BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=4353
Due to AMD erratum #1467, an SEV-SNP VMSA should not be 2MB aligned. To
work around this issue, allocate two pages instead of one. Because of the
way that page allocation is implemented, always try to use the second
page. If the second page is not 2MB aligned, free the first page and use
the second page. If the second page is 2MB aligned, free the second page
and use the first page. Freeing in this way reduces holes in the memory
map.
Fixes: 06544455d0 ("UefiCpuPkg/MpInitLib: Use SEV-SNP AP Creation ...")
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Ray Ni <ray.ni@intel.com>
https://bugzilla.tianocore.org/show_bug.cgi?id=4353
When parking the APs on exiting from UEFI, a new page allocation is made.
This allocation, however, does not end up being marked reserved in the
memory map supplied to the OS. To avoid this, re-use the VMSA by clearing
the VMSA RMP flag, updating the page contents and re-setting the VMSA RMP
flag.
Fixes: 06544455d0 ("UefiCpuPkg/MpInitLib: Use SEV-SNP AP Creation ...")
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Ray Ni <ray.ni@intel.com>
