powerpc/xive: Fix IPI reset

When resetting an IPI, hw_ipi should also be set to zero.

Fixes: eac1e731b59e ("powerpc/xive: guest exploitation of the XIVE interrupt controller")
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/sysdev/xive/spapr.c

@@ -431,7 +431,11 @@ static int xive_spapr_get_ipi(unsigned int cpu, struct xive_cpu *xc)
 
 static void xive_spapr_put_ipi(unsigned int cpu, struct xive_cpu *xc)
 {
+	if (!xc->hw_ipi)
+		return;
+
 	xive_irq_bitmap_free(xc->hw_ipi);
+	xc->hw_ipi = 0;
 }
 #endif /* CONFIG_SMP */