[PATCH 4/5] vPCI/MSI-X: make use of xzalloc_flex_struct()

[Jan Beulich <jbeulich@xxxxxxxx>]

... instead of effectively open-coding it in a type-unsafe way.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/xen/drivers/vpci/msix.c
+++ b/xen/drivers/vpci/msix.c
@@ -23,8 +23,6 @@
 #include <asm/msi.h>
 #include <asm/p2m.h>
 
-#define VMSIX_SIZE(num) offsetof(struct vpci_msix, entries[num])
-
 #define VMSIX_ADDR_IN_RANGE(addr, vpci, nr)                               \
     ((addr) >= vmsix_table_addr(vpci, nr) &&                              \
      (addr) < vmsix_table_addr(vpci, nr) + vmsix_table_size(vpci, nr))
@@ -449,7 +447,8 @@ static int init_msix(struct pci_dev *pde
 
     max_entries = msix_table_size(control);
 
-    pdev->vpci->msix = xzalloc_bytes(VMSIX_SIZE(max_entries));
+    pdev->vpci->msix = xzalloc_flex_struct(struct vpci_msix, entries,
+                                           max_entries);
     if ( !pdev->vpci->msix )
         return -ENOMEM;