KVM: s390: implement KVM_REQ_TLB_FLUSH and make use of it

Use the KVM_REQ_TLB_FLUSH request in order to trigger tlb flushes instead
of manipulating the SIE control block whenever we need it. Also trigger it for
a control register sync directly instead of (ab)using kvm_s390_set_prefix().

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

2 files changed, 9 insertions, 3 deletions

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index ab7cd645c127..56193becdca5 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -1051,6 +1051,11 @@ retry:
                 goto retry;
         }
 
+        if (kvm_check_request(KVM_REQ_TLB_FLUSH, vcpu)) {
+                vcpu->arch.sie_block->ihcpu = 0xffff;
+                goto retry;
+        }
+
         if (kvm_check_request(KVM_REQ_ENABLE_IBS, vcpu)) {
                 if (!ibs_enabled(vcpu)) {
                         trace_kvm_s390_enable_disable_ibs(vcpu->vcpu_id, 1);
@@ -1306,7 +1311,8 @@ static void sync_regs(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
                 kvm_s390_set_prefix(vcpu, kvm_run->s.regs.prefix);
         if (kvm_run->kvm_dirty_regs & KVM_SYNC_CRS) {
                 memcpy(&vcpu->arch.sie_block->gcr, &kvm_run->s.regs.crs, 128);
-                kvm_s390_set_prefix(vcpu, kvm_run->s.regs.prefix);
+                /* some control register changes require a tlb flush */
+                kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
         }
         if (kvm_run->kvm_dirty_regs & KVM_SYNC_ARCH0) {
                 vcpu->arch.sie_block->cputm = kvm_run->s.regs.cputm;
@@ -1519,7 +1525,7 @@ void kvm_s390_vcpu_start(struct kvm_vcpu *vcpu)
          * Another VCPU might have used IBS while we were offline.
          * Let's play safe and flush the VCPU at startup.
          */
-        vcpu->arch.sie_block->ihcpu  = 0xffff;
+        kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
         spin_unlock(&vcpu->kvm->arch.start_stop_lock);
         return;
 }
diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h
index 894fa4653dfb..54c25fd5bed6 100644
--- a/arch/s390/kvm/kvm-s390.h
+++ b/arch/s390/kvm/kvm-s390.h
@@ -70,7 +70,7 @@ static inline u32 kvm_s390_get_prefix(struct kvm_vcpu *vcpu)
 static inline void kvm_s390_set_prefix(struct kvm_vcpu *vcpu, u32 prefix)
 {
         vcpu->arch.sie_block->prefix = prefix >> GUEST_PREFIX_SHIFT;
-        vcpu->arch.sie_block->ihcpu  = 0xffff;
+        kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
         kvm_make_request(KVM_REQ_MMU_RELOAD, vcpu);
 }