Re: [edk2-devel] [PATCH v12 00/46] SEV-ES guest support

["Laszlo Ersek" <lersek@redhat.com>]

On 07/27/20 19:41, Laszlo Ersek wrote:
> Hi Tom,
> 
> On 07/27/20 17:25, Lendacky, Thomas wrote:
>> From: Tom Lendacky <thomas.lendacky@amd.com>
>>
>> This patch series provides support for running EDK2/OVMF under SEV-ES.
>>
>> Secure Encrypted Virtualization - Encrypted State (SEV-ES) expands on the
>> SEV support to protect the guest register state from the hypervisor. See
>> "AMD64 Architecture Programmer's Manual Volume 2: System Programming",
>> section "15.35 Encrypted State (SEV-ES)" [1].
>>
>> In order to allow a hypervisor to perform functions on behalf of a guest,
>> there is architectural support for notifying a guest's operating system
>> when certain types of VMEXITs are about to occur. This allows the guest to
>> selectively share information with the hypervisor to satisfy the requested
>> function. The notification is performed using a new exception, the VMM
>> Communication exception (#VC). The information is shared through the
>> Guest-Hypervisor Communication Block (GHCB) using the VMGEXIT instruction.
>> The GHCB format and the protocol for using it is documented in "SEV-ES
>> Guest-Hypervisor Communication Block Standardization" [2].
>>
>> The main areas of the EDK2 code that are updated to support SEV-ES are
>> around the exception handling support and the AP boot support.
>>
>> Exception support is required starting in Sec, continuing through Pei
>> and into Dxe in order to handle #VC exceptions that are generated.  Each
>> AP requires it's own GHCB page as well as a page to hold values specific
>> to that AP.
>>
>> AP booting poses some interesting challenges. The INIT-SIPI-SIPI sequence
>> is typically used to boot the APs. However, the hypervisor is not allowed
>> to update the guest registers. The GHCB document [2] talks about how SMP
>> booting under SEV-ES is performed.
>>
>> Since the GHCB page must be a shared (unencrypted) page, the processor
>> must be running in long mode in order for the guest and hypervisor to
>> communicate with each other. As a result, SEV-ES is only supported under
>> the X64 architecture.
>>
>> [1] https://www.amd.com/system/files/TechDocs/24593.pdf
>> [2] https://developer.amd.com/wp-content/resources/56421.pdf
>>
>> ---
>>
>> These patches are based on commit:
>> 6074f57e5b19 ("MdePkg/Include/IndustryStandard: Main CXL header")
>>
>> A version of the tree can be found at:
>> https://github.com/AMDESE/ovmf/tree/sev-es-v20
>>
>> Cc: Andrew Fish <afish@apple.com>
>> Cc: Anthony Perard <anthony.perard@citrix.com>
>> Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
>> Cc: Benjamin You <benjamin.you@intel.com>
>> Cc: Dandan Bi <dandan.bi@intel.com>
>> Cc: Eric Dong <eric.dong@intel.com>
>> Cc: Guo Dong <guo.dong@intel.com>
>> Cc: Hao A Wu <hao.a.wu@intel.com>
>> Cc: Jian J Wang <jian.j.wang@intel.com>
>> Cc: Jordan Justen <jordan.l.justen@intel.com>
>> Cc: Julien Grall <julien@xen.org>
>> Cc: Laszlo Ersek <lersek@redhat.com>
>> Cc: Leif Lindholm <leif@nuviainc.com>
>> Cc: Liming Gao <liming.gao@intel.com>
>> Cc: Maurice Ma <maurice.ma@intel.com>
>> Cc: Michael D Kinney <michael.d.kinney@intel.com>
>> Cc: Ray Ni <ray.ni@intel.com>
>>
>> Changes since v11:
>> - Make the XGETBV and VMGEXIT .nasm files buildable for all environments
>>   and remove the updates that add these instructions to GccInline.c
> 
> Patches 40-46 (inclusive) seem to be missing from my mailbox (and the
> list archive on groups.io lacks them too, apparently).
> 
> Did you get rate-limited by some component when sending the series, perhaps?

On a second / closer look, that seems quite likely, because my INBOX
does have all the (directly delivered) patches; only my list folder is
missing the tail.

Thanks
Laszlo