Re: [RFC PATCH-not-for-5.1? v2] hw/isa/isa-bus: Ensure ISA I/O regions are 8/16-bit accessible

[Philippe Mathieu-Daudé]

On 7/20/20 9:45 PM, Michael Tokarev wrote:
> 20.07.2020 21:57, Philippe Mathieu-Daudé пишет:
>> Since commit 5d971f9e67 we don't accept mismatching sizes
>> in memory_region_access_valid(). This gives troubles when
>> a device is on an ISA bus, because the CPU is free to use
>> 8/16-bit accesses on the bus (or up to 32-bit on EISA bus),
>> regardless what range is valid for the device.
>>
>> Add a check to ensure devices plugged on the ISA bus can
>> accept 8/16-bits accesses.
>>
>> Related bug reports:
>>
>> - 
>> https://lore.kernel.org/xen-devel/20200630170913.123646-1-anthony.perard@citrix.com/T/
>> - https://bugs.debian.org/964793
>> - https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=964247
>> - https://bugs.launchpad.net/bugs/1886318
> 
> Here's the output (of a similar patch), after I fixed the 3 acpi core
> devies, of one of my windows7 test VMs. I guess we need to fix either
> these devices or the registration, before 5.1 is out, or else more
> difficult-to-catch breakage like the above will pop up..
> 
> For now we don't have any released qemu version with this situation
> so not many project enabled workarounds for broken qemu behavour
> like the xen-devel link above.
> 
> qemu-system-x86_64: ISA device 'kvm-i8259' requires I/O max_access_size of 2
> qemu-system-x86_64: ISA device 'kvm-i8259' requires I/O max_access_size of 2
> qemu-system-x86_64: ISA device 'kvm-i8259' requires I/O max_access_size of 2
> qemu-system-x86_64: ISA device 'kvm-i8259' requires I/O max_access_size of 2
> qemu-system-x86_64: ISA device 'mc146818rtc' requires I/O max_access_size of 2
> qemu-system-x86_64: ISA device 'kvm-pit' requires I/O max_access_size of 2
> qemu-system-x86_64: ISA device 'isa-pcspk' requires I/O max_access_size of 2
> qemu-system-x86_64: ISA device 'isa-serial' requires I/O max_access_size of 2
> qemu-system-x86_64: ISA device 'i8042' requires I/O max_access_size of 2
> qemu-system-x86_64: ISA device 'i8042' requires I/O max_access_size of 2
> qemu-system-x86_64: ISA device 'vmport' requires I/O max_access_size of 2
> qemu-system-x86_64: ISA device 'port92' requires I/O max_access_size of 2

This is better to find the full list:

$ git grep -l isa_register_ioport
hw/audio/cs4231a.c
hw/audio/pcspk.c
hw/char/serial-isa.c
hw/i386/port92.c
hw/i386/vmport.c
hw/input/pckbd.c
hw/intc/i8259_common.c
hw/ipmi/isa_ipmi_bt.c
hw/ipmi/isa_ipmi_kcs.c
hw/isa/isa-bus.c
hw/isa/pc87312.c
hw/misc/applesmc.c
hw/misc/pvpanic.c
hw/net/ne2000-isa.c
hw/rtc/m48t59-isa.c
hw/rtc/mc146818rtc.c
hw/timer/i8254_common.c
include/hw/isa/isa.h

> 
> Thanks,
> 
> /mjt