[xen staging] x86/HVM: fold hvm_io_assist() into its only caller

[patchbot@xxxxxxx]

commit 83bb55fa38f7cbd4c8a670c9a01c8c47642d969e
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Fri Jul 17 17:50:09 2020 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Fri Jul 17 17:50:09 2020 +0200

    x86/HVM: fold hvm_io_assist() into its only caller
    
    While there are two call sites, the function they're in can be slightly
    re-arranged such that the code sequence can be added at its bottom. Note
    that the function's only caller has already checked sv->pending, and
    that the prior while() loop was just a slightly more fancy if()
    (allowing an early break out of the construct).
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Paul Durrant <paul@xxxxxxx>
---
 xen/arch/x86/hvm/ioreq.c | 26 ++++++++++----------------
 1 file changed, 10 insertions(+), 16 deletions(-)

diff --git a/xen/arch/x86/hvm/ioreq.c b/xen/arch/x86/hvm/ioreq.c
index 724007016d..41cc02f434 100644
--- a/xen/arch/x86/hvm/ioreq.c
+++ b/xen/arch/x86/hvm/ioreq.c
@@ -103,23 +103,12 @@ bool hvm_io_pending(struct vcpu *v)
     return false;
 }
 
-static void hvm_io_assist(struct hvm_ioreq_vcpu *sv, uint64_t data)
-{
-    struct vcpu *v = sv->vcpu;
-    ioreq_t *ioreq = &v->arch.hvm.hvm_io.io_req;
-
-    if ( hvm_ioreq_needs_completion(ioreq) )
-        ioreq->data = data;
-
-    sv->pending = false;
-}
-
 static bool hvm_wait_for_io(struct hvm_ioreq_vcpu *sv, ioreq_t *p)
 {
     unsigned int prev_state = STATE_IOREQ_NONE;
+    uint64_t data = ~0;
 
-    while ( sv->pending )
-    {
+    do {
         unsigned int state = p->state;
 
         smp_rmb();
@@ -132,7 +121,6 @@ static bool hvm_wait_for_io(struct hvm_ioreq_vcpu *sv, 
ioreq_t *p)
              * emulator is dying and it races with an I/O being
              * requested.
              */
-            hvm_io_assist(sv, ~0ul);
             break;
         }
 
@@ -149,7 +137,7 @@ static bool hvm_wait_for_io(struct hvm_ioreq_vcpu *sv, 
ioreq_t *p)
         {
         case STATE_IORESP_READY: /* IORESP_READY -> NONE */
             p->state = STATE_IOREQ_NONE;
-            hvm_io_assist(sv, p->data);
+            data = p->data;
             break;
         case STATE_IOREQ_READY:  /* IOREQ_{READY,INPROCESS} -> IORESP_READY */
         case STATE_IOREQ_INPROCESS:
@@ -164,7 +152,13 @@ static bool hvm_wait_for_io(struct hvm_ioreq_vcpu *sv, 
ioreq_t *p)
             domain_crash(sv->vcpu->domain);
             return false; /* bail */
         }
-    }
+    } while ( false );
+
+    p = &sv->vcpu->arch.hvm.hvm_io.io_req;
+    if ( hvm_ioreq_needs_completion(p) )
+        p->data = data;
+
+    sv->pending = false;
 
     return true;
 }
--
generated by git-patchbot for /home/xen/git/xen.git#staging