KVM: PPC: Book3S HV: Add missing barriers to XIVE code and document them
This adds missing memory barriers to order updates/tests of
the virtual CPPR and MFRR, thus fixing a lost IPI problem.
While at it also document all barriers in this file.
This fixes a bug causing guest IPIs to occasionally get lost. The
symptom then is hangs or stalls in the guest.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Tested-by: Guilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
1 file changed