KVM: s390: backup the currently enabled gmap when scheduled out

Nested virtualization will have to enable own gmaps. Current code
would enable the wrong gmap whenever scheduled out and back in,
therefore resulting in the wrong gmap being enabled.

This patch reenables the last enabled gmap, therefore avoiding having to
touch vcpu->arch.gmap when enabling a different gmap.

Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

1 files changed, 5 insertions, 3 deletions

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 45a8316ba1eb..a890f7d20711 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -1719,7 +1719,7 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 
         save_access_regs(vcpu->arch.host_acrs);
         restore_access_regs(vcpu->run->s.regs.acrs);
-        gmap_enable(vcpu->arch.gmap);
+        gmap_enable(vcpu->arch.enabled_gmap);
         atomic_or(CPUSTAT_RUNNING, &vcpu->arch.sie_block->cpuflags);
         if (vcpu->arch.cputm_enabled && !is_vcpu_idle(vcpu))
                 __start_cpu_timer_accounting(vcpu);
@@ -1732,7 +1732,8 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
         if (vcpu->arch.cputm_enabled && !is_vcpu_idle(vcpu))
                 __stop_cpu_timer_accounting(vcpu);
         atomic_andnot(CPUSTAT_RUNNING, &vcpu->arch.sie_block->cpuflags);
-        gmap_disable(vcpu->arch.gmap);
+        vcpu->arch.enabled_gmap = gmap_get_enabled();
+        gmap_disable(vcpu->arch.enabled_gmap);
 
         /* Save guest register state */
         save_fpu_regs();
@@ -1781,7 +1782,8 @@ void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)
                 vcpu->arch.gmap = vcpu->kvm->arch.gmap;
                 sca_add_vcpu(vcpu);
         }
-
+        /* make vcpu_load load the right gmap on the first trigger */
+        vcpu->arch.enabled_gmap = vcpu->arch.gmap;
 }
 
 static void kvm_s390_vcpu_crypto_setup(struct kvm_vcpu *vcpu)