Re: access shared_info?

[Gerd Hoffmann <kraxel@suse.de>]

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> Even if you could get address of shared_info, you can't map it into user
> space without some kernel hacking to make that possible (/dev/mem can
> only map I/O memory when running on Xen).

Ok, different attack ;)

How about the attached patch?  It makes /proc/iomem under xen dom0 look
like on native hardware.  Also for domU it has some sensible values then
instead of being empty.

cheers,

  Gerd

-- 
Gerd Hoffmann <kraxel@suse.de>
http://www.suse.de/~kraxel/julika-dora.jpeg

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diff -r c191c649cdb3 linux-2.6-xen-sparse/arch/i386/kernel/setup-xen.c
--- a/linux-2.6-xen-sparse/arch/i386/kernel/setup-xen.c	Tue Jun  6 09:25:59 2006
+++ b/linux-2.6-xen-sparse/arch/i386/kernel/setup-xen.c	Wed Jun  7 17:48:10 2006
@@ -1352,10 +1352,23 @@
  * Request address space for all standard RAM and ROM resources
  * and also for regions reported as reserved by the e820.
  */
+
+static void __init register_kernel_ressources(struct resource *res)
+{
+	/*
+	 *  We don't know which RAM region contains kernel data,
+	 *  so we try it repeatedly and let the resource manager
+	 *  test it.
+	 */
+	request_resource(res, &code_resource);
+	request_resource(res, &data_resource);
+#ifdef CONFIG_KEXEC
+	request_resource(res, &crashk_res);
+#endif
+}
+
 static void __init
-legacy_init_iomem_resources(struct e820entry *e820, int nr_map,
-			    struct resource *code_resource,
-			    struct resource *data_resource)
+legacy_init_iomem_resources(struct e820entry *e820, int nr_map)
 {
 	int i;
 
@@ -1378,21 +1391,23 @@
 		res->end = res->start + e820[i].size - 1;
 		res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
 		request_resource(&iomem_resource, res);
-#ifndef CONFIG_XEN
-		if (e820[i].type == E820_RAM) {
-			/*
-			 *  We don't know which RAM region contains kernel data,
-			 *  so we try it repeatedly and let the resource manager
-			 *  test it.
-			 */
-			request_resource(res, code_resource);
-			request_resource(res, data_resource);
-#ifdef CONFIG_KEXEC
-			request_resource(res, &crashk_res);
-#endif
-		}
-#endif
-	}
+		if (e820[i].type == E820_RAM)
+			register_kernel_ressources(res);
+	}
+}
+
+static void __init
+domU_init_iomem_resources(void)
+{
+	struct resource *res;
+	
+	res = alloc_bootmem_low(sizeof(struct resource));
+	res->name  = "System RAM";
+	res->start = 0;
+	res->end   = (max_pfn * PAGE_SIZE) - 1;
+	res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
+	request_resource(&iomem_resource, res);
+	register_kernel_ressources(res);
 }
 
 /*
@@ -1460,8 +1475,10 @@
 	int	      i;
 
 	/* Nothing to do if not running in dom0. */
-	if (!(xen_start_info->flags & SIF_INITDOMAIN))
+	if (!(xen_start_info->flags & SIF_INITDOMAIN)) {
+		domU_init_iomem_resources();
 		return;
+	}
 
 #ifdef CONFIG_XEN
 	machine_e820 = alloc_bootmem_low_pages(PAGE_SIZE);
@@ -1471,14 +1488,12 @@
 
 	BUG_ON(HYPERVISOR_memory_op(XENMEM_machine_memory_map, &memmap));
 
-	legacy_init_iomem_resources(machine_e820, memmap.nr_entries,
-				    &code_resource, &data_resource);
+	legacy_init_iomem_resources(machine_e820, memmap.nr_entries);
 #else
 	if (efi_enabled)
 		efi_initialize_iomem_resources(&code_resource, &data_resource);
 	else
-		legacy_init_iomem_resources(e820.map, e820.nr_map,
-					    &code_resource, &data_resource);
+		legacy_init_iomem_resources(e820.map, e820.nr_map);
 #endif
 
 	/* EFI systems may still have VGA */
@@ -1698,11 +1713,10 @@
 	init_mm.brk = (PFN_UP(__pa(xen_start_info->pt_base)) +
 		       xen_start_info->nr_pt_frames) << PAGE_SHIFT;
 
-	/* XEN: This is nonsense: kernel may not even be contiguous in RAM. */
-	/*code_resource.start = virt_to_phys(_text);*/
-	/*code_resource.end = virt_to_phys(_etext)-1;*/
-	/*data_resource.start = virt_to_phys(_etext);*/
-	/*data_resource.end = virt_to_phys(_edata)-1;*/
+	code_resource.start = virt_to_phys(_text);
+	code_resource.end = virt_to_phys(_etext)-1;
+	data_resource.start = virt_to_phys(_etext);
+	data_resource.end = virt_to_phys(_edata)-1;
 
 	parse_cmdline_early(cmdline_p);
 

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