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Commit 66686c2a authored by Glauber de Oliveira Costa's avatar Glauber de Oliveira Costa Committed by Rusty Russell
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lguest: per-vcpu lguest task management 



lguest uses tasks to control its running behaviour (like sending
breaks, controlling halted state, etc). In a per-vcpu environment,
each vcpu will have its own underlying task. So this patch
makes the infrastructure for that possible

Signed-off-by: default avatarGlauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent fc708b3e

drivers/lguest/core.c

+2 −2
Original line number Diff line number Diff line
@@ -197,7 +197,7 @@ int run_guest(struct lg_cpu *cpu, unsigned long __user *user) 
			return -ERESTARTSYS;



		/* If Waker set break_out, return to Launcher. */

		if (lg->break_out)

		if (cpu->break_out)

			return -EAGAIN;



		/* Check if there are any interrupts which can be delivered
@@ -217,7 +217,7 @@ int run_guest(struct lg_cpu *cpu, unsigned long __user *user) 


		/* If the Guest asked to be stopped, we sleep.  The Guest's

		 * clock timer or LHCALL_BREAK from the Waker will wake us. */

		if (lg->halted) {

		if (cpu->halted) {

			set_current_state(TASK_INTERRUPTIBLE);

			schedule();

			continue;

drivers/lguest/hypercalls.c

+1 −1
Original line number Diff line number Diff line
@@ -88,7 +88,7 @@ static void do_hcall(struct lg_cpu *cpu, struct hcall_args *args) 
		break;

	case LHCALL_HALT:

		/* Similarly, this sets the halted flag for run_guest(). */

		lg->halted = 1;

		cpu->halted = 1;

		break;

	case LHCALL_NOTIFY:

		lg->pending_notify = args->arg1;

drivers/lguest/interrupts_and_traps.c

+4 −4
Original line number Diff line number Diff line
@@ -161,11 +161,11 @@ void maybe_do_interrupt(struct lg_cpu *cpu) 
		return;



	/* If they're halted, interrupts restart them. */

	if (lg->halted) {

	if (cpu->halted) {

		/* Re-enable interrupts. */

		if (put_user(X86_EFLAGS_IF, &lg->lguest_data->irq_enabled))

			kill_guest(lg, "Re-enabling interrupts");

		lg->halted = 0;

		cpu->halted = 0;

	} else {

		/* Otherwise we check if they have interrupts disabled. */

		u32 irq_enabled;
@@ -497,8 +497,8 @@ static enum hrtimer_restart clockdev_fn(struct hrtimer *timer) 
	/* Remember the first interrupt is the timer interrupt. */

	set_bit(0, cpu->irqs_pending);

	/* If the Guest is actually stopped, we need to wake it up. */

	if (cpu->lg->halted)

		wake_up_process(cpu->lg->tsk);

	if (cpu->halted)

		wake_up_process(cpu->tsk);

	return HRTIMER_NORESTART;

}

drivers/lguest/lg.h

+7 −7
Original line number Diff line number Diff line
@@ -43,6 +43,8 @@ struct lguest; 
struct lg_cpu {

	unsigned int id;

	struct lguest *lg;

	struct task_struct *tsk;

	struct mm_struct *mm; 	/* == tsk->mm, but that becomes NULL on exit */



	/* At end of a page shared mapped over lguest_pages in guest.  */

	unsigned long regs_page;
@@ -55,6 +57,11 @@ struct lg_cpu { 
	/* Virtual clock device */

	struct hrtimer hrt;



	/* Do we need to stop what we're doing and return to userspace? */

	int break_out;

	wait_queue_head_t break_wq;

	int halted;



	/* Pending virtual interrupts */

	DECLARE_BITMAP(irqs_pending, LGUEST_IRQS);
@@ -65,8 +72,6 @@ struct lg_cpu { 
struct lguest

{

	struct lguest_data __user *lguest_data;

	struct task_struct *tsk;

	struct mm_struct *mm; 	/* == tsk->mm, but that becomes NULL on exit */

	struct lg_cpu cpus[NR_CPUS];

	unsigned int nr_cpus;
@@ -76,15 +81,10 @@ struct lguest 
	void __user *mem_base;

	unsigned long kernel_address;

	u32 cr2;

	int halted;

	int ts;

	u32 esp1;

	u8 ss1;



	/* Do we need to stop what we're doing and return to userspace? */

	int break_out;

	wait_queue_head_t break_wq;



	/* Bitmap of what has changed: see CHANGED_* above. */

	int changed;

	struct lguest_pages *last_pages;

drivers/lguest/lguest_user.c

+28 −25
Original line number Diff line number Diff line
@@ -13,7 +13,7 @@ 
 * LHREQ_BREAK and the value "1" to /dev/lguest to do this.  Once the Launcher

 * has done whatever needs attention, it writes LHREQ_BREAK and "0" to release

 * the Waker. */

static int break_guest_out(struct lguest *lg, const unsigned long __user *input)

static int break_guest_out(struct lg_cpu *cpu, const unsigned long __user*input)

{

	unsigned long on;
@@ -22,14 +22,14 @@ static int break_guest_out(struct lguest *lg, const unsigned long __user *input) 
		return -EFAULT;



	if (on) {

		lg->break_out = 1;

		cpu->break_out = 1;

		/* Pop it out of the Guest (may be running on different CPU) */

		wake_up_process(lg->tsk);

		wake_up_process(cpu->tsk);

		/* Wait for them to reset it */

		return wait_event_interruptible(lg->break_wq, !lg->break_out);

		return wait_event_interruptible(cpu->break_wq, !cpu->break_out);

	} else {

		lg->break_out = 0;

		wake_up(&lg->break_wq);

		cpu->break_out = 0;

		wake_up(&cpu->break_wq);

		return 0;

	}

}
@@ -69,7 +69,7 @@ static ssize_t read(struct file *file, char __user *user, size_t size,loff_t*o) 
	cpu = &lg->cpus[cpu_id];



	/* If you're not the task which owns the Guest, go away. */

	if (current != lg->tsk)

	if (current != cpu->tsk)

		return -EPERM;



	/* If the guest is already dead, we indicate why */
@@ -119,6 +119,18 @@ static int lg_cpu_start(struct lg_cpu *cpu, unsigned id, unsigned long start_ip) 
	 * address. */

	lguest_arch_setup_regs(cpu, start_ip);



	/* Initialize the queue for the waker to wait on */

	init_waitqueue_head(&cpu->break_wq);



	/* We keep a pointer to the Launcher task (ie. current task) for when

	 * other Guests want to wake this one (inter-Guest I/O). */

	cpu->tsk = current;



	/* We need to keep a pointer to the Launcher's memory map, because if

	 * the Launcher dies we need to clean it up.  If we don't keep a

	 * reference, it is destroyed before close() is called. */

	cpu->mm = get_task_mm(cpu->tsk);



	return 0;

}
@@ -180,17 +192,6 @@ static int initialize(struct file *file, const unsigned long __user *input) 
	if (err)

		goto free_regs;



	/* We keep a pointer to the Launcher task (ie. current task) for when

	 * other Guests want to wake this one (inter-Guest I/O). */

	lg->tsk = current;

	/* We need to keep a pointer to the Launcher's memory map, because if

	 * the Launcher dies we need to clean it up.  If we don't keep a

	 * reference, it is destroyed before close() is called. */

	lg->mm = get_task_mm(lg->tsk);



	/* Initialize the queue for the waker to wait on */

	init_waitqueue_head(&lg->break_wq);



	/* We remember which CPU's pages this Guest used last, for optimization

	 * when the same Guest runs on the same CPU twice. */

	lg->last_pages = NULL;
@@ -246,7 +247,7 @@ static ssize_t write(struct file *file, const char __user *in, 
		return -ENOENT;



	/* If you're not the task which owns the Guest, you can only break */

	if (lg && current != lg->tsk && req != LHREQ_BREAK)

	if (lg && current != cpu->tsk && req != LHREQ_BREAK)

		return -EPERM;



	switch (req) {
@@ -255,7 +256,7 @@ static ssize_t write(struct file *file, const char __user *in, 
	case LHREQ_IRQ:

		return user_send_irq(cpu, input);

	case LHREQ_BREAK:

		return break_guest_out(lg, input);

		return break_guest_out(cpu, input);

	default:

		return -EINVAL;

	}
@@ -280,17 +281,19 @@ static int close(struct inode *inode, struct file *file) 
	/* We need the big lock, to protect from inter-guest I/O and other

	 * Launchers initializing guests. */

	mutex_lock(&lguest_lock);



	/* Free up the shadow page tables for the Guest. */

	free_guest_pagetable(lg);



	for (i = 0; i < lg->nr_cpus; i++) {

		/* Cancels the hrtimer set via LHCALL_SET_CLOCKEVENT. */

		hrtimer_cancel(&lg->cpus[i].hrt);

		/* We can free up the register page we allocated. */

		free_page(lg->cpus[i].regs_page);

		/* Now all the memory cleanups are done, it's safe to release

		 * the Launcher's memory management structure. */

		mmput(lg->cpus[i].mm);

	}

	/* Free up the shadow page tables for the Guest. */

	free_guest_pagetable(lg);

	/* Now all the memory cleanups are done, it's safe to release the

	 * Launcher's memory management structure. */

	mmput(lg->mm);

	/* If lg->dead doesn't contain an error code it will be NULL or a

	 * kmalloc()ed string, either of which is ok to hand to kfree(). */

	if (!IS_ERR(lg->dead))