More console fixes; these are the theoretical ones which didn't get

CC:stable.  But for that reason, I did a merge with master partway
 through to avoid an unnecessary conflict.
 
 Also: a fun lguest bug turns out if you don't clear the TF flag when trapping
 Bad Things happen to the guest kernel as the stack overflows...
 
 Cheers,
 Rusty.
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Merge tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

Pull virtio update from Rusty Russell:
 "More console fixes; these are the theoretical ones which didn't get
  CC:stable.  But for that reason, I did a merge with master partway
  through to avoid an unnecessary conflict.

  Also: a fun lguest bug turns out if you don't clear the TF flag when
  trapping Bad Things happen to the guest kernel as the stack
  overflows..."

* tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
  virtio_pci: pm: Use CONFIG_PM_SLEEP instead of CONFIG_PM
  lguest: fix GPF in guest when using gdb.
  lguest: fix guest kernel stack overflow when TF bit set.
  lguest: fix BUG_ON() in invalid guest page table.
  virtio: console: prevent use-after-free of port name in port unplug
  virtio: console: cleanup an error message
  virtio: console: fix locking around send_sigio_to_port()
  virtio: console: add locking in port unplug path
  virtio: console: add locks around buffer removal in port unplug path
  tools/lguest: offer VIRTIO_F_ANY_LAYOUT for net device.
  virtio tools: add .gitignore
  lguest: Point to the right directory for the lguest launcher

arch/x86/lguest/boot.c

@@ -7,8 +7,7 @@
  * kernel and insert a module (lg.ko) which allows us to run other Linux
  * kernels the same way we'd run processes.  We call the first kernel the Host,
  * and the others the Guests.  The program which sets up and configures Guests
- * (such as the example in Documentation/virtual/lguest/lguest.c) is called the
- * Launcher.
+ * (such as the example in tools/lguest/lguest.c) is called the Launcher.
  *
  * Secondly, we only run specially modified Guests, not normal kernels: setting
  * CONFIG_LGUEST_GUEST to "y" compiles this file into the kernel so it knows
@@ -1057,6 +1056,12 @@ static void lguest_load_sp0(struct tss_struct *tss,
 }
 
 /* Let's just say, I wouldn't do debugging under a Guest. */
+static unsigned long lguest_get_debugreg(int regno)
+{
+	/* FIXME: Implement */
+	return 0;
+}
+
 static void lguest_set_debugreg(int regno, unsigned long value)
 {
 	/* FIXME: Implement */
@@ -1304,6 +1309,7 @@ __init void lguest_init(void)
 	pv_cpu_ops.load_tr_desc = lguest_load_tr_desc;
 	pv_cpu_ops.set_ldt = lguest_set_ldt;
 	pv_cpu_ops.load_tls = lguest_load_tls;
+	pv_cpu_ops.get_debugreg = lguest_get_debugreg;
 	pv_cpu_ops.set_debugreg = lguest_set_debugreg;
 	pv_cpu_ops.clts = lguest_clts;
 	pv_cpu_ops.read_cr0 = lguest_read_cr0;

drivers/char/virtio_console.c

@@ -1529,18 +1529,22 @@ static void remove_port_data(struct port *port)
 {
 	struct port_buffer *buf;
 
+	spin_lock_irq(&port->inbuf_lock);
 	/* Remove unused data this port might have received. */
 	discard_port_data(port);
 
-	reclaim_consumed_buffers(port);
-
 	/* Remove buffers we queued up for the Host to send us data in. */
 	while ((buf = virtqueue_detach_unused_buf(port->in_vq)))
 		free_buf(buf, true);
+	spin_unlock_irq(&port->inbuf_lock);
+
+	spin_lock_irq(&port->outvq_lock);
+	reclaim_consumed_buffers(port);
 
 	/* Free pending buffers from the out-queue. */
 	while ((buf = virtqueue_detach_unused_buf(port->out_vq)))
 		free_buf(buf, true);
+	spin_unlock_irq(&port->outvq_lock);
 }
 
 /*
@@ -1554,6 +1558,7 @@ static void unplug_port(struct port *port)
 	list_del(&port->list);
 	spin_unlock_irq(&port->portdev->ports_lock);
 
+	spin_lock_irq(&port->inbuf_lock);
 	if (port->guest_connected) {
 		/* Let the app know the port is going down. */
 		send_sigio_to_port(port);
@@ -1564,6 +1569,7 @@ static void unplug_port(struct port *port)
 
 		wake_up_interruptible(&port->waitqueue);
 	}
+	spin_unlock_irq(&port->inbuf_lock);
 
 	if (is_console_port(port)) {
 		spin_lock_irq(&pdrvdata_lock);
@@ -1585,9 +1591,8 @@ static void unplug_port(struct port *port)
 	device_destroy(pdrvdata.class, port->dev->devt);
 	cdev_del(port->cdev);
 
-	kfree(port->name);
-
 	debugfs_remove(port->debugfs_file);
+	kfree(port->name);
 
 	/*
 	 * Locks around here are not necessary - a port can't be
@@ -1681,7 +1686,9 @@ static void handle_control_message(struct ports_device *portdev,
 		 * If the guest is connected, it'll be interested in
 		 * knowing the host connection state changed.
 		 */
+		spin_lock_irq(&port->inbuf_lock);
 		send_sigio_to_port(port);
+		spin_unlock_irq(&port->inbuf_lock);
 		break;
 	case VIRTIO_CONSOLE_PORT_NAME:
 		/*
@@ -1801,13 +1808,13 @@ static void in_intr(struct virtqueue *vq)
 	if (!port->guest_connected && !is_rproc_serial(port->portdev->vdev))
 		discard_port_data(port);
 
+	/* Send a SIGIO indicating new data in case the process asked for it */
+	send_sigio_to_port(port);
+
 	spin_unlock_irqrestore(&port->inbuf_lock, flags);
 
 	wake_up_interruptible(&port->waitqueue);
 
-	/* Send a SIGIO indicating new data in case the process asked for it */
-	send_sigio_to_port(port);
-
 	if (is_console_port(port) && hvc_poll(port->cons.hvc))
 		hvc_kick();
 }
@@ -2241,10 +2248,8 @@ static int __init init(void)
 	}
 
 	pdrvdata.debugfs_dir = debugfs_create_dir("virtio-ports", NULL);
-	if (!pdrvdata.debugfs_dir) {
-		pr_warning("Error %ld creating debugfs dir for virtio-ports\n",
-			   PTR_ERR(pdrvdata.debugfs_dir));
-	}
+	if (!pdrvdata.debugfs_dir)
+		pr_warning("Error creating debugfs dir for virtio-ports\n");
 	INIT_LIST_HEAD(&pdrvdata.consoles);
 	INIT_LIST_HEAD(&pdrvdata.portdevs);
 

drivers/lguest/interrupts_and_traps.c

@@ -139,6 +139,16 @@ static void set_guest_interrupt(struct lg_cpu *cpu, u32 lo, u32 hi,
 	cpu->regs->cs = (__KERNEL_CS|GUEST_PL);
 	cpu->regs->eip = idt_address(lo, hi);
 
+	/*
+	 * Trapping always clears these flags:
+	 * TF: Trap flag
+	 * VM: Virtual 8086 mode
+	 * RF: Resume
+	 * NT: Nested task.
+	 */
+	cpu->regs->eflags &=
+		~(X86_EFLAGS_TF|X86_EFLAGS_VM|X86_EFLAGS_RF|X86_EFLAGS_NT);
+
 	/*
 	 * There are two kinds of interrupt handlers: 0xE is an "interrupt
 	 * gate" which expects interrupts to be disabled on entry.

drivers/lguest/page_tables.c

@@ -669,8 +669,10 @@ unsigned long guest_pa(struct lg_cpu *cpu, unsigned long vaddr)
 
 #ifdef CONFIG_X86_PAE
 	gpmd = lgread(cpu, gpmd_addr(gpgd, vaddr), pmd_t);
-	if (!(pmd_flags(gpmd) & _PAGE_PRESENT))
+	if (!(pmd_flags(gpmd) & _PAGE_PRESENT)) {
 		kill_guest(cpu, "Bad address %#lx", vaddr);
+		return -1UL;
+	}
 	gpte = lgread(cpu, gpte_addr(cpu, gpmd, vaddr), pte_t);
 #else
 	gpte = lgread(cpu, gpte_addr(cpu, gpgd, vaddr), pte_t);

drivers/virtio/virtio_pci.c

@@ -766,7 +766,7 @@ static void virtio_pci_remove(struct pci_dev *pci_dev)
 	kfree(vp_dev);
 }
 
-#ifdef CONFIG_PM
+#ifdef CONFIG_PM_SLEEP
 static int virtio_pci_freeze(struct device *dev)
 {
 	struct pci_dev *pci_dev = to_pci_dev(dev);
@@ -824,7 +824,7 @@ static struct pci_driver virtio_pci_driver = {
 	.id_table	= virtio_pci_id_table,
 	.probe		= virtio_pci_probe,
 	.remove		= virtio_pci_remove,
-#ifdef CONFIG_PM
+#ifdef CONFIG_PM_SLEEP
 	.driver.pm	= &virtio_pci_pm_ops,
 #endif
 };

tools/lguest/lguest.c

@@ -42,6 +42,10 @@
 #include <pwd.h>
 #include <grp.h>
 
+#ifndef VIRTIO_F_ANY_LAYOUT
+#define VIRTIO_F_ANY_LAYOUT		27
+#endif
+
 /*L:110
  * We can ignore the 43 include files we need for this program, but I do want
  * to draw attention to the use of kernel-style types.
@@ -1544,6 +1548,8 @@ static void setup_tun_net(char *arg)
 	add_feature(dev, VIRTIO_NET_F_HOST_ECN);
 	/* We handle indirect ring entries */
 	add_feature(dev, VIRTIO_RING_F_INDIRECT_DESC);
+	/* We're compliant with the damn spec. */
+	add_feature(dev, VIRTIO_F_ANY_LAYOUT);
 	set_config(dev, sizeof(conf), &conf);
 
 	/* We don't need the socket any more; setup is done. */

tools/virtio/.gitignore

@@ -0,0 +1,3 @@
+*.d
+virtio_test
+vringh_test