[PATCH 2/3] lguest: 2.6.21-mm1 update: lguest-magic-signature.patch

[PATCH 2/3] lguest: 2.6.21-mm1 update: lguest-magic-signature.patch

[Rusty Russell]

paravirt_probe() and its infrastructure proved as popular as it was
pretty.  In anticipation of its imminent demise, this switches lguest to
use a magic string to identify a different entry point.

This is not the long-term solution: that will take a new bootloader rev
and will hopefully be done in the next few months.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
 Documentation/lguest/lguest.c |   25 +++++++++++++++++++++----
 drivers/lguest/lguest.c       |    2 --
 drivers/lguest/lguest_asm.S   |   23 +++++++++--------------
 3 files changed, 30 insertions(+), 20 deletions(-)

===================================================================
--- a/Documentation/lguest/lguest.c
+++ b/Documentation/lguest/lguest.c
@@ -96,6 +96,19 @@ static void *map_zeroed_pages(unsigned l
 	return (void *)addr;
 }
 
+/* Find magic string marking entry point, return entry point. */
+static unsigned long entry_point(void *start, void *end,
+				 unsigned long page_offset)
+{
+	void *p;
+
+	for (p = start; p < end; p++)
+		if (memcmp(p, "GenuineLguest", strlen("GenuineLguest")) == 0)
+			return (long)p + strlen("GenuineLguest") + page_offset;
+
+	err(1, "Is this image a genuine lguest?");
+}
+
 /* Returns the entry point */
 static unsigned long map_elf(int elf_fd, const Elf32_Ehdr *ehdr,
 			     unsigned long *page_offset)
@@ -103,6 +116,7 @@ static unsigned long map_elf(int elf_fd,
 	void *addr;
 	Elf32_Phdr phdr[ehdr->e_phnum];
 	unsigned int i;
+	unsigned long start = -1UL, end = 0;
 
 	/* Sanity checks. */
 	if (ehdr->e_type != ET_EXEC
@@ -131,6 +145,11 @@ static unsigned long map_elf(int elf_fd,
 			*page_offset = phdr[i].p_vaddr - phdr[i].p_paddr;
 		else if (*page_offset != phdr[i].p_vaddr - phdr[i].p_paddr)
 			errx(1, "Page offset of section %i different", i);
+
+		if (phdr[i].p_paddr < start)
+			start = phdr[i].p_paddr;
+		if (phdr[i].p_paddr + phdr[i].p_filesz > end)
+			end = phdr[i].p_paddr + phdr[i].p_filesz;
 
 		/* We map everything private, writable. */
 		addr = mmap((void *)phdr[i].p_paddr,
@@ -143,8 +162,7 @@ static unsigned long map_elf(int elf_fd,
 			    i, addr, (void *)phdr[i].p_paddr);
 	}
 
-	/* Entry is physical address: convert to virtual */
-	return ehdr->e_entry + *page_offset;
+	return entry_point((void *)start, (void *)end, *page_offset);
 }
 
 /* This is amazingly reliable. */
@@ -175,8 +193,7 @@ static unsigned long unpack_bzimage(int 
 	verbose("Unpacked size %i addr %p\n", len, img);
 	*page_offset = intuit_page_offset(img, len);
 
-	/* Entry is physical address: convert to virtual */
-	return (unsigned long)img + *page_offset;
+	return entry_point(img, img + len, *page_offset);
 }
 
 static unsigned long load_bzimage(int fd, unsigned long *page_offset)
===================================================================
--- a/drivers/lguest/lguest.c
+++ b/drivers/lguest/lguest.c
@@ -43,7 +43,6 @@ extern const char lgstart_popf[], lgend_
 extern const char lgstart_popf[], lgend_popf[];
 extern const char lgstart_pushf[], lgend_pushf[];
 extern const char lgstart_iret[], lgend_iret[];
-extern asmlinkage void lguest_maybe_init(void);
 extern void lguest_iret(void);
 
 struct lguest_data lguest_data = {
@@ -497,4 +496,3 @@ __init void lguest_init(void)
 	pm_power_off = lguest_power_off;
 	start_kernel();
 }
-paravirt_probe(lguest_maybe_init);
===================================================================
--- a/drivers/lguest/lguest_asm.S
+++ b/drivers/lguest/lguest_asm.S
@@ -1,29 +1,24 @@
 #include <linux/linkage.h>
 #include <linux/lguest.h>
 #include <asm/asm-offsets.h>
+#include <asm/thread_info.h>
 
 /* FIXME: Once asm/processor-flags.h goes in, include that */
 #define X86_EFLAGS_IF 0x00000200
 
 /*
- * This is where we begin: head.S notes that paging is already enabled (which
- * doesn't happen in native boot) and calls the registered paravirt_probe
- * functions one at a time.  Ours is a simple assembler test for magic
- * registers.  If they're correct we jump to lguest_init.
+ * This is where we begin: we have a magic signature which the launcher looks
+ * for.  The plan is that the Linux boot protocol will be extended with a
+ * "platform type" field which will guide us here from the normal entry point,
+ * but for the moment this suffices.
  *
  * We put it in .init.text will be discarded after boot.
  */
 .section .init.text, "ax", @progbits
-ENTRY(lguest_maybe_init)
-	cmpl $LGUEST_MAGIC_EBP, %ebp
-	jne out
-	cmpl $LGUEST_MAGIC_EDI, %edi
-	jne out
-	cmpl $LGUEST_MAGIC_ESI, %esi
-	jne out
-	je lguest_init
-out:
-	ret
+.ascii "GenuineLguest"
+	/* Set up initial stack. */
+ 	movl $(init_thread_union+THREAD_SIZE),%esp
+	jmp lguest_init
 
 /* The templates for inline patching. */
 #define LGUEST_PATCH(name, insns...)			\

[PATCH 3/3] lguest: 2.6.21-mm1 update: lguest-net-stats-inline.patch

[Rusty Russell]

Now inline net_device_stats is upstream, we can use it in the lguest
net driver.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
 drivers/net/lguest_net.c |   20 +++++---------------
 1 file changed, 5 insertions(+), 15 deletions(-)

===================================================================
--- a/drivers/net/lguest_net.c
+++ b/drivers/net/lguest_net.c
@@ -38,8 +38,6 @@ struct lguestnet_info
 	/* My peerid. */
 	unsigned int me;
 
-	struct net_device_stats stats;
-
 	/* Receive queue. */
 	struct sk_buff *skb[NUM_SKBS];
 	struct lguest_dma dma[NUM_SKBS];
@@ -120,13 +118,13 @@ static void transfer_packet(struct net_d
 
 	hcall(LHCALL_SEND_DMA, peer_key(info,peernum), __pa(&dma), 0);
 	if (dma.used_len != skb->len) {
-		info->stats.tx_carrier_errors++;
+		dev->stats.tx_carrier_errors++;
 		pr_debug("Bad xfer to peer %i: %i of %i (dma %p/%i)\n",
 			 peernum, dma.used_len, skb->len,
 			 (void *)dma.addr[0], dma.len[0]);
 	} else {
-		info->stats.tx_bytes += skb->len;
-		info->stats.tx_packets++;
+		dev->stats.tx_bytes += skb->len;
+		dev->stats.tx_packets++;
 	}
 }
 
@@ -212,8 +210,8 @@ static irqreturn_t lguestnet_rcv(int irq
 		pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
 			 ntohs(skb->protocol), skb->len, skb->pkt_type);
 
-		info->stats.rx_bytes += skb->len;
-		info->stats.rx_packets++;
+		dev->stats.rx_bytes += skb->len;
+		dev->stats.rx_packets++;
 		netif_rx(skb);
 	}
 	return done ? IRQ_HANDLED : IRQ_NONE;
@@ -258,13 +256,6 @@ static int lguestnet_close(struct net_de
 	for (i = 0; i < ARRAY_SIZE(info->dma); i++)
 		dev_kfree_skb(info->skb[i]);
 	return 0;
-}
-
-static struct net_device_stats *lguestnet_get_stats(struct net_device *dev)
-{
-	struct lguestnet_info *info = dev->priv;
-
-	return &info->stats;
 }
 
 static int lguestnet_probe(struct lguest_device *lgdev)
@@ -295,7 +286,6 @@ static int lguestnet_probe(struct lguest
 	dev->open = lguestnet_open;
 	dev->stop = lguestnet_close;
 	dev->hard_start_xmit = lguestnet_start_xmit;
-	dev->get_stats = lguestnet_get_stats;
 
 	/* Turning on/off promisc will call dev->set_multicast_list.
 	 * We don't actually support multicast yet */