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=-6.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=ham 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 DA1E6C4332D for ; Thu, 19 Mar 2020 15:08:51 +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 A9FFD2072D for ; Thu, 19 Mar 2020 15:08:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="cqSKa+f5" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A9FFD2072D 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]:39380 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jEwmw-0003sw-QU for qemu-devel@archiver.kernel.org; Thu, 19 Mar 2020 11:08:50 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:58945) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jEwmN-0003Qy-8M for qemu-devel@nongnu.org; Thu, 19 Mar 2020 11:08:16 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1jEwmL-00010b-Gb for qemu-devel@nongnu.org; Thu, 19 Mar 2020 11:08:14 -0400 Received: from us-smtp-delivery-74.mimecast.com ([216.205.24.74]:47487) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1jEwmL-000101-Cx for qemu-devel@nongnu.org; Thu, 19 Mar 2020 11:08:13 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1584630492; 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=/mtgzCdv9sKXyH05tbd38LH95LLZVXgjX5yGisTonng=; b=cqSKa+f5he9znPhsfOBTZj7Upe1Wl2pY3Ch+O2NVzZVyv3Fkvz+OElaevSqZ0jM9REdMy8 ovy+WiucIbISh43+WzTYBrMntnL4NbOyUD6Op+tW0cPIxSS9jPqguhJ6VEkWMGKG4Fmldl PDzhLDOVpeMyTIQo872WBLJBVZA2RTU= 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-355-CgnmQsQ6M--FMSGClc5o4w-1; Thu, 19 Mar 2020 11:08:09 -0400 X-MC-Unique: CgnmQsQ6M--FMSGClc5o4w-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B088F801E6C; Thu, 19 Mar 2020 15:08:07 +0000 (UTC) Received: from localhost (unknown [10.40.208.100]) by smtp.corp.redhat.com (Postfix) with ESMTP id DD1E7BBBD7; Thu, 19 Mar 2020 15:08:01 +0000 (UTC) Date: Thu, 19 Mar 2020 16:08:00 +0100 From: Igor Mammedov To: Philippe =?UTF-8?B?TWF0aGlldS1EYXVkw6k=?= Subject: Re: [PATCH-for-5.0 1/2] hw/acpi/piix4: Add 'system-hotplug-support' property Message-ID: <20200319160800.614de5fb@redhat.com> In-Reply-To: <4d42697e-ba84-e5af-3a17-a2cc52cf0dbc@redhat.com> References: <20200318221531.22910-1-philmd@redhat.com> <20200318221531.22910-2-philmd@redhat.com> <20200319114424.5723e777@office.mammed.net> <4d42697e-ba84-e5af-3a17-a2cc52cf0dbc@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 216.205.24.74 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: Eduardo Habkost , "Michael S. Tsirkin" , Marcelo Tosatti , qemu-devel@nongnu.org, Aleksandar Markovic , =?UTF-8?B?SGVydsOp?= Poussineau , Paolo Bonzini , Aurelien Jarno , Richard Henderson Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, 19 Mar 2020 12:04:11 +0100 Philippe Mathieu-Daud=C3=A9 wrote: > On 3/19/20 11:44 AM, Igor Mammedov wrote: > > On Wed, 18 Mar 2020 23:15:30 +0100 > > Philippe Mathieu-Daud=C3=A9 wrote: > > =20 > >> The I/O ranges registered by the piix4_acpi_system_hot_add_init() > >> function are not documented in the PIIX4 datasheet. > >> This appears to be a PC-only feature added in commit 5e3cb5347e > >> ("initialize hot add system / acpi gpe") which was then moved > >> to the PIIX4 device model in commit 9d5e77a22f ("make > >> qemu_system_device_hot_add piix independent") > >> Add a property (default enabled, to not modify the current > >> behavior) to allow machines wanting to model a simple PIIX4 > >> to disable this feature. > >> > >> Signed-off-by: Philippe Mathieu-Daud=C3=A9 =20 > >=20 > > it's already pretty twisted code and adding one more knob > > to workaround other compat knobs makes it worse. > >=20 > > Even though it's not really welcomed approach, > > we can ifdef all hotplug parts and compile them out for mips > > dropping along the way linking with not needed dependencies =20 >=20 > We can't use use target-specific poisoned definitions to ifdef out in=20 > generic hw/ code. >=20 > > or > > more often used, make stubs from hotplug parts for mips > > and link with them. =20 >=20 > So the problem is this device doesn't match the hardware datasheet, has= =20 > extra features helping virtualization, and now we can not simplify it=20 > due to backward compat. >=20 > Once Michael said he doesn't care about the PIIX4, only the PIIX3=20 > southbridge [1] [2], but then the i440fx pc machine uses a PIIX3 with a= =20 > pci PM function from PIIX4, and made that PII4_PM Frankenstein. >=20 > You are asking me to choose between worse versus ugly? That 'ugly' is typically used within QEMU to deal with such things probably due to its low complexity. > The saner outcome I see is make the current PIIX4_PM x86-specific, not=20 > modifying the code, and start a fresh new copy respecting the datasheet. properly implementing spec would be quite a task (although if motivation is just for fun, then why not) >=20 > Note I'm not particularly interested in MIPS here, but having model=20 > respecting the hardware. >=20 > [1] https://www.mail-archive.com/qemu-devel@nongnu.org/msg504270.html > [2] https://www.mail-archive.com/qemu-devel@nongnu.org/msg601512.html >=20 > > =20 > >> --- > >> Should I squash this with the next patch and start with > >> default=3Dfalse, which is closer to the hardware model? > >> --- > >> hw/acpi/piix4.c | 9 +++++++-- > >> 1 file changed, 7 insertions(+), 2 deletions(-) > >> > >> diff --git a/hw/acpi/piix4.c b/hw/acpi/piix4.c > >> index 964d6f5990..9c970336ac 100644 > >> --- a/hw/acpi/piix4.c > >> +++ b/hw/acpi/piix4.c > >> @@ -78,6 +78,7 @@ typedef struct PIIX4PMState { > >> =20 > >> AcpiPciHpState acpi_pci_hotplug; > >> bool use_acpi_pci_hotplug; > >> + bool use_acpi_system_hotplug; > >> =20 > >> uint8_t disable_s3; > >> uint8_t disable_s4; > >> @@ -503,8 +504,10 @@ static void piix4_pm_realize(PCIDevice *dev, Erro= r **errp) > >> s->machine_ready.notify =3D piix4_pm_machine_ready; > >> qemu_add_machine_init_done_notifier(&s->machine_ready); > >> =20 > >> - piix4_acpi_system_hot_add_init(pci_address_space_io(dev), > >> - pci_get_bus(dev), s); > >> + if (s->use_acpi_system_hotplug) { > >> + piix4_acpi_system_hot_add_init(pci_address_space_io(dev), > >> + pci_get_bus(dev), s); > >> + } > >> qbus_set_hotplug_handler(BUS(pci_get_bus(dev)), OBJECT(s), &erro= r_abort); > >> =20 > >> piix4_pm_add_propeties(s); > >> @@ -635,6 +638,8 @@ static Property piix4_pm_properties[] =3D { > >> use_acpi_pci_hotplug, true), > >> DEFINE_PROP_BOOL("memory-hotplug-support", PIIX4PMState, > >> acpi_memory_hotplug.is_enabled, true), > >> + DEFINE_PROP_BOOL("system-hotplug-support", PIIX4PMState, > >> + use_acpi_system_hotplug, true), > >> DEFINE_PROP_END_OF_LIST(), > >> }; > >> =20 > > =20 >=20 >=20