---

yaml
---
r: 234172
b: refs/heads/master
c: fc25151
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 2222e71bd6eff7b2ad026d4ee663b6327c5a49f5
+refs/heads/master: fc25151d9ac7d809239fe68de0a1490b504bb94a

trunk/arch/x86/xen/Kconfig

@@ -48,3 +48,11 @@ config XEN_DEBUG_FS
 	help
 	  Enable statistics output and various tuning options in debugfs.
 	  Enabling this option may incur a significant performance overhead.
+
+config XEN_DEBUG
+	bool "Enable Xen debug checks"
+	depends on XEN
+	default n
+	help
+	  Enable various WARN_ON checks in the Xen MMU code.
+	  Enabling this option WILL incur a significant performance overhead.

trunk/arch/x86/xen/mmu.c

@@ -547,6 +547,41 @@ pte_t xen_make_pte(pteval_t pte)
 }
 PV_CALLEE_SAVE_REGS_THUNK(xen_make_pte);
 
+#ifdef CONFIG_XEN_DEBUG
+pte_t xen_make_pte_debug(pteval_t pte)
+{
+	phys_addr_t addr = (pte & PTE_PFN_MASK);
+	phys_addr_t other_addr;
+	bool io_page = false;
+	pte_t _pte;
+
+	if (pte & _PAGE_IOMAP)
+		io_page = true;
+
+	_pte = xen_make_pte(pte);
+
+	if (!addr)
+		return _pte;
+
+	if (io_page &&
+	    (xen_initial_domain() || addr >= ISA_END_ADDRESS)) {
+		other_addr = pfn_to_mfn(addr >> PAGE_SHIFT) << PAGE_SHIFT;
+		WARN(addr != other_addr,
+			"0x%lx is using VM_IO, but it is 0x%lx!\n",
+			(unsigned long)addr, (unsigned long)other_addr);
+	} else {
+		pteval_t iomap_set = (_pte.pte & PTE_FLAGS_MASK) & _PAGE_IOMAP;
+		other_addr = (_pte.pte & PTE_PFN_MASK);
+		WARN((addr == other_addr) && (!io_page) && (!iomap_set),
+			"0x%lx is missing VM_IO (and wasn't fixed)!\n",
+			(unsigned long)addr);
+	}
+
+	return _pte;
+}
+PV_CALLEE_SAVE_REGS_THUNK(xen_make_pte_debug);
+#endif
+
 pgd_t xen_make_pgd(pgdval_t pgd)
 {
 	pgd = pte_pfn_to_mfn(pgd);
@@ -1957,6 +1992,9 @@ __init void xen_ident_map_ISA(void)
 
 static __init void xen_post_allocator_init(void)
 {
+#ifdef CONFIG_XEN_DEBUG
+	pv_mmu_ops.make_pte = PV_CALLEE_SAVE(xen_make_pte_debug);
+#endif
 	pv_mmu_ops.set_pte = xen_set_pte;
 	pv_mmu_ops.set_pmd = xen_set_pmd;
 	pv_mmu_ops.set_pud = xen_set_pud;