From e5faff45b381e053c31214713ed783d97f49177b Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Fri, 20 Jul 2007 22:11:13 +1000 Subject: [PATCH] lguest: fix sense if IF flag on interrupt injection The sense of the IF bit is backwards in the host interrupt handling. This means we always save "IF=1" on the stack when injecting an interrupt. It turns out this is almost always correct (unless the guest is taking a page fault in an interrupt due to an unpopulated vmalloc mapping), so went unnoticed. Signed-off-by: Rusty Russell Signed-off-by: Linus Torvalds --- drivers/lguest/interrupts_and_traps.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/drivers/lguest/interrupts_and_traps.c b/drivers/lguest/interrupts_and_traps.c index d9de5bbc613f..bee029bb2c7b 100644 --- a/drivers/lguest/interrupts_and_traps.c +++ b/drivers/lguest/interrupts_and_traps.c @@ -38,12 +38,12 @@ static void set_guest_interrupt(struct lguest *lg, u32 lo, u32 hi, int has_err) ss = lg->regs->ss; } - /* We use IF bit in eflags to indicate whether irqs were disabled - (it's always 0, since irqs are enabled when guest is running). */ + /* We use IF bit in eflags to indicate whether irqs were enabled + (it's always 1, since irqs are enabled when guest is running). */ eflags = lg->regs->eflags; - if (get_user(irq_enable, &lg->lguest_data->irq_enabled)) - irq_enable = 0; - eflags |= (irq_enable & X86_EFLAGS_IF); + if (get_user(irq_enable, &lg->lguest_data->irq_enabled) == 0 + && !(irq_enable & X86_EFLAGS_IF)) + eflags &= ~X86_EFLAGS_IF; push_guest_stack(lg, &gstack, eflags); push_guest_stack(lg, &gstack, lg->regs->cs); -- 2.11.0