powerpc/pseries: Set UNISOLATE on dlpar_memory_remove_by_ic() error

As previously done in dlpar_cpu_remove() for CPUs, this patch changes
dlpar_memory_remove_by_ic() to unisolate the LMB DRC when the LMB is
failed to be removed. The hypervisor, seeing a LMB DRC that was supposed
to be removed being unisolated instead, can do error recovery on its
side.

This change is done in dlpar_memory_remove_by_ic() only because, as of
today, only QEMU is using this code path for error recovery (via the
PSERIES_HP_ELOG_ID_DRC_IC event). phyp treats it as a no-op.

Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210512202809.95363-2-danielhb413@gmail.com

diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c
index 3d93f1c48e23b38f1ff4487097f250ec1ab3fe36..5d831756d1f3396b53be17301e35cb227d28c244 100644 (file)
--- a/arch/powerpc/platforms/pseries/hotplug-memory.c
+++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
@@ -551,6 +551,13 @@ static int dlpar_memory_remove_by_ic(u32 lmbs_to_remove, u32 drc_index)
                        if (!drmem_lmb_reserved(lmb))
                                continue;
 
+                       /*
+                        * Setting the isolation state of an UNISOLATED/CONFIGURED
+                        * device to UNISOLATE is a no-op, but the hypervisor can
+                        * use it as a hint that the LMB removal failed.
+                        */
+                       dlpar_unisolate_drc(lmb->drc_index);
+
                        rc = dlpar_add_lmb(lmb);
                        if (rc)
                                pr_err("Failed to add LMB, drc index %x\n",