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| author | Andrea Arcangeli <aarcange@redhat.com> | 2016-12-17 18:43:52 +0100 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2016-12-19 15:45:14 +0100 |
| commit | 931f261b42f10c8c8c9ab53f5ceb47ce51af7cf5 (patch) | |
| tree | 1c9dd7e4ee202ecb6d7aef52c4e25c8d2a0c3f76 /arch/x86 | |
| parent | KVM: hyperv: fix locking of struct kvm_hv fields (diff) | |
| download | linux-931f261b42f10c8c8c9ab53f5ceb47ce51af7cf5.tar.xz linux-931f261b42f10c8c8c9ab53f5ceb47ce51af7cf5.zip | |
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: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kvm/x86.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 49da1064ef50..8ce1139a08b5 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -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(); |