KVM: s390: Multiple Epoch Facility support

Allow for the enablement of MEF and the support for the extended
epoch in SIE and VSIE for the extended guest TOD-Clock.

A new interface is used for getting/setting a guest's extended TOD-Clock
that uses a single ioctl invocation, KVM_S390_VM_TOD_EXT.  Since the
host time is a moving target that might see an epoch switch or STP sync
checks we need an atomic ioctl and cannot use the exisiting two
interfaces. The old method of getting and setting the guest TOD-Clock is
still retained and is used when the old ioctls are called.

Signed-off-by: Collin L. Walling <walling@linux.vnet.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.vnet.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.vnet.ibm.com>
Reviewed-by: Jason J. Herne <jjherne@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

diff --git a/Documentation/virtual/kvm/devices/vm.txt b/Documentation/virtual/kvm/devices/vm.txt
index 903fc926860b522bc92122a65c750d4f28be2d71..95ca68d663a4c111eb99b280e6d1d60c85461804 100644 (file)
--- a/Documentation/virtual/kvm/devices/vm.txt
+++ b/Documentation/virtual/kvm/devices/vm.txt
@@ -176,7 +176,8 @@ Architectures: s390
 
 3.1. ATTRIBUTE: KVM_S390_VM_TOD_HIGH
 
-Allows user space to set/get the TOD clock extension (u8).
+Allows user space to set/get the TOD clock extension (u8) (superseded by
+KVM_S390_VM_TOD_EXT).
 
 Parameters: address of a buffer in user space to store the data (u8) to
 Returns:    -EFAULT if the given address is not accessible from kernel space
@@ -190,6 +191,17 @@ the POP (u64).
 Parameters: address of a buffer in user space to store the data (u64) to
 Returns:    -EFAULT if the given address is not accessible from kernel space
 
+3.3. ATTRIBUTE: KVM_S390_VM_TOD_EXT
+Allows user space to set/get bits 0-63 of the TOD clock register as defined in
+the POP (u64). If the guest CPU model supports the TOD clock extension (u8), it
+also allows user space to get/set it. If the guest CPU model does not support
+it, it is stored as 0 and not allowed to be set to a value != 0.
+
+Parameters: address of a buffer in user space to store the data
+            (kvm_s390_vm_tod_clock) to
+Returns:    -EFAULT if the given address is not accessible from kernel space
+           -EINVAL if setting the TOD clock extension to != 0 is not supported
+
 4. GROUP: KVM_S390_VM_CRYPTO
 Architectures: s390
 

diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index a409d59919344a277fac0858c2bd12ece1bd83c9..51375e766e905a955a4df21fa185c669bfaa9544 100644 (file)
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -226,7 +226,9 @@ struct kvm_s390_sie_block {
 #define ECB3_RI  0x01
        __u8    ecb3;                   /* 0x0063 */
        __u32   scaol;                  /* 0x0064 */
-       __u8    reserved68[4];          /* 0x0068 */
+       __u8    reserved68;             /* 0x0068 */
+       __u8    epdx;                   /* 0x0069 */
+       __u8    reserved6a[2];          /* 0x006a */
        __u32   todpr;                  /* 0x006c */
        __u8    reserved70[16];         /* 0x0070 */
        __u64   mso;                    /* 0x0080 */
@@ -265,6 +267,7 @@ struct kvm_s390_sie_block {
        __u64   cbrlo;                  /* 0x01b8 */
        __u8    reserved1c0[8];         /* 0x01c0 */
 #define ECD_HOSTREGMGMT        0x20000000
+#define ECD_MEF                0x08000000
        __u32   ecd;                    /* 0x01c8 */
        __u8    reserved1cc[18];        /* 0x01cc */
        __u64   pp;                     /* 0x01de */
@@ -739,6 +742,7 @@ struct kvm_arch{
        struct kvm_s390_cpu_model model;
        struct kvm_s390_crypto crypto;
        struct kvm_s390_vsie vsie;
+       u8 epdx;
        u64 epoch;
        struct kvm_s390_migration_state *migration_state;
        /* subset of available cpu features enabled by user space */

diff --git a/arch/s390/include/uapi/asm/kvm.h b/arch/s390/include/uapi/asm/kvm.h
index 69d09c39bbcd00858121ebf9f6bb1f7a57ff20e1..cd7359e23d869465d1cb70b637c64c85283e37ac 100644 (file)
--- a/arch/s390/include/uapi/asm/kvm.h
+++ b/arch/s390/include/uapi/asm/kvm.h
@@ -88,6 +88,12 @@ struct kvm_s390_io_adapter_req {
 /* kvm attributes for KVM_S390_VM_TOD */
 #define KVM_S390_VM_TOD_LOW            0
 #define KVM_S390_VM_TOD_HIGH           1
+#define KVM_S390_VM_TOD_EXT            2
+
+struct kvm_s390_vm_tod_clock {
+       __u8  epoch_idx;
+       __u64 tod;
+};
 
 /* kvm attributes for KVM_S390_VM_CPU_MODEL */
 /* processor related attributes are r/w */

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index af09d3437631d348dca2f1a6699c34ed49c624ed..e65b7637cc45d33fa8b173ecf76c61841f0ae27e 100644 (file)
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -130,6 +130,12 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
        { NULL }
 };
 
+struct kvm_s390_tod_clock_ext {
+       __u8 epoch_idx;
+       __u64 tod;
+       __u8 reserved[7];
+} __packed;
+
 /* allow nested virtualization in KVM (if enabled by user space) */
 static int nested;
 module_param(nested, int, S_IRUGO);
@@ -874,6 +880,26 @@ static int kvm_s390_vm_get_migration(struct kvm *kvm,
        return 0;
 }
 
+static int kvm_s390_set_tod_ext(struct kvm *kvm, struct kvm_device_attr *attr)
+{
+       struct kvm_s390_vm_tod_clock gtod;
+
+       if (copy_from_user(&gtod, (void __user *)attr->addr, sizeof(gtod)))
+               return -EFAULT;
+
+       if (test_kvm_facility(kvm, 139))
+               kvm_s390_set_tod_clock_ext(kvm, &gtod);
+       else if (gtod.epoch_idx == 0)
+               kvm_s390_set_tod_clock(kvm, gtod.tod);
+       else
+               return -EINVAL;
+
+       VM_EVENT(kvm, 3, "SET: TOD extension: 0x%x, TOD base: 0x%llx",
+               gtod.epoch_idx, gtod.tod);
+
+       return 0;
+}
+
 static int kvm_s390_set_tod_high(struct kvm *kvm, struct kvm_device_attr *attr)
 {
        u8 gtod_high;
@@ -909,6 +935,9 @@ static int kvm_s390_set_tod(struct kvm *kvm, struct kvm_device_attr *attr)
                return -EINVAL;
 
        switch (attr->attr) {
+       case KVM_S390_VM_TOD_EXT:
+               ret = kvm_s390_set_tod_ext(kvm, attr);
+               break;
        case KVM_S390_VM_TOD_HIGH:
                ret = kvm_s390_set_tod_high(kvm, attr);
                break;
@@ -922,6 +951,43 @@ static int kvm_s390_set_tod(struct kvm *kvm, struct kvm_device_attr *attr)
        return ret;
 }
 
+static void kvm_s390_get_tod_clock_ext(struct kvm *kvm,
+                                       struct kvm_s390_vm_tod_clock *gtod)
+{
+       struct kvm_s390_tod_clock_ext htod;
+
+       preempt_disable();
+
+       get_tod_clock_ext((char *)&htod);
+
+       gtod->tod = htod.tod + kvm->arch.epoch;
+       gtod->epoch_idx = htod.epoch_idx + kvm->arch.epdx;
+
+       if (gtod->tod < htod.tod)
+               gtod->epoch_idx += 1;
+
+       preempt_enable();
+}
+
+static int kvm_s390_get_tod_ext(struct kvm *kvm, struct kvm_device_attr *attr)
+{
+       struct kvm_s390_vm_tod_clock gtod;
+
+       memset(&gtod, 0, sizeof(gtod));
+
+       if (test_kvm_facility(kvm, 139))
+               kvm_s390_get_tod_clock_ext(kvm, &gtod);
+       else
+               gtod.tod = kvm_s390_get_tod_clock_fast(kvm);
+
+       if (copy_to_user((void __user *)attr->addr, &gtod, sizeof(gtod)))
+               return -EFAULT;
+
+       VM_EVENT(kvm, 3, "QUERY: TOD extension: 0x%x, TOD base: 0x%llx",
+               gtod.epoch_idx, gtod.tod);
+       return 0;
+}
+
 static int kvm_s390_get_tod_high(struct kvm *kvm, struct kvm_device_attr *attr)
 {
        u8 gtod_high = 0;
@@ -954,6 +1020,9 @@ static int kvm_s390_get_tod(struct kvm *kvm, struct kvm_device_attr *attr)
                return -EINVAL;
 
        switch (attr->attr) {
+       case KVM_S390_VM_TOD_EXT:
+               ret = kvm_s390_get_tod_ext(kvm, attr);
+               break;
        case KVM_S390_VM_TOD_HIGH:
                ret = kvm_s390_get_tod_high(kvm, attr);
                break;
@@ -2369,6 +2438,9 @@ int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
                vcpu->arch.sie_block->eca |= ECA_VX;
                vcpu->arch.sie_block->ecd |= ECD_HOSTREGMGMT;
        }
+       if (test_kvm_facility(vcpu->kvm, 139))
+               vcpu->arch.sie_block->ecd |= ECD_MEF;
+
        vcpu->arch.sie_block->sdnxo = ((unsigned long) &vcpu->run->s.regs.sdnx)
                                        | SDNXC;
        vcpu->arch.sie_block->riccbd = (unsigned long) &vcpu->run->s.regs.riccb;
@@ -2855,6 +2927,35 @@ retry:
        return 0;
 }
 
+void kvm_s390_set_tod_clock_ext(struct kvm *kvm,
+                                const struct kvm_s390_vm_tod_clock *gtod)
+{
+       struct kvm_vcpu *vcpu;
+       struct kvm_s390_tod_clock_ext htod;
+       int i;
+
+       mutex_lock(&kvm->lock);
+       preempt_disable();
+
+       get_tod_clock_ext((char *)&htod);
+
+       kvm->arch.epoch = gtod->tod - htod.tod;
+       kvm->arch.epdx = gtod->epoch_idx - htod.epoch_idx;
+
+       if (kvm->arch.epoch > gtod->tod)
+               kvm->arch.epdx -= 1;
+
+       kvm_s390_vcpu_block_all(kvm);
+       kvm_for_each_vcpu(i, vcpu, kvm) {
+               vcpu->arch.sie_block->epoch = kvm->arch.epoch;
+               vcpu->arch.sie_block->epdx  = kvm->arch.epdx;
+       }
+
+       kvm_s390_vcpu_unblock_all(kvm);
+       preempt_enable();
+       mutex_unlock(&kvm->lock);
+}
+
 void kvm_s390_set_tod_clock(struct kvm *kvm, u64 tod)
 {
        struct kvm_vcpu *vcpu;

diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h
index 6fedc8bc7a37393bd1fa50be94d22d53f431a076..9f8fdd7b231134da9b2d2d4d8971a05546b33c6b 100644 (file)
--- a/arch/s390/kvm/kvm-s390.h
+++ b/arch/s390/kvm/kvm-s390.h
@@ -272,6 +272,8 @@ int kvm_s390_handle_sigp_pei(struct kvm_vcpu *vcpu);
 int handle_sthyi(struct kvm_vcpu *vcpu);
 
 /* implemented in kvm-s390.c */
+void kvm_s390_set_tod_clock_ext(struct kvm *kvm,
+                                const struct kvm_s390_vm_tod_clock *gtod);
 void kvm_s390_set_tod_clock(struct kvm *kvm, u64 tod);
 long kvm_arch_fault_in_page(struct kvm_vcpu *vcpu, gpa_t gpa, int writable);
 int kvm_s390_store_status_unloaded(struct kvm_vcpu *vcpu, unsigned long addr);

diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c
index 715c19c45d9adbf565c28839d6f9d45cdb627b15..d471910bd9ea5c864f4b4fd03358cf9658c0495f 100644 (file)
--- a/arch/s390/kvm/vsie.c
+++ b/arch/s390/kvm/vsie.c
@@ -349,6 +349,9 @@ static int shadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
                scb_s->eca |= scb_o->eca & ECA_IB;
        if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_CEI))
                scb_s->eca |= scb_o->eca & ECA_CEI;
+       /* Epoch Extension */
+       if (test_kvm_facility(vcpu->kvm, 139))
+               scb_s->ecd |= scb_o->ecd & ECD_MEF;
 
        prepare_ibc(vcpu, vsie_page);
        rc = shadow_crycb(vcpu, vsie_page);
@@ -919,6 +922,13 @@ static void register_shadow_scb(struct kvm_vcpu *vcpu,
         */
        preempt_disable();
        scb_s->epoch += vcpu->kvm->arch.epoch;
+
+       if (scb_s->ecd & ECD_MEF) {
+               scb_s->epdx += vcpu->kvm->arch.epdx;
+               if (scb_s->epoch < vcpu->kvm->arch.epoch)
+                       scb_s->epdx += 1;
+       }
+
        preempt_enable();
 }
 

diff --git a/arch/s390/tools/gen_facilities.c b/arch/s390/tools/gen_facilities.c
index 181db5b8f8b3e6fa1014d7dedc182caf9d25539b..601bfcf99e2a9ecd871a21861d6a083d58ef84ce 100644 (file)
--- a/arch/s390/tools/gen_facilities.c
+++ b/arch/s390/tools/gen_facilities.c
@@ -81,6 +81,7 @@ static struct facility_def facility_defs[] = {
                        130, /* instruction-execution-protection */
                        131, /* enhanced-SOP 2 and side-effect */
                        138, /* configuration z/architecture mode (czam) */
+                       139, /* multiple epoch facility */
                        146, /* msa extension 8 */
                        -1  /* END */
                }