Re: [PATCH v11 00/46] SEV-ES guest support

["Lendacky, Thomas" <thomas.lendacky@amd.com>]

On 7/22/20 3:13 PM, Laszlo Ersek wrote:
> On 07/21/20 23:18, Tom Lendacky 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://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.amd.com%2Fsystem%2Ffiles%2FTechDocs%2F24593.pdf&amp;data=02%7C01%7Cthomas.lendacky%40amd.com%7C55f66571386d4639169308d82e7bb6c1%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637310457204828040&amp;sdata=FUhx4fmdzpMota0nG9nudA3aA%2F9Z4Pj2tShJL8UvyhI%3D&amp;reserved=0
>> [2] https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdeveloper.amd.com%2Fwp-content%2Fresources%2F56421.pdf&amp;data=02%7C01%7Cthomas.lendacky%40amd.com%7C55f66571386d4639169308d82e7bb6c1%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637310457204838018&amp;sdata=Krm34z0vbUIvbx3YUNdAFjVJ14hopxmR95tyfpUMquA%3D&amp;reserved=0
>>
>> ---
>>
>> These patches are based on commit:
>> 9132a31b9c83 ("MdeModulePkg/DxeCorePerformanceLib: Switch to UnicodeStrnToAsciiStrS")
>>
>> A version of the tree can be found at:
>> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2FAMDESE%2Fovmf%2Ftree%2Fsev-es-v19&amp;data=02%7C01%7Cthomas.lendacky%40amd.com%7C55f66571386d4639169308d82e7bb6c1%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637310457204838018&amp;sdata=IObhTmWtA4zHG1k5rM8lNjaUfOjYR%2BdV2b1pp2G7Lw4%3D&amp;reserved=0
>>
>> 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 v10:
>> - Fix conflicts around GccInline.c file after moving to latest commit
>> - Fix conflicts with OVMF PCD values after moving to latest commit
> 
> The updates in patch 29 (OvmfPkg: Create a GHCB page for use during Sec
> phase) look OK; thanks.
> 
> My understanding is that the MdePkg and MdeModulePkg patches remain
> needing approval; is that correct?

Yes, those are the only patches that don't have a Reviewed-by: or Acked-by:.

Thanks,
Tom

> 
> Thanks!
> Laszlo
>