[PATCH v3 0/3] elf2dmp: identify faulting CPU in Windows crash dumps

When a Windows guest crashes and QEMU generates a memory dump via
pvpanic, elf2dmp currently always sets CPU 0's context in the dump
header. This makes WinDbg default to CPU 0 when opening the dump,
even if the actual crash happened on a different CPU.

This series adds crash_occurred tracking from the runstate layer
through to the QEMUCPUState in the ELF dump, and teaches elf2dmp
to identify and use the faulting CPU's context.

Changes since v2:
   - Remove unused fault_cpu variable in fill_context()
   - Use per-CPU size check (s->size >= offsetof + sizeof) instead
     of global has_is_crash_occurred_cpu flag, fixing heterogeneous
     dumps where CPU notes have different sizes
   - Remove has_is_crash_occurred_cpu from QEMU_Elf struct and
     init_states() since per-CPU check makes it unnecessary
   - Move QEMUCPUState struct growth from patch 2 to patch 3 so
     sizeof() change and init_states() update stay together
     (bisectability)
   - Fix patch 1 commit message: soften "is never called" to
     "is not always called when crash dumping is enabled"
   - Fix patch 2 commit message: clarify compatibility description
     for both old-tools/new-dumps and new-tools/old-dumps directions
   - Clamp state->size to MIN(state->size, n_descsz) in init_states()
     to prevent reading beyond note descriptor boundary
   - Compare state_size against offsetof + sizeof(kernel_gs_base)
     instead of sizeof(*state) to avoid misclassifying valid old
     440-byte notes as lacking kernel_gs_base

Changes since v1:
   - Set header context before best-effort guest memory operations
     to avoid losing faulting CPU context on partial dump failures
   - Use LIVE_SYSTEM_DUMP when BugcheckCode is zero
   - Use PRIx32 for BugcheckCode format specifier
   - Use linux.alibaba.com identity

Zhengrong Li (3):
  runstate: set crash_occurred on guest crashloaded
  dump: add crash_occurred flag to QEMUCPUState
  elf2dmp: fill ContextBuffer with faulting CPU context

 contrib/elf2dmp/kdbg.h     |  9 +++++++
 contrib/elf2dmp/main.c     | 50 ++++++++++++++++++++++++++++++++++++--
 contrib/elf2dmp/qemu_elf.c | 10 +++++++-
 contrib/elf2dmp/qemu_elf.h |  2 ++
 system/runstate.c          |  5 ++++
 target/i386/arch_dump.c    |  6 +++++
 6 files changed, 79 insertions(+), 3 deletions(-)

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2.43.0