[Bug 2037661] [NEW] Intel TDX Azure instances crash during boot due to glibc bug part 2

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[IMPACT]

This is a continuation of the lp # 2011421

Intel TDX Azure instances are segfaulting due to an error in glibc.

The glibc error is fixed with this patch [1]

FYI elaborating on the commit back-port request [1]

https://www.intel.com/content/www/us/en/architecture-and-
technology/64-ia-32-architectures-software-developer-vol-1-manual.html

19.1 USING THE CPUID INSTRUCTION
Use the CPUID instruction for processor identification in the Pentium M processor family, Pentium 4 processor
family, Intel Xeon processor family, P6 family, Pentium processor, and later Intel486 processors. This instruction
returns the family, model and (for some processors) a brand string for the processor that executes the instruction.
It also indicates the features that are present in the processor and gives information about the processor’s caches
and TLB.
The ID flag (bit 21) in the EFLAGS register indicates support for the CPUID instruction. If a software procedure can
set and clear this flag, the processor executing the procedure supports the CPUID instruction. The CPUID instruc-
tion will cause the invalid opcode exception (#UD) if executed on a processor that does not support it.
To obtain processor identification information, a source operand value is placed in the EAX register to select the
type of information to be returned. When the CPUID instruction is executed, selected information is returned in the
EAX, EBX, ECX, and EDX registers. For a complete description of the CPUID instruction, tables indicating values
returned, and example code, see CPUID—CPU Identification in Chapter 3 of the Intel® 64 and IA-32 Architectures
Software Developer’s Manual, Volume 2A

https://www.intel.com/content/www/us/en/architecture-and-
technology/64-ia-32-architectures-software-developer-vol-2a-manual.pdf

Obtain feature flags, status, and system information by using the CPUID instruction, by checking control register
bits, and by reading model-specific registers. We are moving toward a new syntax to represent this information.
See Figure 1-2.
pg 217

[TEST CASE]

Test case requires an azure TDX instance.

Testing instructions from [2] being

getconf  -a | grep CACHE

showing non-zero entries for the cache values

[REGRESSION POTENTIAL]
Compatibility impact on applications which invoke CPUID directly.

[OTHER]

This will affect Mantic, Jammy, Focal

[0] https://azure.microsoft.com/en-us/blog/azure-confidential-computing-on-4th-gen-intel-xeon-scalable-processors-with-intel-tdx/
[1] https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=1493622f4f9048ffede3fbedb64695efa49d662a
[2] https://sourceware.org/bugzilla/show_bug.cgi?id=30643#c12

** Affects: glibc (Ubuntu)
     Importance: Undecided
         Status: New

** Affects: glibc (Ubuntu Focal)
     Importance: Undecided
     Assignee: Heather Lemon (hypothetical-lemon)
         Status: New

** Affects: glibc (Ubuntu Jammy)
     Importance: Undecided
         Status: New

** Affects: glibc (Ubuntu Mantic)
     Importance: Undecided
         Status: New


** Tags: patch
-- 
Intel TDX Azure instances crash during boot due to glibc bug part 2 
https://bugs.launchpad.net/bugs/2037661
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