[Xen-devel] [PATCH 2/3] xen: split up xen_hvm_init_shared_info()

[Juergen Gross <jgross@xxxxxxxx>]

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@xxxxxxxx>
---
 arch/x86/xen/enlighten_hvm.c | 45 +++++++++++++++++++++++---------------------
 1 file changed, 24 insertions(+), 21 deletions(-)

diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c
index 87d791356ea9..d23531f5f17e 100644
--- a/arch/x86/xen/enlighten_hvm.c
+++ b/arch/x86/xen/enlighten_hvm.c
@@ -21,29 +21,9 @@
 #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;
-       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
-                * by the mapping.
-                * Starting below X86_RESERVE_LOW (usually 64kB) is fine as
-                * the BIOS used for HVM guests is well behaved and won't
-                * clobber memory other than the first 4kB.
-                */
-               for (pa = PAGE_SIZE;
-                    !e820__mapped_all(pa, pa + PAGE_SIZE, E820_TYPE_RAM) ||
-                    memblock_is_reserved(pa);
-                    pa += PAGE_SIZE)
-                       ;
-
-               memblock_reserve(pa, PAGE_SIZE);
-               HYPERVISOR_shared_info = __va(pa);
-       }
 
        xatp.domid = DOMID_SELF;
        xatp.idx = 0;
@@ -53,6 +33,28 @@ void __ref xen_hvm_init_shared_info(void)
                BUG();
 }
 
+static void __init reserve_shared_info(void)
+{
+       u64 pa;
+
+       /*
+        * Search for a free page starting at 4kB physical address.
+        * Low memory is preferred to avoid an EPT large page split up
+        * by the mapping.
+        * Starting below X86_RESERVE_LOW (usually 64kB) is fine as
+        * the BIOS used for HVM guests is well behaved and won't
+        * clobber memory other than the first 4kB.
+        */
+       for (pa = PAGE_SIZE;
+            !e820__mapped_all(pa, pa + PAGE_SIZE, E820_TYPE_RAM) ||
+            memblock_is_reserved(pa);
+            pa += PAGE_SIZE)
+               ;
+
+       memblock_reserve(pa, PAGE_SIZE);
+       HYPERVISOR_shared_info = __va(pa);
+}
+
 static void __init init_hvm_pv_info(void)
 {
        int major, minor;
@@ -153,6 +155,7 @@ static void __init xen_hvm_guest_init(void)
 
        init_hvm_pv_info();
 
+       reserve_shared_info();
        xen_hvm_init_shared_info();
 
        /*
-- 
2.12.3


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