Hi Andre,
On 06/04/17 00:19, Andre Przywara wrote:
The DISCARD command drops the connection between a DeviceID/EventID
and an LPI/collection pair.
We mark the respective structure entries as not allocated and make
sure that any queued IRQs are removed.
Signed-off-by: Andre Przywara <andre.przyw...@arm.com>
---
xen/arch/arm/vgic-v3-its.c | 32 ++++++++++++++++++++++++++++++++
1 file changed, 32 insertions(+)
diff --git a/xen/arch/arm/vgic-v3-its.c b/xen/arch/arm/vgic-v3-its.c
index 6afb915..47f2884 100644
--- a/xen/arch/arm/vgic-v3-its.c
+++ b/xen/arch/arm/vgic-v3-its.c
@@ -549,6 +549,35 @@ out_unlock:
return ret;
}
+static int its_handle_discard(struct virt_its *its, uint64_t *cmdptr)
+{
+ uint32_t devid = its_cmd_get_deviceid(cmdptr);
+ uint32_t eventid = its_cmd_get_id(cmdptr);
+ struct pending_irq *pirq;
+ struct vcpu *vcpu;
+ uint32_t vlpi;
+
+ if ( !read_itte(its, devid, eventid, &vcpu, &vlpi) )
+ return -1;
+
+ pirq = its->d->arch.vgic.handler->lpi_to_pending(its->d, vlpi);
+ if ( pirq )
+ {
+ clear_bit(GIC_IRQ_GUEST_QUEUED, &pirq->status);
+ gic_remove_from_queues(vcpu, vlpi);
+ }
Do we expect to have pirq returning NULL? If so, in which case?
Also, why not directly using
pirq = gicv3_assign_guest(....);
This would prevent the issue below where it would not be possible to
write back in the guest memory, and leave the mapping with the host LPI.
+
+ if ( !write_itte(its, devid, eventid, UNMAPPED_COLLECTION, INVALID_LPI,
+ NULL) )
+ return -1;
+
+ if ( !gicv3_assign_guest_event(its->d, its->doorbell_address,
+ devid, eventid, NULL, 0) )
In which case gicv3_assign_guest_event can fail? And what would happen
if it fails. By that I mean, would we need to carry some clean-up for
host lpi during domain destruction?
+ return -1;
+
+ return 0;
+}
+
#define ITS_CMD_BUFFER_SIZE(baser) ((((baser) & 0xff) + 1) << 12)
/*
@@ -580,6 +609,9 @@ static int vgic_its_handle_cmds(struct domain *d, struct
virt_its *its)
case GITS_CMD_CLEAR:
ret = its_handle_clear(its, command);
break;
+ case GITS_CMD_DISCARD:
+ ret = its_handle_discard(its, command);
+ break;
case GITS_CMD_INT:
ret = its_handle_int(its, command);
break;
Cheers,
--
Julien Grall
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