[edk2-devel] [PATCH v8 0/7] Add safe unaccepted memory behavior
Dionna Glaze via groups.io
dionnaglaze=google.com at groups.io
Tue Nov 8 16:22:46 UTC 2022
On Tue, Nov 8, 2022 at 8:09 AM Yao, Jiewen <jiewen.yao at intel.com> wrote:
>
> Hi Tom/Dionna
> I think this patch is addressing https://bugzilla.tianocore.org/show_bug.cgi?id=3987.
>
> For patch 1~3, I am OK for the API which we already agreed, such as EfiMemoryAcceptProtocol and EFI_EVENT_GROUP_BEFORE_EXIT_BOOT_SERVICES.
> I have given Acked by: Jiewen Yao <Jiewen.yao at intel.com>
>
> For patch 4, it changed the behavior to accept all. I don’t believe it should be 4. It should be the latest one. (please correct me if I am wrong.)
>
The acceptance protocol (5-6) and the accept-all behavior (4) could be
swapped in order, but they really only make sense as a pair. No client
would use a new protocol to disable the behavior of something that
doesn't happen.
The accept-all behavior (4) must be default before SEV-SNP introduces
unaccepted memory (7).
> For patch 5~6, I cannot give R-B for BZ3987_MEMORY_ACCEPTANCE_PROTOCAL proposed here because it does not address my concern. Please refer to the discussion in the Bugzilla.
>
I don't think your concern is addressable given the constraints of a
smooth upgrade path. I think the right folks to discuss this with you
from the Intel side are Min Xu and Kirill Shutemov. Kirill will know
what is feasible for the OS to inform the UEFI of in terms of memory
required, and how to not break OSes that don't use the new protocol,
whereas Min should know where that kind of information should be
communicated.
>
> If you want to split the patch series and submit 1~3 as standalone one, that will match SEV to TDX on lazy accept part. I believe we may merge them after we get R-B from right person.
>
I can do that.
> Thank you
> Yao, Jiewen
>
>
> > -----Original Message-----
> > From: devel at edk2.groups.io <devel at edk2.groups.io> On Behalf Of
> > Lendacky, Thomas via groups.io
> > Sent: Tuesday, November 8, 2022 10:38 PM
> > To: Dionna Glaze <dionnaglaze at google.com>; devel at edk2.groups.io
> > Cc: Ard Biescheuvel <ardb at kernel.org>; Xu, Min M <min.m.xu at intel.com>;
> > Gerd Hoffmann <kraxel at redhat.com>; James Bottomley
> > <jejb at linux.ibm.com>; Yao, Jiewen <jiewen.yao at intel.com>; Aktas, Erdem
> > <erdemaktas at google.com>; Andrew Fish <afish at apple.com>; Kinney,
> > Michael D <michael.d.kinney at intel.com>
> > Subject: Re: [edk2-devel] [PATCH v8 0/7] Add safe unaccepted memory
> > behavior
> >
> > On 10/24/22 15:41, Dionna Glaze wrote:
> > > These seven patches build on the lazy-accept patch series
> > >
> > > "Introduce Lazy-accept for Tdx guest"
> >
> > Since the above series was accepted into the EDK2 tree, can this series
> > also be pulled in so that both TDX and SNP can support unaccepted
> > memory
> > in the same release?
> >
> > Thanks,
> > Tom
> >
> > >
> > > by adding SEV-SNP support for the MemoryAccept protocol, and
> > > importantly making eager memory acceptance the default behavior.
> > >
> > > We implement a standardized event group from UEFI v2.9,
> > > EFI_EVENT_GROUP_BEFORE_EXIT_BOOT_SERVICES, since it provides
> > exactly
> > > the right invocation point for eagerly accepting memory if eager
> > > acceptance has not been disabled.
> > >
> > > To make use of this event group, we add a new driver that is meant to
> > > carry behavior that is needed for all confidential compute technologies,
> > > not just specific platforms, CocoDxe. In CocoDxe we implement the
> > > default safe behavior to accept all unaccepted memory and invalidate
> > > the MemoryMap on ExitBootServices.
> > >
> > > To allow the OS loader to prevent the eager acceptance, we add a new
> > > protocol, up for standardization, AcceptAllUnacceptedMemoryProtocol.
> > > This protocol has one interface, Disable(). The OS loader can inform the
> > > UEFI that it supports the unaccepted memory type and accepts the
> > > responsibility to accept it.
> > >
> > > All images that support unaccepted memory must now locate and call
> > this
> > > new BZ3987_ACCEPT_ALL_UNACCEPTED_MEMORY_PROTOCOL and call
> > the Disable
> > > function.
> > >
> > > Changes since v7:
> > > - Rebased onto lazy accept v4 patch series, so memory accept protocol
> > > has the EDKII prefix, and the unaccepted memory type has the BZ3937
> > > prefix.
> > > - Removed a bad #include to a header removed in v7.
> > > - Renamed the protocol to BZ3987_MEMORY_ACCEPTANCE_PROTOCOL
> > as per the
> > > discussion on the buganizer issue.
> > > - Uncrustify formatting
> > >
> > > Changes since v6:
> > > - Added implementation of
> > EFI_EVENT_GROUP_BEFORE_EXIT_BOOT_SERVICES.
> > > - Changed callback protocol of v5 to instead use the standardized event
> > > group for before_exit_boot_services.
> > >
> > > Changes since v5:
> > > - Generic callback protocol moved to MdeModulePkg
> > > - Removed use of EFI_WARN_STALE_DATA and added comment that the
> > callback
> > > should only return EFI_SUCCESS or EFI_INVALID_PARAMETER.
> > > - Removed errant log statement and fixed formatting.
> > >
> > > Changes since v4:
> > > - Commit message wording
> > > - Replaced direct change to DxeMain with a more generic callback
> > > protocol.
> > > - Implemented the direct change as an instance of the callback protocol
> > > from a new CocoDxe driver.
> > > - Replaced "enable" protocol with a "disable" protocol, since the name
> > > was confusing. The AcceptAllUnacceptedMemory protocol directly
> > names
> > > the behavior that is disabling.
> > >
> > > Changes since v3:
> > > - "DxeMain accepts all memory" patch split into 3 to make each patch
> > > affect only one package at a time.
> > >
> > > Changes since v2:
> > > - Removed the redundant memory accept interface and added the accept
> > > behavior to the DXE implementation of
> > > MemEncryptSevSnpPreValidateSystemRam.
> > > - Fixed missing #include in >=4GB patch.
> > >
> > > Changes since v1:
> > > - Added a patch to classify SEV-SNP memory above 4GB unaccepted.
> > > - Fixed style problems in EfiMemoryAcceptProtocol implementation.
> > >
> > > Cc: Ard Biescheuvel <ardb at kernel.org>
> > > Cc: "Min M. Xu" <min.m.xu at intel.com>
> > > Cc: Gerd Hoffmann <kraxel at redhat.com>
> > > Cc: James Bottomley <jejb at linux.ibm.com>
> > > Cc: Tom Lendacky <Thomas.Lendacky at amd.com>
> > > Cc: Jiewen Yao <jiewen.yao at intel.com>
> > > Cc: Erdem Aktas <erdemaktas at google.com>
> > > Cc: Andrew Fish <afish at apple.com>
> > > Cc: "Michael D. Kinney" <michael.d.kinney at intel.com>
> > >
> > > Signed-off-by: Dionna Glaze <dionnaglaze at google.com>
> > >
> > > Dionna Glaze (7):
> > > OvmfPkg: Realize EfiMemoryAcceptProtocol in AmdSevDxe
> > > MdePkg: Add EFI_EVENT_BEFORE_EXIT_BOOT_SERVICES_GUID
> > > MdeModulePkg: Notify BeforeExitBootServices in CoreExitBootServices
> > > OvmfPkg: Introduce CocoDxe driver
> > > MdePkg: Introduce the MemoryAcceptance protocol
> > > OvmfPkg: Implement AcceptAllUnacceptedMemory in CocoDxe
> > > OvmfPkg/PlatformPei: SEV-SNP make >=4GB unaccepted
> > >
> > > MdeModulePkg/Core/Dxe/DxeMain.inf | 1 +
> > > MdeModulePkg/Core/Dxe/DxeMain/DxeMain.c | 6 +
> > > MdePkg/Include/Guid/EventGroup.h | 5 +
> > > MdePkg/Include/Protocol/MemoryAcceptance.h | 40
> > +++++
> > > MdePkg/MdePkg.dec | 8 +-
> > > OvmfPkg/AmdSev/AmdSevX64.dsc | 1 +
> > > OvmfPkg/AmdSev/AmdSevX64.fdf | 1 +
> > > OvmfPkg/AmdSevDxe/AmdSevDxe.c | 55 ++++++-
> > > OvmfPkg/AmdSevDxe/AmdSevDxe.inf | 3 +
> > > OvmfPkg/CocoDxe/CocoDxe.c | 174
> > ++++++++++++++++++++
> > > OvmfPkg/CocoDxe/CocoDxe.inf | 46 ++++++
> > > OvmfPkg/IntelTdx/IntelTdxX64.dsc | 1 +
> > > OvmfPkg/IntelTdx/IntelTdxX64.fdf | 1 +
> > >
> > OvmfPkg/Library/BaseMemEncryptSevLib/X64/DxeSnpSystemRamValidate.
> > c | 24 ++-
> > > OvmfPkg/OvmfPkgIa32X64.dsc | 1 +
> > > OvmfPkg/OvmfPkgIa32X64.fdf | 1 +
> > > OvmfPkg/OvmfPkgX64.dsc | 1 +
> > > OvmfPkg/OvmfPkgX64.fdf | 1 +
> > > OvmfPkg/PlatformPei/AmdSev.c | 5 +
> > > 19 files changed, 366 insertions(+), 9 deletions(-)
> > > create mode 100644 MdePkg/Include/Protocol/MemoryAcceptance.h
> > > create mode 100644 OvmfPkg/CocoDxe/CocoDxe.c
> > > create mode 100644 OvmfPkg/CocoDxe/CocoDxe.inf
> > >
> >
> >
> >
> >
>
--
-Dionna Glaze, PhD (she/her)
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