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lguest: remove obsolete LHREQ_BREAK call

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We no longer need an efficient mechanism to force the Guest back into
host userspace, as each device is serviced without bothering the main
Guest process (aka. the Launcher).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell 2009-06-12 22:27:10 -06:00
parent 659a0e6633
commit 5dac051bc6
4 changed files with 5 additions and 43 deletions
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11
drivers/lguest/core.c
View File

@ -209,10 +209,6 @@ int run_guest(struct lg_cpu *cpu, unsigned long __user *user)
if (signal_pending(current))
return -ERESTARTSYS;
/* If Waker set break_out, return to Launcher. */
if (cpu->break_out)
return -EAGAIN;
/* Check if there are any interrupts which can be delivered now:
* if so, this sets up the hander to be executed when we next
* run the Guest. */
@ -231,13 +227,12 @@ int run_guest(struct lg_cpu *cpu, unsigned long __user *user)
break;
/* If the Guest asked to be stopped, we sleep. The Guest's
* clock timer or LHREQ_BREAK from the Waker will wake us. */
* clock timer will wake us. */
if (cpu->halted) {
set_current_state(TASK_INTERRUPTIBLE);
/* Just before we sleep, make sure nothing snuck in
/* Just before we sleep, make sure no interrupt snuck in
* which we should be doing. */
if (interrupt_pending(cpu, &more) < LGUEST_IRQS
|| cpu->break_out)
if (interrupt_pending(cpu, &more) < LGUEST_IRQS)
set_current_state(TASK_RUNNING);
else
schedule();

4
drivers/lguest/lg.h
View File

@ -71,9 +71,7 @@ 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;
/* Did the Guest tell us to halt? */
int halted;
/* Pending virtual interrupts */

31
drivers/lguest/lguest_user.c
View File

@ -11,32 +11,6 @@
#include <linux/file.h>
#include "lg.h"
/*L:055 When something happens, the Waker process needs a way to stop the
* kernel running the Guest and return to the Launcher. So the Waker writes
* 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 lg_cpu *cpu, const unsigned long __user*input)
{
unsigned long on;
/* Fetch whether they're turning break on or off. */
if (get_user(on, input) != 0)
return -EFAULT;
if (on) {
cpu->break_out = 1;
if (!wake_up_process(cpu->tsk))
kick_process(cpu->tsk);
/* Wait for them to reset it */
return wait_event_interruptible(cpu->break_wq, !cpu->break_out);
} else {
cpu->break_out = 0;
wake_up(&cpu->break_wq);
return 0;
}
}
bool send_notify_to_eventfd(struct lg_cpu *cpu)
{
unsigned int i;
@ -202,9 +176,6 @@ 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 (eg. console input). */
cpu->tsk = current;
@ -344,8 +315,6 @@ static ssize_t write(struct file *file, const char __user *in,
return initialize(file, input);
case LHREQ_IRQ:
return user_send_irq(cpu, input);
case LHREQ_BREAK:
return break_guest_out(cpu, input);
case LHREQ_EVENTFD:
return attach_eventfd(lg, input);
default:

2
include/linux/lguest_launcher.h
View File

@ -57,7 +57,7 @@ enum lguest_req
LHREQ_INITIALIZE, /* + base, pfnlimit, start */
LHREQ_GETDMA, /* No longer used */
LHREQ_IRQ, /* + irq */
LHREQ_BREAK, /* + on/off flag (on blocks until someone does off) */
LHREQ_BREAK, /* No longer used */
LHREQ_EVENTFD, /* + address, fd. */
};