From: "Lendacky, Thomas" <thomas.lendacky@amd.com>
To: devel@edk2.groups.io
Cc: Brijesh Singh <brijesh.singh@amd.com>,
James Bottomley <jejb@linux.ibm.com>,
Jordan Justen <jordan.l.justen@intel.com>,
Laszlo Ersek <lersek@redhat.com>,
Ard Biesheuvel <ard.biesheuvel@arm.com>
Subject: [PATCH v3 04/15] OvmfPkg/ResetVector: Perform a simple SEV-ES sanity check
Date: Thu, 7 Jan 2021 12:48:14 -0600 [thread overview]
Message-ID: <afa2030b95b852313b13982df82d472187e59b92.1610045305.git.thomas.lendacky@amd.com> (raw)
In-Reply-To: <cover.1610045305.git.thomas.lendacky@amd.com>
From: Tom Lendacky <thomas.lendacky@amd.com>
BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3108
If a hypervisor incorrectly reports through CPUID that SEV-ES is not
active, ensure that a #VC exception was not taken. If it is found that
a #VC was taken, then the code enters a HLT loop.
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
---
OvmfPkg/ResetVector/Ia32/PageTables64.asm | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/OvmfPkg/ResetVector/Ia32/PageTables64.asm b/OvmfPkg/ResetVector/Ia32/PageTables64.asm
index ccc95ad4715d..a1771dfdec23 100644
--- a/OvmfPkg/ResetVector/Ia32/PageTables64.asm
+++ b/OvmfPkg/ResetVector/Ia32/PageTables64.asm
@@ -154,6 +154,22 @@ SevEncBitLowHlt:
jmp SevEncBitLowHlt
NoSev:
+ ;
+ ; Perform an SEV-ES sanity check by seeing if a #VC exception occurred.
+ ;
+ cmp byte[SEV_ES_WORK_AREA], 0
+ jz NoSevPass
+
+ ;
+ ; A #VC was received, yet CPUID indicates no SEV-ES support, something
+ ; isn't right.
+ ;
+NoSevEsVcHlt:
+ cli
+ hlt
+ jmp NoSevEsVcHlt
+
+NoSevPass:
xor eax, eax
SevExit:
--
2.30.0
next prev parent reply other threads:[~2021-01-07 18:49 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-07 18:48 [PATCH v3 00/15] SEV-ES security mitigations Lendacky, Thomas
2021-01-07 18:48 ` [PATCH v3 01/15] Ovmf/ResetVector: Simplify and consolidate the SEV features checks Lendacky, Thomas
2021-01-07 18:48 ` [PATCH v3 02/15] OvmfPkg/Sec: Move SEV-ES SEC workarea definition to common header file Lendacky, Thomas
2021-01-07 18:48 ` [PATCH v3 03/15] OvmfPkg/ResetVector: Validate the encryption bit position for SEV/SEV-ES Lendacky, Thomas
2021-01-07 18:48 ` Lendacky, Thomas [this message]
2021-01-07 18:48 ` [PATCH v3 05/15] OvmfPkg/ResetVector: Save the encryption mask at boot time Lendacky, Thomas
2021-01-07 18:48 ` [PATCH v3 06/15] OvmfPkg/MemEncryptSevLib: Add an interface to retrieve the encryption mask Lendacky, Thomas
2021-01-07 18:48 ` [PATCH v3 07/15] OvmfPkg: Obtain SEV encryption mask with the new MemEncryptSevLib API Lendacky, Thomas
2021-01-07 18:48 ` [PATCH v3 08/15] OvmfPkg/AmdSevDxe: Clear encryption bit on PCIe MMCONFIG range Lendacky, Thomas
2021-01-07 18:48 ` [PATCH v3 09/15] OvmfPkg/VmgExitLib: Check for an explicit DR7 cached value Lendacky, Thomas
2021-01-07 18:48 ` [PATCH v3 10/15] OvmfPkg/MemEncryptSevLib: Coding style fixes in prep for SEC library Lendacky, Thomas
2021-01-07 18:48 ` [PATCH v3 11/15] OvmfPkg/MemEncryptSevLib: Make the MemEncryptSevLib available for SEC Lendacky, Thomas
2021-01-07 19:08 ` [edk2-devel] " Laszlo Ersek
2021-01-07 18:48 ` [PATCH v3 12/15] OvmfPkg/MemEncryptSevLib: Address range encryption state interface Lendacky, Thomas
2021-01-07 18:48 ` [PATCH v3 13/15] OvmfPkg/VmgExitLib: Support nested #VCs Lendacky, Thomas
2021-01-07 18:48 ` [PATCH v3 14/15] OvmfPkg/PlatformPei: Reserve GHCB backup pages if S3 is supported Lendacky, Thomas
2021-01-07 18:48 ` [PATCH v3 15/15] OvfmPkg/VmgExitLib: Validate #VC MMIO is to un-encrypted memory Lendacky, Thomas
2021-01-07 19:41 ` [edk2-devel] [PATCH v3 00/15] SEV-ES security mitigations Laszlo Ersek
2021-01-07 19:50 ` Lendacky, Thomas
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