xen/debugfs: Add 'p2m' file for printing out the P2M layout.

We walk over the whole P2M tree and construct a simplified view of
which PFN regions belong to what level and what type they are.

Only enabled if CONFIG_XEN_DEBUG_FS is set.

[v2: UNKN->UNKNOWN, use uninitialized_var]
[v3: Rebased on top of mmu->p2m code split]
[v4: Fixed the else if]
Reviewed-by: Ian Campbell <Ian.Campbell@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

1 files changed, 78 insertions, 0 deletions

diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index 4631cf99e71..65f21f4b396 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