Re: [PATCH 07/13] tests/avocado/kvm_xen_guest.py: cope with asset RW requirements

[David Woodhouse]

On Mon, 2024-07-29 at 11:58 +0100, Daniel P. Berrangé wrote:
> On Fri, Jul 26, 2024 at 09:44:32AM -0400, Cleber Rosa wrote:
> > Some of these tests actually require the root filesystem image,
> > obtained through Avocado's asset feature and kept in a common cache
> > location, to be writable.

Hm, I'm not sure *why* they require a writable image. Mostly they're
just testing the interrupt routing. What's the failure mode for a read-
only image?

> > @@ -56,11 +57,19 @@ def common_vm_setup(self):
> >                                            
> > "367962983d0d32109998a70b45dcee4672d0b045")
> >          self.rootfs = self.get_asset("rootfs.ext4",
> >                                       
> > "f1478401ea4b3fa2ea196396be44315bab2bb5e4")
> > +        if readwrite:
> > +            dest = os.path.join(self.workdir, 
> > os.path.basename(self.rootfs))
> > +            shutil.copy(self.rootfs, dest)
> > +            self.rootfs = dest
> 
> This is a very expensive way of creating a writable disk. Better to
> avoid adding this 'readwrite' parameter at all, and instead create
> a throwaway qcow2 overlay for the image for all tests. That ensures
> writability for everything in a cheap manner.

Or just use -snapshot?

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