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| author | Rusty Russell <rusty@rustcorp.com.au> | 2007-07-20 22:11:13 +1000 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-07-20 09:05:16 -0700 |
| commit | e5faff45b381e053c31214713ed783d97f49177b (patch) | |
| tree | 0a2b906f9f087b33e4ca9cb892f35f649ab67fb6 /drivers/lguest/interrupts_and_traps.c | |
| parent | bd6dc742a4b1945861795a66dc27c65365c5f28e (diff) | |
| download | lwn-e5faff45b381e053c31214713ed783d97f49177b.tar.gz lwn-e5faff45b381e053c31214713ed783d97f49177b.zip | |
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 <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/lguest/interrupts_and_traps.c')
| -rw-r--r-- | drivers/lguest/interrupts_and_traps.c | 10 |
1 files 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); |