Re: [PATCH v11 2/4] MdePkg: Introduce the SevMemoryAcceptance protocol

["Ard Biesheuvel" <ardb@kernel.org>]

On Fri, 27 Jan 2023 at 00:11, Tom Lendacky <thomas.lendacky@amd.com> wrote:
>
> Might want to fix up the commit title from MdePkg to OvmfPkg before
> committing.
>

I've fixed that up - thanks.


> On 1/26/23 15:17, Dionna Glaze wrote:
> > The default behavior for unaccepted memory in SEV-SNP is to accept all
> > memory when ExitBootServices is called. An OS loader can use this
> > protocol to disable this behavior to assume responsibility for memory
> > acceptance and to affirm that the OS can handle the unaccepted memory
> > type.
> >
> > Cc: Gerd Hoffmann <kraxel@redhat.com>
> > Cc: James Bottomley <jejb@linux.ibm.com>
> > Cc: Jiewen Yao <jiewen.yao@intel.com>
> > Cc: Tom Lendacky <thomas.lendacky@amd.com>
> > Cc: Ard Biesheuvel <ardb@kernel.org>
> > Cc: "Min M. Xu" <min.m.xu@intel.com>
> > Cc: Andrew Fish <afish@apple.com>
> > Cc: "Michael D. Kinney" <michael.d.kinney@intel.com>
> >
> > Signed-off-by: Dionna Glaze <dionnaglaze@google.com>
> > ---
> >   OvmfPkg/Include/Protocol/SevMemoryAcceptance.h | 42 ++++++++++++++++++++
> >   OvmfPkg/OvmfPkg.dec                            |  1 +
> >   2 files changed, 43 insertions(+)
> >
> > diff --git a/OvmfPkg/Include/Protocol/SevMemoryAcceptance.h b/OvmfPkg/Include/Protocol/SevMemoryAcceptance.h
> > new file mode 100644
> > index 0000000000..c45b499006
> > --- /dev/null
> > +++ b/OvmfPkg/Include/Protocol/SevMemoryAcceptance.h
> > @@ -0,0 +1,42 @@
> > +/** @file
> > +  The file provides the protocol that disables the behavior that all memory
> > +  gets accepted at ExitBootServices(). This protocol is only meant to be called
> > +  by the OS loader, and not EDK2 itself. The SEV naming is due to the coincidence
> > +  that only SEV-SNP needs this protocol, since SEV-SNP kernel support released
> > +  before kernel support for unaccepted memory. The technology enablement thus
> > +  does not strictly imply support for the unaccepted memory type.
> > +
> > +  Copyright (c) 2023, Google LLC. All rights reserved.<BR>
> > +  SPDX-License-Identifier: BSD-2-Clause-Patent
> > +**/
> > +
> > +#ifndef SEV_MEMORY_ACCEPTANCE_H_
> > +#define SEV_MEMORY_ACCEPTANCE_H_
> > +
> > +#define OVMF_SEV_MEMORY_ACCEPTANCE_PROTOCOL_GUID \
> > +  {0xc5a010fe, \
> > +   0x38a7, \
> > +   0x4531, \
> > +   {0x8a, 0x4a, 0x05, 0x00, 0xd2, 0xfd, 0x16, 0x49}}
> > +
> > +typedef struct _OVMF_SEV_MEMORY_ACCEPTANCE_PROTOCOL
> > +    OVMF_SEV_MEMORY_ACCEPTANCE_PROTOCOL;
> > +
> > +/**
> > +  @param This A pointer to a OVMF_SEV_MEMORY_ACCEPTANCE_PROTOCOL.
> > +**/
> > +typedef
> > +  EFI_STATUS
> > +(EFIAPI *OVMF_SEV_ALLOW_UNACCEPTED_MEMORY)(
> > +  IN  OVMF_SEV_MEMORY_ACCEPTANCE_PROTOCOL  *This
> > +  );
> > +
> > +///
> > +/// The OVMF_SEV_MEMORY_ACCEPTANCE_PROTOCOL allows the OS loader to
> > +/// indicate to EDK2 that ExitBootServices should not accept all memory.
> > +///
> > +struct _OVMF_SEV_MEMORY_ACCEPTANCE_PROTOCOL {
> > +  OVMF_SEV_ALLOW_UNACCEPTED_MEMORY    AllowUnacceptedMemory;
> > +};
> > +
> > +#endif
> > diff --git a/OvmfPkg/OvmfPkg.dec b/OvmfPkg/OvmfPkg.dec
> > index 1b521f2604..a22eb246c6 100644
> > --- a/OvmfPkg/OvmfPkg.dec
> > +++ b/OvmfPkg/OvmfPkg.dec
> > @@ -184,6 +184,7 @@
> >     gEfiLegacyInterruptProtocolGuid       = {0x31ce593d, 0x108a, 0x485d, {0xad, 0xb2, 0x78, 0xf2, 0x1f, 0x29, 0x66, 0xbe}}
> >     gEfiVgaMiniPortProtocolGuid           = {0xc7735a2f, 0x88f5, 0x4882, {0xae, 0x63, 0xfa, 0xac, 0x8c, 0x8b, 0x86, 0xb3}}
> >     gOvmfLoadedX86LinuxKernelProtocolGuid = {0xa3edc05d, 0xb618, 0x4ff6, {0x95, 0x52, 0x76, 0xd7, 0x88, 0x63, 0x43, 0xc8}}
> > +  gOvmfSevMemoryAcceptanceProtocolGuid  = {0xc5a010fe, 0x38a7, 0x4531, {0x8a, 0x4a, 0x05, 0x00, 0xd2, 0xfd, 0x16, 0x49}}
> >     gQemuAcpiTableNotifyProtocolGuid      = {0x928939b2, 0x4235, 0x462f, {0x95, 0x80, 0xf6, 0xa2, 0xb2, 0xc2, 0x1a, 0x4f}}
> >     gEfiMpInitLibMpDepProtocolGuid        = {0xbb00a5ca, 0x8ce,  0x462f, {0xa5, 0x37, 0x43, 0xc7, 0x4a, 0x82, 0x5c, 0xa4}}
> >     gEfiMpInitLibUpDepProtocolGuid        = {0xa9e7cef1, 0x5682, 0x42cc, {0xb1, 0x23, 0x99, 0x30, 0x97, 0x3f, 0x4a, 0x9f}}