From: Jack Lange <jarusl@cs.northwestern.edu>
Date: Wed, 12 Aug 2009 22:10:07 +0000 (-0500)
Subject: added linux swap header
X-Git-Url: http://v3vee.org/palacios/gitweb/gitweb.cgi?p=palacios.git;a=commitdiff_plain;h=1a24d4e8fb3918a42b124777db5b41940150023e

added linux swap header
---

diff --git a/palacios/src/devices/sym_swap.c b/palacios/src/devices/sym_swap.c
index f525db6..f2057f4 100644
--- a/palacios/src/devices/sym_swap.c
+++ b/palacios/src/devices/sym_swap.c
@@ -23,6 +23,28 @@
 
 #define SWAP_CAPACITY (150 * 1024 * 1024)
 
+
+/* This is the first page that linux writes to the swap area */
+/* Taken from Linux */
+union swap_header {
+    struct {
+	char reserved[PAGE_SIZE - 10];
+	char magic[10];			/* SWAP-SPACE or SWAPSPACE2 */
+    } magic;
+    struct {
+	char	         	bootbits[1024];	/* Space for disklabel etc. */
+	uint32_t		version;
+	uint32_t		last_page;
+	uint32_t		nr_badpages;
+	unsigned char   	sws_uuid[16];
+	unsigned char	        sws_volume[16];
+	uint32_t                type;           // The index into the swap_map
+	uint32_t		padding[116];
+	//		uint32_t		padding[117];
+	uint32_t		badpages[1];
+    } info;
+};
+
 struct swap_state {
     
     struct vm_device * blk_dev;
@@ -82,6 +104,20 @@ static int swap_write(uint8_t * buf, int sector_count, uint64_t lba, void * priv
 	PrintError("Swapping out length that is not a page multiple\n");
     }
 
+    if (offset == 0) {
+	// This is the swap header page 
+	union swap_header * hdr;
+	if (length != 4096) {
+	    PrintError("Initializing Swap space by not writing page multiples. This sucks...\n");
+	    return -1;
+	}
+
+	hdr = (union swap_header *)buf;
+	
+
+	PrintDebug("Swap Type=%d (magic=%s)\n", hdr->info.type, hdr->magic.magic);
+    }
+
     memcpy(swap->swap_space + offset, buf, length);
 
     swap->swapped_pages += (length / 4096);