[S390] kvm: fix address mode switching

598841ca9919d008b520114d8a4378c4ce4e40a1 ([S390] use gmap address
spaces for kvm guest images) changed kvm to use a separate address
space for kvm guests. This address space was switched in __vcpu_run
In some cases (preemption, page fault) there is the possibility that
this address space switch is lost.
The typical symptom was a huge amount of validity intercepts or
random guest addressing exceptions.
Fix this by doing the switch in sie_loop and sie_exit and saving the
address space in the gmap structure itself. Also use the preempt
notifier.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index f17296e4fc8..b4eced131e5 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -263,10 +263,12 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
         vcpu->arch.guest_fpregs.fpc &= FPC_VALID_MASK;
         restore_fp_regs(&vcpu->arch.guest_fpregs);
         restore_access_regs(vcpu->arch.guest_acrs);
+        gmap_enable(vcpu->arch.gmap);
 }
 
 void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
 {
+        gmap_disable(vcpu->arch.gmap);
         save_fp_regs(&vcpu->arch.guest_fpregs);
         save_access_regs(vcpu->arch.guest_acrs);
         restore_fp_regs(&vcpu->arch.host_fpregs);
@@ -461,7 +463,6 @@ static void __vcpu_run(struct kvm_vcpu *vcpu)
         local_irq_disable();
         kvm_guest_enter();
         local_irq_enable();
-        gmap_enable(vcpu->arch.gmap);
         VCPU_EVENT(vcpu, 6, "entering sie flags %x",
                    atomic_read(&vcpu->arch.sie_block->cpuflags));
         if (sie64a(vcpu->arch.sie_block, vcpu->arch.guest_gprs)) {
@@ -470,7 +471,6 @@ static void __vcpu_run(struct kvm_vcpu *vcpu)
         }
         VCPU_EVENT(vcpu, 6, "exit sie icptcode %d",
                    vcpu->arch.sie_block->icptcode);
-        gmap_disable(vcpu->arch.gmap);
         local_irq_disable();
         kvm_guest_exit();
         local_irq_enable();