dump: fix Windows dump memory run mapping

We should map and use guest memory run by parts if it can't be mapped as
a whole.
After this patch, continuos guest physical memory blocks which are not
continuos in host virtual address space will be processed correctly.

Signed-off-by: Viktor Prutyanov <viktor.prutyanov@virtuozzo.com>
Message-Id: <1535567456-6904-1-git-send-email-viktor.prutyanov@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

win_dump.c

@@ -30,28 +30,32 @@ static size_t write_run(WinDumpPhyMemRun64 *run, int fd, Error **errp)
     void *buf;
     uint64_t addr = run->BasePage << TARGET_PAGE_BITS;
     uint64_t size = run->PageCount << TARGET_PAGE_BITS;
-    uint64_t len = size;
+    uint64_t len, l;
+    size_t total = 0;
 
-    buf = cpu_physical_memory_map(addr, &len, false);
-    if (!buf) {
-        error_setg(errp, "win-dump: failed to map run");
-        return 0;
-    }
-    if (len != size) {
-        error_setg(errp, "win-dump: failed to map entire run");
-        len = 0;
-        goto out_unmap;
-    }
+    while (size) {
+        len = size;
 
-    len = qemu_write_full(fd, buf, len);
-    if (len != size) {
-        error_setg(errp, QERR_IO_ERROR);
-    }
+        buf = cpu_physical_memory_map(addr, &len, false);
+        if (!buf) {
+            error_setg(errp, "win-dump: failed to map physical range"
+                             " 0x%016" PRIx64 "-0x%016" PRIx64, addr, addr + size - 1);
+            return 0;
+        }
+
+        l = qemu_write_full(fd, buf, len);
+        cpu_physical_memory_unmap(buf, addr, false, len);
+        if (l != len) {
+            error_setg(errp, QERR_IO_ERROR);
+            return 0;
+        }
 
-out_unmap:
-    cpu_physical_memory_unmap(buf, addr, false, len);
+        addr += l;
+        size -= l;
+        total += l;
+    }
 
-    return len;
+    return total;
 }
 
 static void write_runs(DumpState *s, WinDumpHeader64 *h, Error **errp)