Re: [kvm-unit-tests PATCH V2 4/4] powerpc/tm: Add a test for H_CEDE while tm suspended

[Suraj Jitindar Singh <sjitindarsingh@gmail.com>]

On Wed, 2016-08-10 at 13:33 +0200, Thomas Huth wrote:
> On 10.08.2016 03:59, Suraj Jitindar Singh wrote:
> > 
> > On Power machines if a guest cedes while a tm transaction is in the
> > suspended state then the checkpointed state of the vcpu may be lost
> > and we
> > lose the cpu in the host.
> > 
> > Add a file for tm tests "powerpc/tm.c" and add a test to check if
> > the fix
> > has been applied to the host kernel. If this fix hasn't been
> > applied then
> > the test will never complete and the cpu will be lost. Otherwise
> > the test
> > should succeed. Since this has the ability to mess things up in the
> > host
> > mark this test as don't run by default.
> > 
> > Based on initial work done by: Cyril Bur <cyril.bur@au1.ibm.com>
> > 
> > Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
> > ---
> [...]
> > 
> > +	/*
> > +	 * Begin a transaction and guarantee we are in the suspend
> > state
> > +	 * before continuing
> > +	 */
> > +	asm volatile (	"1: tbegin.\n\t"
> > +			"beq 2f\n\t"
> > +			"tsuspend.\n\t"
> > +			"2: tcheck cr0\n\t"
> > +			"bf 2,1b"		:
> > +						:
> > +						: "cr0"
> > +		     );
> I now also tried to compile your patches, and looks like my standard
> GCC
> cross-compiler does not know about these mnemonics yet:
> 
> /tmp/ccGEtgIa.s: Assembler messages:
> /tmp/ccGEtgIa.s:96: Error: unrecognized opcode: `tbegin.'
> /tmp/ccGEtgIa.s:98: Error: unrecognized opcode: `tsuspend.'
> /tmp/ccGEtgIa.s:99: Error: unrecognized opcode: `tcheck'
> 
> That's happening with the standard cross-compiler which is shipping
> with
> RHEL 7.2 (GCC 4.8.1 20130717). Could you please use ".long 0x..."
> statements with the corresponding opcode values here instead, so that
> it
> also compiles with such older versions of GCC?
I'll fix this up, thanks for the catch
> 
>  Thanks,
>   Thomas
>