From e5c301428294cb8925667c9ee39f817c4ab1c2c9 Mon Sep 17 00:00:00 2001 From: Avi Kivity Date: Tue, 11 Jan 2011 12:15:54 +0200 Subject: [PATCH] KVM: Initialize fpu state in preemptible context init_fpu() (which is indirectly called by the fpu switching code) assumes it is in process context. Rather than makeing init_fpu() use an atomic allocation, which can cause a task to be killed, make sure the fpu is already initialized when we enter the run loop. KVM-Stable-Tag. Reported-and-tested-by: Kirill A. Shutemov Acked-by: Pekka Enberg Reviewed-by: Christoph Lameter Signed-off-by: Avi Kivity --- arch/x86/kernel/i387.c | 1 + arch/x86/kvm/x86.c | 3 +++ 2 files changed, 4 insertions(+) diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c index 58bb239..e60c38c 100644 --- a/arch/x86/kernel/i387.c +++ b/arch/x86/kernel/i387.c @@ -169,6 +169,7 @@ int init_fpu(struct task_struct *tsk) set_stopped_child_used_math(tsk); return 0; } +EXPORT_SYMBOL_GPL(init_fpu); /* * The xstateregs_active() routine is the same as the fpregs_active() routine, diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index fa708c9..9dda70d 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -5376,6 +5376,9 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) int r; sigset_t sigsaved; + if (!tsk_used_math(current) && init_fpu(current)) + return -ENOMEM; + if (vcpu->sigset_active) sigprocmask(SIG_SETMASK, &vcpu->sigset, &sigsaved); -- 2.7.4