From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sender4-op-o11.zoho.com (sender4-op-o11.zoho.com [136.143.188.11]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2DEAC19046E; Thu, 9 Jul 2026 00:48:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=136.143.188.11 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783558083; cv=pass; b=aJenZtiSBT7wWDmEgwnKPZFH5gGTGsdW2Wq+95ko//5K3lXfu/NDkszO8VznBAij+aB1oBcshtyMreK2jzFlhiOXytfQSyNwGLZZUE0zT5guBA1rDHIqBV9OIAGQZlcm/ppbFY/uMomymaJQtY7vZ5ObaeadzKlwfeLqsw8TO/k= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783558083; c=relaxed/simple; bh=/lTl3P86QqfKk1OWhpH8vkka1+Hljs1sOLic8azDb5M=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=QDHx1OugjHy/7o5bvzPkRblsLR5rNfn/7bJr0PYr9IXafZm8KWi38RvB9ICZNTjMT7VrKJRWKmvRzIYMBrgf4qegpkRsDKfBT08ANmkzyjm9XdzZi4uQLS+MrapcLxjJ0qlMkyumSyf3hCsuLf35cDLXnDaTwCSL3scto3mgTNo= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (1024-bit key) header.d=collabora.com header.i=deborah.brouwer@collabora.com header.b=BuoMboPW; arc=pass smtp.client-ip=136.143.188.11 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=collabora.com header.i=deborah.brouwer@collabora.com header.b="BuoMboPW" ARC-Seal: i=1; a=rsa-sha256; t=1783558055; cv=none; d=zohomail.com; s=zohoarc; b=f/Ogy6If4harVV+2QWbmjRMgifp+bpek2pw47jlmoueeQZSXOrgny9G3qvmvKZVRW4keZIM2oULie9DJ4RZ7M7iG3rk6ZQnwn3AhxHNrVMcq7IPsRIbVmrCI/yHW/RHguJ3RQutvnkXLyF4F3djp9eU8xTE3Ms9BndrATDjZsIY= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1783558055; h=Content-Type:Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:Subject:To:To:Message-Id:Reply-To; bh=qpo1GpV6sk1WVtPptJhiq2FiJGO1cXEHyZJCt5K62l4=; b=A6WY2JTIkWRhUx6EJxc/RcnKq9TmqeYNPvbfO6ew8tZq2bJkQfUpUSXFfKS8Kav9XkOsmZQJ8dtIWQEhs9YW7CDm2DVWc4l3DTdx188Yw75l7k7cFDTSr8mcWRQURdEXrXBMsx0mtNWvSvUqFudKEoQZRnzO2pnOkko+cmMPGLQ= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=collabora.com; spf=pass smtp.mailfrom=deborah.brouwer@collabora.com; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1783558055; s=zohomail; d=collabora.com; i=deborah.brouwer@collabora.com; h=From:From:Date:Date:Subject:Subject:MIME-Version:Content-Type:Content-Transfer-Encoding:Message-Id:Message-Id:References:In-Reply-To:To:To:Cc:Cc:Reply-To; bh=qpo1GpV6sk1WVtPptJhiq2FiJGO1cXEHyZJCt5K62l4=; b=BuoMboPWdwbGD9b17I+ukx0Cj7Ln0inq77S5N185Irv/kK0b/yf85zQJZhZk9bv7 swTu9j4l7pVib4kVdLMs9m1Q3sF1NOqtJ7EzV6mYHJ2BqWNSb9suReOEUlDyIJjsusJ 1AfL67LkyUOzJKuc7pugdAI5DI78IXuph+fcWXbY= Received: by mx.zohomail.com with SMTPS id 1783558053468326.4234319283055; Wed, 8 Jul 2026 17:47:33 -0700 (PDT) From: Deborah Brouwer Date: Wed, 08 Jul 2026 17:47:11 -0700 Subject: [PATCH v5 5/7] drm/tyr: add a kernel buffer object Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260708-fw-boot-b4-v5-5-7792ab68e359@collabora.com> References: <20260708-fw-boot-b4-v5-0-7792ab68e359@collabora.com> In-Reply-To: <20260708-fw-boot-b4-v5-0-7792ab68e359@collabora.com> To: Daniel Almeida , Alice Ryhl , Danilo Krummrich , David Airlie , Simona Vetter , Benno Lossin , Gary Guo Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org, Deborah Brouwer , boris.brezillon@collabora.com, work@onurozkan.dev, samitolvanen@google.com, steven.price@arm.com, laura.nao@collabora.com, alvin.sun@linux.dev, beata.michalska@arm.com, acourbot@nvidia.com, lyude@redhat.com X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=openpgp-sha256; l=4385; i=deborah.brouwer@collabora.com; h=from:subject:message-id; bh=/lTl3P86QqfKk1OWhpH8vkka1+Hljs1sOLic8azDb5M=; b=owGbwMvMwCVWuULzOU9c7WvG02pJDFl+7+efDWZkcOt/q3o5dkX4ovkXjzLEWDbeS1sVtpR5b hXjl2taHaUsDGJcDLJiiixn7Y16xKveG+nO/98MM4eVCWQIAxenAEykrJ2RYe8/8e5+5tripDua u5zPpNQ9vlbg2/my9m6S64rZZfrL/jL8jzVZl7tJcY+kI8uKpxdV5OKTBI4WdhfJ/JwlnP6ZfXY 2DwA= X-Developer-Key: i=deborah.brouwer@collabora.com; a=openpgp; fpr=CD3F328C177AEF322D9FFF8379A829E70C5E7DEB Introduce a buffer object type (KernelBo) for internal driver allocations that are managed by the kernel rather than userspace. KernelBo wraps a GEM shmem object and automatically handles GPU virtual address space mapping during creation and unmapping on drop. This provides a safe and convenient way for the driver to both allocate and clean up internal buffers for kernel-managed resources. Co-developed-by: Boris Brezillon Signed-off-by: Boris Brezillon Signed-off-by: Deborah Brouwer --- drivers/gpu/drm/tyr/gem.rs | 101 +++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 97 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/tyr/gem.rs b/drivers/gpu/drm/tyr/gem.rs index c28be61a01bb..47a05a33388e 100644 --- a/drivers/gpu/drm/tyr/gem.rs +++ b/drivers/gpu/drm/tyr/gem.rs @@ -4,18 +4,29 @@ //! This module provides buffer object (BO) management functionality using //! DRM's GEM subsystem with shmem backing. +use core::ops::Range; + use kernel::{ drm::gem::{ self, shmem, // }, prelude::*, - sync::aref::ARef, // + sync::{ + aref::ARef, + Arc, // + }, // }; -use crate::driver::{ - TyrDrmDevice, - TyrDrmDriver, // +use crate::{ + driver::{ + TyrDrmDevice, + TyrDrmDriver, // + }, + vm::{ + Vm, + VmMapFlags, // + }, }; /// Tyr's DriverObject type for GEM objects. @@ -56,3 +67,85 @@ pub(crate) fn new_dummy_object(ddev: &TyrDrmDevice) -> Result> { Ok(bo) } + +/// Specifies how to choose a GPU virtual address for a [`KernelBo`]. +/// An automatic VA allocation strategy will be added in the future. +pub(crate) enum KernelBoVaAlloc { + /// Explicit VA address specified by the caller. + #[expect(dead_code)] + Explicit(u64), +} + +/// A kernel-owned buffer object with automatic GPU virtual address mapping. +/// +/// This structure represents a buffer object that is created and managed entirely +/// by the kernel driver, as opposed to userspace-created GEM objects. It combines +/// a GEM object with automatic GPU virtual address (VA) space mapping and cleanup. +/// +/// When dropped, the buffer is automatically unmapped from the GPU VA space. +pub(crate) struct KernelBo<'bound> { + /// The underlying GEM buffer object. + #[expect(dead_code)] + pub(crate) bo: ARef, + /// The GPU VM this buffer is mapped into. + vm: Arc>, + /// The GPU VA range occupied by this buffer. + va_range: Range, +} + +impl<'bound> KernelBo<'bound> { + /// Creates a new kernel-owned buffer object and maps it into GPU VA space. + /// + /// This function allocates a new shmem-backed GEM object and immediately maps + /// it into the specified GPU virtual memory space. The mapping is automatically + /// cleaned up when the [`KernelBo`] is dropped. + #[expect(dead_code)] + pub(crate) fn new( + ddev: &TyrDrmDevice, + vm: Arc>, + size: u64, + va_alloc: KernelBoVaAlloc, + flags: VmMapFlags, + ) -> Result { + if size == 0 { + pr_err!("Cannot create KernelBo with size 0\n"); + return Err(EINVAL); + } + + let KernelBoVaAlloc::Explicit(va) = va_alloc; + + let bo = Bo::new( + ddev, + size as usize, + shmem::ObjectConfig { + map_wc: true, + parent_resv_obj: None, + }, + BoCreateArgs { flags: 0 }, + )?; + + vm.map_bo_range(&bo, 0, size, va, flags)?; + + Ok(KernelBo { + bo, + vm, + va_range: va..(va + size), + }) + } +} + +impl Drop for KernelBo<'_> { + fn drop(&mut self) { + let va = self.va_range.start; + let size = self.va_range.end - self.va_range.start; + + if let Err(e) = self.vm.unmap_range(va, size) { + pr_err!( + "Failed to unmap KernelBo range {:#x}..{:#x}: {:?}\n", + self.va_range.start, + self.va_range.end, + e + ); + } + } +} -- 2.54.0