6 files changed, 22 insertions, 13 deletions

diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index dc182a5b02b7..a27f5007062a 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -82,7 +82,9 @@ struct sca_block {
 
 struct kvm_s390_sie_block {
         atomic_t cpuflags;              /* 0x0000 */
-        __u32   prefix;                 /* 0x0004 */
+        __u32 : 1;                      /* 0x0004 */
+        __u32 prefix : 18;
+        __u32 : 13;
         __u8    reserved08[4];          /* 0x0008 */
 #define PROG_IN_SIE (1<<0)
         __u32   prog0c;                 /* 0x000c */
diff --git a/arch/s390/kvm/diag.c b/arch/s390/kvm/diag.c
index 004d385d9519..0161675878a2 100644
--- a/arch/s390/kvm/diag.c
+++ b/arch/s390/kvm/diag.c
@@ -23,7 +23,7 @@
 static int diag_release_pages(struct kvm_vcpu *vcpu)
 {
         unsigned long start, end;
-        unsigned long prefix  = vcpu->arch.sie_block->prefix;
+        unsigned long prefix  = kvm_s390_get_prefix(vcpu);
 
         start = vcpu->run->s.regs.gprs[(vcpu->arch.sie_block->ipa & 0xf0) >> 4];
         end = vcpu->run->s.regs.gprs[vcpu->arch.sie_block->ipa & 0xf] + 4096;
diff --git a/arch/s390/kvm/gaccess.h b/arch/s390/kvm/gaccess.h
index 68db43e4254f..a07ee08ac478 100644
--- a/arch/s390/kvm/gaccess.h
+++ b/arch/s390/kvm/gaccess.h
@@ -30,7 +30,7 @@
 static inline unsigned long kvm_s390_real_to_abs(struct kvm_vcpu *vcpu,
                                                  unsigned long gra)
 {
-        unsigned long prefix = vcpu->arch.sie_block->prefix;
+        unsigned long prefix  = kvm_s390_get_prefix(vcpu);
 
         if (gra < 2 * PAGE_SIZE)
                 gra += prefix;
@@ -99,7 +99,7 @@ static inline unsigned long kvm_s390_logical_to_effective(struct kvm_vcpu *vcpu,
         unsigned long __gpa;                                    \
                                                                 \
         __gpa = (unsigned long)(gra);                           \
-        __gpa += __vcpu->arch.sie_block->prefix;                \
+        __gpa += kvm_s390_get_prefix(__vcpu);                   \
         kvm_write_guest(__vcpu->kvm, __gpa, &__x, sizeof(__x)); \
 })
 
@@ -124,7 +124,7 @@ static inline __must_check
 int write_guest_lc(struct kvm_vcpu *vcpu, unsigned long gra, void *data,
                    unsigned long len)
 {
-        unsigned long gpa = gra + vcpu->arch.sie_block->prefix;
+        unsigned long gpa = gra + kvm_s390_get_prefix(vcpu);
 
         return kvm_write_guest(vcpu->kvm, gpa, data, len);
 }
@@ -150,7 +150,7 @@ static inline __must_check
 int read_guest_lc(struct kvm_vcpu *vcpu, unsigned long gra, void *data,
                   unsigned long len)
 {
-        unsigned long gpa = gra + vcpu->arch.sie_block->prefix;
+        unsigned long gpa = gra + kvm_s390_get_prefix(vcpu);
 
         return kvm_read_guest(vcpu->kvm, gpa, data, len);
 }
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 2c243124a4e2..e519860c6031 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -753,7 +753,7 @@ static void kvm_gmap_notifier(struct gmap *gmap, unsigned long address)
 
         kvm_for_each_vcpu(i, vcpu, kvm) {
                 /* match against both prefix pages */
-                if (vcpu->arch.sie_block->prefix == (address & ~0x1000UL)) {
+                if (kvm_s390_get_prefix(vcpu) == (address & ~0x1000UL)) {
                         VCPU_EVENT(vcpu, 2, "gmap notifier for %lx", address);
                         kvm_make_request(KVM_REQ_MMU_RELOAD, vcpu);
                         exit_sie_sync(vcpu);
@@ -1017,7 +1017,7 @@ retry:
         if (kvm_check_request(KVM_REQ_MMU_RELOAD, vcpu)) {
                 int rc;
                 rc = gmap_ipte_notify(vcpu->arch.gmap,
-                                      vcpu->arch.sie_block->prefix,
+                                      kvm_s390_get_prefix(vcpu),
                                       PAGE_SIZE * 2);
                 if (rc)
                         return rc;
@@ -1338,7 +1338,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 
         kvm_run->psw_mask     = vcpu->arch.sie_block->gpsw.mask;
         kvm_run->psw_addr     = vcpu->arch.sie_block->gpsw.addr;
-        kvm_run->s.regs.prefix = vcpu->arch.sie_block->prefix;
+        kvm_run->s.regs.prefix = kvm_s390_get_prefix(vcpu);
         memcpy(&kvm_run->s.regs.crs, &vcpu->arch.sie_block->gcr, 128);
 
         if (vcpu->sigset_active)
@@ -1357,6 +1357,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 int kvm_s390_store_status_unloaded(struct kvm_vcpu *vcpu, unsigned long gpa)
 {
         unsigned char archmode = 1;
+        unsigned int px;
         u64 clkcomp;
         int rc;
 
@@ -1375,8 +1376,9 @@ int kvm_s390_store_status_unloaded(struct kvm_vcpu *vcpu, unsigned long gpa)
                               vcpu->run->s.regs.gprs, 128);
         rc |= write_guest_abs(vcpu, gpa + offsetof(struct save_area, psw),
                               &vcpu->arch.sie_block->gpsw, 16);
+        px = kvm_s390_get_prefix(vcpu);
         rc |= write_guest_abs(vcpu, gpa + offsetof(struct save_area, pref_reg),
-                              &vcpu->arch.sie_block->prefix, 4);
+                              &px, 4);
         rc |= write_guest_abs(vcpu,
                               gpa + offsetof(struct save_area, fp_ctrl_reg),
                               &vcpu->arch.guest_fpregs.fpc, 4);
diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h
index 87edfc919db9..a8655ed31616 100644
--- a/arch/s390/kvm/kvm-s390.h
+++ b/arch/s390/kvm/kvm-s390.h
@@ -61,9 +61,15 @@ static inline int kvm_is_ucontrol(struct kvm *kvm)
 #endif
 }
 
+#define GUEST_PREFIX_SHIFT 13
+static inline u32 kvm_s390_get_prefix(struct kvm_vcpu *vcpu)
+{
+        return vcpu->arch.sie_block->prefix << GUEST_PREFIX_SHIFT;
+}
+
 static inline void kvm_s390_set_prefix(struct kvm_vcpu *vcpu, u32 prefix)
 {
-        vcpu->arch.sie_block->prefix = prefix & 0x7fffe000u;
+        vcpu->arch.sie_block->prefix = prefix >> GUEST_PREFIX_SHIFT;
         vcpu->arch.sie_block->ihcpu  = 0xffff;
         kvm_make_request(KVM_REQ_MMU_RELOAD, vcpu);
 }
diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
index d99f5f0305a0..6296159ac883 100644
--- a/arch/s390/kvm/priv.c
+++ b/arch/s390/kvm/priv.c
@@ -119,8 +119,7 @@ static int handle_store_prefix(struct kvm_vcpu *vcpu)
         if (operand2 & 3)
                 return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
 
-        address = vcpu->arch.sie_block->prefix;
-        address = address & 0x7fffe000u;
+        address = kvm_s390_get_prefix(vcpu);
 
         /* get the value */
         rc = write_guest(vcpu, operand2, &address, sizeof(address));