Re: [Qemu-devel] [PATCH] qmp: extend QMP to provide read/write access to physical memory

[Bryan D. Payne]

> For those that prefer text, here's the numbers (in microseconds):
> QMP/pmemsave: 77706
> HMC/xp command: 92552
> QMP/pmemaccess: 95

I completed a proof of concept implementation for doing this memory access completely over QMP.  Basically, it works much like pmemsave except instead of sending the data to a file it does a base64 encode and sends it back over the QMP connection.  Interestingly, my testing shows that this is slightly slower than the pmemsave option.  Running the same test as before (virtual address translation), I get 88063 microsecs on average.  So I don't believe this option is viable.

Look good. I believe QMP will be in between, and if it doesn't work as well,

could you also try to use QEMU's char dev instead of limit this to unix socket?

I'm moving forward to try the Qemu chardev approach now.  I haven't working much with this construct before, so any pointers are appreciated.  From what I'm seeing, it looks like the user would create a chardev using one of the QMP @chardev* commands?  The schema doesn't indicate that these commands return the chardev id, which seems odd as I was then assuming that one could obtain the id and pass this into the pmemaccess QMP command.  Thoughts?

-bryan