[edk2-devel] [PATCH v2 3/4] OvmfPkg: Define a new PPI GUID to signal TPM MMIO accessability

[Lendacky, Thomas]

From: Tom Lendacky <thomas.lendacky at amd.com>

Define a new PPI GUID that is to be used as a signal of when it is safe
to access the TPM MMIO range. This is needed so that, when SEV is active,
the MMIO range can be mapped unencrypted before it is accessed.

Cc: Laszlo Ersek <lersek at redhat.com>
Cc: Ard Biesheuvel <ardb+tianocore at kernel.org>
Cc: Jordan Justen <jordan.l.justen at intel.com>
Cc: Brijesh Singh <brijesh.singh at amd.com>
Cc: Erdem Aktas <erdemaktas at google.com>
Cc: James Bottomley <jejb at linux.ibm.com>
Cc: Jiewen Yao <jiewen.yao at intel.com>
Cc: Min Xu <min.m.xu at intel.com>
Cc: Marc-Andr?? Lureau <marcandre.lureau at redhat.com>
Cc: Stefan Berger <stefanb at linux.ibm.com>
Signed-off-by: Tom Lendacky <thomas.lendacky at amd.com>
---
 OvmfPkg/OvmfPkg.dec | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/OvmfPkg/OvmfPkg.dec b/OvmfPkg/OvmfPkg.dec
index 9629707020ba..6ae733f6e39f 100644
--- a/OvmfPkg/OvmfPkg.dec
+++ b/OvmfPkg/OvmfPkg.dec
@@ -128,6 +128,10 @@ [Ppis]
   # has been discovered and recorded
   gOvmfTpmDiscoveredPpiGuid             = {0xb9a61ad0, 0x2802, 0x41f3, {0xb5, 0x13, 0x96, 0x51, 0xce, 0x6b, 0xd5, 0x75}}
 
+  # This PPI signals that accessing the MMIO range of the TPM is possible in
+  # the PEI phase, regardless of memory encryption
+  gOvmfTpmMmioAccessiblePpiGuid         = {0x35c84ff2, 0x7bfe, 0x453d, {0x84, 0x5f, 0x68, 0x3a, 0x49, 0x2c, 0xf7, 0xb7}}
+
 [Protocols]
   gVirtioDeviceProtocolGuid             = {0xfa920010, 0x6785, 0x4941, {0xb6, 0xec, 0x49, 0x8c, 0x57, 0x9f, 0x16, 0x0a}}
   gXenBusProtocolGuid                   = {0x3d3ca290, 0xb9a5, 0x11e3, {0xb7, 0x5d, 0xb8, 0xac, 0x6f, 0x7d, 0x65, 0xe6}}
-- 
2.31.0



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