[PULL 00/49] ppc-for-9.0 queue

Nicholas Piggin posted 49 patches 8 months, 3 weeks ago
Only 48 patches received!
There is a newer version of this series
MAINTAINERS                                  |  11 +-
docs/about/deprecated.rst                    |   8 +
docs/devel/testing.rst                       |  11 +
hw/misc/Kconfig                              |   4 +
hw/misc/meson.build                          |   1 +
hw/misc/pca9552.c                            |  58 ++-
hw/misc/pca9554.c                            | 328 +++++++++++++++
hw/ppc/Kconfig                               |   2 +
hw/ppc/meson.build                           |   5 +-
hw/ppc/pnv.c                                 | 131 +++++-
hw/ppc/pnv_chiptod.c                         | 586 +++++++++++++++++++++++++++
hw/ppc/pnv_i2c.c                             | 146 +------
hw/ppc/pnv_n1_chiplet.c                      | 173 ++++++++
hw/ppc/pnv_nest_pervasive.c                  | 208 ++++++++++
hw/ppc/spapr.c                               |  12 +-
hw/ppc/spapr_hcall.c                         |  12 +-
hw/ppc/spapr_irq.c                           |   6 +-
hw/ppc/{spapr_softmmu.c => spapr_vhyp_mmu.c} |  13 +-
hw/ppc/trace-events                          |   4 +
include/hw/i2c/pnv_i2c_regs.h                | 143 +++++++
include/hw/misc/pca9552.h                    |   3 +-
include/hw/misc/pca9554.h                    |  36 ++
include/hw/misc/pca9554_regs.h               |  19 +
include/hw/ppc/pnv.h                         |   3 +
include/hw/ppc/pnv_chip.h                    |   5 +
include/hw/ppc/pnv_chiptod.h                 |  53 +++
include/hw/ppc/pnv_n1_chiplet.h              |  32 ++
include/hw/ppc/pnv_nest_pervasive.h          |  32 ++
include/hw/ppc/pnv_xscom.h                   |  18 +
include/hw/ppc/spapr.h                       |   9 +-
include/hw/ppc/spapr_irq.h                   |  14 +-
pc-bios/skiboot.lid                          | Bin 2527240 -> 2527328 bytes
target/ppc/cpu.h                             |  57 ++-
target/ppc/cpu_init.c                        |  20 +-
target/ppc/excp_helper.c                     |  36 +-
target/ppc/gdbstub.c                         |  40 +-
target/ppc/helper_regs.c                     |  41 +-
target/ppc/mmu_helper.c                      | 105 +++--
target/ppc/ppc-qmp-cmds.c                    |   4 +
target/ppc/tcg-stub.c                        |  15 -
target/ppc/timebase_helper.c                 | 309 +++++++++++++-
target/ppc/translate.c                       |  42 +-
target/ppc/translate/vsx-impl.c.inc          |   2 +-
tests/avocado/boot_freebsd.py                | 174 ++++++++
tests/avocado/boot_linux.py                  |  16 +-
tests/avocado/boot_linux_console.py          |  11 +-
tests/avocado/migration.py                   |   1 -
tests/avocado/ppc_hv_tests.py                | 203 ++++++++++
tests/avocado/ppc_powernv.py                 |  23 +-
tests/avocado/ppc_pseries.py                 |  20 +-
tests/qtest/meson.build                      |   1 +
tests/qtest/pca9552-test.c                   |   6 +-
tests/qtest/pnv-host-i2c-test.c              | 491 ++++++++++++++++++++++
tests/qtest/pnv-xscom-test.c                 |  61 +--
tests/qtest/pnv-xscom.h                      |  80 ++++
55 files changed, 3492 insertions(+), 352 deletions(-)
create mode 100644 hw/misc/pca9554.c
create mode 100644 hw/ppc/pnv_chiptod.c
create mode 100644 hw/ppc/pnv_n1_chiplet.c
create mode 100644 hw/ppc/pnv_nest_pervasive.c
rename hw/ppc/{spapr_softmmu.c => spapr_vhyp_mmu.c} (97%)
create mode 100644 include/hw/i2c/pnv_i2c_regs.h
create mode 100644 include/hw/misc/pca9554.h
create mode 100644 include/hw/misc/pca9554_regs.h
create mode 100644 include/hw/ppc/pnv_chiptod.h
create mode 100644 include/hw/ppc/pnv_n1_chiplet.h
create mode 100644 include/hw/ppc/pnv_nest_pervasive.h
create mode 100644 tests/avocado/boot_freebsd.py
create mode 100644 tests/avocado/ppc_hv_tests.py
create mode 100644 tests/qtest/pnv-host-i2c-test.c
create mode 100644 tests/qtest/pnv-xscom.h
[PULL 00/49] ppc-for-9.0 queue
Posted by Nicholas Piggin 8 months, 3 weeks ago
The following changes since commit da96ad4a6a2ef26c83b15fa95e7fceef5147269c:

  Merge tag 'hw-misc-20240215' of https://github.com/philmd/qemu into staging (2024-02-16 11:05:14 +0000)

are available in the Git repository at:

  https://gitlab.com/npiggin/qemu.git tags/pull-ppc-for-9.0-20240219

for you to fetch changes up to 922e408e12315121d3e09304b8b8f462ea051af1:

  target/ppc: optimise ppcemb_tlb_t flushing (2024-02-19 18:09:19 +1000)

----------------------------------------------------------------
* Avocado tests for ppc64 to boot FreeBSD, run guests with emulated
  or nested hypervisor facilities, among other things.
* Update ppc64 CPU defaults to Power10.
* Add a new powernv10-rainier machine to better capture differences
  between the different Power10 systems.
* Implement more device models for powernv.
* 4xx TLB flushing performance and correctness improvements.
* Correct gdb implementation to access some important SPRs.
* Misc cleanups and bug fixes.

I dropped the BHRB patches, they are very close but minor issue only
noticed recently held them up. Hopefully we can get those and a bunch
of other outstanding submissions in for 9.0 but this PR was taking too
long as it was.

Thanks,
Nick
----------------------------------------------------------------
Chalapathi V (3):
      hw/ppc: Add pnv nest pervasive common chiplet model
      hw/ppc: Add N1 chiplet model
      hw/ppc: N1 chiplet wiring

Cédric Le Goater (1):
      spapr: Tag pseries-2.1 - 2.11 machines as deprecated

Glenn Miles (9):
      misc/pca9552: Fix inverted input status
      misc/pca9552: Let external devices set pca9552 inputs
      ppc/pnv: New powernv10-rainier machine type
      ppc/pnv: Add pca9552 to powernv10-rainier for PCIe hotplug power control
      ppc/pnv: Wire up pca9552 GPIO pins for PCIe hotplug power control
      ppc/pnv: Use resettable interface to reset child I2C buses
      misc: Add a pca9554 GPIO device model
      ppc/pnv: Add a pca9554 I2C device to powernv10-rainier
      ppc/pnv: Test pnv i2c master and connected devices

Harsh Prateek Bora (2):
      ppc/spapr: Introduce SPAPR_IRQ_NR_IPIS to refer IRQ range for CPU IPIs.
      ppc/spapr: Initialize max_cpus limit to SPAPR_IRQ_NR_IPIS.

Nicholas Piggin (28):
      target/ppc: Fix lxv/stxv MSR facility check
      target/ppc: Fix crash on machine check caused by ifetch
      tests/avocado: mark boot_linux.py long runtime instead of flaky
      tests/avocado: improve flaky ppc/pnv boot_linux_console.py test
      tests/avocado: ppc add powernv10 boot_linux_console test
      tests/avocado: Add ppc pseries and powernv hash MMU tests
      tests/avocado: Add pseries KVM boot_linux test
      tests/avocado: ppc add hypervisor tests
      tests/avocado: Add FreeBSD distro boot tests for ppc
      tests/avocado: Use default CPU for pseries machine
      ppc/pnv: Update skiboot to v7.1
      target/ppc: Rename registers to match ISA
      ppc/spapr: change pseries machine default to POWER10 CPU
      ppc/pnv: Change powernv default to powernv10
      target/ppc: Rename TBL to TB on 64-bit
      target/ppc: Improve timebase register defines naming
      target/ppc: Fix move-to timebase SPR access permissions
      ppc/pnv: Add POWER9/10 chiptod model
      ppc/pnv: Wire ChipTOD model to powernv9 and powernv10 machines
      ppc/pnv: Implement the ChipTOD to Core transfer
      target/ppc: Implement core timebase state machine and TFMR
      target/ppc: Add SMT support to time facilities
      target/ppc: Fix 440 tlbwe TLB invalidation gaps
      target/ppc: Factor out 4xx ppcemb_tlb_t flushing
      target/ppc: 4xx don't flush TLB for a newly written software TLB entry
      target/ppc: 4xx optimise tlbwe_lo TLB flushing
      target/ppc: 440 optimise tlbwe TLB flushing
      target/ppc: optimise ppcemb_tlb_t flushing

Peter Maydell (1):
      hw/pci-host/raven.c: Mark raven_io_ops as implementing unaligned accesses

Philippe Mathieu-Daudé (4):
      hw/ppc/spapr: Add missing license
      hw/ppc/spapr_hcall: Allow elision of softmmu_resize_hpt_prep
      hw/ppc/spapr_hcall: Rename {softmmu -> vhyp_mmu}_resize_hpt_pr
      hw/ppc/spapr: Rename 'softmmu' -> 'vhyp_mmu'

Saif Abrar (1):
      target/ppc: Update gdbstub to read SPR's CFAR, DEC, HDEC, TB-L/U

 MAINTAINERS                                  |  11 +-
 docs/about/deprecated.rst                    |   8 +
 docs/devel/testing.rst                       |  11 +
 hw/misc/Kconfig                              |   4 +
 hw/misc/meson.build                          |   1 +
 hw/misc/pca9552.c                            |  58 ++-
 hw/misc/pca9554.c                            | 328 +++++++++++++++
 hw/ppc/Kconfig                               |   2 +
 hw/ppc/meson.build                           |   5 +-
 hw/ppc/pnv.c                                 | 131 +++++-
 hw/ppc/pnv_chiptod.c                         | 586 +++++++++++++++++++++++++++
 hw/ppc/pnv_i2c.c                             | 146 +------
 hw/ppc/pnv_n1_chiplet.c                      | 173 ++++++++
 hw/ppc/pnv_nest_pervasive.c                  | 208 ++++++++++
 hw/ppc/spapr.c                               |  12 +-
 hw/ppc/spapr_hcall.c                         |  12 +-
 hw/ppc/spapr_irq.c                           |   6 +-
 hw/ppc/{spapr_softmmu.c => spapr_vhyp_mmu.c} |  13 +-
 hw/ppc/trace-events                          |   4 +
 include/hw/i2c/pnv_i2c_regs.h                | 143 +++++++
 include/hw/misc/pca9552.h                    |   3 +-
 include/hw/misc/pca9554.h                    |  36 ++
 include/hw/misc/pca9554_regs.h               |  19 +
 include/hw/ppc/pnv.h                         |   3 +
 include/hw/ppc/pnv_chip.h                    |   5 +
 include/hw/ppc/pnv_chiptod.h                 |  53 +++
 include/hw/ppc/pnv_n1_chiplet.h              |  32 ++
 include/hw/ppc/pnv_nest_pervasive.h          |  32 ++
 include/hw/ppc/pnv_xscom.h                   |  18 +
 include/hw/ppc/spapr.h                       |   9 +-
 include/hw/ppc/spapr_irq.h                   |  14 +-
 pc-bios/skiboot.lid                          | Bin 2527240 -> 2527328 bytes
 target/ppc/cpu.h                             |  57 ++-
 target/ppc/cpu_init.c                        |  20 +-
 target/ppc/excp_helper.c                     |  36 +-
 target/ppc/gdbstub.c                         |  40 +-
 target/ppc/helper_regs.c                     |  41 +-
 target/ppc/mmu_helper.c                      | 105 +++--
 target/ppc/ppc-qmp-cmds.c                    |   4 +
 target/ppc/tcg-stub.c                        |  15 -
 target/ppc/timebase_helper.c                 | 309 +++++++++++++-
 target/ppc/translate.c                       |  42 +-
 target/ppc/translate/vsx-impl.c.inc          |   2 +-
 tests/avocado/boot_freebsd.py                | 174 ++++++++
 tests/avocado/boot_linux.py                  |  16 +-
 tests/avocado/boot_linux_console.py          |  11 +-
 tests/avocado/migration.py                   |   1 -
 tests/avocado/ppc_hv_tests.py                | 203 ++++++++++
 tests/avocado/ppc_powernv.py                 |  23 +-
 tests/avocado/ppc_pseries.py                 |  20 +-
 tests/qtest/meson.build                      |   1 +
 tests/qtest/pca9552-test.c                   |   6 +-
 tests/qtest/pnv-host-i2c-test.c              | 491 ++++++++++++++++++++++
 tests/qtest/pnv-xscom-test.c                 |  61 +--
 tests/qtest/pnv-xscom.h                      |  80 ++++
 55 files changed, 3492 insertions(+), 352 deletions(-)
 create mode 100644 hw/misc/pca9554.c
 create mode 100644 hw/ppc/pnv_chiptod.c
 create mode 100644 hw/ppc/pnv_n1_chiplet.c
 create mode 100644 hw/ppc/pnv_nest_pervasive.c
 rename hw/ppc/{spapr_softmmu.c => spapr_vhyp_mmu.c} (97%)
 create mode 100644 include/hw/i2c/pnv_i2c_regs.h
 create mode 100644 include/hw/misc/pca9554.h
 create mode 100644 include/hw/misc/pca9554_regs.h
 create mode 100644 include/hw/ppc/pnv_chiptod.h
 create mode 100644 include/hw/ppc/pnv_n1_chiplet.h
 create mode 100644 include/hw/ppc/pnv_nest_pervasive.h
 create mode 100644 tests/avocado/boot_freebsd.py
 create mode 100644 tests/avocado/ppc_hv_tests.py
 create mode 100644 tests/qtest/pnv-host-i2c-test.c
 create mode 100644 tests/qtest/pnv-xscom.h

Re: [PULL 00/49] ppc-for-9.0 queue
Posted by Peter Maydell 8 months, 3 weeks ago
On Mon, 19 Feb 2024 at 08:31, Nicholas Piggin <npiggin@gmail.com> wrote:
>
> The following changes since commit da96ad4a6a2ef26c83b15fa95e7fceef5147269c:
>
>   Merge tag 'hw-misc-20240215' of https://github.com/philmd/qemu into staging (2024-02-16 11:05:14 +0000)
>
> are available in the Git repository at:
>
>   https://gitlab.com/npiggin/qemu.git tags/pull-ppc-for-9.0-20240219
>
> for you to fetch changes up to 922e408e12315121d3e09304b8b8f462ea051af1:
>
>   target/ppc: optimise ppcemb_tlb_t flushing (2024-02-19 18:09:19 +1000)
>
> ----------------------------------------------------------------
> * Avocado tests for ppc64 to boot FreeBSD, run guests with emulated
>   or nested hypervisor facilities, among other things.
> * Update ppc64 CPU defaults to Power10.
> * Add a new powernv10-rainier machine to better capture differences
>   between the different Power10 systems.
> * Implement more device models for powernv.
> * 4xx TLB flushing performance and correctness improvements.
> * Correct gdb implementation to access some important SPRs.
> * Misc cleanups and bug fixes.
>
> I dropped the BHRB patches, they are very close but minor issue only
> noticed recently held them up. Hopefully we can get those and a bunch
> of other outstanding submissions in for 9.0 but this PR was taking too
> long as it was.

> Peter Maydell (1):
>       hw/pci-host/raven.c: Mark raven_io_ops as implementing unaligned accesses

Hi Nick -- this commit went upstream via a different route, and
so it now appears in this pullrequest as a commit with a commit
message but no contents. Could I ask you to respin the pullreq
with that commit dropped, please?

thanks
-- PMM
Re: [PULL 00/49] ppc-for-9.0 queue
Posted by Nicholas Piggin 8 months, 3 weeks ago
On Tue Feb 20, 2024 at 3:06 AM AEST, Peter Maydell wrote:
> On Mon, 19 Feb 2024 at 08:31, Nicholas Piggin <npiggin@gmail.com> wrote:
> >
> > The following changes since commit da96ad4a6a2ef26c83b15fa95e7fceef5147269c:
> >
> >   Merge tag 'hw-misc-20240215' of https://github.com/philmd/qemu into staging (2024-02-16 11:05:14 +0000)
> >
> > are available in the Git repository at:
> >
> >   https://gitlab.com/npiggin/qemu.git tags/pull-ppc-for-9.0-20240219
> >
> > for you to fetch changes up to 922e408e12315121d3e09304b8b8f462ea051af1:
> >
> >   target/ppc: optimise ppcemb_tlb_t flushing (2024-02-19 18:09:19 +1000)
> >
> > ----------------------------------------------------------------
> > * Avocado tests for ppc64 to boot FreeBSD, run guests with emulated
> >   or nested hypervisor facilities, among other things.
> > * Update ppc64 CPU defaults to Power10.
> > * Add a new powernv10-rainier machine to better capture differences
> >   between the different Power10 systems.
> > * Implement more device models for powernv.
> > * 4xx TLB flushing performance and correctness improvements.
> > * Correct gdb implementation to access some important SPRs.
> > * Misc cleanups and bug fixes.
> >
> > I dropped the BHRB patches, they are very close but minor issue only
> > noticed recently held them up. Hopefully we can get those and a bunch
> > of other outstanding submissions in for 9.0 but this PR was taking too
> > long as it was.
>
> > Peter Maydell (1):
> >       hw/pci-host/raven.c: Mark raven_io_ops as implementing unaligned accesses
>
> Hi Nick -- this commit went upstream via a different route, and
> so it now appears in this pullrequest as a commit with a commit
> message but no contents. Could I ask you to respin the pullreq
> with that commit dropped, please?

Yeah, sorry about that :( I think I noticed it when rebasing but did
not check that I'd fixed it. It's nice to keep gunk out of the upstream
so I agree, I will respin it.

Thanks,
Nick
[PULL 22/49] hw/pci-host/raven.c: Mark raven_io_ops as implementing unaligned accesses
Posted by Nicholas Piggin 8 months, 3 weeks ago
From: Peter Maydell <peter.maydell@linaro.org>

The raven_io_ops MemoryRegionOps is the only one in the source tree
which sets .valid.unaligned to indicate that it should support
unaligned accesses and which does not also set .impl.unaligned to
indicate that its read and write functions can do the unaligned
handling themselves.  This is a problem, because at the moment the
core memory system does not implement the support for handling
unaligned accesses by doing a series of aligned accesses and
combining them (system/memory.c:access_with_adjusted_size() has a
TODO comment noting this).

Fortunately raven_io_read() and raven_io_write() will correctly deal
with the case of being passed an unaligned address, so we can fix the
missing unaligned access support by setting .impl.unaligned in the
MemoryRegionOps struct.

Fixes: 9a1839164c9c8f06 ("raven: Implement non-contiguous I/O region")
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Tested-by: Cédric Le Goater <clg@redhat.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
-- 
2.42.0


Re: [PULL 22/49] hw/pci-host/raven.c: Mark raven_io_ops as implementing unaligned accesses
Posted by BALATON Zoltan 8 months, 3 weeks ago
On Mon, 19 Feb 2024, Nicholas Piggin wrote:
> From: Peter Maydell <peter.maydell@linaro.org>
>
> The raven_io_ops MemoryRegionOps is the only one in the source tree
> which sets .valid.unaligned to indicate that it should support
> unaligned accesses and which does not also set .impl.unaligned to
> indicate that its read and write functions can do the unaligned
> handling themselves.  This is a problem, because at the moment the
> core memory system does not implement the support for handling
> unaligned accesses by doing a series of aligned accesses and
> combining them (system/memory.c:access_with_adjusted_size() has a
> TODO comment noting this).
>
> Fortunately raven_io_read() and raven_io_write() will correctly deal
> with the case of being passed an unaligned address, so we can fix the
> missing unaligned access support by setting .impl.unaligned in the
> MemoryRegionOps struct.
>
> Fixes: 9a1839164c9c8f06 ("raven: Implement non-contiguous I/O region")
> Reviewed-by: Cédric Le Goater <clg@redhat.com>
> Tested-by: Cédric Le Goater <clg@redhat.com>
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>

Hm, this seems to be missing the actual patch.

Regards,
BALATON Zoltan
Re: [PULL 22/49] hw/pci-host/raven.c: Mark raven_io_ops as implementing unaligned accesses
Posted by Cédric Le Goater 8 months, 3 weeks ago
On 2/19/24 15:49, BALATON Zoltan wrote:
> On Mon, 19 Feb 2024, Nicholas Piggin wrote:
>> From: Peter Maydell <peter.maydell@linaro.org>
>>
>> The raven_io_ops MemoryRegionOps is the only one in the source tree
>> which sets .valid.unaligned to indicate that it should support
>> unaligned accesses and which does not also set .impl.unaligned to
>> indicate that its read and write functions can do the unaligned
>> handling themselves.  This is a problem, because at the moment the
>> core memory system does not implement the support for handling
>> unaligned accesses by doing a series of aligned accesses and
>> combining them (system/memory.c:access_with_adjusted_size() has a
>> TODO comment noting this).
>>
>> Fortunately raven_io_read() and raven_io_write() will correctly deal
>> with the case of being passed an unaligned address, so we can fix the
>> missing unaligned access support by setting .impl.unaligned in the
>> MemoryRegionOps struct.
>>
>> Fixes: 9a1839164c9c8f06 ("raven: Implement non-contiguous I/O region")
>> Reviewed-by: Cédric Le Goater <clg@redhat.com>
>> Tested-by: Cédric Le Goater <clg@redhat.com>
>> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
>> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> 
> Hm, this seems to be missing the actual patch.

It's merged already and git knows how to handle this.

Thanks,

C.



Re: [PULL 22/49] hw/pci-host/raven.c: Mark raven_io_ops as implementing unaligned accesses
Posted by Peter Maydell 8 months, 3 weeks ago
On Mon, 19 Feb 2024 at 14:53, Cédric Le Goater <clg@kaod.org> wrote:
>
> On 2/19/24 15:49, BALATON Zoltan wrote:
> > On Mon, 19 Feb 2024, Nicholas Piggin wrote:
> >> From: Peter Maydell <peter.maydell@linaro.org>
> >>
> >> The raven_io_ops MemoryRegionOps is the only one in the source tree
> >> which sets .valid.unaligned to indicate that it should support
> >> unaligned accesses and which does not also set .impl.unaligned to
> >> indicate that its read and write functions can do the unaligned
> >> handling themselves.  This is a problem, because at the moment the
> >> core memory system does not implement the support for handling
> >> unaligned accesses by doing a series of aligned accesses and
> >> combining them (system/memory.c:access_with_adjusted_size() has a
> >> TODO comment noting this).
> >>
> >> Fortunately raven_io_read() and raven_io_write() will correctly deal
> >> with the case of being passed an unaligned address, so we can fix the
> >> missing unaligned access support by setting .impl.unaligned in the
> >> MemoryRegionOps struct.
> >>
> >> Fixes: 9a1839164c9c8f06 ("raven: Implement non-contiguous I/O region")
> >> Reviewed-by: Cédric Le Goater <clg@redhat.com>
> >> Tested-by: Cédric Le Goater <clg@redhat.com>
> >> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> >> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> >
> > Hm, this seems to be missing the actual patch.
>
> It's merged already and git knows how to handle this.

Mmm, though this is the result of "rebased onto a tree that
already had the commit" rather than "two merges both contain
the commit", so we end up with a genuinely empty commit upstream,
which is a bit odd looking, though harmless.

-- PMM
Re: [PULL 22/49] hw/pci-host/raven.c: Mark raven_io_ops as implementing unaligned accesses
Posted by Cédric Le Goater 8 months, 3 weeks ago
On 2/19/24 15:55, Peter Maydell wrote:
> On Mon, 19 Feb 2024 at 14:53, Cédric Le Goater <clg@kaod.org> wrote:
>>
>> On 2/19/24 15:49, BALATON Zoltan wrote:
>>> On Mon, 19 Feb 2024, Nicholas Piggin wrote:
>>>> From: Peter Maydell <peter.maydell@linaro.org>
>>>>
>>>> The raven_io_ops MemoryRegionOps is the only one in the source tree
>>>> which sets .valid.unaligned to indicate that it should support
>>>> unaligned accesses and which does not also set .impl.unaligned to
>>>> indicate that its read and write functions can do the unaligned
>>>> handling themselves.  This is a problem, because at the moment the
>>>> core memory system does not implement the support for handling
>>>> unaligned accesses by doing a series of aligned accesses and
>>>> combining them (system/memory.c:access_with_adjusted_size() has a
>>>> TODO comment noting this).
>>>>
>>>> Fortunately raven_io_read() and raven_io_write() will correctly deal
>>>> with the case of being passed an unaligned address, so we can fix the
>>>> missing unaligned access support by setting .impl.unaligned in the
>>>> MemoryRegionOps struct.
>>>>
>>>> Fixes: 9a1839164c9c8f06 ("raven: Implement non-contiguous I/O region")
>>>> Reviewed-by: Cédric Le Goater <clg@redhat.com>
>>>> Tested-by: Cédric Le Goater <clg@redhat.com>
>>>> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
>>>> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
>>>
>>> Hm, this seems to be missing the actual patch.
>>
>> It's merged already and git knows how to handle this.
> 
> Mmm, though this is the result of "rebased onto a tree that
> already had the commit" rather than "two merges both contain
> the commit", so we end up with a genuinely empty commit upstream,
> which is a bit odd looking, though harmless.

git rebase -i db5f7f9e3ceb and dropping the first patch would
cleanup the empty patch.

C.