From: "Gerd Hoffmann" <kraxel@redhat.com>
To: Min Xu <min.m.xu@intel.com>
Cc: devel@edk2.groups.io, Ard Biesheuvel <ardb+tianocore@kernel.org>,
Jordan Justen <jordan.l.justen@intel.com>,
Brijesh Singh <brijesh.singh@amd.com>,
Erdem Aktas <erdemaktas@google.com>,
James Bottomley <jejb@linux.ibm.com>,
Jiewen Yao <jiewen.yao@intel.com>,
Tom Lendacky <thomas.lendacky@amd.com>
Subject: Re: [PATCH V9 4/4] OvmfPkg: Enable TDX in ResetVector
Date: Tue, 12 Oct 2021 09:43:18 +0200 [thread overview]
Message-ID: <20211012074318.evyxxk67jbbauv57@sirius.home.kraxel.org> (raw)
In-Reply-To: <b5fad086a9804b80cab90d4fa2d035d550355a4c.1634005437.git.min.m.xu@intel.com>
Hi,
> +; Load the GDT and set the CR0.
> +;
> +; Modified: EAX, EBX, CR0, CR4, DS, ES, FS, GS, SS, CS
> +;
> +ReloadFlat32:
> +
> + cli
> + mov ebx, ADDR_OF(gdtr)
> + lgdt [ebx]
No need to modify ebx here, eax should do fine.
> + mov eax, SEC_DEFAULT_CR0
> + mov cr0, eax
> +
> + jmp LINEAR_CODE_SEL:dword ADDR_OF(jumpToFlat32BitAndLandHere)
> +
> +jumpToFlat32BitAndLandHere:
Strictly speaking this is not correct, you are already in Flat32 mode,
so this only loads cs.
> +InitTdx:
> + ;
> + ; Save EBX in EBP because EBX will be changed in ReloadFlat32
> + ;
> + mov ebp, ebx
See above, there is no need to modify ebx in ReloadFlat32.
Also: seems ebx is never restored ...
take care,
Gerd
next prev parent reply other threads:[~2021-10-12 7:43 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-12 2:37 [PATCH V9 0/4] Add Intel TDX support in OvmfPkg/ResetVector Min Xu
2021-10-12 2:37 ` [PATCH V9 1/4] OvmfPkg: Copy Main.asm from UefiCpuPkg to OvmfPkg's ResetVector Min Xu
2021-10-12 7:02 ` Gerd Hoffmann
2021-10-13 0:39 ` Min Xu
2021-10-12 2:37 ` [PATCH V9 2/4] OvmfPkg: Clear WORK_AREA_GUEST_TYPE in Main.asm Min Xu
2021-10-12 7:02 ` Gerd Hoffmann
2021-10-12 13:22 ` Lendacky, Thomas
2021-10-13 0:58 ` [edk2-devel] " Min Xu
2021-10-13 15:45 ` Brijesh Singh
2021-10-14 1:50 ` Min Xu
2021-10-12 2:37 ` [PATCH V9 3/4] OvmfPkg: Add IntelTdxMetadata.asm Min Xu
2021-10-12 7:22 ` Gerd Hoffmann
2021-10-13 11:44 ` [edk2-devel] " Brijesh Singh
2021-10-13 13:07 ` Gerd Hoffmann
2021-10-12 2:37 ` [PATCH V9 4/4] OvmfPkg: Enable TDX in ResetVector Min Xu
2021-10-12 7:43 ` Gerd Hoffmann [this message]
2021-10-13 5:16 ` [edk2-devel] " Min Xu
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