Commit 931f261b authored by Andrea Arcangeli's avatar Andrea Arcangeli Committed by Paolo Bonzini
Browse files

kvm: fix schedule in atomic in kvm_steal_time_set_preempted() 



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

Signed-off-by: default avatarAndrea Arcangeli <aarcange@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 3f5ad8be

arch/x86/kvm/x86.c

+10 −0
Original line number Diff line number Diff line
@@ -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();