[ANNOUNCE] x86-cpuid-db: Release v3.0

[Ahmed S. Darwish]

Hi,

I'm happy to announce release 3.0 of the x86-cpuid-db project:

   https://gitlab.com/x86-cpuid.org/x86-cpuid-db
   https://gitlab.com/x86-cpuid.org/x86-cpuid-db/-/releases/v3.0

Changelog v3.0
--------------

Introduce the Linux-defined synthetic CPUID leaves 0x4c780001 and
0x4c780002.  The range ID prefix 0x4c78 is for Linux in its shorthand ASCII
form "Lx", where Linux becomes a virtual vendor akin to hardware vendors
like AMD or Intel.

In these leaves, provide a 1:1 bitfield mapping for what Linux defines in
its synthetic X86_FEATURE words at <asm/cpufeatures.h>.  Designate leaf
0x4c780001 for feature words in a linear order; i.e., subleaf 0 registers
EAX to EDX, then subleaf 1 registers, and so on.  Similarly, designate leaf
0x4c780001 for the X86_BUG words.

Here is the synthetic leaves bitfield listing:

   https://gitlab.com/x86-cpuid.org/x86-cpuid-db/-/blob/v3.0/db/xml/leaf_4c780001.xml
   https://gitlab.com/x86-cpuid.org/x86-cpuid-db/-/blob/v3.0/db/xml/leaf_4c780002.xml

With that, the Linux kernel x86 feature query code can have zero special
cases.  The synthetic CPUID leaves and X86_FEATURE words are collected,
parsed, modified, and queried just like their hardware-backed counterparts.

Update the CPUID database:

 - Leaf 0x23: Introduce subleaf 2, Auto Counter Reload (ACR)
 - Leaf 0x23: Introduce subleaf 4/5, PEBS capabilities and counters
 - Leaf 0x1c: Return LBR depth as a bitmask instead of individual bits
 - Leaf 0x0a: Define more descriptive PMU bitfield names

Thanks to Dave Hansen (Intel), also add the bits:

 - Leaf 0x0a: Various missing PMU events
 - Leaf 0x06: Missing IA32_HWP_CTL flag
 - Leaf 0x0f: Missing non-CPU (IO) Intel RDT bits

Release coverage
----------------

   CPUID leaves:        64 leaves
   CPUID bitfields:     1104 entries
   Linux feature flags: 465 entries
   Xen feature flags:   198 entries

Artifacts
---------

The generated CSV and C header files can be quickly checked in full from
the release artifacts at:

   https://gitlab.com/x86-cpuid.org/x86-cpuid-db/-/releases/v3.0

Thanks!
Ahmed