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authorThomas Gleixner <tglx@linutronix.de>2020-12-10 20:26:03 +0100
committerThomas Gleixner <tglx@linutronix.de>2020-12-15 16:19:36 +0100
commitf7a6f994b4f0ee69c656dda3da11431d92d6b08f (patch)
tree816d9d37df2488243d6290ca066c2bbd3d92f500 /drivers
parentxen/events: Use immediate affinity setting (diff)
downloadlinux-f7a6f994b4f0ee69c656dda3da11431d92d6b08f.tar.xz
linux-f7a6f994b4f0ee69c656dda3da11431d92d6b08f.zip
xen/events: Only force affinity mask for percpu interrupts
All event channel setups bind the interrupt on CPU0 or the target CPU for percpu interrupts and overwrite the affinity mask with the corresponding cpumask. That does not make sense. The XEN implementation of irqchip::irq_set_affinity() already picks a single target CPU out of the affinity mask and the actual target is stored in the effective CPU mask, so destroying the user chosen affinity mask which might contain more than one CPU is wrong. Change the implementation so that the channel is bound to CPU0 at the XEN level and leave the affinity mask alone. At startup of the interrupt affinity will be assigned out of the affinity mask and the XEN binding will be updated. Only keep the enforcement for real percpu interrupts. On resume the overwrite is not required either because info->cpu and the affinity mask are still the same as at the time of suspend. Same for rebind_evtchn_irq(). This also prepares for proper interrupt spreading. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Juergen Gross <jgross@suse.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Link: https://lore.kernel.org/r/20201210194045.250321315@linutronix.de
Diffstat (limited to 'drivers')
-rw-r--r--drivers/xen/events/events_base.c48
1 files changed, 34 insertions, 14 deletions
diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index eaba42a89c8f..679b2cbd2de4 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -433,15 +433,20 @@ static bool pirq_needs_eoi_flag(unsigned irq)
return info->u.pirq.flags & PIRQ_NEEDS_EOI;
}
-static void bind_evtchn_to_cpu(evtchn_port_t evtchn, unsigned int cpu)
+static void bind_evtchn_to_cpu(evtchn_port_t evtchn, unsigned int cpu,
+ bool force_affinity)
{
int irq = get_evtchn_to_irq(evtchn);
struct irq_info *info = info_for_irq(irq);
BUG_ON(irq == -1);
-#ifdef CONFIG_SMP
- cpumask_copy(irq_get_affinity_mask(irq), cpumask_of(cpu));
-#endif
+
+ if (IS_ENABLED(CONFIG_SMP) && force_affinity) {
+ cpumask_copy(irq_get_affinity_mask(irq), cpumask_of(cpu));
+ cpumask_copy(irq_get_effective_affinity_mask(irq),
+ cpumask_of(cpu));
+ }
+
xen_evtchn_port_bind_to_cpu(evtchn, cpu, info->cpu);
info->cpu = cpu;
@@ -788,7 +793,7 @@ static unsigned int __startup_pirq(unsigned int irq)
goto err;
info->evtchn = evtchn;
- bind_evtchn_to_cpu(evtchn, 0);
+ bind_evtchn_to_cpu(evtchn, 0, false);
rc = xen_evtchn_port_setup(evtchn);
if (rc)
@@ -1107,8 +1112,14 @@ static int bind_evtchn_to_irq_chip(evtchn_port_t evtchn, struct irq_chip *chip)
irq = ret;
goto out;
}
- /* New interdomain events are bound to VCPU 0. */
- bind_evtchn_to_cpu(evtchn, 0);
+ /*
+ * New interdomain events are initially bound to vCPU0 This
+ * is required to setup the event channel in the first
+ * place and also important for UP guests because the
+ * affinity setting is not invoked on them so nothing would
+ * bind the channel.
+ */
+ bind_evtchn_to_cpu(evtchn, 0, false);
} else {
struct irq_info *info = info_for_irq(irq);
WARN_ON(info == NULL || info->type != IRQT_EVTCHN);
@@ -1156,7 +1167,11 @@ static int bind_ipi_to_irq(unsigned int ipi, unsigned int cpu)
irq = ret;
goto out;
}
- bind_evtchn_to_cpu(evtchn, cpu);
+ /*
+ * Force the affinity mask to the target CPU so proc shows
+ * the correct target.
+ */
+ bind_evtchn_to_cpu(evtchn, cpu, true);
} else {
struct irq_info *info = info_for_irq(irq);
WARN_ON(info == NULL || info->type != IRQT_IPI);
@@ -1269,7 +1284,11 @@ int bind_virq_to_irq(unsigned int virq, unsigned int cpu, bool percpu)
goto out;
}
- bind_evtchn_to_cpu(evtchn, cpu);
+ /*
+ * Force the affinity mask for percpu interrupts so proc
+ * shows the correct target.
+ */
+ bind_evtchn_to_cpu(evtchn, cpu, percpu);
} else {
struct irq_info *info = info_for_irq(irq);
WARN_ON(info == NULL || info->type != IRQT_VIRQ);
@@ -1634,8 +1653,7 @@ void rebind_evtchn_irq(evtchn_port_t evtchn, int irq)
mutex_unlock(&irq_mapping_update_lock);
- bind_evtchn_to_cpu(evtchn, info->cpu);
- irq_set_affinity(irq, cpumask_of(info->cpu));
+ bind_evtchn_to_cpu(evtchn, info->cpu, false);
/* Unmask the event channel. */
enable_irq(irq);
@@ -1669,7 +1687,7 @@ static int xen_rebind_evtchn_to_cpu(evtchn_port_t evtchn, unsigned int tcpu)
* it, but don't do the xenlinux-level rebind in that case.
*/
if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_vcpu, &bind_vcpu) >= 0)
- bind_evtchn_to_cpu(evtchn, tcpu);
+ bind_evtchn_to_cpu(evtchn, tcpu, false);
if (!masked)
unmask_evtchn(evtchn);
@@ -1798,7 +1816,8 @@ static void restore_cpu_virqs(unsigned int cpu)
/* Record the new mapping. */
(void)xen_irq_info_virq_setup(cpu, irq, evtchn, virq);
- bind_evtchn_to_cpu(evtchn, cpu);
+ /* The affinity mask is still valid */
+ bind_evtchn_to_cpu(evtchn, cpu, false);
}
}
@@ -1823,7 +1842,8 @@ static void restore_cpu_ipis(unsigned int cpu)
/* Record the new mapping. */
(void)xen_irq_info_ipi_setup(cpu, irq, evtchn, ipi);
- bind_evtchn_to_cpu(evtchn, cpu);
+ /* The affinity mask is still valid */
+ bind_evtchn_to_cpu(evtchn, cpu, false);
}
}