[PATCH v2 0/6] Rework x86 page table walks

[Don Porter <porter@cs.unc.edu>]

This version of the 'info pg' command adopts Peter Maydell's request
to write some guest-agnostic page table iterator and accessor code,
along with architecture-specific hooks.  The first patch in this
series contributes a generic page table iterator and an x86
instantiation.  As a client, we first introduce an 'info pg' monitor
command, as well as a compressing callback hook for creating succinct
page table representations.

After this, each successive patch replaces an exisitng x86 page table
walker with a use of common iterator code.

I could use advice on how to ensure this is sufficiently well tested.
I used 'make check' and 'make check-avocado', which both pass; what is
the typical standard for testing something like a page table related
change?

As far as generality, I have only attempted this on x86, but I expect
the design would work for any similar radix-tree style page table.

I am still new enough to the code base that I wasn't certain about
where to put the generic code, as well as naming conventions.

Per David Gilbert's suggestion, I was careful to ensure that monitor
calls do not perturb TLB state (see the read-only flag in some
functions).

I appreciate Nadav's suggestion about other ways to pursue the same
goal: I ended up deciding I would like to try my hand at consolidating
the x86 page table code.

Don Porter (6):
  Add an "info pg" command that prints the current page tables
  Convert 'info tlb' to use generic iterator
  Convert 'info mem' to use generic iterator
  Convert x86_cpu_get_memory_mapping() to use generic iterators
  Move tcg implementation of x86 get_physical_address into common helper
    code.
  Convert x86_mmu_translate() to use common code.

 hmp-commands-info.hx                 |  26 +
 include/monitor/hmp-target.h         |   1 +
 target/i386/arch_memory_mapping.c    | 735 +++++++++++++++-------
 target/i386/cpu.h                    |  66 ++
 target/i386/helper.c                 | 518 ++++++++++++----
 target/i386/monitor.c                | 883 +++++++++++++--------------
 target/i386/tcg/sysemu/excp_helper.c | 555 +----------------
 7 files changed, 1439 insertions(+), 1345 deletions(-)

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2.34.1