3 files changed, 95 insertions, 0 deletions

diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h
index 65fa4f26aa34..78ebbeb88d9c 100644
--- a/arch/x86/include/asm/xen/page.h
+++ b/arch/x86/include/asm/xen/page.h
@@ -52,6 +52,9 @@ extern int m2p_remove_override(struct page *page);
 extern struct page *m2p_find_override(unsigned long mfn);
 extern unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn);
 
+#ifdef CONFIG_XEN_DEBUG_FS
+extern int p2m_dump_show(struct seq_file *m, void *v);
+#endif
 static inline unsigned long pfn_to_mfn(unsigned long pfn)
 {
         unsigned long mfn;
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index 9c9e07615139..b13b6ca9052a 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -46,6 +46,7 @@
 #include <linux/module.h>
 #include <linux/gfp.h>
 #include <linux/memblock.h>
+#include <linux/seq_file.h>
 
 #include <asm/pgtable.h>
 #include <asm/tlbflush.h>
@@ -2367,6 +2368,18 @@ EXPORT_SYMBOL_GPL(xen_remap_domain_mfn_range);
 
 #ifdef CONFIG_XEN_DEBUG_FS
 
+static int p2m_dump_open(struct inode *inode, struct file *filp)
+{
+        return single_open(filp, p2m_dump_show, NULL);
+}
+
+static const struct file_operations p2m_dump_fops = {
+        .open           = p2m_dump_open,
+        .read           = seq_read,
+        .llseek         = seq_lseek,
+        .release        = single_release,
+};
+
 static struct dentry *d_mmu_debug;
 
 static int __init xen_mmu_debugfs(void)
@@ -2422,6 +2435,7 @@ static int __init xen_mmu_debugfs(void)
         debugfs_create_u32("prot_commit_batched", 0444, d_mmu_debug,
                            &mmu_stats.prot_commit_batched);
 
+        debugfs_create_file("p2m", 0600, d_mmu_debug, NULL, &p2m_dump_fops);
         return 0;
 }
 fs_initcall(xen_mmu_debugfs);
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index 4631cf99e714..65f21f4b3962 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -153,6 +153,7 @@
 #include <linux/list.h>
 #include <linux/hash.h>
 #include <linux/sched.h>
+#include <linux/seq_file.h>
 
 #include <asm/cache.h>
 #include <asm/setup.h>
@@ -758,3 +759,80 @@ unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn)
         return ret;
 }
 EXPORT_SYMBOL_GPL(m2p_find_override_pfn);
+
+#ifdef CONFIG_XEN_DEBUG_FS
+
+int p2m_dump_show(struct seq_file *m, void *v)
+{
+        static const char * const level_name[] = { "top", "middle",
+                                                "entry", "abnormal" };
+        static const char * const type_name[] = { "identity", "missing",
+                                                "pfn", "abnormal"};
+#define TYPE_IDENTITY 0
+#define TYPE_MISSING 1
+#define TYPE_PFN 2
+#define TYPE_UNKNOWN 3
+        unsigned long pfn, prev_pfn_type = 0, prev_pfn_level = 0;
+        unsigned int uninitialized_var(prev_level);
+        unsigned int uninitialized_var(prev_type);
+
+        if (!p2m_top)
+                return 0;
+
+        for (pfn = 0; pfn < MAX_DOMAIN_PAGES; pfn++) {
+                unsigned topidx = p2m_top_index(pfn);
+                unsigned mididx = p2m_mid_index(pfn);
+                unsigned idx = p2m_index(pfn);
+                unsigned lvl, type;
+
+                lvl = 4;
+                type = TYPE_UNKNOWN;
+                if (p2m_top[topidx] == p2m_mid_missing) {
+                        lvl = 0; type = TYPE_MISSING;
+                } else if (p2m_top[topidx] == NULL) {
+                        lvl = 0; type = TYPE_UNKNOWN;
+                } else if (p2m_top[topidx][mididx] == NULL) {
+                        lvl = 1; type = TYPE_UNKNOWN;
+                } else if (p2m_top[topidx][mididx] == p2m_identity) {
+                        lvl = 1; type = TYPE_IDENTITY;
+                } else if (p2m_top[topidx][mididx] == p2m_missing) {
+                        lvl = 1; type = TYPE_MISSING;
+                } else if (p2m_top[topidx][mididx][idx] == 0) {
+                        lvl = 2; type = TYPE_UNKNOWN;
+                } else if (p2m_top[topidx][mididx][idx] == IDENTITY_FRAME(pfn)) {
+                        lvl = 2; type = TYPE_IDENTITY;
+                } else if (p2m_top[topidx][mididx][idx] == INVALID_P2M_ENTRY) {
+                        lvl = 2; type = TYPE_MISSING;
+                } else if (p2m_top[topidx][mididx][idx] == pfn) {
+                        lvl = 2; type = TYPE_PFN;
+                } else if (p2m_top[topidx][mididx][idx] != pfn) {
+                        lvl = 2; type = TYPE_PFN;
+                }
+                if (pfn == 0) {
+                        prev_level = lvl;
+                        prev_type = type;
+                }
+                if (pfn == MAX_DOMAIN_PAGES-1) {
+                        lvl = 3;
+                        type = TYPE_UNKNOWN;
+                }
+                if (prev_type != type) {
+                        seq_printf(m, " [0x%lx->0x%lx] %s\n",
+                                prev_pfn_type, pfn, type_name[prev_type]);
+                        prev_pfn_type = pfn;
+                        prev_type = type;
+                }
+                if (prev_level != lvl) {
+                        seq_printf(m, " [0x%lx->0x%lx] level %s\n",
+                                prev_pfn_level, pfn, level_name[prev_level]);
+                        prev_pfn_level = pfn;
+                        prev_level = lvl;
+                }
+        }
+        return 0;
+#undef TYPE_IDENTITY
+#undef TYPE_MISSING
+#undef TYPE_PFN
+#undef TYPE_UNKNOWN
+}
+#endif