KVM: s390: expose no-DAT to guest and migration support

The STFLE bit 147 indicates whether the ESSA no-DAT operation code is
valid, the bit is not normally provided to the host; the host is
instead provided with an SCLP bit that indicates whether guests can
support the feature.

This patch:
* enables the STFLE bit in the guest if the corresponding SCLP bit is
  present in the host.
* adds support for migrating the no-DAT bit in the PGSTEs
* fixes the software interpretation of the ESSA instruction that is
  used when migrating, both for the new operation code and for the old
  "set stable", as per specifications.

Signed-off-by: Claudio Imbrenda <imbrenda@linux.vnet.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

diff --git a/arch/s390/include/asm/page-states.h b/arch/s390/include/asm/page-states.h
index ca21b28..22b0f49 100644 (file)
--- a/arch/s390/include/asm/page-states.h
+++ b/arch/s390/include/asm/page-states.h
@@ -15,6 +15,6 @@
 #define ESSA_SET_STABLE_IF_RESIDENT    6
 #define ESSA_SET_STABLE_NODAT          7
 
-#define ESSA_MAX       ESSA_SET_STABLE_IF_RESIDENT
+#define ESSA_MAX       ESSA_SET_STABLE_NODAT
 
 #endif

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index e65b763..84c069a 100644 (file)
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -1574,7 +1574,7 @@ static int kvm_s390_get_cmma_bits(struct kvm *kvm,
                if (r < 0)
                        pgstev = 0;
                /* save the value */
-               res[i++] = (pgstev >> 24) & 0x3;
+               res[i++] = (pgstev >> 24) & 0x43;
                /*
                 * if the next bit is too far away, stop.
                 * if we reached the previous "next", find the next one
@@ -1652,7 +1652,7 @@ static int kvm_s390_set_cmma_bits(struct kvm *kvm,
 
                pgstev = bits[i];
                pgstev = pgstev << 24;
-               mask &= _PGSTE_GPS_USAGE_MASK;
+               mask &= _PGSTE_GPS_USAGE_MASK | _PGSTE_GPS_NODAT;
                set_pgste_bits(kvm->mm, hva, mask, pgstev);
        }
        srcu_read_unlock(&kvm->srcu, srcu_idx);
@@ -1929,6 +1929,10 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
 
        set_kvm_facility(kvm->arch.model.fac_mask, 74);
        set_kvm_facility(kvm->arch.model.fac_list, 74);
+       if (MACHINE_HAS_TLB_GUEST) {
+               set_kvm_facility(kvm->arch.model.fac_mask, 147);
+               set_kvm_facility(kvm->arch.model.fac_list, 147);
+       }
 
        kvm->arch.model.cpuid = kvm_s390_get_initial_cpuid();
        kvm->arch.model.ibc = sclp.ibc & 0x0fff;

diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
index 8a1dac7..91dc4a8 100644 (file)
--- a/arch/s390/kvm/priv.c
+++ b/arch/s390/kvm/priv.c
@@ -988,6 +988,8 @@ static inline int do_essa(struct kvm_vcpu *vcpu, const int orc)
                if (pgstev & _PGSTE_GPS_ZERO)
                        res |= 1;
        }
+       if (pgstev & _PGSTE_GPS_NODAT)
+               res |= 0x20;
        vcpu->run->s.regs.gprs[r1] = res;
        /*
         * It is possible that all the normal 511 slots were full, in which case
@@ -1027,7 +1029,9 @@ static int handle_essa(struct kvm_vcpu *vcpu)
                return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);
        /* Check for invalid operation request code */
        orc = (vcpu->arch.sie_block->ipb & 0xf0000000) >> 28;
-       if (orc > ESSA_MAX)
+       /* ORCs 0-6 are always valid */
+       if (orc > (test_kvm_facility(vcpu->kvm, 147) ? ESSA_SET_STABLE_NODAT
+                                               : ESSA_SET_STABLE_IF_RESIDENT))
                return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
 
        if (likely(!vcpu->kvm->arch.migration_state)) {

diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
index 8d018c7..459716d 100644 (file)
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c
@@ -919,7 +919,7 @@ int pgste_perform_essa(struct mm_struct *mm, unsigned long hva, int orc,
        case ESSA_GET_STATE:
                break;
        case ESSA_SET_STABLE:
-               pgstev &= ~_PGSTE_GPS_USAGE_MASK;
+               pgstev &= ~(_PGSTE_GPS_USAGE_MASK | _PGSTE_GPS_NODAT);
                pgstev |= _PGSTE_GPS_USAGE_STABLE;
                break;
        case ESSA_SET_UNUSED:
@@ -965,6 +965,10 @@ int pgste_perform_essa(struct mm_struct *mm, unsigned long hva, int orc,
                        pgstev |= _PGSTE_GPS_USAGE_STABLE;
                }
                break;
+       case ESSA_SET_STABLE_NODAT:
+               pgstev &= ~_PGSTE_GPS_USAGE_MASK;
+               pgstev |= _PGSTE_GPS_USAGE_STABLE | _PGSTE_GPS_NODAT;
+               break;
        default:
                /* we should never get here! */
                break;