From: "Ni, Ray" <ray.ni@intel.com>
To: "Dong, Guo" <guo.dong@intel.com>,
"devel@edk2.groups.io" <devel@edk2.groups.io>,
"thomas.lendacky@amd.com" <thomas.lendacky@amd.com>,
Laszlo Ersek <lersek@redhat.com>
Cc: "Dong, Eric" <eric.dong@intel.com>,
"Kumar, Rahul1" <rahul1.kumar@intel.com>
Subject: Re: [edk2-devel] [PATCH] UefiCpuPkg/CpuDxe: Fix boot error
Date: Fri, 11 Dec 2020 01:47:43 +0000 [thread overview]
Message-ID: <CO1PR11MB4930C439D14D166E30B501BE8CCA0@CO1PR11MB4930.namprd11.prod.outlook.com> (raw)
In-Reply-To: <BYAPR11MB3622AE151C22681277C59C509ECB0@BYAPR11MB3622.namprd11.prod.outlook.com>
>
> [Guo] From my view point, it is not necessary to have these code for X64 since CS base
> address would always use 0 in long mode. But I will leave this to package owner
> to decide to remove it or not.
> For now to support AMD case, maybe we could check rax value to decide to use
> dword jump or qword jump. If high 4 bytes of rax is zero, dword jump will be used.
> With this, it has exact same behavior when CpuDxe driver is dispatch below 4GB.
>
> >
> > If more time is needed to figure it out, though, it is probably best to
> > revert this in the mean time since I can't launch a VM (be it legacy or
> > SEV) on the latest tree.
>
> [Guo] If we agree the above change to check rax, I could create a patch today.
> Let me know if having other comments.
>
Tom,
We don't need to consider shadow stack because shadow stack is only enabled in SMM environment.
Guo,
I suggest we either revert the patch to keep the original 4G limitation, or use RETF to be maximum
compatible to Intel and AMD processors.
Checking high 4 bytes of RAX hides the problem in AMD processors.
Thanks,
Ray
next prev parent reply other threads:[~2020-12-11 1:47 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-02 21:38 [edk2-devel] [PATCH] UefiCpuPkg/CpuDxe: Fix boot error Guo Dong
2020-12-03 2:23 ` Ni, Ray
2020-12-03 7:08 ` Dong, Eric
2020-12-03 10:21 ` Laszlo Ersek
2020-12-08 21:39 ` Guo Dong
2020-12-09 20:02 ` Lendacky, Thomas
2020-12-10 8:49 ` Laszlo Ersek
2020-12-10 14:37 ` Lendacky, Thomas
2020-12-10 16:54 ` Guo Dong
2020-12-11 1:47 ` Ni, Ray [this message]
2020-12-11 3:11 ` Guo Dong
-- strict thread matches above, loose matches on Subject: below --
2020-12-24 20:04 Guo Dong
2021-01-05 4:31 ` Michael D Kinney
2021-01-06 0:51 ` Guo Dong
2021-01-06 2:00 ` Michael D Kinney
2021-01-06 15:37 ` Laszlo Ersek
2021-01-06 14:25 ` Laszlo Ersek
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