Revision 0447378a4a793da008451fad50bc0f93e9675ae6 authored by Marc Orr on 21 June 2018, 00:21:29 UTC, committed by Radim Krčmář on 22 June 2018, 14:46:26 UTC
This patch extends the checks done prior to a nested VM entry. Specifically, it extends the check_vmentry_prereqs function with checks for fields relevant to the VM-entry event injection information, as described in the Intel SDM, volume 3. This patch is motivated by a syzkaller bug, where a bad VM-entry interruption information field is generated in the VMCS02, which causes the nested VM launch to fail. Then, KVM fails to resume L1. While KVM should be improved to correctly resume L1 execution after a failed nested launch, this change is justified because the existing code to resume L1 is flaky/ad-hoc and the test coverage for resuming L1 is sparse. Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Marc Orr <marcorr@google.com> [Removed comment whose parts were describing previous revisions and the rest was obvious from function/variable naming. - Radim] Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
1 parent 5f9077c
pm.c
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
*
* This file contains power management functions related to interrupts.
*/
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/suspend.h>
#include <linux/syscore_ops.h>
#include "internals.h"
bool irq_pm_check_wakeup(struct irq_desc *desc)
{
if (irqd_is_wakeup_armed(&desc->irq_data)) {
irqd_clear(&desc->irq_data, IRQD_WAKEUP_ARMED);
desc->istate |= IRQS_SUSPENDED | IRQS_PENDING;
desc->depth++;
irq_disable(desc);
pm_system_irq_wakeup(irq_desc_get_irq(desc));
return true;
}
return false;
}
/*
* Called from __setup_irq() with desc->lock held after @action has
* been installed in the action chain.
*/
void irq_pm_install_action(struct irq_desc *desc, struct irqaction *action)
{
desc->nr_actions++;
if (action->flags & IRQF_FORCE_RESUME)
desc->force_resume_depth++;
WARN_ON_ONCE(desc->force_resume_depth &&
desc->force_resume_depth != desc->nr_actions);
if (action->flags & IRQF_NO_SUSPEND)
desc->no_suspend_depth++;
else if (action->flags & IRQF_COND_SUSPEND)
desc->cond_suspend_depth++;
WARN_ON_ONCE(desc->no_suspend_depth &&
(desc->no_suspend_depth +
desc->cond_suspend_depth) != desc->nr_actions);
}
/*
* Called from __free_irq() with desc->lock held after @action has
* been removed from the action chain.
*/
void irq_pm_remove_action(struct irq_desc *desc, struct irqaction *action)
{
desc->nr_actions--;
if (action->flags & IRQF_FORCE_RESUME)
desc->force_resume_depth--;
if (action->flags & IRQF_NO_SUSPEND)
desc->no_suspend_depth--;
else if (action->flags & IRQF_COND_SUSPEND)
desc->cond_suspend_depth--;
}
static bool suspend_device_irq(struct irq_desc *desc)
{
if (!desc->action || irq_desc_is_chained(desc) ||
desc->no_suspend_depth)
return false;
if (irqd_is_wakeup_set(&desc->irq_data)) {
irqd_set(&desc->irq_data, IRQD_WAKEUP_ARMED);
/*
* We return true here to force the caller to issue
* synchronize_irq(). We need to make sure that the
* IRQD_WAKEUP_ARMED is visible before we return from
* suspend_device_irqs().
*/
return true;
}
desc->istate |= IRQS_SUSPENDED;
__disable_irq(desc);
/*
* Hardware which has no wakeup source configuration facility
* requires that the non wakeup interrupts are masked at the
* chip level. The chip implementation indicates that with
* IRQCHIP_MASK_ON_SUSPEND.
*/
if (irq_desc_get_chip(desc)->flags & IRQCHIP_MASK_ON_SUSPEND)
mask_irq(desc);
return true;
}
/**
* suspend_device_irqs - disable all currently enabled interrupt lines
*
* During system-wide suspend or hibernation device drivers need to be
* prevented from receiving interrupts and this function is provided
* for this purpose.
*
* So we disable all interrupts and mark them IRQS_SUSPENDED except
* for those which are unused, those which are marked as not
* suspendable via an interrupt request with the flag IRQF_NO_SUSPEND
* set and those which are marked as active wakeup sources.
*
* The active wakeup sources are handled by the flow handler entry
* code which checks for the IRQD_WAKEUP_ARMED flag, suspends the
* interrupt and notifies the pm core about the wakeup.
*/
void suspend_device_irqs(void)
{
struct irq_desc *desc;
int irq;
for_each_irq_desc(irq, desc) {
unsigned long flags;
bool sync;
if (irq_settings_is_nested_thread(desc))
continue;
raw_spin_lock_irqsave(&desc->lock, flags);
sync = suspend_device_irq(desc);
raw_spin_unlock_irqrestore(&desc->lock, flags);
if (sync)
synchronize_irq(irq);
}
}
EXPORT_SYMBOL_GPL(suspend_device_irqs);
static void resume_irq(struct irq_desc *desc)
{
irqd_clear(&desc->irq_data, IRQD_WAKEUP_ARMED);
if (desc->istate & IRQS_SUSPENDED)
goto resume;
/* Force resume the interrupt? */
if (!desc->force_resume_depth)
return;
/* Pretend that it got disabled ! */
desc->depth++;
irq_state_set_disabled(desc);
irq_state_set_masked(desc);
resume:
desc->istate &= ~IRQS_SUSPENDED;
__enable_irq(desc);
}
static void resume_irqs(bool want_early)
{
struct irq_desc *desc;
int irq;
for_each_irq_desc(irq, desc) {
unsigned long flags;
bool is_early = desc->action &&
desc->action->flags & IRQF_EARLY_RESUME;
if (!is_early && want_early)
continue;
if (irq_settings_is_nested_thread(desc))
continue;
raw_spin_lock_irqsave(&desc->lock, flags);
resume_irq(desc);
raw_spin_unlock_irqrestore(&desc->lock, flags);
}
}
/**
* irq_pm_syscore_ops - enable interrupt lines early
*
* Enable all interrupt lines with %IRQF_EARLY_RESUME set.
*/
static void irq_pm_syscore_resume(void)
{
resume_irqs(true);
}
static struct syscore_ops irq_pm_syscore_ops = {
.resume = irq_pm_syscore_resume,
};
static int __init irq_pm_init_ops(void)
{
register_syscore_ops(&irq_pm_syscore_ops);
return 0;
}
device_initcall(irq_pm_init_ops);
/**
* resume_device_irqs - enable interrupt lines disabled by suspend_device_irqs()
*
* Enable all non-%IRQF_EARLY_RESUME interrupt lines previously
* disabled by suspend_device_irqs() that have the IRQS_SUSPENDED flag
* set as well as those with %IRQF_FORCE_RESUME.
*/
void resume_device_irqs(void)
{
resume_irqs(false);
}
EXPORT_SYMBOL_GPL(resume_device_irqs);
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