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KVM: avoid fx_init() schedule in atomic 

This make sure not to schedule in atomic during fx_init. I also
changed the name of fpu_init to fx_finit to avoid duplicating the name
with fpu_init that is already used in the kernel, this makes grep
simpler if nothing else.

Signed-off-by: Andrea Arcangeli <andrea@qumranet.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
This commit is contained in:
Andrea Arcangeli 2008-05-01 18:43:33 +02:00 committed by Avi Kivity
parent b4f14abd95
commit bc1a34f1bf
2 changed files with 11 additions and 2 deletions
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11
arch/x86/kvm/x86.c
View File

@ -3703,10 +3703,19 @@ void fx_init(struct kvm_vcpu *vcpu)
{ {
unsigned after_mxcsr_mask; unsigned after_mxcsr_mask;
/*
* Touch the fpu the first time in non atomic context as if
* this is the first fpu instruction the exception handler
* will fire before the instruction returns and it'll have to
* allocate ram with GFP_KERNEL.
*/
if (!used_math())
fx_save(&vcpu->arch.host_fx_image);
/* Initialize guest FPU by resetting ours and saving into guest's */ /* Initialize guest FPU by resetting ours and saving into guest's */
preempt_disable(); preempt_disable();
fx_save(&vcpu->arch.host_fx_image); fx_save(&vcpu->arch.host_fx_image);
fpu_init(); fx_finit();
fx_save(&vcpu->arch.guest_fx_image); fx_save(&vcpu->arch.guest_fx_image);
fx_restore(&vcpu->arch.host_fx_image); fx_restore(&vcpu->arch.host_fx_image);
preempt_enable(); preempt_enable();

2
include/asm-x86/kvm_host.h
View File

@ -627,7 +627,7 @@ static inline void fx_restore(struct i387_fxsave_struct *image)
asm("fxrstor (%0)":: "r" (image)); asm("fxrstor (%0)":: "r" (image));
} }
static inline void fpu_init(void) static inline void fx_finit(void)
{ {
asm("finit"); asm("finit");
} }