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 X-Spam-Level: X-Spam-Status: No, score=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E3F4BC433DF for ; Thu, 21 May 2020 07:33:17 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id A3B1020738 for ; Thu, 21 May 2020 07:33:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="WUxlfHDw" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A3B1020738 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:55410 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jbfhc-0007lJ-QS for qemu-devel@archiver.kernel.org; Thu, 21 May 2020 03:33:16 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:46468) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jbfh0-0007Ep-Up for qemu-devel@nongnu.org; Thu, 21 May 2020 03:32:38 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:45350 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jbfgw-0003Td-P9 for qemu-devel@nongnu.org; Thu, 21 May 2020 03:32:38 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1590046353; 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: in-reply-to:in-reply-to:references:references; bh=LWx1+pgTzSZSK4usE4tc0IpyjV026cs8yGpd5cmkQLA=; b=WUxlfHDwxNDRA9NqFKrfpaCiVvKt6cmlE5WlOqe0zGlI87nQ6kFKEsBJvUbEhjPZO3sSI/ xlHMGdJL4VsdhhnP611HIh6AHrN9yKLbnKbnu8lKotwWCoGRepu8oxTM8BK45a9s60greQ TgHrueVf71/C8Pr9FNfowCGZN1E7c/o= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-342-bKxZiIVjMZWSGH5nRjNz_A-1; Thu, 21 May 2020 03:32:29 -0400 X-MC-Unique: bKxZiIVjMZWSGH5nRjNz_A-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 17A2180B724; Thu, 21 May 2020 07:32:28 +0000 (UTC) Received: from nas.mammed.net (unknown [10.40.193.252]) by smtp.corp.redhat.com (Postfix) with ESMTP id D31AE649D5; Thu, 21 May 2020 07:32:19 +0000 (UTC) Date: Thu, 21 May 2020 09:32:17 +0200 From: Igor Mammedow To: "Michael S. Tsirkin" Subject: Re: [PATCH V2] Add a new PIIX option to control PCI hot unplugging of devices on non-root buses Message-ID: <20200521093217.4f440fbc@nas.mammed.net> In-Reply-To: <20200520121043-mutt-send-email-mst@kernel.org> References: <9941B800-BBEF-4DF8-BEE0-EC39D2A20D98@nutanix.com> <20200513214312.0dfa4752@redhat.com> <7FF83CE8-F25A-4458-80A7-EAA6296EF175@nutanix.com> <20200520114354.1982cb63@nas.mammed.net> <20200520054714-mutt-send-email-mst@kernel.org> <20200520115626.6a2a2355@nas.mammed.net> <20200520060645-mutt-send-email-mst@kernel.org> <20200520130547.7ac568b8@nas.mammed.net> <20200520072055-mutt-send-email-mst@kernel.org> <20200520142012.5394b2f6@nas.mammed.net> <20200520121043-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=205.139.110.120; envelope-from=imammedo@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/21 00:43:26 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] 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_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Ani Sinha , Eduardo Habkost , Julia Suvorova , "qemu-devel@nongnu.org" , Aleksandar Markovic , Ani Sinha , Paolo Bonzini , Philippe =?UTF-8?B?TWF0aGlldS1EYXVkw6k=?= , Aurelien Jarno , Richard Henderson Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Wed, 20 May 2020 12:13:35 -0400 "Michael S. Tsirkin" wrote: > On Wed, May 20, 2020 at 02:20:12PM +0200, Igor Mammedow wrote: > > On Wed, 20 May 2020 07:23:21 -0400 > > "Michael S. Tsirkin" wrote: > > =20 > > > On Wed, May 20, 2020 at 01:05:47PM +0200, Igor Mammedow wrote: =20 > > > > On Wed, 20 May 2020 06:28:37 -0400 > > > > "Michael S. Tsirkin" wrote: > > > > =20 > > > > > On Wed, May 20, 2020 at 11:56:26AM +0200, Igor Mammedow > > > > > wrote: =20 > > > > > > On Wed, 20 May 2020 05:47:53 -0400 > > > > > > "Michael S. Tsirkin" wrote: > > > > > > =20 > > > > > > > On Wed, May 20, 2020 at 11:43:54AM +0200, Igor Mammedow > > > > > > > wrote: =20 > > > > > > > > On Fri, 15 May 2020 12:13:53 +0000 > > > > > > > > Ani Sinha wrote: > > > > > > > > =20 > > > > > > > > > > On May 14, 2020, at 1:13 AM, Igor Mammedov > > > > > > > > > > wrote: =20 > > > > > > > > > >>=20 > > > > > > > > > >> =20 > > > > > > > > > >>> Will following hack work for you? > > > > > > > > > >>> possible permutations > > > > > > > > > >>> 1) ACPI hotplug everywhere > > > > > > > > > >>> -global PIIX4_PM.acpi-pci-hotplug=3Don -global > > > > > > > > > >>> PIIX4_PM.acpi-pci-hotplug-with-bridge-support=3Don > > > > > > > > > >>> -device pci-bridge,chassis_nr=3D1,shpc=3Ddoesnt_matte= r > > > > > > > > > >>> -device e1000,bus=3Dpci.1,addr=3D01,id=3Dnetdev1=20 > > > > > > > > > >>>=20 > > > > > > > > > >>> 2) No hotplug at all > > > > > > > > > >>> -global PIIX4_PM.acpi-pci-hotplug=3Doff -global > > > > > > > > > >>> PIIX4_PM.acpi-pci-hotplug-with-bridge-support=3Don > > > > > > > > > >>> -device pci-bridge,chassis_nr=3D1,shpc=3Doff -device > > > > > > > > > >>> e1000,bus=3Dpci.1,addr=3D01,id=3Dnetdev1 > > > > > > > > > >>>=20 > > > > > > > > > >>> -global PIIX4_PM.acpi-pci-hotplug=3Doff -global > > > > > > > > > >>> PIIX4_PM.acpi-pci-hotplug-with-bridge-support=3Doff > > > > > > > > > >>> -device pci-bridge,chassis_nr=3D1,shpc=3Ddoesnt_matte= r > > > > > > > > > >>> -device e1000,bus=3Dpci.1,addr=3D01,id=3Dnetdev1 > > > > > > > > > >>> =20 > > > > > > > > > >>=20 > > > > > > > > > >> Given that my patch is not acceptable, I=E2=80=99d pre= fer > > > > > > > > > >> the following in the order of preference: > > > > > > > > > >>=20 > > > > > > > > > >> (a) Have an option to disable hot ejection of > > > > > > > > > >> PCI-PCI bridge so that Windows does not even show > > > > > > > > > >> this HW in the =E2=80=9Csafely remove HW=E2=80=9D opti= on. If we > > > > > > > > > >> can do this then from OS perspective the GUI > > > > > > > > > >> options will be same as what is available with > > > > > > > > > >> PCIE/q35 - none of the devices will be hot > > > > > > > > > >> ejectable if the hot plug option is turned off > > > > > > > > > >> from the PCIE slots where devices are plugged > > > > > > > > > >> into. I looked at the code. It seems to manipulate > > > > > > > > > >> ACPI tables of the empty slots of the root bus > > > > > > > > > >> where no devices are attached (see comment "/* add > > > > > > > > > >> hotplug slots for non present devices */ =E2=80=9C). F= or > > > > > > > > > >> cold plugged bridges, it recurses down to scan the > > > > > > > > > >> slots of the bridge. Is it possible to disable hot > > > > > > > > > >> plug for the slot to which the bridge is attached? > > > > > > > > > >> =20 > > > > > > > > > >=20 > > > > > > > > > > I don't think it's possible to have per slot > > > > > > > > > > hotplug on conventional PCI hardware. it's per > > > > > > > > > > bridge property.=20 > > > > > > > > >=20 > > > > > > > > > We add the AMLs per empty slot though. When the pic > > > > > > > > > bridge is attached, we do nothing, just recurse into > > > > > > > > > the bridge slots. That is what I was asking, if it was > > > > > > > > > possible to just disable the AMLs or use some tricks > > > > > > > > > to say that this particular slot is not hotpluggable. > > > > > > > > > I am not sure why Windows is trying to eject the PCI > > > > > > > > > bridge and failing. Maybe something related to this > > > > > > > > > comment? > > > > > > > > >=20 > > > > > > > > >=20 > > > > > > > > > /* When hotplug for bridges is enabled, bridges are > > > > > > > > > =20 > > > > > > > > > * described in ACPI separately (see > > > > > > > > > build_pci_bus_end).=20 > > > > > > > > > * In this case they aren't themselves > > > > > > > > > hot-pluggable.=20 > > > > > > > > > * Hotplugged bridges *are* hot-pluggable. > > > > > > > > > */ =20 > > > > > > > >=20 > > > > > > > > thinking some more on this topic, it seems that with > > > > > > > > ACPI hotplug we already have implicit non-hotpluggble > > > > > > > > slot (slot with bridge) while the rest are staying > > > > > > > > hotpluggable. > > > > > > > >=20 > > > > > > > > So my question is: if it's acceptable to add > > > > > > > > 'PCIDevice::hotpluggable" property to all PCI devices so > > > > > > > > that user / libvirt could set it to false in case they > > > > > > > > do not want coldplugged device be considered as > > > > > > > > hotpluggable? (this way other devices could be treated > > > > > > > > the same way as bridges) > > > > > > > >=20 > > > > > > > > [...] =20 > > > > > > >=20 > > > > > > >=20 > > > > > > > I think Julia already posted a patch adding this to > > > > > > > downstream pcie bridges. Adding this to pci slots sounds > > > > > > > like a reasonable thing. =20 > > > > > > Question was more about external interface, were we do not > > > > > > have ports as separate devices with conventional PCI. The > > > > > > only knob we have is a a PCI device, where we have a > > > > > > property to turn on/off hotplug. ex: -device > > > > > > e1000,hotpluggable=3Doff and if libvirt would be able to use > > > > > > it =20 > > > > >=20 > > > > > It would make sense but is it practical to add the capability > > > > > is added in a generic way to all bridges and hosts? > > > > > If not how do users probe for presence of the capability? =20 > > > > it probably won't work with native SHPC hotplug (which looks to > > > > be incomplete in QEMU anyway), but it should work with ACPI and > > > > per port PCIE hotplugs. > > > > In case of SHPC, we probably should be able to cleanly error out > > > > with 'unsupported' reason if "hotpluggable" conflicts with > > > > bridge policy. =20 > > >=20 > > > "Try it and see if it works" is somewhat problematic from > > > management POV since there's a never ending stream of new things > > > they would have to try. If this approach is taken, we'd have to > > > try to loop in some people from libvirt and see what's their > > > take. =20 > > to clarify, we are talking here about bridges to conventional > > PCI with native SHPC hotplug semantics wrt mgmt and > > potential pcidevice.hotpluggable property. > > (the later should work fine in ACPI and PCIE hoptlug cases). > >=20 > > currently by default pci bridges have property shpc=3Doff, so mgmt > > should know that deals with PCI bridge and has to enable SHPC > > on bridge explicitly, =20 >=20 > Wait a second does that actually affect hotplug with ACPI too? What do you mean exactly? > > in which case it could probably be taught that > > using conflicting hotpluggable for device attached to bridge and > > shpc values is wrong thing. > > If that's not it, then I'm not sure what kind of discovery you are > > talking about. =20 >=20 >=20 >=20 >=20