From: Yazen Ghannam <yazen.ghannam@amd.com>
To: "Luck, Tony" <tony.luck@intel.com>,
Borislav Petkov <bp@alien8.de>,
Elliott Mitchell <ehem+xen@m5p.com>
Cc: yazen.ghannam@amd.com,
"smita.koralahallichannabasappa@amd.com"
<smita.koralahallichannabasappa@amd.com>,
"linux-edac@vger.kernel.org" <linux-edac@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"x86@kernel.org" <x86@kernel.org>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
"rric@kernel.org" <rric@kernel.org>,
"james.morse@arm.com" <james.morse@arm.com>
Subject: Re: [PATCH] Revert "EDAC/mce_amd: Do not load edac_mce_amd module on guests"
Date: Wed, 13 Sep 2023 12:21:23 -0400 [thread overview]
Message-ID: <fa5ec285-4d0f-4635-a35d-d290fd73ddfa@amd.com> (raw)
In-Reply-To: <SJ1PR11MB6083BDC4D10D139EF28E0058FCF0A@SJ1PR11MB6083.namprd11.prod.outlook.com>
On 9/13/23 11:50 AM, Luck, Tony wrote:
>> Also, please note that the EDAC modules don't handle MCE events
>> directly. They act on information passed from the MCE subsystem.
>>
>> Furthermore, there are other EDAC modules that have the same !hypervisor
>> check, so why change only this one?
>
> The older Intel EDAC drivers translated system physical addresses to DIMM
> addresses by digging around in the CONFIG and MMIO space of the memory
> controller devices. It would seem unwise for a VMM to give access to those
> addresses to a guest (in general ... perhaps OK for a Xen style "DOM0" guest that is
> handling many tasks for the VMM?).
>
> What system resources do AMD EDAC drivers need access to? Could they
> work inside a guest?
>
The MCE decoder may access some newer MCA registers, or request info
from the MCE subsystem. But this is for informational error decoding. It
won't support any actions that a guest could take.
The AMD64 EDAC module reads system-specific memory controller registers
through non-architectural interfaces. So also unwise or not useful for a
guest to access.
Thanks,
Yazen
next prev parent reply other threads:[~2023-09-13 16:21 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-28 17:27 [PATCH] EDAC/mce_amd: Do not load edac_mce_amd module on guests Smita Koralahalli
2021-07-08 20:41 ` Yazen Ghannam
2021-07-23 18:18 ` Kim Phillips
2021-08-09 10:44 ` Borislav Petkov
2023-09-08 3:08 ` [PATCH] Revert "EDAC/mce_amd: Do not load edac_mce_amd module on guests" Elliott Mitchell
2023-09-08 3:59 ` Borislav Petkov
2023-09-13 14:36 ` Yazen Ghannam
2023-09-13 15:50 ` Luck, Tony
2023-09-13 16:21 ` Yazen Ghannam [this message]
2023-09-14 17:02 ` Elliott Mitchell
2023-09-15 11:56 ` Borislav Petkov
2023-09-21 21:18 ` Elliott Mitchell
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