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kvm: fix schedule in atomic in kvm_steal_time_set_preempted()

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kvm_steal_time_set_preempted() isn't disabling the pagefaults before
calling __copy_to_user and the kernel debug notices.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Andrea Arcangeli 2016-12-17 18:43:52 +01:00 committed by Paolo Bonzini
parent 3f5ad8be37
commit 931f261b42
1 changed files with 10 additions and 0 deletions
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10
arch/x86/kvm/x86.c
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@ -2844,7 +2844,17 @@ static void kvm_steal_time_set_preempted(struct kvm_vcpu *vcpu)
void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
{
/*
* Disable page faults because we're in atomic context here.
* kvm_write_guest_offset_cached() would call might_fault()
* that relies on pagefault_disable() to tell if there's a
* bug. NOTE: the write to guest memory may not go through if
* during postcopy live migration or if there's heavy guest
* paging.
*/
pagefault_disable();
kvm_steal_time_set_preempted(vcpu);
pagefault_enable();
kvm_x86_ops->vcpu_put(vcpu);
kvm_put_guest_fpu(vcpu);
vcpu->arch.last_host_tsc = rdtsc();