On Tue, 22 Mar 2016 09:25:58 +0100 Laurent Vivier <lvivier@xxxxxxxxxx> wrote: > On 22/03/2016 09:12, Thomas Huth wrote: > > On 22.03.2016 00:56, David Gibson wrote: > >> On Mon, 21 Mar 2016 12:33:34 +0100 > >> Laurent Vivier <lvivier@xxxxxxxxxx> wrote: > >> > >>> For lswx in little-endian mode, an alignment interrupt occurs. > >>> > >>> Signed-off-by: Laurent Vivier <lvivier@xxxxxxxxxx> > >>> Reviewed-by: Thomas Huth <thuth@xxxxxxxxxx> > >> > >> I'm not entirely clear here; will the test fail if the alignment > >> exception doesn't occur in little endian mode? > > > > I think so, yes. > > > >> The general trend in Power has been for less and less things to trigger > >> alignment exceptions, so failing to cause an alignment exception > >> shouldn't cause a test failure (as long as the unaligned case is > >> correctly processed, of course). > > > > According to the PowerISA 2.07, chapter 6.5.8, lswx should always > > trigger an alignment exception in little endian mode. So that's > > architected behavior and the test should be OK, as far as I can see... > > In case this gets changed with a future CPU, I think the test could be > > adapted later, too? > > Exactly. > > Then in the kernel, the instruction is emulated. It's why I didn't > understand why this test case fails with kvm in little endian mode, > while is was working on a real host or in a guest. Ok, then. -- David Gibson <dgibson@xxxxxxxxxx> Senior Software Engineer, Virtualization, Red Hat
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