approach for query > based on triggered reports within oa buffer. > > Triggering reports into the OA buffer is achieved by writing into a > a trigger register. Optionally an unused counter/register is set with a > marker value such that a triggered report can be identified in the OA > buffer. Reports are usually triggered at the start and end of work that > is measured. > > Since OA buffer is large and queries can be frequent, an efficient way > to look for triggered reports is required. By knowing the current head > and tail offsets into the OA buffer, it is easier to determine the > locality of the reports of interest. > > Current perf OA interface does not expose head/tail information to the > user and it filters out invalid reports before sending data to user. > Also considering limited size of user buffer used during a query, > creating a 1:1 copy of the OA buffer at the user space added undesired > complexity. > > The solution was to map the OA buffer to user space provided > > (1) that it is accessed from a privileged user. > (2) OA report filtering is not used. > > These 2 conditions would satisfy the safety criteria that the current > perf interface addresses. > > To enable the query: > - Add an ioctl to expose head and tail to the user > - Add an ioctl to return size and offset of the OA buffer > - Map the OA buffer to the user space > > v2: > - Improve commit message (Chris) > - Do not mmap based on gem object filp. Instead, use perf_fd and support > mmap syscall (Chris) > - Pass non-zero offset in mmap to enforce the right object is > mapped (Chris) > - Do not expose gpu_address (Chris) > - Verify start and length of vma for page alignment (Lionel) > - Move SQNTL config out (Lionel) > > v3: (Chris) > - Omit redundant checks > - Return VM_FAULT_SIGBUS is old stream is closed > - Maintain reference counts to stream in vm_open and vm_close > - Use switch to identify object to be mapped > > v4: Call kref_put on closing perf fd (Chris) > v5: > - Strip access to OA buffer from unprivileged child of a privileged > parent. Use VM_DONTCOPY > - Enforce MAP_PRIVATE by checking for VM_MAYSHARE > > v6: > (Chris) > - Use len of -1 in unmap_mapping_range > - Don't use stream->oa_buffer.vma->obj in vm_fault_oa > - Use kernel block comment style > - do_mmap gets a reference to the file and puts it in do_munmap, so > no need to maintain a reference to i915_perf_stream. Hence, remove > vm_open/vm_close and stream->closed hooks/checks. > (Umesh) > - Do not allow mmap if SAMPLE_OA_REPORT is not set during > i915_perf_open_ioctl. > - Drop ioctl returning head/tail since this information is already > whitelisted. Remove hooks to read head register. > > v7: (Chris) > - unmap before destroy > - change ioctl argument struct > > v8: Documentation and more checks (Chris) > > Signed-off-by: Piotr Maciejewski > Signed-off-by: Umesh Nerlige Ramappa > Reviewed-by: Chris Wilson > --- > drivers/gpu/drm/i915/gem/i915_gem_mman.c | 2 +- > drivers/gpu/drm/i915/gem/i915_gem_mman.h | 2 + > drivers/gpu/drm/i915/i915_perf.c | 126 ++++++++++++++++++++++- > include/uapi/drm/i915_drm.h | 33 ++++++ > 4 files changed, 161 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/i915_gem_mman.c > index 3d69e51f3e4d..2ab08b152b9d 100644 > --- a/drivers/gpu/drm/i915/gem/i915_gem_mman.c > +++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.c > @@ -204,7 +204,7 @@ compute_partial_view(const struct drm_i915_gem_object *obj, > return view; > } > > -static vm_fault_t i915_error_to_vmf_fault(int err) > +vm_fault_t i915_error_to_vmf_fault(int err) > { > switch (err) { > default: > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.h b/drivers/gpu/drm/i915/gem/i915_gem_mman.h > index efee9e0d2508..1190a3a228ea 100644 > --- a/drivers/gpu/drm/i915/gem/i915_gem_mman.h > +++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.h > @@ -29,4 +29,6 @@ void i915_gem_object_release_mmap_gtt(struct drm_i915_gem_object *obj); > > void i915_gem_object_release_mmap_offset(struct drm_i915_gem_object *obj); > > +vm_fault_t i915_error_to_vmf_fault(int err); > + > #endif > diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c > index c91f2da84189..6fd669b520d8 100644 > --- a/drivers/gpu/drm/i915/i915_perf.c > +++ b/drivers/gpu/drm/i915/i915_perf.c > @@ -192,10 +192,12 @@ > */ > > #include > +#include > #include > #include > > #include "gem/i915_gem_context.h" > +#include "gem/i915_gem_mman.h" > #include "gt/intel_engine_pm.h" > #include "gt/intel_engine_user.h" > #include "gt/intel_gt.h" > @@ -3291,6 +3293,44 @@ static long i915_perf_config_locked(struct i915_perf_stream *stream, > return ret; > } > > +#define I915_PERF_OA_BUFFER_MMAP_OFFSET 1 > + > +/** > + * i915_perf_oa_buffer_info_locked - size and offset of the OA buffer > + * @stream: i915 perf stream > + * @cmd: ioctl command > + * @arg: pointer to oa buffer info filled by this function. > + */ > +static int i915_perf_oa_buffer_info_locked(struct i915_perf_stream *stream, > + unsigned int cmd, > + unsigned long arg) > +{ > + struct drm_i915_perf_oa_buffer_info info; > + void __user *output = (void __user *)arg; > + > + if (i915_perf_stream_paranoid && !perfmon_capable()) { > + DRM_DEBUG("Insufficient privileges to access OA buffer info\n"); > + return -EACCES; > + } > + > + if (_IOC_SIZE(cmd) != sizeof(info)) > + return -EINVAL; > + > + if (copy_from_user(&info, output, sizeof(info))) > + return -EFAULT; > + > + if (info.type || info.flags || info.rsvd) > + return -EINVAL; > + > + info.size = stream->oa_buffer.vma->size; > + info.offset = I915_PERF_OA_BUFFER_MMAP_OFFSET * PAGE_SIZE; > + > + if (copy_to_user(output, &info, sizeof(info))) > + return -EFAULT; > + > + return 0; > +} > + > /** > * i915_perf_ioctl_locked - support ioctl() usage with i915 perf stream FDs > * @stream: An i915 perf stream > @@ -3316,6 +3356,8 @@ static long i915_perf_ioctl_locked(struct i915_perf_stream *stream, > return 0; > case I915_PERF_IOCTL_CONFIG: > return i915_perf_config_locked(stream, arg); > + case I915_PERF_IOCTL_GET_OA_BUFFER_INFO: > + return i915_perf_oa_buffer_info_locked(stream, cmd, arg); > } > > return -EINVAL; > @@ -3387,6 +3429,14 @@ static int i915_perf_release(struct inode *inode, struct file *file) > struct i915_perf_stream *stream = file->private_data; > struct i915_perf *perf = stream->perf; > > + /* > + * User could have multiple vmas from multiple mmaps. We want to zap > + * them all here. Note that a fresh fault cannot occur as the mmap holds > + * a reference to the stream via the vma->vm_file, so before user's > + * munmap, the stream cannot be destroyed. > + */ > + unmap_mapping_range(file->f_mapping, 0, -1, 1); > + > mutex_lock(&perf->lock); > i915_perf_destroy_locked(stream); > mutex_unlock(&perf->lock); > @@ -3397,6 +3447,75 @@ static int i915_perf_release(struct inode *inode, struct file *file) > return 0; > } > > +static vm_fault_t vm_fault_oa(struct vm_fault *vmf) > +{ > + struct vm_area_struct *vma = vmf->vma; > + struct i915_perf_stream *stream = vma->vm_private_data; > + int err; > + > + err = remap_io_sg(vma, > + vma->vm_start, vma->vm_end - vma->vm_start, > + stream->oa_buffer.vma->pages->sgl, -1); > + > + return i915_error_to_vmf_fault(err); > +} > + > +static const struct vm_operations_struct vm_ops_oa = { > + .fault = vm_fault_oa, > +}; > + > +static int i915_perf_mmap(struct file *file, struct vm_area_struct *vma) > +{ > + struct i915_perf_stream *stream = file->private_data; > + > + /* mmap-ing OA buffer to user space MUST absolutely be privileged */ > + if (i915_perf_stream_paranoid && !perfmon_capable()) { > + DRM_DEBUG("Insufficient privileges to map OA buffer\n"); > + return -EACCES; > + } > + > + switch (vma->vm_pgoff) { > + /* > + * A non-zero offset ensures that we are mapping the right object. Also > + * leaves room for future objects added to this implementation. > + */ > + case I915_PERF_OA_BUFFER_MMAP_OFFSET: > + if (!(stream->sample_flags & SAMPLE_OA_REPORT)) > + return -EINVAL; > + > + if (vma->vm_end - vma->vm_start > OA_BUFFER_SIZE) > + return -EINVAL; > + > + /* > + * Only support VM_READ. Enforce MAP_PRIVATE by checking for > + * VM_MAYSHARE. > + */ > + if (vma->vm_flags & (VM_WRITE | VM_EXEC | > + VM_SHARED | VM_MAYSHARE)) > + return -EINVAL; > + > + vma->vm_flags &= ~(VM_MAYWRITE | VM_MAYEXEC); > + > + /* > + * If the privileged parent forks and child drops root > + * privilege, we do not want the child to retain access to the > + * mapped OA buffer. Explicitly set VM_DONTCOPY to avoid such > + * cases. > + */ > + vma->vm_flags |= VM_PFNMAP | VM_DONTEXPAND | > + VM_DONTDUMP | VM_DONTCOPY; > + break; > + > + default: > + return -EINVAL; > + } > + > + vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); > + vma->vm_private_data = stream; > + vma->vm_ops = &vm_ops_oa; > + > + return 0; > +} > > static const struct file_operations fops = { > .owner = THIS_MODULE, > @@ -3409,6 +3528,7 @@ static const struct file_operations fops = { > * to handle 32bits compatibility. > */ > .compat_ioctl = i915_perf_ioctl, > + .mmap = i915_perf_mmap, > }; > > > @@ -4559,8 +4679,12 @@ int i915_perf_ioctl_version(void) > * > * - OA buffer head/tail/status/buffer registers for read only > * - OA counters A18, A19, A20 for read/write > + * > + * 8: Added an option to map oa buffer at umd driver level and trigger > + * oa reports within oa buffer from command buffer. See > + * I915_PERF_IOCTL_GET_OA_BUFFER_INFO. > */ > - return 7; > + return 8; > } > > #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST) > diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h > index fa1f3d62f9a6..cc1702ddc859 100644 > --- a/include/uapi/drm/i915_drm.h > +++ b/include/uapi/drm/i915_drm.h > @@ -2101,6 +2101,39 @@ struct drm_i915_perf_open_param { > */ > #define I915_PERF_IOCTL_CONFIG _IO('i', 0x2) > > +/** > + * Returns OA buffer properties to be used with mmap. > + * > + * This ioctl is available in perf revision 8. > + */ > +#define I915_PERF_IOCTL_GET_OA_BUFFER_INFO _IOWR('i', 0x3, struct drm_i915_perf_oa_buffer_info) > + > +/** > + * OA buffer size and offset. > + * > + * OA output buffer > + * type: 0 > + * flags: mbz > + * > + * After querying the info, pass (size,offset) to mmap(), > + * > + * mmap(0, info.size, PROT_READ, MAP_PRIVATE, perf_fd, info.offset). > + * > + * Note that only a private (not shared between processes, or across fork()) > + * read-only mmapping is allowed. > + * > + * Userspace must treat the incoming data as tainted, but it conforms to the OA > + * format as specified by user config. The buffer provides reports that have > + * OA counters - A, B and C. > + */ > +struct drm_i915_perf_oa_buffer_info { > + __u32 type; /* in */ > + __u32 flags; /* in */ > + __u64 size; /* out */ > + __u64 offset; /* out */ > + __u64 rsvd; /* mbz */ > +}; > + > /** > * Common to all i915 perf records > */ > -- > 2.20.1 > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/intel-gfx _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx