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

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

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.

> 
> 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
>