From 66686c2ab08feb721ca4d98285fba64acdf6017f Mon Sep 17 00:00:00 2001 From: Glauber de Oliveira Costa Date: Mon, 7 Jan 2008 11:05:34 -0200 Subject: [PATCH] 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: Glauber de Oliveira Costa Signed-off-by: Rusty Russell --- drivers/lguest/core.c | 4 +- drivers/lguest/hypercalls.c | 2 +- drivers/lguest/interrupts_and_traps.c | 8 ++-- drivers/lguest/lg.h | 14 +++---- drivers/lguest/lguest_user.c | 53 ++++++++++++++------------- 5 files changed, 42 insertions(+), 39 deletions(-) diff --git a/drivers/lguest/core.c b/drivers/lguest/core.c index d8e1ac305d..66c3d3b17f 100644 --- a/drivers/lguest/core.c +++ b/drivers/lguest/core.c @@ -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; diff --git a/drivers/lguest/hypercalls.c b/drivers/lguest/hypercalls.c index 6f8c70ae38..83323b1cc0 100644 --- a/drivers/lguest/hypercalls.c +++ b/drivers/lguest/hypercalls.c @@ -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; diff --git a/drivers/lguest/interrupts_and_traps.c b/drivers/lguest/interrupts_and_traps.c index 306b93c71d..9c1c479e8c 100644 --- a/drivers/lguest/interrupts_and_traps.c +++ b/drivers/lguest/interrupts_and_traps.c @@ -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; } diff --git a/drivers/lguest/lg.h b/drivers/lguest/lg.h index d08b85342b..e7123fa612 100644 --- a/drivers/lguest/lg.h +++ b/drivers/lguest/lg.h @@ -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; diff --git a/drivers/lguest/lguest_user.c b/drivers/lguest/lguest_user.c index d21d95b2b1..980b3550db 100644 --- a/drivers/lguest/lguest_user.c +++ b/drivers/lguest/lguest_user.c @@ -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)) -- 2.39.5