From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 C8A4C41D631 for ; Tue, 14 Jul 2026 20:02:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784059372; cv=none; b=dbBDCMl4Vrr491cs74XIl/ig9vMWrYWYb6OD37L+Y7XMI1FUT3EbjwbPYzZw3lAGaLGhCNR+EaMj13s2TPYTk2qCzfMcPCp/53NMEW2Qv/3vSJutN9ad8ksJXmeuN4UX35Vuf7bczQfs/LTNEQlsEpBIjTwPx7q3Act3KTPf/7o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784059372; c=relaxed/simple; bh=6S5KhnlsUqcKHaqwSZYc47TJMiXHIr3XZqlfuHARySA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=esMXvmX1QwJKAERYC6C25+d42TZdoaMTdW23TL/W6dv800BqHZVqKT1epny4NVzWmEqHy3tU1OVZgTQ5ayaP9xNjshBtCNLNIlqnKWgvHu7Nh+rI+z+vjgBnf1YBuGmFrTJlTyswDRwROgU0vmZVa3wIcfsRgQDK2UXaAUYcXAg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=K98S5DoJ; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="K98S5DoJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8BFB61F000E9; Tue, 14 Jul 2026 20:02:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784059362; bh=jxmnUOo0HISi01ksBhaz2fDCmFrhfvrhP8UO5K5gexU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=K98S5DoJlEVaTKmW6DK6V7WI9FS6+pEodbGmLwnrwnGQF2jqVJQook9bL92NvBHUE ilxJ8I0tfPAdNrVI7uMGzYU9CNu4dXgeVrDe06NHaEQBEynZB4M+p+IB3ReodPemjk 9KZpYUWf2nK9qpr9/DGI0G+jlhQOA4+2GpU1VEtblh/4mqnqz0DcAhxVpU1/yVG+7d WR+c0xfXRre2pghvZeUzzNppApExKwV+0/f1GtAW7ogBIo/axH4VW18QaQgCuHtWE2 HRQ20mgONYyZicDXbPAAcwG4zEGeQAQM6S2ANCt0tUf/51sFWQTXONzc9qxhSRX4q9 V8ThjsYueY0PQ== From: Sasha Levin To: stable@vger.kernel.org Cc: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= , Simon Richter , =?UTF-8?q?Alex=20Benn=C3=A9e?= , Bjorn Helgaas , =?UTF-8?q?Christian=20K=C3=B6nig?= , Sasha Levin Subject: [PATCH 6.18.y 5/8] PCI: Fix restoring BARs on BAR resize rollback path Date: Tue, 14 Jul 2026 16:02:33 -0400 Message-ID: <20260714200236.3153778-5-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260714200236.3153778-1-sashal@kernel.org> References: <2026071350-unfold-lather-d66a@gregkh> <20260714200236.3153778-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Ilpo Järvinen [ Upstream commit 337b1b566db087347194e4543ddfdfa5645275cc ] BAR resize operation is implemented in the pci_resize_resource() and pbus_reassign_bridge_resources() functions. pci_resize_resource() can be called either from __resource_resize_store() from sysfs or directly by the driver for the Endpoint Device. The pci_resize_resource() requires that caller has released the device resources that share the bridge window with the BAR to be resized as otherwise the bridge window is pinned in place and cannot be changed. pbus_reassign_bridge_resources() rolls back resources if the resize operation fails, but rollback is performed only for the bridge windows. Because releasing the device resources are done by the caller of the BAR resize interface, these functions performing the BAR resize do not have access to the device resources as they were before the resize. pbus_reassign_bridge_resources() could try __pci_bridge_assign_resources() after rolling back the bridge windows as they were, however, it will not guarantee the resource are assigned due to differences in how FW and the kernel assign the resources (alignment of the start address and tail). To perform rollback robustly, the BAR resize interface has to be altered to also release the device resources that share the bridge window with the BAR to be resized. Also, remove restoring from the entries failed list as saved list should now contain both the bridge windows and device resources so the extra restore is duplicated work. Some drivers (currently only amdgpu) want to prevent releasing some resources. Add exclude_bars param to pci_resize_resource() and make amdgpu pass its register BAR (BAR 2 or 5), which should never be released during resize operation. Normally 64-bit prefetchable resources do not share a bridge window with the 32-bit only register BAR, but there are various fallbacks in the resource assignment logic which may make the resources share the bridge window in rare cases. This change (together with the driver side changes) is to counter the resource releases that had to be done to prevent resource tree corruption in the ("PCI: Release assigned resource before restoring them") change. As such, it likely restores functionality in cases where device resources were released to avoid resource tree conflicts which appeared to be "working" when such conflicts were not correctly detected by the kernel. Reported-by: Simon Richter Link: https://lore.kernel.org/linux-pci/f9a8c975-f5d3-4dd2-988e-4371a1433a60@hogyros.de/ Reported-by: Alex Bennée Link: https://lore.kernel.org/linux-pci/874irqop6b.fsf@draig.linaro.org/ Signed-off-by: Ilpo Järvinen [bhelgaas: squash amdgpu BAR selection from https: //lore.kernel.org/r/20251114103053.13778-1-ilpo.jarvinen@linux.intel.com] Signed-off-by: Bjorn Helgaas Tested-by: Alex Bennée # AVA, AMD GPU Reviewed-by: Christian König Link: https://patch.msgid.link/20251113162628.5946-7-ilpo.jarvinen@linux.intel.com Stable-dep-of: ee7471fe968d ("PCI: Skip Resizable BAR restore on read error") Signed-off-by: Sasha Levin --- drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 4 +- drivers/gpu/drm/i915/gt/intel_region_lmem.c | 2 +- drivers/gpu/drm/xe/xe_vram.c | 2 +- drivers/pci/pci-sysfs.c | 17 +--- drivers/pci/pci.h | 4 +- drivers/pci/setup-bus.c | 100 +++++++++++++++----- drivers/pci/setup-res.c | 23 ++--- include/linux/pci.h | 3 +- 8 files changed, 93 insertions(+), 62 deletions(-) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c index c22aea46efcdfb..56791c5b53a49e 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c @@ -1736,7 +1736,9 @@ int amdgpu_device_resize_fb_bar(struct amdgpu_device *adev) pci_release_resource(adev->pdev, 0); - r = pci_resize_resource(adev->pdev, 0, rbar_size); + r = pci_resize_resource(adev->pdev, 0, rbar_size, + (adev->asic_type >= CHIP_BONAIRE) ? 1 << 5 + : 1 << 2); if (r == -ENOSPC) dev_info(adev->dev, "Not enough PCI address space for a large BAR."); diff --git a/drivers/gpu/drm/i915/gt/intel_region_lmem.c b/drivers/gpu/drm/i915/gt/intel_region_lmem.c index 51bb27e10a4f87..7699e8fcf5edf2 100644 --- a/drivers/gpu/drm/i915/gt/intel_region_lmem.c +++ b/drivers/gpu/drm/i915/gt/intel_region_lmem.c @@ -37,7 +37,7 @@ _resize_bar(struct drm_i915_private *i915, int resno, resource_size_t size) _release_bars(pdev); - ret = pci_resize_resource(pdev, resno, bar_size); + ret = pci_resize_resource(pdev, resno, bar_size, 0); if (ret) { drm_info(&i915->drm, "Failed to resize BAR%d to %dM (%pe)\n", resno, 1 << bar_size, ERR_PTR(ret)); diff --git a/drivers/gpu/drm/xe/xe_vram.c b/drivers/gpu/drm/xe/xe_vram.c index 652df7a5f4f65d..a4076f56a3c988 100644 --- a/drivers/gpu/drm/xe/xe_vram.c +++ b/drivers/gpu/drm/xe/xe_vram.c @@ -56,7 +56,7 @@ static void resize_bar(struct xe_device *xe, int resno, resource_size_t size) release_bars(pdev); - ret = pci_resize_resource(pdev, resno, bar_size); + ret = pci_resize_resource(pdev, resno, bar_size, 0); if (ret) { drm_info(&xe->drm, "Failed to resize BAR%d to %dM (%pe). Consider enabling 'Resizable BAR' support in your BIOS\n", resno, 1 << bar_size, ERR_PTR(ret)); diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index d36b46849fee2f..edb9bc34c0c583 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -1571,18 +1571,13 @@ static ssize_t __resource_resize_store(struct device *dev, int n, { struct pci_dev *pdev = to_pci_dev(dev); struct pci_bus *bus = pdev->bus; - struct resource *b_win, *res; unsigned long size; - int ret, i; + int ret; u16 cmd; if (kstrtoul(buf, 0, &size) < 0) return -EINVAL; - b_win = pbus_select_window(bus, pci_resource_n(pdev, n)); - if (!b_win) - return -EINVAL; - device_lock(dev); if (dev->driver || pci_num_vf(pdev)) { ret = -EBUSY; @@ -1604,15 +1599,7 @@ static ssize_t __resource_resize_store(struct device *dev, int n, pci_remove_resource_files(pdev); - pci_dev_for_each_resource(pdev, res, i) { - if (i >= PCI_BRIDGE_RESOURCES) - break; - - if (b_win == pbus_select_window(bus, res)) - pci_release_resource(pdev, i); - } - - ret = pci_resize_resource(pdev, n, size); + ret = pci_resize_resource(pdev, n, size, 0); pci_assign_unassigned_bus_resources(bus); diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 549f60d2198648..5336a4b5b45676 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -439,8 +439,10 @@ enum pci_bar_type { struct device *pci_get_host_bridge_device(struct pci_dev *dev); void pci_put_host_bridge_device(struct device *dev); +void pci_resize_resource_set_size(struct pci_dev *dev, int resno, int size); +int pci_do_resource_release_and_resize(struct pci_dev *dev, int resno, int size, + int exclude_bars); unsigned int pci_rescan_bus_bridge_resize(struct pci_dev *bridge); -int pbus_reassign_bridge_resources(struct pci_bus *bus, struct resource *res); int __must_check pci_reassign_resource(struct pci_dev *dev, int i, resource_size_t add_size, resource_size_t align); int pci_configure_extended_tags(struct pci_dev *dev, void *ign); diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c index 5985ee441c7e2a..03eadc81dc7d3a 100644 --- a/drivers/pci/setup-bus.c +++ b/drivers/pci/setup-bus.c @@ -2372,18 +2372,16 @@ EXPORT_SYMBOL_GPL(pci_assign_unassigned_bridge_resources); * release it when possible. If the bridge window contains assigned * resources, it cannot be released. */ -int pbus_reassign_bridge_resources(struct pci_bus *bus, struct resource *res) +static int pbus_reassign_bridge_resources(struct pci_bus *bus, struct resource *res, + struct list_head *saved) { unsigned long type = res->flags; struct pci_dev_resource *dev_res; struct pci_dev *bridge = NULL; - LIST_HEAD(saved); LIST_HEAD(added); LIST_HEAD(failed); unsigned int i; - int ret; - - down_read(&pci_bus_sem); + int ret = 0; while (!pci_is_root_bus(bus)) { bridge = bus->self; @@ -2395,9 +2393,9 @@ int pbus_reassign_bridge_resources(struct pci_bus *bus, struct resource *res) /* Ignore BARs which are still in use */ if (!res->child) { - ret = add_to_list(&saved, bridge, res, 0, 0); + ret = add_to_list(saved, bridge, res, 0, 0); if (ret) - goto cleanup; + return ret; pci_release_resource(bridge, i); } else { @@ -2420,34 +2418,78 @@ int pbus_reassign_bridge_resources(struct pci_bus *bus, struct resource *res) free_list(&added); if (!list_empty(&failed)) { - if (pci_required_resource_failed(&failed, type)) { + if (pci_required_resource_failed(&failed, type)) ret = -ENOSPC; - goto cleanup; - } - /* Only resources with unrelated types failed (again) */ free_list(&failed); + if (ret) + return ret; + + /* Only resources with unrelated types failed (again) */ } - list_for_each_entry(dev_res, &saved, list) { + list_for_each_entry(dev_res, saved, list) { struct pci_dev *dev = dev_res->dev; /* Skip the bridge we just assigned resources for */ if (bridge == dev) continue; + if (!dev->subordinate) + continue; + pci_setup_bridge(dev->subordinate); } - free_list(&saved); - up_read(&pci_bus_sem); return 0; +} -cleanup: - /* Restore size and flags */ - list_for_each_entry(dev_res, &failed, list) - restore_dev_resource(dev_res); - free_list(&failed); +int pci_do_resource_release_and_resize(struct pci_dev *pdev, int resno, int size, + int exclude_bars) +{ + struct resource *res = pci_resource_n(pdev, resno); + struct pci_dev_resource *dev_res; + struct pci_bus *bus = pdev->bus; + struct resource *b_win, *r; + LIST_HEAD(saved); + unsigned int i; + int ret = 0; + + b_win = pbus_select_window(bus, res); + if (!b_win) + return -EINVAL; + + pci_dev_for_each_resource(pdev, r, i) { + if (i >= PCI_BRIDGE_RESOURCES) + break; + + if (exclude_bars & BIT(i)) + continue; + if (b_win != pbus_select_window(bus, r)) + continue; + + ret = add_to_list(&saved, pdev, r, 0, 0); + if (ret) + goto restore; + pci_release_resource(pdev, i); + } + + pci_resize_resource_set_size(pdev, resno, size); + + if (!bus->self) + goto out; + + down_read(&pci_bus_sem); + ret = pbus_reassign_bridge_resources(bus, res, &saved); + if (ret) + goto restore; + +out: + up_read(&pci_bus_sem); + free_list(&saved); + return ret; + +restore: /* Revert to the old configuration */ list_for_each_entry(dev_res, &saved, list) { struct resource *res = dev_res->res; @@ -2462,13 +2504,21 @@ int pbus_reassign_bridge_resources(struct pci_bus *bus, struct resource *res) restore_dev_resource(dev_res); - pci_claim_resource(dev, i); - pci_setup_bridge(dev->subordinate); - } - up_read(&pci_bus_sem); - free_list(&saved); + ret = pci_claim_resource(dev, i); + if (ret) + continue; - return ret; + if (i < PCI_BRIDGE_RESOURCES) { + const char *res_name = pci_resource_name(dev, i); + + pci_update_resource(dev, i); + pci_info(dev, "%s %pR: old value restored\n", + res_name, res); + } + if (dev->subordinate) + pci_setup_bridge(dev->subordinate); + } + goto out; } void pci_assign_unassigned_bus_resources(struct pci_bus *bus) diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c index 53338eb45f038f..25a64358feea96 100644 --- a/drivers/pci/setup-res.c +++ b/drivers/pci/setup-res.c @@ -446,8 +446,7 @@ static bool pci_resize_is_memory_decoding_enabled(struct pci_dev *dev, return cmd & PCI_COMMAND_MEMORY; } -static void pci_resize_resource_set_size(struct pci_dev *dev, int resno, - int size) +void pci_resize_resource_set_size(struct pci_dev *dev, int resno, int size) { resource_size_t res_size = pci_rebar_size_to_bytes(size); struct resource *res = pci_resource_n(dev, resno); @@ -458,9 +457,9 @@ static void pci_resize_resource_set_size(struct pci_dev *dev, int resno, resource_set_size(res, res_size); } -int pci_resize_resource(struct pci_dev *dev, int resno, int size) +int pci_resize_resource(struct pci_dev *dev, int resno, int size, + int exclude_bars) { - struct resource *res = pci_resource_n(dev, resno); struct pci_host_bridge *host; int old, ret; u32 sizes; @@ -470,10 +469,6 @@ int pci_resize_resource(struct pci_dev *dev, int resno, int size) if (host->preserve_config) return -ENOTSUPP; - /* Make sure the resource isn't assigned before resizing it. */ - if (!(res->flags & IORESOURCE_UNSET)) - return -EBUSY; - if (pci_resize_is_memory_decoding_enabled(dev, resno)) return -EBUSY; @@ -492,19 +487,13 @@ int pci_resize_resource(struct pci_dev *dev, int resno, int size) if (ret) return ret; - pci_resize_resource_set_size(dev, resno, size); - - /* Check if the new config works by trying to assign everything. */ - if (dev->bus->self) { - ret = pbus_reassign_bridge_resources(dev->bus, res); - if (ret) - goto error_resize; - } + ret = pci_do_resource_release_and_resize(dev, resno, size, exclude_bars); + if (ret) + goto error_resize; return 0; error_resize: pci_rebar_set_size(dev, resno, old); - pci_resize_resource_set_size(dev, resno, old); return ret; } EXPORT_SYMBOL(pci_resize_resource); diff --git a/include/linux/pci.h b/include/linux/pci.h index 89f5a4290b6e20..505bf6e009b18a 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1425,7 +1425,8 @@ static inline int pci_rebar_bytes_to_size(u64 bytes) } u32 pci_rebar_get_possible_sizes(struct pci_dev *pdev, int bar); -int __must_check pci_resize_resource(struct pci_dev *dev, int i, int size); +int __must_check pci_resize_resource(struct pci_dev *dev, int i, int size, + int exclude_bars); int pci_select_bars(struct pci_dev *dev, unsigned long flags); bool pci_device_is_present(struct pci_dev *pdev); void pci_ignore_hotplug(struct pci_dev *dev); -- 2.53.0