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 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 D8869C76196 for ; Thu, 6 Apr 2023 06:22:43 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pkJ0A-0001jH-G2; Thu, 06 Apr 2023 02:21:42 -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 1pkJ08-0001j2-Kp for qemu-devel@nongnu.org; Thu, 06 Apr 2023 02:21:40 -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 1pkJ06-00035u-5x for qemu-devel@nongnu.org; Thu, 06 Apr 2023 02:21:40 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1680762096; 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: in-reply-to:in-reply-to:references:references; bh=aOlU/PvIUp3IktFvOFRK/DTr9vbqGL5wpm2rOJIDfIk=; b=fnA8SVdRojY31dgpq0cJPcTYEM78Ka8q1Z2WWWeXyW0KJs7YWPDS11H6HrfXMi8J4J9QuD NsgI2uzRMsGtkEY6tamRFkosxM76mBGj7lKPCkF7dvfs9ovuRDuUWmRsju5WNP/4YdgNgi Ct9if9nH5Lnpdf3sDs8I0sMWIERcoNw= Received: from mail-pf1-f197.google.com (mail-pf1-f197.google.com [209.85.210.197]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-299-NuUWPzWpNc-kCRA0hpWnFw-1; Thu, 06 Apr 2023 02:21:32 -0400 X-MC-Unique: NuUWPzWpNc-kCRA0hpWnFw-1 Received: by mail-pf1-f197.google.com with SMTP id m12-20020a62f20c000000b0062612a76a08so17009946pfh.2 for ; Wed, 05 Apr 2023 23:21:32 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1680762091; h=mime-version:references:message-id:in-reply-to:subject:cc:to:from :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=aOlU/PvIUp3IktFvOFRK/DTr9vbqGL5wpm2rOJIDfIk=; b=CdTIl6WBU+YxK/CIjZrRH2Y4aGE/SQgpbJAR7gZOusvEqrdPARYm/3ZJktYgNCWUyX kbM9ujZkW5xBys502IwFIgCcXbbNO7dke5lciCT5Zmjx1X0MNBd7rdoFuMwRGUxBqJkG kmr4i68KeME8otZIX2hAuFmvmbvpTUjB9QkZbHLnfEzubHF5vcv1z+4gMLMtNmO6scV8 mjCGZRy5yj5w4H1axLfikaOpizpE6c0GHQ3qVu/OlznO9mAPM4kxB/KszdK+38Rft4Vx Wz74MM+myZV5mwaJuZOjiey2nxPJ96shuTnMlIsFTCha3cgsRDvIDKozzgf2lkX/cxK5 UjGA== X-Gm-Message-State: AAQBX9f7q63x/D/i8fP3lMlNh672KAe0YD//DH6gPwT6NH3gU9/VOrY2 p9DKSqfFckk6avkm4lW+S/m4iuMRHFXBN2bCpW9fn2uXw+qfWG3Bq7tw5qIZq4aKqee+Q8MwbA0 AdtNbvWKnngSme6M= X-Received: by 2002:a62:1cc6:0:b0:62e:11:2e57 with SMTP id c189-20020a621cc6000000b0062e00112e57mr7798181pfc.22.1680762091372; Wed, 05 Apr 2023 23:21:31 -0700 (PDT) X-Google-Smtp-Source: AKy350YW3kQ9Y2PMfK4lN7tk2XGqz65bLYrzD5xDLhNxUCRg26F5tqGHQFqBsaJXzukbSz/QTKBktA== X-Received: by 2002:a62:1cc6:0:b0:62e:11:2e57 with SMTP id c189-20020a621cc6000000b0062e00112e57mr7798161pfc.22.1680762091038; Wed, 05 Apr 2023 23:21:31 -0700 (PDT) Received: from fc37-ani ([115.96.127.238]) by smtp.googlemail.com with ESMTPSA id c12-20020aa78e0c000000b0062b5a55835dsm424157pfr.213.2023.04.05.23.21.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 05 Apr 2023 23:21:30 -0700 (PDT) Date: Thu, 6 Apr 2023 11:51:25 +0530 (IST) From: Ani Sinha To: Igor Mammedov cc: qemu-devel@nongnu.org, mst@redhat.com, jusual@redhat.com, kraxel@redhat.com Subject: Re: [PATCH v2] acpi: pcihp: make pending delete blocking action expire In-Reply-To: <20230405083444.1536720-1-imammedo@redhat.com> Message-ID: <8d03fb3d-8541-c6f5-0fac-ca61e8d7325c@redhat.com> References: <20230405083444.1536720-1-imammedo@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Received-SPF: pass client-ip=170.10.129.124; envelope-from=anisinha@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 On Wed, 5 Apr 2023, Igor Mammedov wrote: > 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 Reviewed-by: Ani Sinha > --- > v2: > * change timeout to 1ms > * add comment to expire usage > * massage commit message to be a bit more clear > > CC: mst@redhat.com > CC: anisinha@redhat.com > CC: jusual@redhat.com > CC: kraxel@redhat.com > --- > hw/acpi/pcihp.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/hw/acpi/pcihp.c b/hw/acpi/pcihp.c > index dcfb779a7a..5daa732a33 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. BAnd 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); > } > -- > 2.39.1 > >