xen: split up xen_hvm_init_shared_info()

Instead of calling xen_hvm_init_shared_info() on boot and resume split
it up into a boot time function searching for the pfn to use and a
mapping function doing the hypervisor mapping call.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Juergen Gross <jgross@suse.com>

arch/x86/xen/enlighten_hvm.c

@@ -21,12 +21,22 @@
 #include "mmu.h"
 #include "smp.h"
 
-void __ref xen_hvm_init_shared_info(void)
+void xen_hvm_init_shared_info(void)
 {
 	struct xen_add_to_physmap xatp;
+
+	xatp.domid = DOMID_SELF;
+	xatp.idx = 0;
+	xatp.space = XENMAPSPACE_shared_info;
+	xatp.gpfn = virt_to_pfn(HYPERVISOR_shared_info);
+	if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp))
+		BUG();
+}
+
+static void __init reserve_shared_info(void)
+{
 	u64 pa;
 
-	if (HYPERVISOR_shared_info == &xen_dummy_shared_info) {
 	/*
 	 * Search for a free page starting at 4kB physical address.
 	 * Low memory is preferred to avoid an EPT large page split up
@@ -43,14 +53,6 @@ void __ref xen_hvm_init_shared_info(void)
 
 	memblock_reserve(pa, PAGE_SIZE);
 	HYPERVISOR_shared_info = __va(pa);
-	}
-
-	xatp.domid = DOMID_SELF;
-	xatp.idx = 0;
-	xatp.space = XENMAPSPACE_shared_info;
-	xatp.gpfn = virt_to_pfn(HYPERVISOR_shared_info);
-	if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp))
-		BUG();
 }
 
 static void __init init_hvm_pv_info(void)
@@ -153,6 +155,7 @@ static void __init xen_hvm_guest_init(void)
 
 	init_hvm_pv_info();
 
+	reserve_shared_info();
 	xen_hvm_init_shared_info();
 
 	/*