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Subject[PATCH 4.15 102/122] KVM: s390: provide only a single function for setting the tod (fix SCK)
Date
4.15-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Hildenbrand <david@redhat.com>

commit 0e7def5fb0dc53ddbb9f62a497d15f1e11ccdc36 upstream.

Right now, SET CLOCK called in the guest does not properly take care of
the epoch index, as the call goes via the old kvm_s390_set_tod_clock()
interface. So the epoch index is neither reset to 0, if required, nor
properly set to e.g. 0xff on negative values.

Fix this by providing a single kvm_s390_set_tod_clock() function. Move
Multiple-epoch facility handling into it.

Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20180207114647.6220-3-david@redhat.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Fixes: 8fa1696ea781 ("KVM: s390: Multiple Epoch Facility support")
Cc: stable@vger.kernel.org
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/s390/kvm/kvm-s390.c | 46 +++++++++++++++-------------------------------
arch/s390/kvm/kvm-s390.h | 5 ++---
arch/s390/kvm/priv.c | 9 +++++----
3 files changed, 22 insertions(+), 38 deletions(-)

--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -889,12 +889,9 @@ static int kvm_s390_set_tod_ext(struct k
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
+ if (!test_kvm_facility(kvm, 139) && gtod.epoch_idx)
return -EINVAL;
+ kvm_s390_set_tod_clock(kvm, &gtod);

VM_EVENT(kvm, 3, "SET: TOD extension: 0x%x, TOD base: 0x%llx",
gtod.epoch_idx, gtod.tod);
@@ -919,13 +916,14 @@ static int kvm_s390_set_tod_high(struct

static int kvm_s390_set_tod_low(struct kvm *kvm, struct kvm_device_attr *attr)
{
- u64 gtod;
+ struct kvm_s390_vm_tod_clock gtod = { 0 };

- if (copy_from_user(&gtod, (void __user *)attr->addr, sizeof(gtod)))
+ if (copy_from_user(&gtod.tod, (void __user *)attr->addr,
+ sizeof(gtod.tod)))
return -EFAULT;

- kvm_s390_set_tod_clock(kvm, gtod);
- VM_EVENT(kvm, 3, "SET: TOD base: 0x%llx", gtod);
+ kvm_s390_set_tod_clock(kvm, &gtod);
+ VM_EVENT(kvm, 3, "SET: TOD base: 0x%llx", gtod.tod);
return 0;
}

@@ -2947,8 +2945,8 @@ retry:
return 0;
}

-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,
+ const struct kvm_s390_vm_tod_clock *gtod)
{
struct kvm_vcpu *vcpu;
struct kvm_s390_tod_clock_ext htod;
@@ -2960,10 +2958,12 @@ void kvm_s390_set_tod_clock_ext(struct k
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->arch.epdx = 0;
+ if (test_kvm_facility(kvm, 139)) {
+ 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) {
@@ -2974,22 +2974,6 @@ void kvm_s390_set_tod_clock_ext(struct k
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;
- int i;
-
- mutex_lock(&kvm->lock);
- preempt_disable();
- kvm->arch.epoch = tod - get_tod_clock();
- kvm_s390_vcpu_block_all(kvm);
- kvm_for_each_vcpu(i, vcpu, kvm)
- vcpu->arch.sie_block->epoch = kvm->arch.epoch;
- kvm_s390_vcpu_unblock_all(kvm);
- preempt_enable();
- mutex_unlock(&kvm->lock);
}

/**
--- a/arch/s390/kvm/kvm-s390.h
+++ b/arch/s390/kvm/kvm-s390.h
@@ -268,9 +268,8 @@ int kvm_s390_handle_sigp(struct kvm_vcpu
int kvm_s390_handle_sigp_pei(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);
+void kvm_s390_set_tod_clock(struct kvm *kvm,
+ const struct kvm_s390_vm_tod_clock *gtod);
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);
int kvm_s390_vcpu_store_status(struct kvm_vcpu *vcpu, unsigned long addr);
--- a/arch/s390/kvm/priv.c
+++ b/arch/s390/kvm/priv.c
@@ -81,9 +81,10 @@ int kvm_s390_handle_e3(struct kvm_vcpu *
/* Handle SCK (SET CLOCK) interception */
static int handle_set_clock(struct kvm_vcpu *vcpu)
{
+ struct kvm_s390_vm_tod_clock gtod = { 0 };
int rc;
u8 ar;
- u64 op2, val;
+ u64 op2;

if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);
@@ -91,12 +92,12 @@ static int handle_set_clock(struct kvm_v
op2 = kvm_s390_get_base_disp_s(vcpu, &ar);
if (op2 & 7) /* Operand must be on a doubleword boundary */
return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
- rc = read_guest(vcpu, op2, ar, &val, sizeof(val));
+ rc = read_guest(vcpu, op2, ar, &gtod.tod, sizeof(gtod.tod));
if (rc)
return kvm_s390_inject_prog_cond(vcpu, rc);

- VCPU_EVENT(vcpu, 3, "SCK: setting guest TOD to 0x%llx", val);
- kvm_s390_set_tod_clock(vcpu->kvm, val);
+ VCPU_EVENT(vcpu, 3, "SCK: setting guest TOD to 0x%llx", gtod.tod);
+ kvm_s390_set_tod_clock(vcpu->kvm, &gtod);

kvm_s390_set_psw_cc(vcpu, 0);
return 0;

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