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authorHarsh Prateek Bora <harshpb@linux.ibm.com>2024-01-24 10:30:55 +1000
committerMichael Tokarev <mjt@tls.msk.ru>2024-04-16 21:15:05 +0300
commit51da7500632a52b048946486753abd2d331c48c6 (patch)
tree47acbda1f42156e5d8c5df0fd1989d1f18e65fe0
parentc513ee1b91d394a2fa9ef6fa0d9004b59e3b1259 (diff)
ppc/spapr: Initialize max_cpus limit to SPAPR_IRQ_NR_IPIS.
Initialize the machine specific max_cpus limit as per the maximum range of CPU IPIs available. Keeping between 4096 to 8192 will throw IRQ not free error due to XIVE/XICS limitation and keeping beyond 8192 will hit assert in tcg_region_init or spapr_xive_claim_irq. Logs: Without patch fix: [root@host build]# qemu-system-ppc64 -accel tcg -smp 10,maxcpus=4097 qemu-system-ppc64: IRQ 4096 is not free [root@host build]# On LPAR: [root@host build]# qemu-system-ppc64 -accel tcg -smp 10,maxcpus=8193 ** ERROR:../tcg/region.c:774:tcg_region_init: assertion failed: (region_size >= 2 * page_size) Bail out! ERROR:../tcg/region.c:774:tcg_region_init: assertion failed: (region_size >= 2 * page_size) Aborted (core dumped) [root@host build]# On x86: [root@host build]# qemu-system-ppc64 -accel tcg -smp 10,maxcpus=8193 qemu-system-ppc64: ../hw/intc/spapr_xive.c:596: spapr_xive_claim_irq: Assertion `lisn < xive->nr_irqs' failed. Aborted (core dumped) [root@host build]# With patch fix: [root@host build]# qemu-system-ppc64 -accel tcg -smp 10,maxcpus=4097 qemu-system-ppc64: Invalid SMP CPUs 4097. The max CPUs supported by machine 'pseries-8.2' is 4096 [root@host build]# Reported-by: Kowshik Jois <kowsjois@linux.ibm.com> Tested-by: Kowshik Jois <kowsjois@linux.ibm.com> Reviewed-by: Cédric Le Goater <clg@kaod.org> Signed-off-by: Harsh Prateek Bora <harshpb@linux.ibm.com> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> (cherry picked from commit c4f91d7b7be76c47015521ab0109c6e998a369b0) Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
-rw-r--r--hw/ppc/spapr.c9
1 files changed, 3 insertions, 6 deletions
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index df09aa9d6a..222d926f46 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -4647,13 +4647,10 @@ static void spapr_machine_class_init(ObjectClass *oc, void *data)
mc->block_default_type = IF_SCSI;
/*
- * Setting max_cpus to INT32_MAX. Both KVM and TCG max_cpus values
- * should be limited by the host capability instead of hardcoded.
- * max_cpus for KVM guests will be checked in kvm_init(), and TCG
- * guests are welcome to have as many CPUs as the host are capable
- * of emulate.
+ * While KVM determines max cpus in kvm_init() using kvm_max_vcpus(),
+ * In TCG the limit is restricted by the range of CPU IPIs available.
*/
- mc->max_cpus = INT32_MAX;
+ mc->max_cpus = SPAPR_IRQ_NR_IPIS;
mc->no_parallel = 1;
mc->default_boot_order = "";