vmm: don't vmap non-canonical addresses

Signed-off-by: Johannes Wikner <[email protected]>
KernelTestFramework · Nov 12, 2023 · 0f6d58c · 0f6d58c
1 parent 4b44717
commit 0f6d58c
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Showing 2 changed files with 14 additions and 1 deletion.
diff --git a/arch/x86/pagetables.c b/arch/x86/pagetables.c
@@ -92,6 +92,11 @@ static inline void dump_pte(void *entry, mfn_t table, int level, int index) {
            level, index, paddr, flags);
 }
 
+static inline int canonical_va(void *va) {
+    unsigned long sign = (_ul(va) >> (VA_BITS - 1)) & 1;
+    return sign * (_ul(1) << (sizeof(va) * 8 - VA_BITS)) - 1 == _ul(va) >> VA_BITS;
+}
+
 static void dump_pagetable(mfn_t table, int level) {
     pte_t *pt;
 
@@ -262,7 +267,7 @@ static void *_vmap(cr3_t *cr3_ptr, void *va, mfn_t mfn, unsigned int order,
     mfn_t l1t_mfn, l2t_mfn, l3t_mfn;
     pgentry_t *tab, *entry;
 
-    if (!va || (_ul(va) & ~PAGE_ORDER_TO_MASK(order)))
+    if (!va || (_ul(va) & ~PAGE_ORDER_TO_MASK(order)) || !canonical_va(va))
         return NULL;
 
     dprintk("%s: va: 0x%p mfn: 0x%lx (order: %u)\n", __func__, va, mfn, order);

diff --git a/include/arch/x86/page.h b/include/arch/x86/page.h
@@ -150,6 +150,14 @@ typedef enum pat_memory_type pat_memory_type_t;
 typedef unsigned long paddr_t;
 typedef unsigned long mfn_t;
 
+#if defined(__x86_64__)
+#define la57_enabled() 0 // TODO: 5 level paging unsupported for now
+#define VA_BITS        (la57_enabled() ? 57 : 48) /* Number of canonical address bits */
+#else
+#define la57_enabled() 0
+#define VA_BITS        32
+#endif
+
 #define _paddr(addr) ((paddr_t) _ul(addr))
 
 #define PADDR_INVALID (0UL)