mirror of https://github.com/acidanthera/audk.git
0bbed0664f
BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=2198 Protect the memory used by an SEV-ES guest when S3 is supported. This includes the page table used to break down the 2MB page that contains the GHCB so that it can be marked un-encrypted, as well as the GHCB area. Regarding the lifecycle of the GHCB-related memory areas: PcdOvmfSecGhcbPageTableBase PcdOvmfSecGhcbBase (a) when and how it is initialized after first boot of the VM If SEV-ES is enabled, the GHCB-related areas are initialized during the SEC phase [OvmfPkg/ResetVector/Ia32/PageTables64.asm]. (b) how it is protected from memory allocations during DXE If S3 and SEV-ES are enabled, then InitializeRamRegions() [OvmfPkg/PlatformPei/MemDetect.c] protects the ranges with an AcpiNVS memory allocation HOB, in PEI. If S3 is disabled, then these ranges are not protected. DXE's own page tables are first built while still in PEI (see HandOffToDxeCore() [MdeModulePkg/Core/DxeIplPeim/X64/DxeLoadFunc.c]). Those tables are located in permanent PEI memory. After CR3 is switched over to them (which occurs before jumping to the DXE core entry point), we don't have to preserve PcdOvmfSecGhcbPageTableBase. PEI switches to GHCB pages in permanent PEI memory and DXE will use these PEI GHCB pages, so we don't have to preserve PcdOvmfSecGhcbBase. (c) how it is protected from the OS If S3 is enabled, then (b) reserves it from the OS too. If S3 is disabled, then the range needs no protection. (d) how it is accessed on the S3 resume path It is rewritten same as in (a), which is fine because (b) reserved it. (e) how it is accessed on the warm reset path It is rewritten same as in (a). Cc: Jordan Justen <jordan.l.justen@intel.com> Cc: Laszlo Ersek <lersek@redhat.com> Cc: Ard Biesheuvel <ard.biesheuvel@arm.com> Cc: Anthony Perard <anthony.perard@citrix.com> Cc: Julien Grall <julien@xen.org> Reviewed-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> Regression-tested-by: Laszlo Ersek <lersek@redhat.com> |
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| .. | ||
| AmdSev.c | ||
| ClearCache.c | ||
| Cmos.c | ||
| Cmos.h | ||
| FeatureControl.c | ||
| Fv.c | ||
| MemDetect.c | ||
| MemTypeInfo.c | ||
| Platform.c | ||
| Platform.h | ||
| PlatformPei.inf | ||
| Xen.c | ||
| Xen.h | ||