xen/p2m: An early bootup variant of set_phys_to_machine

During early bootup we can't use alloc_page, so to allocate
leaf pages in the P2M we need to use extend_brk. For that
we are utilizing the early_alloc_p2m and early_alloc_p2m_middle
functions to do the job for us. This function follows the
same logic as set_phys_to_machine.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index 952edefcedb3..ffd08c414e91 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -570,6 +570,21 @@ static bool __init early_alloc_p2m(unsigned long pfn)
         }
         return true;
 }
+bool __init early_set_phys_to_machine(unsigned long pfn, unsigned long mfn)
+{
+        if (unlikely(!__set_phys_to_machine(pfn, mfn)))  {
+                if (!early_alloc_p2m(pfn))
+                        return false;
+
+                if (!early_alloc_p2m_middle(pfn, false /* boundary crossover OK!*/))
+                        return false;
+
+                if (!__set_phys_to_machine(pfn, mfn))
+                        return false;
+        }
+
+        return true;
+}
 unsigned long __init set_phys_range_identity(unsigned long pfn_s,
                                       unsigned long pfn_e)
 {