From bc1a34f1bf354fabc03e3f465620c80e510d0e8f Mon Sep 17 00:00:00 2001
From: Andrea Arcangeli <andrea@qumranet.com>
Date: Thu, 1 May 2008 18:43:33 +0200
Subject: [PATCH] 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>
---
arch/x86/kvm/x86.c | 11 ++++++++++-
include/asm-x86/kvm_host.h | 2 +-
2 files changed, 11 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index bc224bba1e87..21338bdb28ff 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3703,10 +3703,19 @@ void fx_init(struct kvm_vcpu *vcpu)
{
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 */
preempt_disable();
fx_save(&vcpu->arch.host_fx_image);
- fpu_init();
+ fx_finit();
fx_save(&vcpu->arch.guest_fx_image);
fx_restore(&vcpu->arch.host_fx_image);
preempt_enable();
diff --git a/include/asm-x86/kvm_host.h b/include/asm-x86/kvm_host.h
index 4baa9c9e1f41..1d8cd01fa514 100644
--- a/include/asm-x86/kvm_host.h
+++ b/include/asm-x86/kvm_host.h
@@ -627,7 +627,7 @@ static inline void fx_restore(struct i387_fxsave_struct *image)
asm("fxrstor (%0)":: "r" (image));
}
-static inline void fpu_init(void)
+static inline void fx_finit(void)
{
asm("finit");
}
--
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