Re: [Qemu-devel] anybody using MMIO tracing?

[Stefan Hajnoczi]

On Mon, Nov 02, 2015 at 09:18:03AM -0800, Hollis Blanchard wrote:
> I'm trying to use the memory_region_ops_read/write tracepoints. They produce
> output like this:
> 
>    memory_region_ops_write 0.000 pid=8861 mr=0x185b1e8 addr=0x0
>    value=0x3 size=0x4
>    memory_region_ops_write 165.000 pid=8861 mr=0x185b1e8 addr=0x80
>    value=0xffffffff size=0x4
>    memory_region_ops_write 155.000 pid=8861 mr=0x1914240 addr=0x0
>    value=0x3 size=0x4
>    memory_region_ops_write 2.000 pid=8861 mr=0x185b320 addr=0x0
>    value=0x3 size=0x4
>    memory_region_ops_write 134.000 pid=8861 mr=0x1914240 addr=0x4
>    value=0x80 size=0x4
> 
> How do I discover which devices are represented by MemoryRegions 0x185b1e8
> and 0x1914240? Or alternatively how do I discover the full addresses?

As a KVM user I use the kvm:kvm_mmio and kvm:kvm_pio kernel trace
events.

I'm not sure of the best way but you could look at memory.c:mtree_info()
(aka "info mtree" monitor command) and print out all MemoryRegion
pointers so you can correlate them with the trace output.

Stefan

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