Re: [Qemu-devel] [PATCH 1/6] tests: Add basic migration precopy test

[Dr. David Alan Gilbert]

* Peter Xu (address@hidden) wrote:
> On Wed, Oct 18, 2017 at 01:10:38PM +0100, Daniel P. Berrange wrote:
> > On Wed, Oct 18, 2017 at 01:36:56PM +0200, Juan Quintela wrote:
> > > Peter Xu <address@hidden> wrote:
> > > > On Wed, Oct 04, 2017 at 12:39:28PM +0200, Juan Quintela wrote:
> > > >
> > > > [...]
> > > >
> > > >> +/* A simple PC boot sector that modifies memory (1-100MB) quickly
> > > >> + * outputing a 'B' every so often if it's still running.
> > > >> + */
> > > >> +unsigned char bootsect[] = {
> > > >> +  0xfa, 0x0f, 0x01, 0x16, 0x74, 0x7c, 0x66, 0xb8, 0x01, 0x00, 0x00, 
> > > >> 0x00,
> > > >> +  0x0f, 0x22, 0xc0, 0x66, 0xea, 0x20, 0x7c, 0x00, 0x00, 0x08, 0x00, 
> > > >> 0x00,
> > > >> +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xe4, 0x92, 0x0c, 
> > > >> 0x02,
> > > >> +  0xe6, 0x92, 0xb8, 0x10, 0x00, 0x00, 0x00, 0x8e, 0xd8, 0x66, 0xb8, 
> > > >> 0x41,
> > > >> +  0x00, 0x66, 0xba, 0xf8, 0x03, 0xee, 0xb3, 0x00, 0xb8, 0x00, 0x00, 
> > > >> 0x10,
> > > >> +  0x00, 0xfe, 0x00, 0x05, 0x00, 0x10, 0x00, 0x00, 0x3d, 0x00, 0x00, 
> > > >> 0x40,
> > > >> +  0x06, 0x7c, 0xf2, 0xfe, 0xc3, 0x75, 0xe9, 0x66, 0xb8, 0x42, 0x00, 
> > > >> 0x66,
> > > >> +  0xba, 0xf8, 0x03, 0xee, 0xeb, 0xde, 0x66, 0x90, 0x00, 0x00, 0x00, 
> > > >> 0x00,
> > > >> +  0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0x00, 0x9a, 0xcf, 
> > > >> 0x00,
> > > >> +  0xff, 0xff, 0x00, 0x00, 0x00, 0x92, 0xcf, 0x00, 0x27, 0x00, 0x5c, 
> > > >> 0x7c,
> > > >> +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
> > > >> 0x00,
> > > >> +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
> > > >> 0x00,
> > > >> +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
> > > >> 0x00,
> > > >> +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
> > > >> 0x00,
> > > >> +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
> > > >> 0x00,
> > > >> +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
> > > >> 0x00,
> > > >> +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
> > > >> 0x00,
> > > >> +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
> > > >> 0x00,
> > > >> +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
> > > >> 0x00,
> > > >> +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
> > > >> 0x00,
> > > >> +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
> > > >> 0x00,
> > > >> +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
> > > >> 0x00,
> > > >> +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
> > > >> 0x00,
> > > >> +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
> > > >> 0x00,
> > > >> +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
> > > >> 0x00,
> > > >> +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
> > > >> 0x00,
> > > >> +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
> > > >> 0x00,
> > > >> +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
> > > >> 0x00,
> > > >> +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
> > > >> 0x00,
> > > >> +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
> > > >> 0x00,
> > > >> +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
> > > >> 0x00,
> > > >> +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
> > > >> 0x00,
> > > >> +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
> > > >> 0x00,
> > > >> +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
> > > >> 0x00,
> > > >> +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
> > > >> 0x00,
> > > >> +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
> > > >> 0x00,
> > > >> +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
> > > >> 0x00,
> > > >> +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
> > > >> 0x00,
> > > >> +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
> > > >> 0x00,
> > > >> +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
> > > >> 0x00,
> > > >> +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
> > > >> 0x00,
> > > >> +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
> > > >> 0x00,
> > > >> +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x55, 0xaa
> > > >> +};
> > > >
> > > > Not sure whether it would be nicer to put this section as binary into
> > > > QEMU's tree as shared, then other test code can use it too directly,
> > > > and it would be easier if someone wants to boot a VM running this
> > > > bootstrap code.  Thanks,
> > > 
> > > I am sharing this code now on a single place.  About getting this
> > > outside ... I will wait for someone that understand how this works, I
> > > have no clue neither how it works nor how to share/use/setup/....
> > 
> > FWIW, we already have a reusuable program that can be used to generate
> > load stress for testing live migration see tests/migration/stress.c
> > This gets compiled into a static binary, put into an initrd, and then
> > run by booting the host OS kernel. So the caveat is that this approach
> > only lets you test a QEMU emulator whose target arch matches the host.
> > That isn't much different from this boot sector though which only lets
> > you test the x86 system emulator.
> 
> Yes, if we can have some C program for all architecture then it sounds
> nicer, though IIUC this program is somehow special since it should be
> writting some "A"/"B" chars to console, and the test program is using
> those chars during the process.
> 
> Maybe it would be nice to rewrite a C program to replace current
> binary sector when someone wants to support postcopy migration test on
> a 3rd platform besides x86 and ppc.

The problem is you then rely on having Linux or booting a full guest;
and then you can't get the memory mapping reliably to allow the test to
examine the physical memory contents.

This little boot sector works quite nicely for x86, and Laurent's line
of Forth works nicely on Power.

Similar trivial tests for other architectures are probably easy.

Dave


> Thanks,
> 
> -- 
> Peter Xu
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK