[PATCH BUILD FIX 2/2] xen: add a dummy xc_hvm_inject_msi for Xen < 4.2

[Stefano Stabellini <stefano.stabellini@eu.citrix.com>]

xc_hvm_inject_msi is only available on Xen >= 4.2: add a dummy
compatibility function for Xen < 4.2.

Also enable msi support only on Xen >= 4.2.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
---
 hw/pc.c         |    2 +-
 hw/xen.h        |   10 ++++++++++
 hw/xen_common.h |   15 +++++++++++++++
 xen-all.c       |    2 +-
 4 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/hw/pc.c b/hw/pc.c
index 1f5aacb..4d34a33 100644
--- a/hw/pc.c
+++ b/hw/pc.c
@@ -916,7 +916,7 @@ static DeviceState *apic_init(void *env, uint8_t apic_id)
         msi_supported = true;
     }
 
-    if (xen_enabled()) {
+    if (xen_msi_support()) {
         msi_supported = true;
     }
 
diff --git a/hw/xen.h b/hw/xen.h
index e5926b7..3ae4cd0 100644
--- a/hw/xen.h
+++ b/hw/xen.h
@@ -57,4 +57,14 @@ void xen_register_framebuffer(struct MemoryRegion *mr);
 #  define HVM_MAX_VCPUS 32
 #endif
 
+static inline int xen_msi_support(void)
+{
+#if defined(CONFIG_XEN_CTRL_INTERFACE_VERSION) \
+    && CONFIG_XEN_CTRL_INTERFACE_VERSION >= 420
+    return xen_enabled();
+#else
+    return 0;
+#endif
+}
+
 #endif /* QEMU_HW_XEN_H */
diff --git a/hw/xen_common.h b/hw/xen_common.h
index 0409ac7..7043c14 100644
--- a/hw/xen_common.h
+++ b/hw/xen_common.h
@@ -133,6 +133,21 @@ static inline int xc_fd(xc_interface *xen_xc)
 }
 #endif
 
+/* Xen before 4.2 */
+#if CONFIG_XEN_CTRL_INTERFACE_VERSION < 420
+static inline int xen_xc_hvm_inject_msi(XenXC xen_xc, domid_t dom,
+        uint64_t addr, uint32_t data)
+{
+    return -ENOSYS;
+}
+#else
+static inline int xen_xc_hvm_inject_msi(XenXC xen_xc, domid_t dom,
+        uint64_t addr, uint32_t data)
+{
+    return xc_hvm_inject_msi(xen_xc, dom, addr, data);
+}
+#endif
+
 void destroy_hvm_domain(void);
 
 #endif /* QEMU_HW_XEN_COMMON_H */
diff --git a/xen-all.c b/xen-all.c
index a08eec0..bdf9c0f 100644
--- a/xen-all.c
+++ b/xen-all.c
@@ -129,7 +129,7 @@ void xen_piix_pci_write_config_client(uint32_t address, uint32_t val, int len)
 
 void xen_hvm_inject_msi(uint64_t addr, uint32_t data)
 {
-    xc_hvm_inject_msi(xen_xc, xen_domid, addr, data);
+    xen_xc_hvm_inject_msi(xen_xc, xen_domid, addr, data);
 }
 
 static void xen_suspend_notifier(Notifier *notifier, void *data)
-- 
1.7.2.5