Re: [PATCH] efistub/tpm: Use ACPI reclaim memory for event log to avoid corruption

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On 30/10/2024 05:25, Jiri Slaby wrote:
> On 25. 10. 24, 15:27, Usama Arif wrote:
>> Could you share the e820 map, reserve setup_data and TPMEventLog address with and without the patch?
>> All of these should be just be in the dmesg.
> 
> It's shared in the aforementioned bug [1] already.
> 
> 6.11.2 dmesg (bad run):
> https://bugzilla.suse.com/attachment.cgi?id=877874
> 
> 6.12-rc2 dmesg (good run):
> https://bugzilla.suse.com/attachment.cgi?id=877887
> 
> FWIW from https://bugzilla.suse.com/attachment.cgi?id=878051:
> good TPMEventLog=0x682aa018
> bad  TPMEventLog=0x65a6b018
> 
> [1] https://bugzilla.suse.com/show_bug.cgi?id=1231465
> 
> wdiff of e820:
> wdiff -n bad good |colordiff
> BIOS-e820: [mem 0x0000000000000000-0x0000000000057fff] usable
> BIOS-e820: [mem 0x0000000000058000-0x0000000000058fff] reserved
> BIOS-e820: [mem 0x0000000000059000-0x000000000009efff] usable
> BIOS-e820: [mem 0x000000000009f000-0x00000000000fffff] reserved
> BIOS-e820: [mem [-0x0000000000100000-0x0000000065a6efff]-] {+0x0000000000100000-0x00000000682abfff]+} usable
> BIOS-e820: [mem [-0x0000000065a6f000-0x0000000065a7dfff]-] {+0x00000000682ac000-0x00000000682bafff]+} ACPI data
> BIOS-e820: [mem [-0x0000000065a7e000-0x000000006a5acfff]-] {+0x00000000682bb000-0x000000006a5acfff]+} usable
> BIOS-e820: [mem 0x000000006a5ad000-0x000000006a5adfff] ACPI NVS
> BIOS-e820: [mem 0x000000006a5ae000-0x000000006a5aefff] reserved
> BIOS-e820: [mem 0x000000006a5af000-0x0000000079e83fff] usable
> BIOS-e820: [mem 0x0000000079e84000-0x000000007a246fff] reserved
> BIOS-e820: [mem 0x000000007a247000-0x000000007a28efff] ACPI data
> BIOS-e820: [mem 0x000000007a28f000-0x000000007abf0fff] ACPI NVS
> BIOS-e820: [mem 0x000000007abf1000-0x000000007b5fefff] reserved
> BIOS-e820: [mem 0x000000007b5ff000-0x000000007b5fffff] usable
> BIOS-e820: [mem 0x000000007b600000-0x000000007f7fffff] reserved
> BIOS-e820: [mem 0x00000000f0000000-0x00000000f7ffffff] reserved
> BIOS-e820: [mem 0x00000000fe000000-0x00000000fe010fff] reserved
> BIOS-e820: [mem 0x00000000fec00000-0x00000000fec00fff] reserved
> BIOS-e820: [mem 0x00000000fee00000-0x00000000fee00fff] reserved
> BIOS-e820: [mem 0x00000000ff000000-0x00000000ffffffff] reserved
> BIOS-e820: [mem 0x0000000100000000-0x000000087e7fffff] usable
> NX (Execute Disable) protection: active
> APIC: Static calls initialized
> e820: update [mem [-0x65a5e018-0x65a6e457]-] {+0x6829b018-0x682ab457]+} usable ==> usable
> extended physical RAM map:
> reserve setup_data: [mem 0x0000000000000000-0x0000000000057fff] usable
> reserve setup_data: [mem 0x0000000000058000-0x0000000000058fff] reserved
> reserve setup_data: [mem 0x0000000000059000-0x000000000009efff] usable
> reserve setup_data: [mem 0x000000000009f000-0x00000000000fffff] reserved
> reserve setup_data: [mem [-0x0000000000100000-0x0000000065a5e017]-] {+0x0000000000100000-0x000000006829b017]+} usable
> reserve setup_data: [mem [-0x0000000065a5e018-0x0000000065a6e457]-] {+0x000000006829b018-0x00000000682ab457]+} usable
> reserve setup_data: [mem [-0x0000000065a6e458-0x0000000065a6efff]-] {+0x00000000682ab458-0x00000000682abfff]+} usable
> reserve setup_data: [mem [-0x0000000065a6f000-0x0000000065a7dfff]-] {+0x00000000682ac000-0x00000000682bafff]+} ACPI data
> reserve setup_data: [mem [-0x0000000065a7e000-0x000000006a5acfff]-] {+0x00000000682bb000-0x000000006a5acfff]+} usable
> reserve setup_data: [mem 0x000000006a5ad000-0x000000006a5adfff] ACPI NVS
> reserve setup_data: [mem 0x000000006a5ae000-0x000000006a5aefff] reserved
> reserve setup_data: [mem 0x000000006a5af000-0x0000000079e83fff] usable
> reserve setup_data: [mem 0x0000000079e84000-0x000000007a246fff] reserved
> reserve setup_data: [mem 0x000000007a247000-0x000000007a28efff] ACPI data
> reserve setup_data: [mem 0x000000007a28f000-0x000000007abf0fff] ACPI NVS
> reserve setup_data: [mem 0x000000007abf1000-0x000000007b5fefff] reserved
> reserve setup_data: [mem 0x000000007b5ff000-0x000000007b5fffff] usable
> reserve setup_data: [mem 0x000000007b600000-0x000000007f7fffff] reserved
> reserve setup_data: [mem 0x00000000f0000000-0x00000000f7ffffff] reserved
> reserve setup_data: [mem 0x00000000fe000000-0x00000000fe010fff] reserved
> reserve setup_data: [mem 0x00000000fec00000-0x00000000fec00fff] reserved
> reserve setup_data: [mem 0x00000000fee00000-0x00000000fee00fff] reserved
> reserve setup_data: [mem 0x00000000ff000000-0x00000000ffffffff] reserved
> reserve setup_data: [mem 0x0000000100000000-0x000000087e7fffff] usable
> efi: EFI v2.6 by American Megatrends
> efi: ACPI=0x7a255000 ACPI 2.0=0x7a255000 SMBIOS=0x7b140000 SMBIOS 3.0=0x7b13f000 TPMFinalLog=0x7a892000 ESRT=0x7b0deb18 [-MEMATTR=0x77535018-] {+MEMATTR=0x77526018+} MOKvar=0x7b13e000 RNG=0x7a254018 [-TPMEventLog=0x65a6f018-] {+TPMEventLog=0x682ac018+}
> 
> 
> thanks,

Thanks for sharing this.

This looks a bit weird for me.

The issue this patch was trying to fix was TPMEventLog being overwritten during kexec.
We are using efi libstub.
Without this patch we would see
BIOS-e820: [mem 0x0000000000100000-0x0000000064763fff] usable 
TPMEventLog=0x5ed47018
i.e. TPMEventLog was usable memory and therefore was prone to corruption during kexec.

With this patch 
BIOS-e820: [mem 0x00000000a8c01000-0x00000000a8cebfff] ACPI data
TPMEventLog=0xa8ca8018 
i.e.  TPMEventLog is reserved as ACPI data, hence cant be corrupted during kexec.


In your case, from the logs you shared, good run without the patch:
[    0.000000] [      T0] BIOS-e820: [mem 0x0000000065a6f000-0x0000000065a7dfff] ACPI data
[    0.000000] [      T0] BIOS-e820: [mem 0x0000000065a7e000-0x000000006a5acfff] usable
[    0.000000] [      T0] BIOS-e820: [mem 0x000000006a5ad000-0x000000006a5adfff] ACPI NVS
TPMEventLog=0x65a6f018 
bad run with the patch:
[    0.000000] [      T0] BIOS-e820: [mem 0x00000000682ac000-0x00000000682bafff] ACPI data
[    0.000000] [      T0] BIOS-e820: [mem 0x00000000682bb000-0x000000006a5acfff] usable
[    0.000000] [      T0] BIOS-e820: [mem 0x000000006a5ad000-0x000000006a5adfff] ACPI NVS
TPMEventLog=0x682ac018
Both with and without the fix, the TPMEventLog is part of ACPI data.

It means your firmware has already marked that area as ACPI data. Are you using efi/libstub?

Thanks,
Usama








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