linux-kernel - RE: [RFC PATCH 0/2] x86: allow to notify host about guest entering s2idle

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Date:   Thu, 7 Jul 2022 15:27:24 +0000
From:   "Limonciello, Mario" <Mario.Limonciello@....com>
To:     Grzegorz Jaszczyk <jaz@...ihalf.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     "dmy@...ihalf.com" <dmy@...ihalf.com>,
        "seanjc@...gle.com" <seanjc@...gle.com>,
        "dbehr@...gle.com" <dbehr@...gle.com>,
        "upstream@...ihalf.com" <upstream@...ihalf.com>,
        "zide.chen@...el.corp-partner.google.com" 
        <zide.chen@...el.corp-partner.google.com>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Len Brown <lenb@...nel.org>,
        Hans de Goede <hdegoede@...hat.com>,
        Mark Gross <markgross@...nel.org>, Pavel Machek <pavel@....cz>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        Sachi King <nakato@...ato.io>,
        "open list:ACPI" <linux-acpi@...r.kernel.org>,
        "open list:X86 PLATFORM DRIVERS" 
        <platform-driver-x86@...r.kernel.org>,
        "open list:HIBERNATION (aka Software Suspend, aka swsusp)" 
        <linux-pm@...r.kernel.org>
Subject: RE: [RFC PATCH 0/2] x86: allow to notify host about guest entering
 s2idle

[Public]



> -----Original Message-----
> From: Grzegorz Jaszczyk <jaz@...ihalf.com>
> Sent: Thursday, July 7, 2022 07:53
> To: linux-kernel@...r.kernel.org
> Cc: jaz@...ihalf.com; dmy@...ihalf.com; Limonciello, Mario
> <Mario.Limonciello@....com>; seanjc@...gle.com; dbehr@...gle.com;
> upstream@...ihalf.com; zide.chen@...el.corp-partner.google.com; Rafael J.
> Wysocki <rafael@...nel.org>; Len Brown <lenb@...nel.org>; Hans de Goede
> <hdegoede@...hat.com>; Mark Gross <markgross@...nel.org>; Pavel Machek
> <pavel@....cz>; Mika Westerberg <mika.westerberg@...ux.intel.com>; Sachi
> King <nakato@...ato.io>; open list:ACPI <linux-acpi@...r.kernel.org>; open
> list:X86 PLATFORM DRIVERS <platform-driver-x86@...r.kernel.org>; open
> list:HIBERNATION (aka Software Suspend, aka swsusp) <linux-
> pm@...r.kernel.org>
> Subject: [RFC PATCH 0/2] x86: allow to notify host about guest entering s2idle
> 
> According to the mailing list discussion [1] about the preferred approach
> for notifying hypervisor/VMM about guest entering s2idle state this RFC was
> implemented.
> 
> Instead of original hypercall based approach, which involves KVM change [2]
> and makes it hypervisor specific, implement different mechanism, which
> takes advantage of MMIO/PIO trapping and makes it hypervisor independent.
> 
> Patch #1 extends S2Idle ops by new notify handler which will be invoked as
> a very last command before system actually enters S2Idle states. It also
> allows to register and use driver specific notification hook which is used
> in patch #2.
> 
> Patch #2 introduces new driver for virtual PMC, which registers
> acpi_s2idle_dev_ops's notify handler. Its implementation is based on an
> ACPI _DSM evaluation, which in turn can perform MMIO access and allow to
> trap and therefore notify the VMM about guest entering S2Idle state.
> 
> Please see individual patches and commit logs for more verbose description.
> 
> This patchset is marked as RFC since patch #2 implements driver for non
> existing device "HYPE0001", which ACPI ID was not registered yet.
> Furthermore the required registration process [3] will not be started
> before getting positive feedback about this patchset.
> 
> [1]
> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpatchw
> ork.kernel.org%2Fproject%2Flinux-pm%2Fpatch%2F20220609110337.1238762-
> 2-
> jaz%40semihalf.com%2F&amp;data=05%7C01%7Cmario.limonciello%40amd.co
> m%7C514a545cf9aa4a7b6d9508da6018138b%7C3dd8961fe4884e608e11a82d9
> 94e183d%7C0%7C0%7C637927953769026163%7CUnknown%7CTWFpbGZsb3d8
> eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%
> 7C3000%7C%7C%7C&amp;sdata=RIDiHUNpHUsBYyK3pwGND%2BWJoioXZNCKt
> mML2%2F1LAxs%3D&amp;reserved=0
> [2]
> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpatchw
> ork.kernel.org%2Fproject%2Flinux-pm%2Fpatch%2F20220609110337.1238762-
> 3-
> jaz%40semihalf.com%2F&amp;data=05%7C01%7Cmario.limonciello%40amd.co
> m%7C514a545cf9aa4a7b6d9508da6018138b%7C3dd8961fe4884e608e11a82d9
> 94e183d%7C0%7C0%7C637927953769026163%7CUnknown%7CTWFpbGZsb3d8
> eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%
> 7C3000%7C%7C%7C&amp;sdata=BqykAwWzO%2BfeGPSsAqTmX13O8F0Vvm3G
> PL56EpmdSJ8%3D&amp;reserved=0
> [3]
> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fuefi.org
> %2FPNP_ACPI_Registry&amp;data=05%7C01%7Cmario.limonciello%40amd.co
> m%7C514a545cf9aa4a7b6d9508da6018138b%7C3dd8961fe4884e608e11a82d9
> 94e183d%7C0%7C0%7C637927953769026163%7CUnknown%7CTWFpbGZsb3d8
> eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%
> 7C3000%7C%7C%7C&amp;sdata=QXK52zFXJGEBm6xIv6IFeF7Xxgz4Yp5UmgLSQ
> diXtlI%3D&amp;reserved=0
> 
> Grzegorz Jaszczyk (2):
>   suspend: extend S2Idle ops by new notify handler
>   platform/x86: Add virtual PMC driver used for S2Idle
> 
>  drivers/acpi/x86/s2idle.c       | 11 +++++
>  drivers/platform/x86/Kconfig    |  7 ++++
>  drivers/platform/x86/Makefile   |  1 +
>  drivers/platform/x86/virt_pmc.c | 73 +++++++++++++++++++++++++++++++++
>  include/linux/acpi.h            |  1 +
>  include/linux/suspend.h         |  1 +
>  kernel/power/suspend.c          |  4 ++
>  7 files changed, 98 insertions(+)
>  create mode 100644 drivers/platform/x86/virt_pmc.c
> 
> --
> 2.37.0.rc0.161.g10f37bed90-goog

Thanks, you matched the implementation I was expecting.
This looks fine by me.