76 lines
2.6 KiB
Diff
76 lines
2.6 KiB
Diff
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From c4f91d7b7be76c47015521ab0109c6e998a369b0 Mon Sep 17 00:00:00 2001
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From: Harsh Prateek Bora <harshpb@linux.ibm.com>
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Date: Wed, 24 Jan 2024 10:30:55 +1000
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Subject: [PATCH] ppc/spapr: Initialize max_cpus limit to SPAPR_IRQ_NR_IPIS.
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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Initialize the machine specific max_cpus limit as per the maximum range
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of CPU IPIs available. Keeping between 4096 to 8192 will throw IRQ not
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free error due to XIVE/XICS limitation and keeping beyond 8192 will hit
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assert in tcg_region_init or spapr_xive_claim_irq.
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Logs:
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Without patch fix:
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[root@host build]# qemu-system-ppc64 -accel tcg -smp 10,maxcpus=4097
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qemu-system-ppc64: IRQ 4096 is not free
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[root@host build]#
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On LPAR:
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[root@host build]# qemu-system-ppc64 -accel tcg -smp 10,maxcpus=8193
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**
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ERROR:../tcg/region.c:774:tcg_region_init: assertion failed:
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(region_size >= 2 * page_size)
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Bail out! ERROR:../tcg/region.c:774:tcg_region_init: assertion failed:
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(region_size >= 2 * page_size)
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Aborted (core dumped)
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[root@host build]#
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On x86:
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[root@host build]# qemu-system-ppc64 -accel tcg -smp 10,maxcpus=8193
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qemu-system-ppc64: ../hw/intc/spapr_xive.c:596: spapr_xive_claim_irq:
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Assertion `lisn < xive->nr_irqs' failed.
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Aborted (core dumped)
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[root@host build]#
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With patch fix:
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[root@host build]# qemu-system-ppc64 -accel tcg -smp 10,maxcpus=4097
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qemu-system-ppc64: Invalid SMP CPUs 4097. The max CPUs supported by
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machine 'pseries-8.2' is 4096
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[root@host build]#
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Reported-by: Kowshik Jois <kowsjois@linux.ibm.com>
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Tested-by: Kowshik Jois <kowsjois@linux.ibm.com>
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Reviewed-by: Cédric Le Goater <clg@kaod.org>
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Signed-off-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
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Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
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---
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hw/ppc/spapr.c | 9 +++------
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1 file changed, 3 insertions(+), 6 deletions(-)
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diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
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index 0d72d286d80f..0028ce0b673b 100644
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--- a/hw/ppc/spapr.c
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+++ b/hw/ppc/spapr.c
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@@ -4639,13 +4639,10 @@ static void spapr_machine_class_init(ObjectClass *oc, void *data)
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mc->block_default_type = IF_SCSI;
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/*
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- * Setting max_cpus to INT32_MAX. Both KVM and TCG max_cpus values
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- * should be limited by the host capability instead of hardcoded.
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- * max_cpus for KVM guests will be checked in kvm_init(), and TCG
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- * guests are welcome to have as many CPUs as the host are capable
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- * of emulate.
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+ * While KVM determines max cpus in kvm_init() using kvm_max_vcpus(),
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+ * In TCG the limit is restricted by the range of CPU IPIs available.
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*/
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- mc->max_cpus = INT32_MAX;
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+ mc->max_cpus = SPAPR_IRQ_NR_IPIS;
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mc->no_parallel = 1;
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mc->default_boot_order = "";
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