x86/physdev: Return pirq that irq was already mapped to

Fix bug introduced by 0762e2502f1f ("x86/physdev: factor out the code to allocate and
map a pirq"). After that re-factoring, when pirq<0 and current_pirq>0, it means
caller want to allocate a free pirq for irq but irq already has a mapped pirq, then
it returns the negative pirq, so it fails. However, the logic before that
re-factoring is different, it should return the current_pirq that irq was already
mapped to and make the call success.

Fixes: 0762e2502f1f ("x86/physdev: factor out the code to allocate and map a pirq")
Signed-off-by: Jiqian Chen <Jiqian.Chen@amd.com>
Signed-off-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Jiqian Chen <Jiqian.Chen@amd.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 0d2b87b5adfc19e87e9027d996db204c66a47f30
master date: 2024-07-08 14:46:12 +0100

diff --git a/xen/arch/x86/irq.c b/xen/arch/x86/irq.c
index 98654ba7843c1f5f924b3e49fca054c9d491b05f..0ef3a2ca375b9096fa5ac797237e96d63a7a632a 100644 (file)
--- a/xen/arch/x86/irq.c
+++ b/xen/arch/x86/irq.c
@@ -2914,6 +2914,7 @@ static int allocate_pirq(struct domain *d, int index, int pirq, int irq,
                     d->domain_id, index, pirq, current_pirq);
             if ( current_pirq < 0 )
                 return -EBUSY;
+            pirq = current_pirq;
         }
         else if ( type == MAP_PIRQ_TYPE_MULTI_MSI )
         {