On 2022-11-20 04:49, joeyli wrote:
Hi Evgeniy,
Thanks for your effort!
On Tue, Oct 25, 2022 at 05:12:38PM +0300, Evgeniy Baskov wrote:
...
Because Peter Jones point out this patchset to me, so I tried it
on OVMF, and I set the EfiLoaderData in DXE memory protection policy:
Index: edk2/MdeModulePkg/MdeModulePkg.dec
===================================================================
--- edk2.orig/MdeModulePkg/MdeModulePkg.dec
+++ edk2/MdeModulePkg/MdeModulePkg.dec
@@ -1392,7 +1392,7 @@
# e.g. 0x7BD4 can be used for all memory except Code and
ACPINVS/Reserved. <BR>
#
# @Prompt Set DXE memory protection policy.
-
gEfiMdeModulePkgTokenSpaceGuid.PcdDxeNxMemoryProtectionPolicy|0x0000000|UINT64|0x00001048^M
+
gEfiMdeModulePkgTokenSpaceGuid.PcdDxeNxMemoryProtectionPolicy|0x0000004|UINT64|0x00001048^M
## PCI Serial Device Info. It is an array of Device, Function, and
Power Management
# information that describes the path that contains zero or more
PCI to PCI bridges
I applied this v2 patch set on top of v6.1-rc5 kernel, and boot with a
shim which
set the PE NX-compatibility DLL Characteristic flag. I got a page
fault exception:
Loading Linux 6.1.0-rc5-default+ ...
Loading initial ramdisk ...
!!!! X64 Exception Type - 0E(#PF - Page-Fault) CPU Apic ID - 00000000
!!!!
ExceptionData - 0000000000000011 I:1 R:0 U:0 W:0 P:1 PK:0 SS:0 SGX:0
RIP - 0000000076A3C390, CS - 0000000000000038, RFLAGS -
0000000000210202
RAX - 000000007D8CCDF8, RCX - 0000000076A3C390, RDX - 000000007DE86000
RBX - 0000000076A3C000, RSP - 000000007FF0D2C8, RBP - 000000007DE86000
RSI - 000000007F9EE018, RDI - 000000007DFD1C18
R8 - 0000000076A3C000, R9 - 0000000000000190, R10 - 000000007FF1D658
R11 - 0000000000000004, R12 - 0000000000000190, R13 - 000000007D8CCE00
R14 - 000000007D8C76B4, R15 - 000000007BF0CBD5
DS - 0000000000000030, ES - 0000000000000030, FS - 0000000000000030
GS - 0000000000000030, SS - 0000000000000030
CR0 - 0000000080010033, CR2 - 0000000076A3C390, CR3 - 000000007FC01000
CR4 - 0000000000000668, CR8 - 0000000000000000
DR0 - 0000000000000000, DR1 - 0000000000000000, DR2 - 0000000000000000
DR3 - 0000000000000000, DR6 - 00000000FFFF0FF0, DR7 - 0000000000000400
GDTR - 000000007F9DE000 0000000000000047, LDTR - 0000000000000000
IDTR - 000000007F2E9018 0000000000000FFF, TR - 0000000000000000
FXSAVE_STATE - 000000007FF0CF20
!!!! Find image based on IP(0x7BF0BAB5)
/mnt/working/source_code-git/edk2/Build/OvmfX64/DEBUG_GCC5/X64/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableRuntimeDxe/DEBUG/VariableRuntimeDxe.dll
(ImageBase=0000000000F40E7C, EntryPoint=0000000000F767B8) !!!!
My question is: Can I just set EfiLoaderData in DXE memory protection
policy
in EDK2/OVMF to test this patchset? Or which platform (virtual or
physical)
can we use for testing?
Thanks a lot!
Joey Lee
Hi,
Thank you for testing!
The EDK2 OVMF with adjusted PcdDxeNxMemoryProtectionPolicy
should work with the kernel itself.
As far as I can see from my testing with EDK2 OVMF, this
#PF occurred inside GRUB code before the first instruction
of the kernel. You can try using GRUB master branch, where
allocations are changed to use EfiLoaderCode type and with
PcdDxeNxMemoryProtectionPolicy=0x0000004 it will still be
executable.
Thanks,
Evgeniy Baskov
