[Qemu-devel] [PATCH v3 00/35] Multi Architecture System Emulation

[Peter Crosthwaite]

Hi All,

This is target-multi, a system-mode build that can support multiple
cpu-types.

Two architectures are initially converted. Microblaze and ARM. Step
by step conversion in done for each. A microblaze is added to
Xilinx Zynq platform as a test case. This will be elaborted more in
future spins. This use case is valid, as Microblazes can be added (any
number of them!) in Zynq FPGA programmable logic configuration.

The general approach (radically different to approach in V1 RFC) is to build
and prelink an object (arch-obj.o) per-arch containing:

1: target-foo/*
2: All uses of env internals and CPU_GET_ENV
    * cputlb, translate-all, cpu-exec
    * TCG backend

This means cputlb and friends are compiled multiple times fo each arch. The
symbols for each of these pre-links are then localised to avoid link time name
collisions. This is based on Paolo's suggestion to templatify cputlb and
friends. Just the net of what to multi-compile is widened to include the TCG
stuff as well now.

Despite being some "major surgery" this approach actually solves many of big
the problems raised in V1. Big problems sovled:

1: With the multi-compile TCG backends there are now multiple tcg_ctx's for
each architecture. This solves the issue PMM raised WRT false positives on TB
hashing as archs no longer share translation context.

2: There is no longer a need to reorder the CPU_COMMON within the ENV or the ENV
within the CPU. This was flagged as a performance issue by multiple people in 
V1.
All users of the env internals as well as ENV_GET_CPU are now in multi-compile
code and so multi-arch does not need to define a generic ENV nor does in need to
def the problematic ENV_GET_CPU.

3: With the prelink symbol localisation, link time namespace collision of
helpers from multiple arches is no longer an issue. No need to bloat all the
function names with arch specific prefixes.

4: The architecture specifics used/defined by cpu-defs can now vary from arch to
arch (incl. target_ulong) greatly reducing coversion effort needed. The list
of restrictions for multi-arch capability is much reduced since V1. No
target_long issues anymore.

include/exec/*.h and some of the common code needs some refactoring to setup
this single vs multi compile split. Mostly code movements.

Some functions (like tcg_enabled) need to be listified for each of the
now-multiple TCG engines.

The interface between the multi compile and single compiled files needs to be
virtualised using QOM cpu functions. But this is now a very low footprint
change as most of the virtualised hooks are now in mutli-compiled code (they
only exist as text once). There are more new hooks than before, but the per
target change pattern is reduced.

For the implementation of the series, the trickiest part is (still) cpu.h
inclusion management. There are now more than one cpu.h's and different
parts of the tree need a different include scheme. target-multi defines
it's own cpu.h which is bare minimum defs as needed by core code only.
target-foo/cpu.h are mostly the same but refactored to avoid collisions
with other cpu.h's. Inclusion scheme goes something like
this (for the multi-arch build):

*: Core code includes only target-multi/cpu.h
*: target-foo/ implementation code includes target-foo/cpu.h locally
*: System level code (e.g. mach models) can use multiple target-foo/cpu.h's

The hardest unasnwered Q is (still) what to do about bootloading. Currently
each arch has it's own architecture specific bootloading which may assume a
single architecture. I have applied some hacks to at least get this
RFC testable using a -kernel -firmware split but going forward being
able to associate an elf/image with a cpu explictitly needs to be
solved.

No support for KVM, im not sure if a mix of TCG and KVM is supported even for
a single arch? (which would be prerequisite to MA KVM).

Depends (not heavily) on some already on list patches:

cef6466141     configure: factor out adding disas configure               
5caa2ae307     disas: Defeature print_target_address                       R:rth
b49c8a6428     cpu_defs: Simplify CPUTLB padding logic                     
R:rth Q:paolo

These deps do not really inhibit at least a high level review of this series.

Regards,
Peter

Changed since v2:
Many changes, individual commit messages have details.
Split off prepatory work for CPU virtualisation to new patches
Applied mechanical changes to all target-* where possible
Improved cpu.h multi-inclusion support.
Major rewrite of the CPU interface virtualisation system.
Rebase on hard-freeze merges (a lot of prep work + some content from v2 is
    now in).

Changed since v1:
Near total rewrite.

Peter Crosthwaite (35):
  cpu-exec: Migrate some generic fns to cpu-exec-common
  translate: Listify tcg_exec_init()
  translate-all: Move tcg_handle_interrupt() to -common
  tcg: split tcg_op_defs to -common
  tcg: Move tcg_tb_ptr to -common
  translate: move real_host_page setting to -common
  cpus: Listify cpu_list() function
  translate-common: Listify tcg_enabled()
  core: Convert tcg_enabled() users to tcg_(any|all)_enabled()
  exec-all: Move cpu_can_do_io() to qom/cpu.h
  cputlb: move CPU_LOOP() for tlb_reset() to exec.c
  cputlb: Change tlb_set_dirty() arg to cpu
  include/exec: Move cputlb exec.c defs out
  cpu-common: Define tb_page_addr_t for everyone
  include/exec: Split target_long def to new header
  cpu-defs: Allow multiple inclusions
  monitor: uninclude cpu_ldst
  target-*: Don't redefine cpu_exec()
  target-*: cpu.h: Undefine core code symbols
  Makefile.target: Introduce arch-obj
  core: virtualise CPU interfaces completely
  core: Introduce multi-arch build
  arm: cpu: static inline cpu_arm_init()
  target-arm: Split cp helper API to new C file
  arm: register cpu_list() function
  arm: enable multi-arch
  hw: arm: Explicitly include cpu.h for consumers
  arm: Remove ELF_MACHINE from cpu.h
  hw: mb: Explicitly include cpu.h for consumers
  mb: Remove ELF_MACHINE from cpu.h
  microblaze: enable multi-arch
  arm: boot: Don't assume all CPUs are ARM
  arm: xilinx_zynq: Add a Microblaze
  HACK: mb: boot: Assume using -firmware for mb software
  HACK: mb: boot: Disable dtb load in multi-arch

 Makefile.target                   |  38 ++++-
 arch_init.c                       |   4 +-
 configure                         |  29 +++-
 cpu-exec-common.c                 | 108 ++++++++++++
 cpu-exec.c                        |  49 ------
 cpus.c                            |  16 +-
 cputlb.c                          |  30 ++--
 default-configs/multi-softmmu.mak |   2 +
 exec.c                            |  38 +++--
 gdbstub.c                         |   2 +-
 hw/arm/armv7m.c                   |   2 +-
 hw/arm/boot.c                     |   8 +-
 hw/arm/strongarm.h                |   2 +
 hw/arm/xilinx_zynq.c              |  15 ++
 hw/microblaze/boot.c              |  12 +-
 hw/microblaze/boot.h              |   2 +
 include/exec/cpu-all.h            |   2 +
 include/exec/cpu-common.h         |   2 +
 include/exec/cpu-defs-clear.h     |  33 ++++
 include/exec/cpu-defs.h           |  84 +++++-----
 include/exec/cputlb.h             |  16 --
 include/exec/exec-all.h           |  46 +++---
 include/exec/ram_addr.h           |   5 +-
 include/exec/target-long.h        |  54 ++++++
 include/hw/arm/arm.h              |   3 +
 include/hw/arm/digic.h            |   2 +
 include/hw/arm/exynos4210.h       |   2 +
 include/hw/arm/omap.h             |   2 +
 include/hw/arm/pxa.h              |   2 +
 include/qemu-common.h             |   6 +
 include/qom/cpu.h                 | 101 ++++++++++++
 include/sysemu/arch_init.h        |   1 +
 include/sysemu/cpus.h             |   7 +
 linux-user/elfload.c              |   3 +
 linux-user/main.c                 |  28 ++--
 memory.c                          |   8 +-
 monitor.c                         |   5 +-
 multi-support/aarch64             |   0
 multi-support/microblazeel        |   0
 target-alpha/Makefile.objs        |   8 +-
 target-alpha/cpu.h                |   3 +-
 target-arm/Makefile.objs          |  24 +--
 target-arm/cpu-qom.h              |   2 +
 target-arm/cpu.c                  |   2 +
 target-arm/cpu.h                  |  58 ++++++-
 target-arm/helper.c               | 334 +-------------------------------------
 target-arm/hw/Makefile.objs       |   1 +
 target-arm/hw/cp.c                | 328 +++++++++++++++++++++++++++++++++++++
 target-cris/Makefile.objs         |   6 +-
 target-cris/cpu.h                 |   3 +-
 target-i386/Makefile.objs         |  14 +-
 target-i386/cpu.h                 |   3 +-
 target-lm32/Makefile.objs         |   8 +-
 target-lm32/cpu.h                 |   4 +-
 target-m68k/Makefile.objs         |   6 +-
 target-m68k/cpu.h                 |   4 +-
 target-microblaze/Makefile.objs   |   6 +-
 target-microblaze/cpu-qom.h       |   2 +
 target-microblaze/cpu.c           |   2 +
 target-microblaze/cpu.h           |  31 +++-
 target-mips/Makefile.objs         |   8 +-
 target-mips/cpu.h                 |   4 +-
 target-moxie/Makefile.objs        |   4 +-
 target-moxie/cpu.h                |   3 +-
 target-multi/cpu.h                |  16 ++
 target-multi/helper.h             |   0
 target-openrisc/Makefile.objs     |   8 +-
 target-openrisc/cpu.h             |   4 +-
 target-ppc/Makefile.objs          |  30 ++--
 target-ppc/cpu.h                  |   3 +-
 target-s390x/Makefile.objs        |  10 +-
 target-s390x/cpu.h                |   3 +-
 target-sh4/Makefile.objs          |   4 +-
 target-sh4/cpu.h                  |   3 +-
 target-sparc/Makefile.objs        |  14 +-
 target-sparc/cpu.h                |   3 +-
 target-tricore/Makefile.objs      |   2 +-
 target-tricore/cpu.h              |   3 +-
 target-unicore32/Makefile.objs    |   6 +-
 target-unicore32/cpu.h            |   3 +-
 target-xtensa/Makefile.objs       |  12 +-
 target-xtensa/cpu.h               |   4 +-
 tcg/tcg-common.c                  |  34 ++++
 tcg/tcg.c                         |   8 +-
 tcg/tci/tcg-target.c              |   2 +-
 tci.c                             |   6 -
 translate-all.c                   |  44 ++---
 translate-common.c                | 131 +++++++++++++++
 88 files changed, 1276 insertions(+), 714 deletions(-)
 create mode 100644 cpu-exec-common.c
 create mode 100644 default-configs/multi-softmmu.mak
 create mode 100644 include/exec/cpu-defs-clear.h
 create mode 100644 include/exec/target-long.h
 create mode 100644 multi-support/aarch64
 create mode 100644 multi-support/microblazeel
 create mode 100644 target-arm/hw/Makefile.objs
 create mode 100644 target-arm/hw/cp.c
 create mode 100644 target-multi/cpu.h
 create mode 100644 target-multi/helper.h
 create mode 100644 tcg/tcg-common.c
 create mode 100644 translate-common.c

-- 
1.9.1