On 06/05/20 15:27, Tom Lendacky wrote:
> BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=2198
> 
> Reserve a fixed area of memory for SEV-ES use and set a fixed PCD,
> PcdSevEsWorkAreaBase, to this value.
> 
> This area will be used by SEV-ES support for two purposes:
>   1. Communicating the SEV-ES status during BSP boot to SEC:
>      Using a byte of memory from the page, the BSP reset vector code can
>      communicate the SEV-ES status to SEC for use before exception
>      handling can be enabled in SEC. After SEC, this field is no longer
>      valid and the standard way of determine if SEV-ES is active should
>      be used.
> 
>   2. Establishing an area of memory for AP boot support:
>      A hypervisor is not allowed to update an SEV-ES guest's register
>      state, so when booting an SEV-ES guest AP, the hypervisor is not
>      allowed to set the RIP to the guest requested value. Instead an
>      SEV-ES AP must be re-directed from within the guest to the actual
>      requested staring location as specified in the INIT-SIPI-SIPI
>      sequence.
> 
>      Use this memory for reset vector code that can be programmed to have
>      the AP jump to the desired RIP location after starting the AP. This
>      is required for only the very first AP reset.
> 
> Cc: Jordan Justen <jordan.l.jus...@intel.com>
> Cc: Laszlo Ersek <ler...@redhat.com>
> Cc: Ard Biesheuvel <ard.biesheu...@arm.com>
> Reviewed-by: Laszlo Ersek <ler...@redhat.com>
> Signed-off-by: Tom Lendacky <thomas.lenda...@amd.com>
> ---
> 
> This patch has been reverted to the previous v6 version.

Thanks!


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