Re: [PATCH] Allow acpi-tmr size=2

[Michael Tokarev]

12.07.2020 15:00, Simon John wrote:
> macos guests no longer boot after commit 
> 5d971f9e672507210e77d020d89e0e89165c8fc9
> 
> acpi-tmr needs 2 byte memory accesses, so breaks as that commit only allows 4 
> bytes.
> 
> Fixes: 5d971f9e672507210e7 (memory: Revert "memory: accept mismatching sizes 
> in memory_region_access_valid")
> Buglink: https://bugs.launchpad.net/qemu/+bug/1886318

Actually this fixes 77d58b1e47c8d1c661f98f12b47ab519d3561488
Author: Gerd Hoffmann <kraxel@redhat.com>
Date:   Thu Nov 22 12:12:30 2012 +0100
Subject: apci: switch timer to memory api
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

because this is the commit which put min_access_size = 4 in there
(5d971f9e672507210e7 is just a messenger, actual error were here
earlier but it went unnoticed).

While min_access_size=4 was most likely an error, I wonder why
we use 1 now, while the subject says it needs 2? What real min
size is here for ACPI PM timer?

/mjt

> Signed-off-by: Simon John <git@the-jedi.co.uk>
> ---
>  hw/acpi/core.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/hw/acpi/core.c b/hw/acpi/core.c
> index f6d9ec4f13..05ff29b9d7 100644
> --- a/hw/acpi/core.c
> +++ b/hw/acpi/core.c
> @@ -527,7 +527,7 @@ static void acpi_pm_tmr_write(void *opaque, hwaddr addr, 
> uint64_t val,
>  static const MemoryRegionOps acpi_pm_tmr_ops = {
>      .read = acpi_pm_tmr_read,
>      .write = acpi_pm_tmr_write,
> -    .valid.min_access_size = 4,
> +    .valid.min_access_size = 1,
>      .valid.max_access_size = 4,
>      .endianness = DEVICE_LITTLE_ENDIAN,
>  };