[PATCH V3 02/23] x86/ioreq: Add IOREQ_STATUS_* #define-s and update code for moving

[Oleksandr Tyshchenko <olekstysh@gmail.com>]

From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>

This patch continues to make some preparation to x86/hvm/ioreq.c
before moving to the common code.

Add IOREQ_STATUS_* #define-s and update candidates for moving
since X86EMUL_* shouldn't be exposed to the common code in
that form.

This support is going to be used on Arm to be able run device
emulator outside of Xen hypervisor.

Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
CC: Julien Grall <julien.grall@arm.com>

---
Please note, this is a split/cleanup/hardening of Julien's PoC:
"Add support for Guest IO forwarding to a device emulator"

Changes V2 -> V3:
 - new patch, was split from
   [PATCH V2 01/23] x86/ioreq: Prepare IOREQ feature for making it common
---
---
 xen/arch/x86/hvm/ioreq.c        | 16 ++++++++--------
 xen/include/asm-x86/hvm/ioreq.h |  4 ++++
 2 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/xen/arch/x86/hvm/ioreq.c b/xen/arch/x86/hvm/ioreq.c
index e3dfb49..9525554 100644
--- a/xen/arch/x86/hvm/ioreq.c
+++ b/xen/arch/x86/hvm/ioreq.c
@@ -1400,7 +1400,7 @@ static int hvm_send_buffered_ioreq(struct hvm_ioreq_server *s, ioreq_t *p)
     pg = iorp->va;
 
     if ( !pg )
-        return X86EMUL_UNHANDLEABLE;
+        return IOREQ_STATUS_UNHANDLED;
 
     /*
      * Return 0 for the cases we can't deal with:
@@ -1430,7 +1430,7 @@ static int hvm_send_buffered_ioreq(struct hvm_ioreq_server *s, ioreq_t *p)
         break;
     default:
         gdprintk(XENLOG_WARNING, "unexpected ioreq size: %u\n", p->size);
-        return X86EMUL_UNHANDLEABLE;
+        return IOREQ_STATUS_UNHANDLED;
     }
 
     spin_lock(&s->bufioreq_lock);
@@ -1440,7 +1440,7 @@ static int hvm_send_buffered_ioreq(struct hvm_ioreq_server *s, ioreq_t *p)
     {
         /* The queue is full: send the iopacket through the normal path. */
         spin_unlock(&s->bufioreq_lock);
-        return X86EMUL_UNHANDLEABLE;
+        return IOREQ_STATUS_UNHANDLED;
     }
 
     pg->buf_ioreq[pg->ptrs.write_pointer % IOREQ_BUFFER_SLOT_NUM] = bp;
@@ -1471,7 +1471,7 @@ static int hvm_send_buffered_ioreq(struct hvm_ioreq_server *s, ioreq_t *p)
     notify_via_xen_event_channel(d, s->bufioreq_evtchn);
     spin_unlock(&s->bufioreq_lock);
 
-    return X86EMUL_OKAY;
+    return IOREQ_STATUS_HANDLED;
 }
 
 int hvm_send_ioreq(struct hvm_ioreq_server *s, ioreq_t *proto_p,
@@ -1487,7 +1487,7 @@ int hvm_send_ioreq(struct hvm_ioreq_server *s, ioreq_t *proto_p,
         return hvm_send_buffered_ioreq(s, proto_p);
 
     if ( unlikely(!vcpu_start_shutdown_deferral(curr)) )
-        return X86EMUL_RETRY;
+        return IOREQ_STATUS_RETRY;
 
     list_for_each_entry ( sv,
                           &s->ioreq_vcpu_list,
@@ -1527,11 +1527,11 @@ int hvm_send_ioreq(struct hvm_ioreq_server *s, ioreq_t *proto_p,
             notify_via_xen_event_channel(d, port);
 
             sv->pending = true;
-            return X86EMUL_RETRY;
+            return IOREQ_STATUS_RETRY;
         }
     }
 
-    return X86EMUL_UNHANDLEABLE;
+    return IOREQ_STATUS_UNHANDLED;
 }
 
 unsigned int hvm_broadcast_ioreq(ioreq_t *p, bool buffered)
@@ -1545,7 +1545,7 @@ unsigned int hvm_broadcast_ioreq(ioreq_t *p, bool buffered)
         if ( !s->enabled )
             continue;
 
-        if ( hvm_send_ioreq(s, p, buffered) == X86EMUL_UNHANDLEABLE )
+        if ( hvm_send_ioreq(s, p, buffered) == IOREQ_STATUS_UNHANDLED )
             failed++;
     }
 
diff --git a/xen/include/asm-x86/hvm/ioreq.h b/xen/include/asm-x86/hvm/ioreq.h
index cc79285..e9c8b2d 100644
--- a/xen/include/asm-x86/hvm/ioreq.h
+++ b/xen/include/asm-x86/hvm/ioreq.h
@@ -74,6 +74,10 @@ unsigned int hvm_broadcast_ioreq(ioreq_t *p, bool buffered);
 
 void hvm_ioreq_init(struct domain *d);
 
+#define IOREQ_STATUS_HANDLED     X86EMUL_OKAY
+#define IOREQ_STATUS_UNHANDLED   X86EMUL_UNHANDLEABLE
+#define IOREQ_STATUS_RETRY       X86EMUL_RETRY
+
 #endif /* __ASM_X86_HVM_IOREQ_H__ */
 
 /*
-- 
2.7.4