diff options
Diffstat (limited to 'drivers/lguest/lguest_user.c')
| -rw-r--r-- | drivers/lguest/lguest_user.c | 98 |
1 files changed, 96 insertions, 2 deletions
diff --git a/drivers/lguest/lguest_user.c b/drivers/lguest/lguest_user.c index 1982b45bd93..f6bf255f183 100644 --- a/drivers/lguest/lguest_user.c +++ b/drivers/lguest/lguest_user.c @@ -7,6 +7,8 @@ #include <linux/miscdevice.h> #include <linux/fs.h> #include <linux/sched.h> +#include <linux/eventfd.h> +#include <linux/file.h> #include "lg.h" /*L:055 When something happens, the Waker process needs a way to stop the @@ -35,6 +37,81 @@ static int break_guest_out(struct lg_cpu *cpu, const unsigned long __user*input) } } +bool send_notify_to_eventfd(struct lg_cpu *cpu) +{ + unsigned int i; + struct lg_eventfd_map *map; + + /* lg->eventfds is RCU-protected */ + rcu_read_lock(); + map = rcu_dereference(cpu->lg->eventfds); + for (i = 0; i < map->num; i++) { + if (map->map[i].addr == cpu->pending_notify) { + eventfd_signal(map->map[i].event, 1); + cpu->pending_notify = 0; + break; + } + } + rcu_read_unlock(); + return cpu->pending_notify == 0; +} + +static int add_eventfd(struct lguest *lg, unsigned long addr, int fd) +{ + struct lg_eventfd_map *new, *old = lg->eventfds; + + if (!addr) + return -EINVAL; + + /* Replace the old array with the new one, carefully: others can + * be accessing it at the same time */ + new = kmalloc(sizeof(*new) + sizeof(new->map[0]) * (old->num + 1), + GFP_KERNEL); + if (!new) + return -ENOMEM; + + /* First make identical copy. */ + memcpy(new->map, old->map, sizeof(old->map[0]) * old->num); + new->num = old->num; + + /* Now append new entry. */ + new->map[new->num].addr = addr; + new->map[new->num].event = eventfd_fget(fd); + if (IS_ERR(new->map[new->num].event)) { + kfree(new); + return PTR_ERR(new->map[new->num].event); + } + new->num++; + + /* Now put new one in place. */ + rcu_assign_pointer(lg->eventfds, new); + + /* We're not in a big hurry. Wait until noone's looking at old + * version, then delete it. */ + synchronize_rcu(); + kfree(old); + + return 0; +} + +static int attach_eventfd(struct lguest *lg, const unsigned long __user *input) +{ + unsigned long addr, fd; + int err; + + if (get_user(addr, input) != 0) + return -EFAULT; + input++; + if (get_user(fd, input) != 0) + return -EFAULT; + + mutex_lock(&lguest_lock); + err = add_eventfd(lg, addr, fd); + mutex_unlock(&lguest_lock); + + return 0; +} + /*L:050 Sending an interrupt is done by writing LHREQ_IRQ and an interrupt * number to /dev/lguest. */ static int user_send_irq(struct lg_cpu *cpu, const unsigned long __user *input) @@ -184,6 +261,13 @@ static int initialize(struct file *file, const unsigned long __user *input) goto unlock; } + lg->eventfds = kmalloc(sizeof(*lg->eventfds), GFP_KERNEL); + if (!lg->eventfds) { + err = -ENOMEM; + goto free_lg; + } + lg->eventfds->num = 0; + /* Populate the easy fields of our "struct lguest" */ lg->mem_base = (void __user *)args[0]; lg->pfn_limit = args[1]; @@ -191,7 +275,7 @@ static int initialize(struct file *file, const unsigned long __user *input) /* This is the first cpu (cpu 0) and it will start booting at args[2] */ err = lg_cpu_start(&lg->cpus[0], 0, args[2]); if (err) - goto release_guest; + goto free_eventfds; /* Initialize the Guest's shadow page tables, using the toplevel * address the Launcher gave us. This allocates memory, so can fail. */ @@ -210,7 +294,9 @@ static int initialize(struct file *file, const unsigned long __user *input) free_regs: /* FIXME: This should be in free_vcpu */ free_page(lg->cpus[0].regs_page); -release_guest: +free_eventfds: + kfree(lg->eventfds); +free_lg: kfree(lg); unlock: mutex_unlock(&lguest_lock); @@ -260,6 +346,8 @@ static ssize_t write(struct file *file, const char __user *in, return user_send_irq(cpu, input); case LHREQ_BREAK: return break_guest_out(cpu, input); + case LHREQ_EVENTFD: + return attach_eventfd(lg, input); default: return -EINVAL; } @@ -297,6 +385,12 @@ static int close(struct inode *inode, struct file *file) * the Launcher's memory management structure. */ mmput(lg->cpus[i].mm); } + + /* Release any eventfds they registered. */ + for (i = 0; i < lg->eventfds->num; i++) + fput(lg->eventfds->map[i].event); + kfree(lg->eventfds); + /* 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)) |