Re: [edk2-devel] [PATCH v3 0/3] SEV Page Encryption Bitmap support for OVMF.

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

On 12/08/20 15:57, Lendacky, Thomas wrote:
> On 12/7/20 8:44 PM, Laszlo Ersek wrote:
>> On 12/04/20 09:10, Ashish Kalra wrote:
>>> On Fri, Dec 04, 2020 at 04:50:05AM +0100, Laszlo Ersek wrote:
>>>> On 12/04/20 01:03, Ashish Kalra wrote:
>>>>> From: Ashish Kalra <ashish.kalra@amd.com>
>>>>>
>>>>> By default all the SEV guest memory regions are considered encrypted,
>>>>> if a guest changes the encryption attribute of the page (e.g mark a
>>>>> page as decrypted) then notify hypervisor. Hypervisor will need to
>>>>> track the unencrypted pages. The information will be used during
>>>>> guest live migration, guest page migration and guest debugging.
>>>>>
>>>>> The patch-set also adds a new SEV and SEV-ES hypercall abstraction
>>>>> library to support SEV Page encryption/decryption status hypercalls
>>>>> for SEV and SEV-ES guests.
>>>>>
>>>>> BaseMemEncryptSevLib invokes hypercalls via this new hypercall library.
>>>>>
>>>>> A branch containing these patches is available here:
>>>>> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fashkalra%2Fedk2%2Ftree%2Fsev_page_encryption_bitmap_v3&amp;data=04%7C01%7Cthomas.lendacky%40amd.com%7Caa286d7e06864008110008d89b233ebc%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637429922982193672%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=EjrGD2LNlji8ualk8KClh%2BhqJa5Fm0UzlmPc4%2FQvb2g%3D&amp;reserved=0
>>>>>
>>>>> Changes since v2:
>>>>>  - GHCB_BASE setup during reset-vector as decrypted is marked explicitly
>>>>>    in the hypervisor page encryption bitmap after setting the 
>>>>>    PcdSevEsIsEnabled PCD.
>>>>>
>>>>> Changes since v1:
>>>>>  - Mark GHCB_BASE setup during reset-vector as decrypted explicitly in
>>>>>    the hypervisor page encryption bitmap.
>>>>>  - Resending the series with correct shallow threading.
>>>>>
>>>>> Ashish Kalra (2):
>>>>>   OvmfPkg/MemEncryptHypercallLib: add library to support SEV hypercalls.
>>>>>   OvmfPkg/PlatformPei: Mark SEC GHCB page in the page encrpytion bitmap.
>>>>>
>>>>> Brijesh Singh (1):
>>>>>   OvmfPkg/BaseMemEncryptLib: Support to issue unencrypted hypercall
>>>>>
>>>>>  .../Include/Library/MemEncryptHypercallLib.h  |  37 ++++++
>>>>>  .../BaseMemEncryptSevLib.inf                  |   1 +
>>>>>  .../BaseMemEncryptSevLib/X64/VirtualMemory.c  |  18 +++
>>>>>  .../MemEncryptHypercallLib.c                  | 105 ++++++++++++++++++
>>>>>  .../MemEncryptHypercallLib.inf                |  39 +++++++
>>>>>  .../X64/AsmHelperStub.nasm                    |  39 +++++++
>>>>>  OvmfPkg/OvmfPkgX64.dsc                        |   1 +
>>>>>  OvmfPkg/PlatformPei/AmdSev.c                  |  10 ++
>>>>>  8 files changed, 250 insertions(+)
>>>>>  create mode 100644 OvmfPkg/Include/Library/MemEncryptHypercallLib.h
>>>>>  create mode 100644 OvmfPkg/Library/MemEncryptHypercallLib/MemEncryptHypercallLib.c
>>>>>  create mode 100644 OvmfPkg/Library/MemEncryptHypercallLib/MemEncryptHypercallLib.inf
>>>>>  create mode 100644 OvmfPkg/Library/MemEncryptHypercallLib/X64/AsmHelperStub.nasm
>>>>>
>>>>
>>>> I'll need some time to get to this series.
>>>>
>>>> I'm fairly certain though, from a quick skim, that this series breaks
>>>> all DSC files under OvmfPkg except X64. Please fix that.
>>>>
>>>>
>>>
>>> Ok thanks Laszlo, i will fix this.
>>
>> Thanks.
>>
>> I can see a new comment for the series from Dov Murik, and I think
>> that's awesome. I'd welcome if there were lively exchanges around OVMF
>> patch sets. I'm selfish of course: I'd like to delegate reviews.
>>
>> So, on this patch set, I notice it does not add the new
>> (MemEncryptHypercallLib-related) files to Maintainers.txt, namely
>> section "OvmfPkg: SEV-related modules".
>>
>> Please include such a patch in v4 -- if Tom and Brijesh agree, I'd like
>> to put the new lib explicitly under their reviewership.
> 
> Yes, no issues with that.

Thank you guys!
Laszlo

> 
>>
>> Also, I plan to review this series (v4, at this point) only for
>> formalities. I'd like to receive an R-b from Tom or Brijesh [*], and
>> another from Dov or a colleague at IBM, for this series; those together
>> should suffice for merging the library.
>>
>> [*] Brijesh seems to be the original author of patch#2, so maybe Tom is
>> a better-poised reviewer for this.
> 
> Will do. I know a new version is coming as well as discussion about the
> hypercall in general, so lets see where that goes.
> 
> Thanks,
> Tom
> 
>>
>> Thanks
>> Laszlo
>>
> 
> 
> 
> 
>