OvmfPkg/Sec/Ia32: seed the temporary RAM with PcdInitValueInTempStack
authorLaszlo Ersek <lersek@redhat.com>
Wed, 8 Nov 2017 18:43:21 +0000 (19:43 +0100)
committerLaszlo Ersek <lersek@redhat.com>
Fri, 17 Nov 2017 17:12:12 +0000 (18:12 +0100)
commit9d9350a579d3f3d52ea1012111fad300c4e19fa2
tree542d624af081ee04d243a37fe33a4f62692dac21
parent9f75aacc7ab5410345b4811901a78a375851aa8b
OvmfPkg/Sec/Ia32: seed the temporary RAM with PcdInitValueInTempStack

This allows the PEI core to report the maximum temporary SEC/PEI stack
usage on the DEBUG_INFO level, in the PeiCheckAndSwitchStack() function
[MdeModulePkg/Core/Pei/Dispatcher/Dispatcher.c]:

* Normal boot:

> Temp Stack : BaseAddress=0x814000 Length=0x4000
> Temp Heap  : BaseAddress=0x810000 Length=0x4000
> Total temporary memory:    32768 bytes.
>   temporary memory stack ever used:       3664 bytes. <----
>   temporary memory heap used for HobList: 5904 bytes.
>   temporary memory heap occupied by memory pages: 0 bytes.

* S3 resume (with PEI decompression / SMM):

> Temp Stack : BaseAddress=0x814000 Length=0x4000
> Temp Heap  : BaseAddress=0x810000 Length=0x4000
> Total temporary memory:    32768 bytes.
>   temporary memory stack ever used:       3428 bytes. <----
>   temporary memory heap used for HobList: 4816 bytes.
>   temporary memory heap occupied by memory pages: 0 bytes.

I unit-tested this change by transitorily adding an infinite loop right
after the "rep stosd", and dumping the guest's temp SEC/PEI RAM (32KB
currently) while the guest was stuck in the loop. The dump includes one
dword from before and after the temp SEC/PEI RAM:

> $ virsh qemu-monitor-command GUEST_NAME --hmp 'xp /8194wx 0x80FFFC'
>
000000000080fffc: 0x00000000 0x5aa55aa5 0x5aa55aa5 0x5aa55aa5
000000000081000c: 0x5aa55aa5 0x5aa55aa5 0x5aa55aa5 0x5aa55aa5
> ...
0000000000817fec: 0x5aa55aa5 0x5aa55aa5 0x5aa55aa5 0x5aa55aa5
0000000000817ffc: 0x5aa55aa5 0x00000000

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=747
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
OvmfPkg/Sec/Ia32/SecEntry.nasm
OvmfPkg/Sec/SecMain.inf