Greg Kurz a9c55f22a0 powerpc/pseries: Don't enforce MSI affinity with kdump ... commit f9619d5e5174867536b7e558683bc4408eab833f upstream. Depending on the number of online CPUs in the original kernel, it is likely for CPU #0 to be offline in a kdump kernel. The associated IRQs in the affinity mappings provided by irq_create_affinity_masks() are thus not started by irq_startup(), as per-design with managed IRQs. This can be a problem with multi-queue block devices driven by blk-mq : such a non-started IRQ is very likely paired with the single queue enforced by blk-mq during kdump (see blk_mq_alloc_tag_set()). This causes the device to remain silent and likely hangs the guest at some point. This is a regression caused by commit 9ea69a55b3 ("powerpc/pseries: Pass MSI affinity to irq_create_mapping()"). Note that this only happens with the XIVE interrupt controller because XICS has a workaround to bypass affinity, which is activated during kdump with the "noirqdistrib" kernel parameter. The issue comes from a combination of factors: - discrepancy between the number of queues detected by the multi-queue block driver, that was used to create the MSI vectors, and the single queue mode enforced later on by blk-mq because of kdump (i.e. keeping all queues fixes the issue) - CPU#0 offline (i.e. kdump always succeed with CPU#0) Given that I couldn't reproduce on x86, which seems to always have CPU#0 online even during kdump, I'm not sure where this should be fixed. Hence going for another approach : fine-grained affinity is for performance and we don't really care about that during kdump. Simply revert to the previous working behavior of ignoring affinity masks in this case only. Fixes: 9ea69a55b3 ("powerpc/pseries: Pass MSI affinity to irq_create_mapping()") Cc: stable@vger.kernel.org # v5.10+ Signed-off-by: Greg Kurz <groug@kaod.org> Reviewed-by: Laurent Vivier <lvivier@redhat.com> Reviewed-by: Cédric Le Goater <clg@kaod.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210215094506.1196119-1-groug@kaod.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2021-03-17 17:06:10 +01:00
..
4xx	powerpc/4xx: Don't unmap NULL mbase	2020-05-28 23:24:36 +10:00
8xx	powerpc/8xx: Fix early debug when SMC1 is relocated	2020-12-30 11:54:16 +01:00
40x	powerpc: Remove IBM405 Erratum #77	2020-05-28 23:24:36 +10:00
44x	powerpc: Move flush_instruction_cache() prototype in asm/cacheflush.h	2020-09-02 11:00:21 +10:00
52xx	powerpc updates for 5.9	2020-08-07 10:33:50 -07:00
82xx	powerpc/82xx: Blacklist pq2_restart() for kprobe	2020-06-02 20:59:09 +10:00
83xx	powerpc: Use simple i2c probe function	2020-09-02 11:00:20 +10:00
85xx	powerpc/smp: Move ppc_md.cpu_die() to smp_ops.cpu_offline_self()	2020-09-18 19:59:43 +10:00
86xx	mm: reorder includes after introduction of linux/pgtable.h	2020-06-09 09:39:13 -07:00
512x
amigaone
cell	powerpc updates for 5.9	2020-08-07 10:33:50 -07:00
chrp	mm: reorder includes after introduction of linux/pgtable.h	2020-06-09 09:39:13 -07:00
embedded6xx	powerpc: Drop _nmask_and_or_msr()	2020-09-02 11:00:20 +10:00
maple	mm: don't include asm/pgtable.h if linux/mm.h is already included	2020-06-09 09:39:13 -07:00
pasemi	powerpc: use for_each_child_of_node() macro	2020-07-29 22:30:33 +10:00
powermac	powerpc/powermac: Fix low_sleep_handler with CONFIG_VMAP_STACK	2020-12-30 11:53:43 +01:00
powernv	powerpc/64: irq replay remove decrementer overflow check	2021-01-06 14:56:54 +01:00
ps3	powerpc updates for 5.10	2020-10-16 12:21:15 -07:00
pseries	powerpc/pseries: Don't enforce MSI affinity with kdump	2021-03-17 17:06:10 +01:00
fsl_uli1575.c
Kconfig	powerpc: Remove CONFIG_PPC601_SYNC_FIX	2020-10-08 21:17:13 +11:00
Kconfig.cputype	powerpc/powermac: Fix low_sleep_handler with CONFIG_VMAP_STACK	2020-12-30 11:53:43 +01:00
Makefile