From: "Ni, Ruiyu" <ruiyu.ni@Intel.com>
To: "Lohr, Paul A" <paul.a.lohr@intel.com>,
Laszlo Ersek <lersek@redhat.com>,
"edk2-devel@lists.01.org" <edk2-devel@lists.01.org>
Cc: "Kinney, Michael D" <michael.d.kinney@intel.com>,
"Yao, Jiewen" <jiewen.yao@intel.com>
Subject: Re: [PATCH] MdeModulePkg/PiSmmIpl: Do not reset SMRAM to UC when CPU driver runs
Date: Tue, 23 Oct 2018 17:36:37 +0800 [thread overview]
Message-ID: <1998f4ff-13e0-3918-db78-74ada10fddc0@Intel.com> (raw)
In-Reply-To: <CDC618B1AC5F1346B65D98DCD05D1028BEE9F90A@fmsmsx118.amr.corp.intel.com>
On 10/23/2018 11:12 AM, Lohr, Paul A wrote:
> Hello,
>
> Code to remove SMRAM = UC (line 650-ish) looks good. I would suggest adding some debug comments in the area it was removed. Thanks.
debug message or comments?
I guess you'd like to have some comments to say "SMRR is enabled by CPU
SMM driver so no need to reset the SMRAM to UC in MTRR". Correct?
>
> Per #4, I also "think" the second SMRAM = UC should be removed, in addition to the SMRAM = WB in the same area. But this is under investigation now. Expect an update in 24-48 hours.
I did some search in close source platform code and found out that the
SMRAM is set to WB by default.
So it turns out setting SMRAM to WB is unnecessary here. But this
introduces a platform assumption. If platform doesn't set SMRAM to WB,
removing the WB set here will cause system boot performance downgrade.
Above is my understanding.
Please post update here once you finish the investigation.
>
> Per #5, I too do not like the "CPU AP" comment, as I initially thought it referred to Application Processor 😊 Yes, please clean that AP comment up!
Sure I will do that.
>
>
> Paul A. Lohr – Server Firmware Enabling
> 512.239.9073 (cell)
> 512.794.5044 (work)
>
next prev parent reply other threads:[~2018-10-23 9:35 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-22 9:03 [PATCH] MdeModulePkg/PiSmmIpl: Do not reset SMRAM to UC when CPU driver runs Ruiyu Ni
2018-10-22 14:30 ` Laszlo Ersek
2018-10-23 3:12 ` Lohr, Paul A
2018-10-23 9:36 ` Ni, Ruiyu [this message]
2018-10-23 9:43 ` Laszlo Ersek
2018-10-29 20:33 ` Lohr, Paul A
2018-10-23 9:21 ` Ni, Ruiyu
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