[edk2-devel] [RFC PATCH 01/19] OvmfPkg: Reserve the Secrets and Cpuid page for the SEV-SNP guest
James Bottomley
jejb at linux.ibm.com
Wed Apr 7 00:44:52 UTC 2021
On Wed, 2021-04-07 at 00:21 +0000, Xu, Min M wrote:
> Hi, Laszlo
>
> For Intel TDX supported guest, all processors start in 32-bit
> protected
> mode, while for Non-Td guest, it starts in 16-bit real mode. To make
> the
> ResetVector work on both Td-guest and Non-Td guest, ResetVector are
> updated as below:
> ------------------------------------------------------------------
> ALIGN 16
> resetVector:
> ;
> ; Reset Vector
> ;
> ; This is where the processor will begin execution
> ;
> nop
> nop
> smsw ax
> test al, 1
> jnz EarlyBspPmEntry
> jmp EarlyBspInitReal16
Well, then use the rel8 jump like the compiler would in this situation:
smsw ax
test al, 1
jz 1f
jmp EarlyBspPmEntry
1:
jmp EarlyBspInitReal16
So now both entries can be 32k away.
James
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