[v3,0/6] Rework x86 page table walks

Message

Don Porter June 6, 2024, 2:02 p.m. UTC

This version of the 'info pg' command adopts Peter Maydell's request
to write 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).

Version 3 of this patch series moves 'info pg' into common monitor
code and implements the architecture-specific code hooks.  I did not
do this with the 'info mem' and 'info tlb' commands, since they have
implementations on other ISAs.

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                 |  13 +
 hw/core/cpu-sysemu.c                 | 140 ++++++
 include/hw/core/cpu.h                |  34 +-
 include/hw/core/sysemu-cpu-ops.h     | 169 +++++++
 include/monitor/hmp-target.h         |   1 +
 include/monitor/monitor.h            |   4 +
 monitor/hmp-cmds-target.c            | 198 ++++++++
 target/i386/arch_memory_mapping.c    | 621 ++++++++++++++---------
 target/i386/cpu.c                    |  12 +
 target/i386/cpu.h                    |  63 +++
 target/i386/helper.c                 | 523 +++++++++++++++----
 target/i386/monitor.c                | 724 +++++++++------------------
 target/i386/tcg/sysemu/excp_helper.c | 555 +-------------------
 13 files changed, 1688 insertions(+), 1369 deletions(-)

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2.34.1