On Thu, 26 Jan 2023 at 01:56, Dionna Glaze <dionnagl...@google.com> wrote:
>
> The added behavior is to accept all unaccepted memory at
> ExitBootServices if the behavior is not disabled. This allows safe
> upgrades for OS loaders to affirm their support for the unaccepted
> memory type.
>
> Cc: Gerd Hoffmann <kra...@redhat.com>
> Cc: James Bottomley <j...@linux.ibm.com>
> Cc: Jiewen Yao <jiewen....@intel.com>
> Cc: Tom Lendacky <thomas.lenda...@amd.com>
> Cc: Ard Biesheuvel <a...@kernel.org>
> Cc: "Min M. Xu" <min.m...@intel.com>
> Cc: Andrew Fish <af...@apple.com>
> Cc: "Michael D. Kinney" <michael.d.kin...@intel.com>
>
> Signed-off-by: Dionna Glaze <dionnagl...@google.com>
> ---
> OvmfPkg/AmdSevDxe/AmdSevDxe.c | 109 ++++++++++++++++++++
> OvmfPkg/AmdSevDxe/AmdSevDxe.inf | 1 +
> 2 files changed, 110 insertions(+)
>
> diff --git a/OvmfPkg/AmdSevDxe/AmdSevDxe.c b/OvmfPkg/AmdSevDxe/AmdSevDxe.c
> index f7600c3c81..5eec76fea2 100644
> --- a/OvmfPkg/AmdSevDxe/AmdSevDxe.c
> +++ b/OvmfPkg/AmdSevDxe/AmdSevDxe.c
> @@ -20,6 +20,7 @@
> #include <Library/UefiBootServicesTableLib.h>
> #include <Guid/ConfidentialComputingSevSnpBlob.h>
> #include <Library/PcdLib.h>
> +#include <Pi/PrePiDxeCis.h>
> #include <Protocol/MemoryAccept.h>
>
> STATIC CONFIDENTIAL_COMPUTING_SNP_BLOB_LOCATION mSnpBootDxeTable = {
> @@ -34,6 +35,10 @@ STATIC CONFIDENTIAL_COMPUTING_SNP_BLOB_LOCATION
> mSnpBootDxeTable = {
>
> STATIC EFI_HANDLE mAmdSevDxeHandle = NULL;
>
> +STATIC BOOLEAN mAcceptAllMemoryAtEBS = TRUE;
> +
> +STATIC EFI_EVENT mAcceptAllMemoryEvent = NULL;
> +
> #define IS_ALIGNED(x, y) ((((x) & ((y) - 1)) == 0))
>
> STATIC
> @@ -62,6 +67,94 @@ AmdSevMemoryAccept (
> return EFI_SUCCESS;
> }
>
> +STATIC
> +EFI_STATUS
> +AcceptAllMemory (
> + IN EDKII_MEMORY_ACCEPT_PROTOCOL *AcceptMemory
> + )
> +{
> + EFI_GCD_MEMORY_SPACE_DESCRIPTOR *AllDescMap;
> + UINTN NumEntries;
> + UINTN Index;
> + EFI_STATUS Status;
> +
> + DEBUG ((DEBUG_INFO, "Accepting all memory\n"));
> +
> + /*
> + * Get a copy of the memory space map to iterate over while
> + * changing the map.
> + */
> + Status = gDS->GetMemorySpaceMap (&NumEntries, &AllDescMap);
> + if (EFI_ERROR (Status)) {
> + return Status;
> + }
> +
> + for (Index = 0; Index < NumEntries; Index++) {
> + CONST EFI_GCD_MEMORY_SPACE_DESCRIPTOR *Desc;
> +
> + Desc = &AllDescMap[Index];
> + if (Desc->GcdMemoryType != EFI_GCD_MEMORY_TYPE_UNACCEPTED) {
> + continue;
> + }
> +
> + Status = AcceptMemory->AcceptMemory (
> + AcceptMemory,
> + Desc->BaseAddress,
> + Desc->Length
> + );
> + if (EFI_ERROR (Status)) {
> + break;
> + }
> +
> + Status = gDS->RemoveMemorySpace (Desc->BaseAddress, Desc->Length);
> + if (EFI_ERROR (Status)) {
> + break;
> + }
> +
> + Status = gDS->AddMemorySpace (
> + EfiGcdMemoryTypeSystemMemory,
> + Desc->BaseAddress,
> + Desc->Length,
> + EFI_MEMORY_CPU_CRYPTO | EFI_MEMORY_XP | EFI_MEMORY_RO |
> EFI_MEMORY_RP
> + );
> + if (EFI_ERROR (Status)) {
> + break;
> + }
> + }
> +
> + gBS->FreePool (AllDescMap);
> + return Status;
> +}
> +
> +VOID
> +EFIAPI
> +ResolveUnacceptedMemory (
> + IN EFI_EVENT Event,
> + IN VOID *Context
> + )
> +{
> + EDKII_MEMORY_ACCEPT_PROTOCOL *AcceptMemory;
> + EFI_STATUS Status;
> +
> + if (!mAcceptAllMemoryAtEBS) {
> + return;
> + }
> +
> + Status = gBS->LocateProtocol (
> + &gEdkiiMemoryAcceptProtocolGuid,
> + NULL,
> + (VOID **)&AcceptMemory
> + );
> + if (Status == EFI_NOT_FOUND) {
> + return;
> + }
> +
This driver is now both the producer and consumer of
gEdkiiMemoryAcceptProtocolGuid.
Are there cases where the protocol we locate here could be different
from the one installed by this driver? If not, we can simplify this,
and just call AmdSevMemoryAccept() directly.
> + ASSERT_EFI_ERROR (Status);
> +
> + Status = AcceptAllMemory (AcceptMemory);
> + ASSERT_EFI_ERROR (Status);
> +}
> +
> STATIC EDKII_MEMORY_ACCEPT_PROTOCOL mMemoryAcceptProtocol = {
> AmdSevMemoryAccept
> };
> @@ -195,6 +288,22 @@ AmdSevDxeEntryPoint (
> );
> ASSERT_EFI_ERROR (Status);
>
> + // SEV-SNP support does not automatically imply unaccepted memory
> support,
> + // so make ExitBootServices accept all unaccepted memory if support is
> + // not communicated.
> + Status = gBS->CreateEventEx (
> + EVT_NOTIFY_SIGNAL,
> + TPL_CALLBACK,
> + ResolveUnacceptedMemory,
> + NULL,
> + &gEfiEventBeforeExitBootServicesGuid,
> + &mAcceptAllMemoryEvent
> + );
> +
> + if (EFI_ERROR (Status)) {
> + DEBUG ((DEBUG_ERROR, "AllowUnacceptedMemory event creation for
> EventBeforeExitBootServices failed.\n"));
> + }
> +
> //
> // If its SEV-SNP active guest then install the
> CONFIDENTIAL_COMPUTING_SEV_SNP_BLOB.
> // It contains the location for both the Secrets and CPUID page.
> diff --git a/OvmfPkg/AmdSevDxe/AmdSevDxe.inf b/OvmfPkg/AmdSevDxe/AmdSevDxe.inf
> index cd1b686c53..5b443d45bc 100644
> --- a/OvmfPkg/AmdSevDxe/AmdSevDxe.inf
> +++ b/OvmfPkg/AmdSevDxe/AmdSevDxe.inf
> @@ -52,6 +52,7 @@
>
> [Guids]
> gConfidentialComputingSevSnpBlobGuid
> + gEfiEventBeforeExitBootServicesGuid
>
> [Pcd]
> gUefiOvmfPkgTokenSpaceGuid.PcdOvmfHostBridgePciDevId
> --
> 2.39.1.456.gfc5497dd1b-goog
>
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