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

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: 243e25112d06 ("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
index d22aeb0b69e107636e94e7811785e573f60880ce..b48454be5b9822fdd1ac75452edf20a988745e5b 100644 (file)
--- 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);