Re: [Qemu-arm] [PATCH 0/6] accel/tcg: Support execution from MMIO and small MMU regions

[Cédric Le Goater]

On 07/23/2018 05:17 PM, Peter Maydell wrote:
> On 23 July 2018 at 15:57, Cédric Le Goater <address@hidden> wrote:
>> On 07/10/2018 06:00 PM, Peter Maydell wrote:
>>> Note for the Xilinx folks: this patchset makes the mmio-exec
>>> testcase for running from the SPI flash pass. Cedric: you might
>>> like to test the aspeed image you had that relies on execution
>>> from an MMIO region too.
>>
>> I have added a memory region alias at 0x0 on the memory region where
>> the first flash device is mapped and all aspeed machines, palmetto,
>> romulus, witherspoon booted fine.
>>
>> More or less 4MB of data access is generated and the slowdown is hardly
>> noticeable, around one second on a laptop.
>>
>> I wonder if I should add a bool option to the machine to activate
>> or not the feature ?
> 
> I would tend to go with "not" -- if we need the feature then
> it's better to run slowly but correctly, and if we don't need
> the feature then it doesn't cost us any speed I think.


I have chosen a brutal activation (for the moment) :

  
https://github.com/legoater/qemu/commit/10b08c5e8df385bba342f02fa0440916203b6fa8

I will send when your patchset is committed.

Images used for tests are here : 

  
https://openpower.xyz/job/openbmc-build/distro=ubuntu,target=romulus/lastSuccessfulBuild/artifact/deploy/images/romulus/flash-romulus

  
https://openpower.xyz/job/openbmc-build/distro=ubuntu,target=palmetto/lastSuccessfulBuild/artifact/deploy/images/palmetto/flash-palmetto

  
https://openpower.xyz/job/openbmc-build/distro=ubuntu,target=witherspoon/lastSuccessfulBuild/artifact/deploy/images/witherspoon/obmc-phosphor-image-witherspoon.ubi.mtd

Thanks,

C.