@@ -156,7 +156,7 @@ void free_domain_pirqs(struct domain *d);
int map_domain_emuirq_pirq(struct domain *d, int pirq, int emuirq);
int unmap_domain_pirq_emuirq(struct domain *d, int pirq);
-/* Reset irq affinities to match the given CPU mask. */
+/* Evacuate interrupts assigned to CPUs not present in the input CPU mask. */
void fixup_irqs(const cpumask_t *mask, bool verbose);
void fixup_eoi(void);
@@ -2525,7 +2525,7 @@ static int __init cf_check setup_dump_irqs(void)
}
__initcall(setup_dump_irqs);
-/* Reset irq affinities to match the given CPU mask. */
+/* Evacuate interrupts assigned to CPUs not present in the input CPU mask. */
void fixup_irqs(const cpumask_t *mask, bool verbose)
{
unsigned int irq;
@@ -2582,7 +2582,12 @@ void fixup_irqs(const cpumask_t *mask, bool verbose)
&cpu_online_map);
}
- if ( !desc->action || cpumask_subset(desc->affinity, mask) )
+ /*
+ * Avoid shuffling the interrupt around as long as current target CPUs
+ * are a subset of the input mask. What fixup_irqs() cares about is
+ * evacuating interrupts from CPUs not in the input mask.
+ */
+ if ( !desc->action || cpumask_subset(desc->arch.cpu_mask, mask) )
{
spin_unlock(&desc->lock);
continue;
The current check used in fixup_irqs() to decide whether to move around interrupts is based on the affinity mask, but such mask can have all bits set, and hence is unlikely to be a subset of the input mask. For example if an interrupt has an affinity mask of all 1s, any input to fixup_irqs() that's not an all set CPU mask would cause that interrupt to be shuffled around unconditionally. What fixup_irqs() care about is evacuating interrupts from CPUs not set on the input CPU mask, and for that purpose it should check whether the interrupt is assigned to a CPU not present in the input mask. Assume that ->arch.cpu_mask is a subset of the ->affinity mask, and keep the current logic that resets the ->affinity mask if the interrupt has to be shuffled around. While there also adjust the comment as to the purpose of fixup_irqs(). Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> --- Changes since v1: - Do not AND ->arch.cpu_mask with cpu_online_map. - Keep using cpumask_subset(). - Integrate into bigger series. --- xen/arch/x86/include/asm/irq.h | 2 +- xen/arch/x86/irq.c | 9 +++++++-- 2 files changed, 8 insertions(+), 3 deletions(-)