On 28/11/2018 21:31, Andrii Anisov wrote:
From: Andrii Anisov <[email protected]>
For GICV2 pending_irq allocation is not concurrent, so reduce
some code under lock.
So this is reverting part of 5f66da659060563df8481a86c017f07455095045
"ARM: vGIC: move irq_to_pending() calls under the VGIC VCPU lock".
The vGIC is meant to be common, so I don't think the patch would be correct for
GICv3.
However, this function can only be called with SPI (PPI/SGI can't migrate). All
but one SPI are associated to a physical interrupts. So I am not entirely
convinced this will have any benefits on GICv2. Do you see any contention on the
lock?
Signed-off-by: Andrii Anisov <[email protected]>
---
xen/arch/arm/vgic.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/xen/arch/arm/vgic.c b/xen/arch/arm/vgic.c
index a64633f..37857b1 100644
--- a/xen/arch/arm/vgic.c
+++ b/xen/arch/arm/vgic.c
@@ -267,17 +267,16 @@ bool vgic_migrate_irq(struct vcpu *old, struct vcpu *new,
unsigned int irq)
ASSERT(!is_lpi(irq));
#endif
- spin_lock_irqsave(&old->arch.vgic.lock, flags);
-
p = irq_to_pending(old, irq);
/* nothing to do for virtual interrupts */
if ( p->desc == NULL )
{
- spin_unlock_irqrestore(&old->arch.vgic.lock, flags);
return true;
}
+ spin_lock_irqsave(&old->arch.vgic.lock, flags);
+
/* migration already in progress, no need to do anything */
if ( test_bit(GIC_IRQ_GUEST_MIGRATING, &p->status) )
{
@@ -569,8 +568,6 @@ void vgic_inject_irq(struct domain *d, struct vcpu *v,
unsigned int virq,
return;
}
- spin_lock_irqsave(&v->arch.vgic.lock, flags);
-
n = irq_to_pending(v, virq);
#ifdef CONFIG_GICV3
/* If an LPI has been removed, there is nothing to inject here. */
@@ -581,6 +578,8 @@ void vgic_inject_irq(struct domain *d, struct vcpu *v,
unsigned int virq,
}
#endif
+ spin_lock_irqsave(&v->arch.vgic.lock, flags);
+
set_bit(GIC_IRQ_GUEST_QUEUED, &n->status);
if ( !list_empty(&n->inflight) )
Cheers,
--
Julien Grall
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