From 0a959c9f2467ca5d925bbf2e5849353f603eb267 Mon Sep 17 00:00:00 2001
From: Olaf Hering <olaf@aepfle.de>
Date: Mon, 1 Oct 2012 21:18:01 +0200
Subject: [PATCH] --- yaml --- r: 333887 b: refs/heads/master c:
 34b6f01a79bd65fbd06511d2cb7b28e33a506246 h: refs/heads/master i:   333885:
 d241df0d753e9bf70799701ec2598357ef32ddec   333883:
 155853d5dbef283ac725deca2a464d849eb9fc02   333879:
 883b79e414adab622672b37c5aac359f74194820   333871:
 e5ad334b609eeeaa6bd823419bbd7d6d13cd0349   333855:
 88ced7231956a3dd7a081a33f41c2950452043af   333823:
 57a241b461ab44410fb256eecf6c0280954c5313 v: v3

---
 [refs]                                   |  2 +-
 trunk/arch/x86/xen/mmu.c                 | 41 ++++++++++++++++++++++++
 trunk/include/xen/interface/hvm/hvm_op.h | 19 +++++++++++
 3 files changed, 61 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index f244b503df2c..4235a5581c2c 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 9b6934a3b449266850149b717597408354039e95
+refs/heads/master: 34b6f01a79bd65fbd06511d2cb7b28e33a506246
diff --git a/trunk/arch/x86/xen/mmu.c b/trunk/arch/x86/xen/mmu.c
index 5a16824cc2b3..963cb2df636a 100644
--- a/trunk/arch/x86/xen/mmu.c
+++ b/trunk/arch/x86/xen/mmu.c
@@ -47,6 +47,7 @@
 #include <linux/gfp.h>
 #include <linux/memblock.h>
 #include <linux/seq_file.h>
+#include <linux/crash_dump.h>
 
 #include <trace/events/xen.h>
 
@@ -2381,6 +2382,43 @@ void xen_destroy_contiguous_region(unsigned long vstart, unsigned int order)
 EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region);
 
 #ifdef CONFIG_XEN_PVHVM
+#ifdef CONFIG_PROC_VMCORE
+/*
+ * This function is used in two contexts:
+ * - the kdump kernel has to check whether a pfn of the crashed kernel
+ *   was a ballooned page. vmcore is using this function to decide
+ *   whether to access a pfn of the crashed kernel.
+ * - the kexec kernel has to check whether a pfn was ballooned by the
+ *   previous kernel. If the pfn is ballooned, handle it properly.
+ * Returns 0 if the pfn is not backed by a RAM page, the caller may
+ * handle the pfn special in this case.
+ */
+static int xen_oldmem_pfn_is_ram(unsigned long pfn)
+{
+	struct xen_hvm_get_mem_type a = {
+		.domid = DOMID_SELF,
+		.pfn = pfn,
+	};
+	int ram;
+
+	if (HYPERVISOR_hvm_op(HVMOP_get_mem_type, &a))
+		return -ENXIO;
+
+	switch (a.mem_type) {
+		case HVMMEM_mmio_dm:
+			ram = 0;
+			break;
+		case HVMMEM_ram_rw:
+		case HVMMEM_ram_ro:
+		default:
+			ram = 1;
+			break;
+	}
+
+	return ram;
+}
+#endif
+
 static void xen_hvm_exit_mmap(struct mm_struct *mm)
 {
 	struct xen_hvm_pagetable_dying a;
@@ -2411,6 +2449,9 @@ void __init xen_hvm_init_mmu_ops(void)
 {
 	if (is_pagetable_dying_supported())
 		pv_mmu_ops.exit_mmap = xen_hvm_exit_mmap;
+#ifdef CONFIG_PROC_VMCORE
+	register_oldmem_pfn_is_ram(&xen_oldmem_pfn_is_ram);
+#endif
 }
 #endif
 
diff --git a/trunk/include/xen/interface/hvm/hvm_op.h b/trunk/include/xen/interface/hvm/hvm_op.h
index a4827f46ee97..956a04682865 100644
--- a/trunk/include/xen/interface/hvm/hvm_op.h
+++ b/trunk/include/xen/interface/hvm/hvm_op.h
@@ -43,4 +43,23 @@ struct xen_hvm_pagetable_dying {
 typedef struct xen_hvm_pagetable_dying xen_hvm_pagetable_dying_t;
 DEFINE_GUEST_HANDLE_STRUCT(xen_hvm_pagetable_dying_t);
  
+enum hvmmem_type_t {
+    HVMMEM_ram_rw,             /* Normal read/write guest RAM */
+    HVMMEM_ram_ro,             /* Read-only; writes are discarded */
+    HVMMEM_mmio_dm,            /* Reads and write go to the device model */
+};
+
+#define HVMOP_get_mem_type    15
+/* Return hvmmem_type_t for the specified pfn. */
+struct xen_hvm_get_mem_type {
+    /* Domain to be queried. */
+    domid_t domid;
+    /* OUT variable. */
+    uint16_t mem_type;
+    uint16_t pad[2]; /* align next field on 8-byte boundary */
+    /* IN variable. */
+    uint64_t pfn;
+};
+DEFINE_GUEST_HANDLE_STRUCT(xen_hvm_get_mem_type);
+
 #endif /* __XEN_PUBLIC_HVM_HVM_OP_H__ */