Remove the disabling of page faults across kvm_steal_time_set_preempted()
as KVM now accesses the steal time struct (shared with the guest) via a
cached mapping (see commit b043138246a4, "x86/KVM: Make sure
KVM_VCPU_FLUSH_TLB flag is not missed".) The cache lookup is flagged as
atomic, thus it would be a bug if KVM tried to resolve a new pfn, i.e.
we want the splat that would be reached via might_fault().
Signed-off-by: Sean Christopherson <sea...@google.com>
---
arch/x86/kvm/x86.c | 10 ----------
1 file changed, 10 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 9a8969a6dd06..3f4b09d9f25b 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4031,15 +4031,6 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
if (vcpu->preempted && !vcpu->arch.guest_state_protected)
vcpu->arch.preempted_in_kernel = !kvm_x86_ops.get_cpl(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_memslots() will be called by
* kvm_write_guest_offset_cached() so take the srcu lock.
@@ -4047,7 +4038,6 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
idx = srcu_read_lock(&vcpu->kvm->srcu);
kvm_steal_time_set_preempted(vcpu);
srcu_read_unlock(&vcpu->kvm->srcu, idx);
- pagefault_enable();
kvm_x86_ops.vcpu_put(vcpu);
vcpu->arch.last_host_tsc = rdtsc();
/*
--
2.30.0.280.ga3ce27912f-goog
