From 0deeab36d179e79de7b93bb930b4d6eb24185416 Mon Sep 17 00:00:00 2001 From: James Bottomley Date: Sat, 16 Jan 2021 14:42:44 -0800 Subject: [PATCH] OvmfPkg/AmdSev: reserve MEMFD space for for firmware config hashes Split the existing 4KB page reserved for SEV launch secrets into two parts: first 3KB for SEV launch secrets and last 1KB for firmware config hashes. The area of the firmware config hashes will be attested (measured) by the PSP and thus the untrusted VMM can't pass in different files from what the guest owner allows. Declare this in the Reset Vector table using GUID 7255371f-3a3b-4b04-927b-1da6efa8d454 and a uint32_t table of a base and size value (similar to the structure used to declare the launch secret block). Cc: Ard Biesheuvel Cc: Jordan Justen Cc: Ashish Kalra Cc: Brijesh Singh Cc: Erdem Aktas Cc: James Bottomley Cc: Jiewen Yao Cc: Min Xu Cc: Tom Lendacky Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=3457 Co-developed-by: Dov Murik Signed-off-by: Dov Murik Signed-off-by: James Bottomley Reviewed-by: Tom Lendacky Reviewed-by: Brijesh Singh Reviewed-by: Jiewen Yao --- OvmfPkg/AmdSev/AmdSevX64.fdf | 5 ++++- OvmfPkg/OvmfPkg.dec | 6 ++++++ OvmfPkg/ResetVector/Ia16/ResetVectorVtf0.asm | 20 ++++++++++++++++++++ OvmfPkg/ResetVector/ResetVector.inf | 2 ++ OvmfPkg/ResetVector/ResetVector.nasmb | 2 ++ 5 files changed, 34 insertions(+), 1 deletion(-) diff --git a/OvmfPkg/AmdSev/AmdSevX64.fdf b/OvmfPkg/AmdSev/AmdSevX64.fdf index 9977b0f00a..0a89749700 100644 --- a/OvmfPkg/AmdSev/AmdSevX64.fdf +++ b/OvmfPkg/AmdSev/AmdSevX64.fdf @@ -59,9 +59,12 @@ gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecGhcbBase|gUefiOvmfPkgTokenSpaceGuid.PcdOvmf 0x00B000|0x001000 gUefiCpuPkgTokenSpaceGuid.PcdSevEsWorkAreaBase|gUefiCpuPkgTokenSpaceGuid.PcdSevEsWorkAreaSize -0x00C000|0x001000 +0x00C000|0x000C00 gUefiOvmfPkgTokenSpaceGuid.PcdSevLaunchSecretBase|gUefiOvmfPkgTokenSpaceGuid.PcdSevLaunchSecretSize +0x00CC00|0x000400 +gUefiOvmfPkgTokenSpaceGuid.PcdQemuHashTableBase|gUefiOvmfPkgTokenSpaceGuid.PcdQemuHashTableSize + 0x00D000|0x001000 gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecGhcbBackupBase|gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecGhcbBackupSize diff --git a/OvmfPkg/OvmfPkg.dec b/OvmfPkg/OvmfPkg.dec index f82228d69c..2ab27f0c73 100644 --- a/OvmfPkg/OvmfPkg.dec +++ b/OvmfPkg/OvmfPkg.dec @@ -324,6 +324,12 @@ gUefiOvmfPkgTokenSpaceGuid.PcdSevLaunchSecretBase|0x0|UINT32|0x42 gUefiOvmfPkgTokenSpaceGuid.PcdSevLaunchSecretSize|0x0|UINT32|0x43 + ## The base address and size of a hash table confirming allowed + # parameters to be passed in via the Qemu firmware configuration + # device + gUefiOvmfPkgTokenSpaceGuid.PcdQemuHashTableBase|0x0|UINT32|0x47 + gUefiOvmfPkgTokenSpaceGuid.PcdQemuHashTableSize|0x0|UINT32|0x48 + [PcdsDynamic, PcdsDynamicEx] gUefiOvmfPkgTokenSpaceGuid.PcdEmuVariableEvent|0|UINT64|2 gUefiOvmfPkgTokenSpaceGuid.PcdOvmfFlashVariablesEnable|FALSE|BOOLEAN|0x10 diff --git a/OvmfPkg/ResetVector/Ia16/ResetVectorVtf0.asm b/OvmfPkg/ResetVector/Ia16/ResetVectorVtf0.asm index 9c0b5853a4..7ec3c6e980 100644 --- a/OvmfPkg/ResetVector/Ia16/ResetVectorVtf0.asm +++ b/OvmfPkg/ResetVector/Ia16/ResetVectorVtf0.asm @@ -47,7 +47,27 @@ TIMES (15 - ((guidedStructureEnd - guidedStructureStart + 15) % 16)) DB 0 ; guidedStructureStart: +; SEV Hash Table Block ; +; This describes the guest ram area where the hypervisor should +; install a table describing the hashes of certain firmware configuration +; device files that would otherwise be passed in unchecked. The current +; use is for the kernel, initrd and command line values, but others may be +; added. The data format is: +; +; base physical address (32 bit word) +; table length (32 bit word) +; +; GUID (SEV FW config hash block): 7255371f-3a3b-4b04-927b-1da6efa8d454 +; +sevFwHashBlockStart: + DD SEV_FW_HASH_BLOCK_BASE + DD SEV_FW_HASH_BLOCK_SIZE + DW sevFwHashBlockEnd - sevFwHashBlockStart + DB 0x1f, 0x37, 0x55, 0x72, 0x3b, 0x3a, 0x04, 0x4b + DB 0x92, 0x7b, 0x1d, 0xa6, 0xef, 0xa8, 0xd4, 0x54 +sevFwHashBlockEnd: + ; SEV Secret block ; ; This describes the guest ram area where the hypervisor should diff --git a/OvmfPkg/ResetVector/ResetVector.inf b/OvmfPkg/ResetVector/ResetVector.inf index dc38f68919..d028c92d8c 100644 --- a/OvmfPkg/ResetVector/ResetVector.inf +++ b/OvmfPkg/ResetVector/ResetVector.inf @@ -47,3 +47,5 @@ [FixedPcd] gUefiOvmfPkgTokenSpaceGuid.PcdSevLaunchSecretBase gUefiOvmfPkgTokenSpaceGuid.PcdSevLaunchSecretSize + gUefiOvmfPkgTokenSpaceGuid.PcdQemuHashTableBase + gUefiOvmfPkgTokenSpaceGuid.PcdQemuHashTableSize diff --git a/OvmfPkg/ResetVector/ResetVector.nasmb b/OvmfPkg/ResetVector/ResetVector.nasmb index 8a3269cfc2..acec46a324 100644 --- a/OvmfPkg/ResetVector/ResetVector.nasmb +++ b/OvmfPkg/ResetVector/ResetVector.nasmb @@ -89,5 +89,7 @@ %define SEV_ES_AP_RESET_IP FixedPcdGet32 (PcdSevEsWorkAreaBase) %define SEV_LAUNCH_SECRET_BASE FixedPcdGet32 (PcdSevLaunchSecretBase) %define SEV_LAUNCH_SECRET_SIZE FixedPcdGet32 (PcdSevLaunchSecretSize) + %define SEV_FW_HASH_BLOCK_BASE FixedPcdGet32 (PcdQemuHashTableBase) + %define SEV_FW_HASH_BLOCK_SIZE FixedPcdGet32 (PcdQemuHashTableSize) %include "Ia16/ResetVectorVtf0.asm" -- 2.39.2