xen: Delay invalidating extra memory

When the physical memory configuration is initialized the p2m entries
for not pouplated memory pages are set to "invalid". As those pages
are beyond the hypervisor built p2m list the p2m tree has to be
extended.

This patch delays processing the extra memory related p2m entries
during the boot process until some more basic memory management
functions are callable. This removes the need to create new p2m
entries until virtual memory management is available.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>

1 files changed, 25 insertions, 103 deletions

diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index 8676f3566fe3..eddec40a4c20 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -181,7 +181,12 @@
 
 static void __init m2p_override_init(void);
 
+unsigned long *xen_p2m_addr __read_mostly;
+EXPORT_SYMBOL_GPL(xen_p2m_addr);
+unsigned long xen_p2m_size __read_mostly;
+EXPORT_SYMBOL_GPL(xen_p2m_size);
 unsigned long xen_max_p2m_pfn __read_mostly;
+EXPORT_SYMBOL_GPL(xen_max_p2m_pfn);
 
 static unsigned long *p2m_mid_missing_mfn;
 static unsigned long *p2m_top_mfn;
@@ -198,13 +203,6 @@ static RESERVE_BRK_ARRAY(unsigned long *, p2m_mid_identity, P2M_MID_PER_PAGE);
 
 RESERVE_BRK(p2m_mid, PAGE_SIZE * (MAX_DOMAIN_PAGES / (P2M_PER_PAGE * P2M_MID_PER_PAGE)));
 
-/* For each I/O range remapped we may lose up to two leaf pages for the boundary
- * violations and three mid pages to cover up to 3GB. With
- * early_can_reuse_p2m_middle() most of the leaf pages will be reused by the
- * remapped region.
- */
-RESERVE_BRK(p2m_identity_remap, PAGE_SIZE * 2 * 3 * MAX_REMAP_RANGES);
-
 static int use_brk = 1;
 
 static inline unsigned p2m_top_index(unsigned long pfn)
@@ -381,9 +379,11 @@ void __init xen_build_dynamic_phys_to_machine(void)
          if (xen_feature(XENFEAT_auto_translated_physmap))
                 return;
 
+        xen_p2m_addr = (unsigned long *)xen_start_info->mfn_list;
         mfn_list = (unsigned long *)xen_start_info->mfn_list;
         max_pfn = min(MAX_DOMAIN_PAGES, xen_start_info->nr_pages);
         xen_max_p2m_pfn = max_pfn;
+        xen_p2m_size = max_pfn;
 
         p2m_missing = alloc_p2m_page();
         p2m_init(p2m_missing);
@@ -499,6 +499,11 @@ unsigned long __init xen_revector_p2m_tree(void)
                 /* This should be the leafs allocated for identity from _brk. */
         }
 
+        xen_p2m_size = xen_max_p2m_pfn;
+        xen_p2m_addr = mfn_list;
+
+        xen_inv_extra_mem();
+
         m2p_override_init();
         return (unsigned long)mfn_list;
 }
@@ -506,6 +511,8 @@ unsigned long __init xen_revector_p2m_tree(void)
 unsigned long __init xen_revector_p2m_tree(void)
 {
         use_brk = 0;
+        xen_p2m_size = xen_max_p2m_pfn;
+        xen_inv_extra_mem();
         m2p_override_init();
         return 0;
 }
@@ -514,8 +521,12 @@ unsigned long get_phys_to_machine(unsigned long pfn)
 {
         unsigned topidx, mididx, idx;
 
-        if (unlikely(pfn >= MAX_P2M_PFN))
+        if (unlikely(pfn >= xen_p2m_size)) {
+                if (pfn < xen_max_p2m_pfn)
+                        return xen_chk_extra_mem(pfn);
+
                 return IDENTITY_FRAME(pfn);
+        }
 
         topidx = p2m_top_index(pfn);
         mididx = p2m_mid_index(pfn);
@@ -613,78 +624,12 @@ static bool alloc_p2m(unsigned long pfn)
         return true;
 }
 
-static bool __init early_alloc_p2m(unsigned long pfn, bool check_boundary)
-{
-        unsigned topidx, mididx, idx;
-        unsigned long *p2m;
-
-        topidx = p2m_top_index(pfn);
-        mididx = p2m_mid_index(pfn);
-        idx = p2m_index(pfn);
-
-        /* Pfff.. No boundary cross-over, lets get out. */
-        if (!idx && check_boundary)
-                return false;
-
-        WARN(p2m_top[topidx][mididx] == p2m_identity,
-                "P2M[%d][%d] == IDENTITY, should be MISSING (or alloced)!\n",
-                topidx, mididx);
-
-        /*
-         * Could be done by xen_build_dynamic_phys_to_machine..
-         */
-        if (p2m_top[topidx][mididx] != p2m_missing)
-                return false;
-
-        /* Boundary cross-over for the edges: */
-        p2m = alloc_p2m_page();
-
-        p2m_init(p2m);
-
-        p2m_top[topidx][mididx] = p2m;
-
-        return true;
-}
-
-static bool __init early_alloc_p2m_middle(unsigned long pfn)
-{
-        unsigned topidx = p2m_top_index(pfn);
-        unsigned long **mid;
-
-        mid = p2m_top[topidx];
-        if (mid == p2m_mid_missing) {
-                mid = alloc_p2m_page();
-
-                p2m_mid_init(mid, p2m_missing);
-
-                p2m_top[topidx] = mid;
-        }
-        return true;
-}
-
-static void __init early_split_p2m(unsigned long pfn)
-{
-        unsigned long mididx, idx;
-
-        mididx = p2m_mid_index(pfn);
-        idx = p2m_index(pfn);
-
-        /*
-         * Allocate new middle and leaf pages if this pfn lies in the
-         * middle of one.
-         */
-        if (mididx || idx)
-                early_alloc_p2m_middle(pfn);
-        if (idx)
-                early_alloc_p2m(pfn, false);
-}
-
 unsigned long __init set_phys_range_identity(unsigned long pfn_s,
                                       unsigned long pfn_e)
 {
         unsigned long pfn;
 
-        if (unlikely(pfn_s >= MAX_P2M_PFN))
+        if (unlikely(pfn_s >= xen_p2m_size))
                 return 0;
 
         if (unlikely(xen_feature(XENFEAT_auto_translated_physmap)))
@@ -693,34 +638,11 @@ unsigned long __init set_phys_range_identity(unsigned long pfn_s,
         if (pfn_s > pfn_e)
                 return 0;
 
-        if (pfn_e > MAX_P2M_PFN)
-                pfn_e = MAX_P2M_PFN;
-
-        early_split_p2m(pfn_s);
-        early_split_p2m(pfn_e);
-
-        for (pfn = pfn_s; pfn < pfn_e;) {
-                unsigned topidx = p2m_top_index(pfn);
-                unsigned mididx = p2m_mid_index(pfn);
-
-                if (!__set_phys_to_machine(pfn, IDENTITY_FRAME(pfn)))
-                        break;
-                pfn++;
-
-                /*
-                 * If the PFN was set to a middle or leaf identity
-                 * page the remainder must also be identity, so skip
-                 * ahead to the next middle or leaf entry.
-                 */
-                if (p2m_top[topidx] == p2m_mid_identity)
-                        pfn = ALIGN(pfn, P2M_MID_PER_PAGE * P2M_PER_PAGE);
-                else if (p2m_top[topidx][mididx] == p2m_identity)
-                        pfn = ALIGN(pfn, P2M_PER_PAGE);
-        }
+        if (pfn_e > xen_p2m_size)
+                pfn_e = xen_p2m_size;
 
-        WARN((pfn - pfn_s) != (pfn_e - pfn_s),
-                "Identity mapping failed. We are %ld short of 1-1 mappings!\n",
-                (pfn_e - pfn_s) - (pfn - pfn_s));
+        for (pfn = pfn_s; pfn < pfn_e; pfn++)
+                xen_p2m_addr[pfn] = IDENTITY_FRAME(pfn);
 
         return pfn - pfn_s;
 }
@@ -734,7 +656,7 @@ bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn)
         if (unlikely(xen_feature(XENFEAT_auto_translated_physmap)))
                 return true;
 
-        if (unlikely(pfn >= MAX_P2M_PFN)) {
+        if (unlikely(pfn >= xen_p2m_size)) {
                 BUG_ON(mfn != INVALID_P2M_ENTRY);
                 return true;
         }