Hi Jiewen,
On 8/4/21 9:18 PM, Yao, Jiewen wrote:
HI Brijesh
Thanks for the startup. Feedback below:
1) I don't think we need a PCD to indicate the header.
gUefiOvmfPkgTokenSpaceGuid.PcdOvmfWorkAreaHeaderSize|4|UINT32|0x51
Instead, if we define a HEADER structure, we can use sizeof() naturally.
Otherwise, when we update this header, we need update 2 different places, which
is not preferred.
Can you use the sizeof() inside the OvmfPkg.fdf ? I was not able to find
a reference usage for it in this file. Also, can a .fdf refer the C
header file ?
We need to know the size of the header so that we can set the fixed
PcdOvmfSevEsWorkArea. In the current approach the .fdf sets the PCD as
shown below:
SET PcdOvmfSevEsWorkArea = PcdOvmfWorkAreaBase + <HeaderSize>
I am hard coding the header size to be 4 so that pcd points to the
correct location within the WorkArea.
thanks
typedef struct {
UINT8 GuestType;
UINT8 Reserved1[3];
} CONFIDENTIAL_COMPUTING_WORK_AREA_HEADER;
2) I don't think we can define a common structure OVMF_WORK_AREA to contain SEV
specific field.
typedef struct _OVMF_WORK_AREA {
UINT8 GuestType;
UINT8 Reserved1[3];
SEC_SEV_ES_WORK_AREA SevEsWorkArea;
} OVMF_WORK_AREA;
A common patter is to define each individual structure, then use UNION.
For example,
typedef struct {
UINT8 GuestType;
UINT8 Reserved1[3];
SEC_SEV_ES_WORK_AREA SevEsWorkArea;
} SEV_WORK_AREA;
typedef union {
CONFIDENTIAL_COMPUTING_WORK_AREA_HEADER Header;
SEV_WORK_AREA Sev;
} OVMF_WORK_AREA;
-----Original Message-----
From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Brijesh
Singh via groups.io
Sent: Thursday, August 5, 2021 4:20 AM
To: devel@edk2.groups.io
Cc: James Bottomley <j...@linux.ibm.com>; Xu, Min M <min.m...@intel.com>;
Yao, Jiewen <jiewen....@intel.com>; Tom Lendacky
<thomas.lenda...@amd.com>; Justen, Jordan L <jordan.l.jus...@intel.com>;
Ard Biesheuvel <ardb+tianoc...@kernel.org>; Erdem Aktas
<erdemak...@google.com>; Michael Roth <michael.r...@amd.com>; Brijesh
Singh <brijesh.si...@amd.com>
Subject: [edk2-devel] [PATCH 0/3] reuse the SevEsWork area
Based on the discussion on the mailing list, we agreed that instead
of wasting extra page in the MEMFD, we can reuse the SevEsWorkArea
buffer for the TDX. To avoid any confusion, lets introduce a OvmfWorkArea
that will contains 32 bytes of header followed by the actual workarea.
While at it, move the code to clear the GHCB page from PageTable build
to AmdSev.asm.
I have used the existing TDX BZ for it because the request came
during the TDX patch review. if anyone have concern please let me know
and I will happily create a new BZ.
Full tree is at:
https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2FAMDESE%2Fovmf%2Ftree%2Fsev-new-work-area&data=04%7C01%7Cbrijesh.singh%40amd.com%7C4c55a642f1804a803c4e08d957b75e61%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637637267367225365%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=NSsUVfQodJMDUcpLCsHSpTaRDHM8et%2BWZJOS8lCS3Kw%3D&reserved=0
Brijesh Singh (3):
OvmfPkg: introduce a common work area
OvmfPkg/ResetVector: update SEV support to use new work area format
OvmfPkg/ResetVector: move the GHCB page setup in AmdSev.asm
Cc: James Bottomley <j...@linux.ibm.com>
Cc: Min Xu <min.m...@intel.com>
Cc: Jiewen Yao <jiewen....@intel.com>
Cc: Tom Lendacky <thomas.lenda...@amd.com>
Cc: Jordan Justen <jordan.l.jus...@intel.com>
Cc: Ard Biesheuvel <ardb+tianoc...@kernel.org>
Cc: Erdem Aktas <erdemak...@google.com>
OvmfPkg/OvmfPkg.dec | 6 ++
OvmfPkg/OvmfPkgX64.fdf | 9 +-
OvmfPkg/PlatformPei/PlatformPei.inf | 4 +-
OvmfPkg/ResetVector/ResetVector.inf | 1 +
OvmfPkg/Sec/SecMain.inf | 1 +
OvmfPkg/Include/Library/MemEncryptSevLib.h | 21 +---
OvmfPkg/Include/WorkArea.h | 53 ++++++++++
OvmfPkg/PlatformPei/MemDetect.c | 32 +++---
OvmfPkg/Sec/SecMain.c | 25 ++++-
OvmfPkg/ResetVector/Ia32/AmdSev.asm | 111 +++++++++++++++++----
OvmfPkg/ResetVector/Ia32/PageTables64.asm | 57 ++---------
OvmfPkg/ResetVector/ResetVector.nasmb | 1 +
12 files changed, 213 insertions(+), 108 deletions(-)
create mode 100644 OvmfPkg/Include/WorkArea.h
--
2.17.1
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