[PATCH v3 03/11] x86/xen: Introduce new function to map HYPERVISOR_shared_info on Resume

[Anchal Agarwal <anchalag@xxxxxxxxxx>]

Introduce a small function which re-uses shared page's PA allocated
during guest initialization time in reserve_shared_info() and not
allocate new page during resume flow.
It also  does the mapping of shared_info_page by calling
xen_hvm_init_shared_info() to use the function.

Changelog:
v1->v2: Remove extra check for shared_info_pfn to be NULL
Signed-off-by: Anchal Agarwal <anchalag@xxxxxxxxxx>
---
 arch/x86/xen/enlighten_hvm.c | 6 ++++++
 arch/x86/xen/xen-ops.h       | 1 +
 2 files changed, 7 insertions(+)

diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c
index 9e87ab010c82..ff7c69278f63 100644
--- a/arch/x86/xen/enlighten_hvm.c
+++ b/arch/x86/xen/enlighten_hvm.c
@@ -29,6 +29,12 @@
 
 static unsigned long shared_info_pfn;
 
+void xen_hvm_map_shared_info(void)
+{
+       xen_hvm_init_shared_info();
+       HYPERVISOR_shared_info = __va(PFN_PHYS(shared_info_pfn));
+}
+
 void xen_hvm_init_shared_info(void)
 {
        struct xen_add_to_physmap xatp;
diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h
index 45d556f71858..9f0a4345220e 100644
--- a/arch/x86/xen/xen-ops.h
+++ b/arch/x86/xen/xen-ops.h
@@ -53,6 +53,7 @@ void xen_enable_sysenter(void);
 void xen_enable_syscall(void);
 void xen_vcpu_restore(void);
 
+void xen_hvm_map_shared_info(void);
 void xen_hvm_init_shared_info(void);
 void xen_unplug_emulated_devices(void);
 
-- 
2.16.6