[Qemu-devel] [PATCH v1 00/15] Multi-Arch Phase 1

[Peter Crosthwaite]

This is the first set of patches needed to enable Multi-arch system
emulation. For full context refer to RFCv3:

[PATCH v3 00/35] Multi Architecture System Emulation
https://lists.gnu.org/archive/html/qemu-devel/2015-07/msg03929.html

This is the first patch-pack intended for merge.

Original cover, as well as overall series state below for further
information.

Regards,
Peter

Original Multi-arch arch patch series cover:

***

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).

***

Current review state of full multi-arch work in progress branch:

cpu-exec: Migrate some generic fns to cpu-exec-common
translate: Listify tcg_exec_init()                          R:rth
translate-all: Move tcg_handle_interrupt() to -common       R:rth
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() uses to any/all variants
exec-all: Move cpu_can_do_io() to qom/cpu.h                 R:rth
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                   R:rth
cpu-common: Define tb_page_addr_t for everyone
monitor: uninclude cpu_ldst
disas: s390x: QOMify target specific disas setup            A:rth
disas: moxie: QOMify target specific disas setup
disas: m68k: QOMify target specific disas setup             R:laurentv R:gerg
disas: sparc: QOMify target specific disas setup
disas: lm32: QOMify target specific disas setup             A:mwalle
disas: sh4: QOMify target specific disas setup              A:aurel
disas: mips: QOMify target specific disas setup             A:lalrae
disas: alpha: QOMify target specific disas setup            A:rth
linux_user: elfload: Default ELF_MACHINE to ELF_ARCH        R:rth
linux-user: elfload: Provide default for elf_check_arch     R:rth
elf_ops: Fix coding style for EM alias case statement       R:rth
elf: Update EM_MOXIE definition                             R:rth
arm: Remove ELF_MACHINE from cpu.h                          R:rth
mb: Remove ELF_MACHINE from cpu.h                           R:rth
m68k: Remove ELF_MACHINE from cpu.h                         R:rth R:gerg 
R:laurentv
cris: Remove ELF_MACHINE from cpu.h                         R:rth
moxie: Remove ELF_MACHINE from cpu.h                        R:rth
unicore: Remove ELF_MACHINE from cpu.h                      R:rth
lm32: Remove ELF_MACHINE from cpu.h                         R:rth
or32: Remove ELF_MACHINE from cpu.h                         R:rth
tricore: Remove ELF_MACHINE from cpu.h                      R:rth
xtensa: Remove ELF_MACHINE from cpu.h                       R:rth
sh4: Remove ELF_MACHINE from cpu.h                          A:aurel R:rth
s390: Remove ELF_MACHINE from cpu.h                         R:rth
sparc: Remove ELF_MACHINE from cpu.h                        R:rth
mips: Remove ELF_MACHINE from cpu.h                         R:aurel R:rth
alpha: Remove ELF_MACHINE from cpu.h                        R:rth
i386: Rename ELF_MACHINE to be x86 specific                 R:eduardo A:eduardo 
R:rth
ppc: Rename ELF_MACHINE to be PPC specific                  R:rth
arm: cpu: assert() on no-EL2 virt IRQ error condition.      R:pmm
arm: Remove hw_error() usages.                              R:pmm
configure: factor out adding disas configure                R:pmm
target-*: Don't redefine cpu_exec()
include/exec: Split target_long def to new header
cpu-defs: Allow multiple inclusions
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
hw: mb: Explicitly include cpu.h for consumers
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


Peter Crosthwaite (15):
  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() uses to any/all variants
  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
  monitor: uninclude cpu_ldst

 Makefile.target           |   3 ++
 cpu-exec-common.c         | 108 ++++++++++++++++++++++++++++++++++++++
 cpu-exec.c                |  49 -----------------
 cpus.c                    |  10 +---
 cputlb.c                  |  30 +++++------
 exec.c                    |  13 ++---
 include/exec/cpu-common.h |   4 ++
 include/exec/cputlb.h     |  16 ------
 include/exec/exec-all.h   |  20 ++++++-
 include/exec/ram_addr.h   |   5 +-
 include/qemu-common.h     |   6 +++
 include/qom/cpu.h         |  22 ++++++++
 include/sysemu/cpus.h     |   7 +++
 memory.c                  |   8 +--
 monitor.c                 |   1 -
 tcg/tcg-common.c          |  35 +++++++++++++
 tcg/tcg.c                 |   8 +--
 tcg/tci/tcg-target.c      |   2 +-
 tci.c                     |   6 ---
 translate-all.c           |  46 ++++------------
 translate-common.c        | 130 ++++++++++++++++++++++++++++++++++++++++++++++
 21 files changed, 375 insertions(+), 154 deletions(-)
 create mode 100644 cpu-exec-common.c
 create mode 100644 tcg/tcg-common.c
 create mode 100644 translate-common.c

-- 
1.9.1