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lguest: fix sense if IF flag on interrupt injection

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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 <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Rusty Russell 2007-07-20 22:11:13 +10:00 committed by Linus Torvalds
parent bd6dc742a4
commit e5faff45b3
1 changed files with 5 additions and 5 deletions
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10
drivers/lguest/interrupts_and_traps.c
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@ -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);