From patchwork Wed Apr 5 09:42:56 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Igor Mammedov X-Patchwork-Id: 13201480 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 55473C76188 for ; Wed, 5 Apr 2023 09:43:19 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pjzfU-0006wa-VB; Wed, 05 Apr 2023 05:43:04 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pjzfT-0006wN-It for qemu-devel@nongnu.org; Wed, 05 Apr 2023 05:43:03 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pjzfR-00026y-VH for qemu-devel@nongnu.org; Wed, 05 Apr 2023 05:43:03 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1680687781; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=2A7cInSBH49H6BWxGFXeW1JkGxgEAxC6mCuE1nHLstY=; b=WngLMkwihIKyTQHGhaZWOSTDuV5xK4GbVSnLdIn91NnMM8JboiaLiaXrewcq1HRbQpXLhT 88O//iI19uoUjUpB6xOCIo8h23ZyOD4iZ08PW+E4JYBS0bQMzPGHVaEEL41rfonmqRLWsa WjEhBpGrxRoOGy3WMEEnJLoTaPoLIEI= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-657-hJel5k-dNOuGioZgg1VhYQ-1; Wed, 05 Apr 2023 05:42:59 -0400 X-MC-Unique: hJel5k-dNOuGioZgg1VhYQ-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 2CC4B101A54F for ; Wed, 5 Apr 2023 09:42:59 +0000 (UTC) Received: from dell-r430-03.lab.eng.brq2.redhat.com (dell-r430-03.lab.eng.brq2.redhat.com [10.37.153.18]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5031440C6EC4; Wed, 5 Apr 2023 09:42:58 +0000 (UTC) From: Igor Mammedov To: qemu-devel@nongnu.org Cc: mst@redhat.com, anisinha@redhat.com, jusual@redhat.com, kraxel@redhat.com Subject: [PATCH v3] acpi: pcihp: make pending delete blocking action expire Date: Wed, 5 Apr 2023 11:42:56 +0200 Message-Id: <20230405094256.1539122-1-imammedo@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 Received-SPF: pass client-ip=170.10.129.124; envelope-from=imammedo@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org with Q35 using ACPI PCI hotplug by default, user's request to unplug device is ignored when it's issued before guest OS has been booted. And any additional attempt to request device hot-unplug afterwards results in following error: "Device XYZ is already in the process of unplug" arguably it can be considered as a regression introduced by [2], before which it was possible to issue unplug request multiple times. Allowing pending delete blocking expire brings ACPI PCI hotplug on par with native PCIe unplug behavior [1] and allows user to repeat unplug requests at propper times. Set expire timeout to arbitrary 1msec so user won't be able to flood guest with SCI interrupts by calling device_del in tight loop. PS: ACPI spec doesn't mandate what OSPM can do with GPEx.status bits set before it's booted => it's impl. depended. Status bits may be retained (I tested with one Windows version) or cleared (Linux since 2.6 kernel times) during guest's ACPI subsystem initialization. Clearing status bits (though not wrong per se) hides the unplug event from guest, and it's upto user to repeat device_del later when guest is able to handle unplug requests. 1) 18416c62e3 ("pcie: expire pending delete") 2) Fixes: cce8944cc9ef ("qdev-monitor: Forbid repeated device_del") Signed-off-by: Igor Mammedov CC: mst@redhat.com CC: anisinha@redhat.com CC: jusual@redhat.com CC: kraxel@redhat.com Acked-by: Gerd Hoffmann --- v3: * fix typo in comment * move CC to the main commit message body v2: * change timeout to 1ms * add comment to expire usage * massage commit message to be a bit more clear --- hw/acpi/pcihp.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/hw/acpi/pcihp.c b/hw/acpi/pcihp.c index dcfb779a7a..cdd6f775a1 100644 --- a/hw/acpi/pcihp.c +++ b/hw/acpi/pcihp.c @@ -357,6 +357,16 @@ void acpi_pcihp_device_unplug_request_cb(HotplugHandler *hotplug_dev, * acpi_pcihp_eject_slot() when the operation is completed. */ pdev->qdev.pending_deleted_event = true; + /* if unplug was requested before OSPM is initialized, + * linux kernel will clear GPE0.sts[] bits during boot, which effectively + * hides unplug event. And than followup qmp_device_del() calls remain + * blocked by above flag permanently. + * Unblock qmp_device_del() by setting expire limit, so user can + * repeat unplug request later when OSPM has been booted. + */ + pdev->qdev.pending_deleted_expires_ms = + qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL); /* 1 msec */ + s->acpi_pcihp_pci_status[bsel].down |= (1U << slot); acpi_send_event(DEVICE(hotplug_dev), ACPI_PCI_HOTPLUG_STATUS); }