powerpc/xive: Fix trying to "push" an already active pool VP

ozbenh · mpe · commit b32e56e5a87a · 2018-04-19T00:49:45.000+10:00
When setting up a CPU, we "push" (activate) a pool VP for it. However it's an error to do so if it already has an active pool VP. This happens when doing soft CPU hotplug on powernv since we don't tear down the CPU on unplug. The HW flags the error which gets captured by the diagnostics. Fix this by making sure to "pull" out any already active pool first. Fixes: 243e251 ("powerpc/xive: Native exploitation of the XIVE interrupt controller") Cc: stable@vger.kernel.org # v4.12+ Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
diff --git a/arch/powerpc/sysdev/xive/native.c b/arch/powerpc/sysdev/xive/native.c
@@ -389,6 +389,10 @@ static void xive_native_setup_cpu(unsigned int cpu, struct xive_cpu *xc)
 	if (xive_pool_vps == XIVE_INVALID_VP)
 		return;
 
+	/* Check if pool VP already active, if it is, pull it */
+	if (in_be32(xive_tima + TM_QW2_HV_POOL + TM_WORD2) & TM_QW2W2_VP)
+		in_be64(xive_tima + TM_SPC_PULL_POOL_CTX);
+
 	/* Enable the pool VP */
 	vp = xive_pool_vps + cpu;
 	pr_debug("CPU %d setting up pool VP 0x%x\n", cpu, vp);
