[Xen-devel] [PATCHv2 09/10] x86/xen: export xen_alloc_p2m_entry()

[David Vrabel <david.vrabel@xxxxxxxxxx>]

Rename alloc_p2m() to xen_alloc_p2m_entry() and export it.

This is useful for ensuring that a p2m entry is allocated (i.e., not a
shared missing or identity entry) so that subsequent set_phys_to_machine()
calls will require no further allocations.

Signed-off-by: David Vrabel <david.vrabel@xxxxxxxxxx>
---
 arch/x86/include/asm/xen/page.h |  2 ++
 arch/x86/xen/p2m.c              | 16 ++++++++++------
 2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h
index c44a5d5..960b380 100644
--- a/arch/x86/include/asm/xen/page.h
+++ b/arch/x86/include/asm/xen/page.h
@@ -45,6 +45,8 @@ extern unsigned long *xen_p2m_addr;
 extern unsigned long  xen_p2m_size;
 extern unsigned long  xen_max_p2m_pfn;
 
+extern int xen_alloc_p2m_entry(unsigned long pfn);
+
 extern unsigned long get_phys_to_machine(unsigned long pfn);
 extern bool set_phys_to_machine(unsigned long pfn, unsigned long mfn);
 extern bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn);
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index 8b7f18e..ef93ccf 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -503,7 +503,7 @@ static pte_t *alloc_p2m_pmd(unsigned long addr, pte_t 
*pte_pg)
  * the new pages are installed with cmpxchg; if we lose the race then
  * simply free the page we allocated and use the one that's there.
  */
-static bool alloc_p2m(unsigned long pfn)
+int xen_alloc_p2m_entry(unsigned long pfn)
 {
        unsigned topidx, mididx;
        unsigned long *top_mfn_p, *mid_mfn;
@@ -524,7 +524,7 @@ static bool alloc_p2m(unsigned long pfn)
                /* PMD level is missing, allocate a new one */
                ptep = alloc_p2m_pmd(addr, pte_pg);
                if (!ptep)
-                       return false;
+                       return -ENOMEM;
        }
 
        if (p2m_top_mfn) {
@@ -541,7 +541,7 @@ static bool alloc_p2m(unsigned long pfn)
 
                        mid_mfn = alloc_p2m_page();
                        if (!mid_mfn)
-                               return false;
+                               return -ENOMEM;
 
                        p2m_mid_mfn_init(mid_mfn, p2m_missing);
 
@@ -567,7 +567,7 @@ static bool alloc_p2m(unsigned long pfn)
 
                p2m = alloc_p2m_page();
                if (!p2m)
-                       return false;
+                       return -ENOMEM;
 
                if (p2m_pfn == PFN_DOWN(__pa(p2m_missing)))
                        p2m_init(p2m);
@@ -590,8 +590,9 @@ static bool alloc_p2m(unsigned long pfn)
                        free_p2m_page(p2m);
        }
 
-       return true;
+       return 0;
 }
+EXPORT_SYMBOL(xen_alloc_p2m);
 
 unsigned long __init set_phys_range_identity(unsigned long pfn_s,
                                      unsigned long pfn_e)
@@ -648,7 +649,10 @@ bool __set_phys_to_machine(unsigned long pfn, unsigned 
long mfn)
 bool set_phys_to_machine(unsigned long pfn, unsigned long mfn)
 {
        if (unlikely(!__set_phys_to_machine(pfn, mfn))) {
-               if (!alloc_p2m(pfn))
+               int ret;
+
+               ret = xen_alloc_p2m_entry(pfn);
+               if (ret < 0)
                        return false;
 
                return __set_phys_to_machine(pfn, mfn);
-- 
2.1.4


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