[PATCH for-4.19 v2] x86/physdev: Return pirq that irq was already mapped to

[Jiqian Chen]

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.c...@amd.com>
Signed-off-by: Huang Rui <ray.hu...@amd.com>
Signed-off-by: Jiqian Chen <jiqian.c...@amd.com>
Reviewed-by: Jan Beulich <jbeul...@suse.com>
---
 xen/arch/x86/irq.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/xen/arch/x86/irq.c b/xen/arch/x86/irq.c
index 017a94e31155..47477d88171b 100644
--- a/xen/arch/x86/irq.c
+++ b/xen/arch/x86/irq.c
@@ -2898,6 +2898,7 @@ 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 )
         {
-- 
2.34.1