From patchwork Thu Dec 14 16:51:02 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bjorn Helgaas X-Patchwork-Id: 13493257 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 E310860BAB; Thu, 14 Dec 2023 16:51:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Rw4g39EK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0D7C4C433C8; Thu, 14 Dec 2023 16:51:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1702572671; bh=/Qylc2+JKzSkPgqtG0O15AfjjZ9hpoVXvrfTV9+uIPA=; h=From:To:Cc:Subject:Date:From; b=Rw4g39EK4Oz975BOvXZXh6h9gnLJDQFsGE9qj6QwJbbXn59dZWCY2oC+Jm3rfAJry poOCUcsm5X+40s3GlTO52kgrnj8YITcOc8xNYA9lzI3rzVZ48/So37jLNPuXi5sbOq C9jCLamZVMBCmLWwVCTl68hCpTqTisLsU5MO2FEQKSAeRPPYCq2oxJopZKk4ICoOn3 dxaryI8HdITj+XGWhhuItNYvo/lJfoUbElVMMu5siFy2DptQgaaeVuPYyUIn8rvo4g Buom6W9VT0cFvLFIF6fUTqIM4NPW1TL3yfM7JrlklrOCfbQzj3yVFllQeMbtzQxG/l AxXqeB39K3a6A== From: Bjorn Helgaas To: linux-pci@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Igor Mammedov , Fiona Ebner , Dongli Zhang , Jonathan Woithe , "Rafael J . Wysocki" , "Michael S . Tsirkin" , Bjorn Helgaas , stable@vger.kernel.org Subject: [PATCH] Revert "PCI: acpiphp: Reassign resources on bridge if necessary" Date: Thu, 14 Dec 2023 10:51:02 -0600 Message-Id: <20231214165102.1093961-1-helgaas@kernel.org> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Bjorn Helgaas This reverts commit 40613da52b13fb21c5566f10b287e0ca8c12c4e9 and the subsequent fix to it: cc22522fd55e ("PCI: acpiphp: Use pci_assign_unassigned_bridge_resources() only for non-root bus") 40613da52b13 fixed a problem where hot-adding a device with large BARs failed if the bridge windows programmed by firmware were not large enough. cc22522fd55e ("PCI: acpiphp: Use pci_assign_unassigned_bridge_resources() only for non-root bus") fixed a problem with 40613da52b13: an ACPI hot-add of a device on a PCI root bus (common in the virt world) or firmware sending ACPI Bus Check to non-existent Root Ports (e.g., on Dell Inspiron 7352/0W6WV0) caused a NULL pointer dereference and suspend/resume hangs. Unfortunately the combination of 40613da52b13 and cc22522fd55e caused other problems: - Fiona reported that hot-add of SCSI disks in QEMU virtual machine fails sometimes. - Dongli reported a similar problem with hot-add of SCSI disks. - Jonathan reported a console freeze during boot on bare metal due to an error in radeon GPU initialization. Revert both patches to avoid adding these problems. This means we will again see the problems with hot-adding devices with large BARs and the NULL pointer dereferences and suspend/resume issues that 40613da52b13 and cc22522fd55e were intended to fix. Fixes: 40613da52b13 ("PCI: acpiphp: Reassign resources on bridge if necessary") Fixes: cc22522fd55e ("PCI: acpiphp: Use pci_assign_unassigned_bridge_resources() only for non-root bus") Reported-by: Fiona Ebner Closes: https://lore.kernel.org/r/9eb669c0-d8f2-431d-a700-6da13053ae54@proxmox.com Reported-by: Dongli Zhang Closes: https://lore.kernel.org/r/3c4a446a-b167-11b8-f36f-d3c1b49b42e9@oracle.com Reported-by: Jonathan Woithe Closes: https://lore.kernel.org/r/ZXpaNCLiDM+Kv38H@marvin.atrad.com.au Signed-off-by: Bjorn Helgaas Cc: Cc: Igor Mammedov Acked-by: Michael S. Tsirkin Acked-by: Igor Mammedov --- drivers/pci/hotplug/acpiphp_glue.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c index 601129772b2d..5b1f271c6034 100644 --- a/drivers/pci/hotplug/acpiphp_glue.c +++ b/drivers/pci/hotplug/acpiphp_glue.c @@ -512,15 +512,12 @@ static void enable_slot(struct acpiphp_slot *slot, bool bridge) if (pass && dev->subordinate) { check_hotplug_bridge(slot, dev); pcibios_resource_survey_bus(dev->subordinate); - if (pci_is_root_bus(bus)) - __pci_bus_size_bridges(dev->subordinate, &add_list); + __pci_bus_size_bridges(dev->subordinate, + &add_list); } } } - if (pci_is_root_bus(bus)) - __pci_bus_assign_resources(bus, &add_list, NULL); - else - pci_assign_unassigned_bridge_resources(bus->self); + __pci_bus_assign_resources(bus, &add_list, NULL); } acpiphp_sanitize_bus(bus);