powerpc: Document how we set AIL on guest kernels
authorMichael Ellerman <mpe@ellerman.id.au>
Thu, 17 Jul 2014 05:29:45 +0000 (15:29 +1000)
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>
Mon, 28 Jul 2014 04:11:27 +0000 (14:11 +1000)
I spent ten minutes scratching my head, trying to work out where we
enabled relocation on interrupts for guest kernels. Expand the doco to
make it clear.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
arch/powerpc/kernel/setup_64.c

index 694339043b569f6a55515b05481639655a2ff7ab..75f94ae20e9ef99f49b7739fabace06e8d60eddb 100644 (file)
@@ -201,7 +201,11 @@ static void cpu_ready_for_interrupts(void)
        /* Set IR and DR in PACA MSR */
        get_paca()->kernel_msr = MSR_KERNEL;
 
-       /* Enable AIL if supported */
+       /*
+        * Enable AIL if supported, and we are in hypervisor mode. If we are
+        * not in hypervisor mode, we enable relocation-on interrupts later
+        * in pSeries_setup_arch() using the H_SET_MODE hcall.
+        */
        if (cpu_has_feature(CPU_FTR_HVMODE) &&
            cpu_has_feature(CPU_FTR_ARCH_207S)) {
                unsigned long lpcr = mfspr(SPRN_LPCR);