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KVM: s390: provide only a single function for setting the tod (fix SCK)
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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: 8fa1696 ("KVM: s390: Multiple Epoch Facility support")
Cc: stable@vger.kernel.org
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
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David Hildenbrand authored and Christian Borntraeger committed Feb 20, 2018
1 parent 1575767 commit 0e7def5
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Showing 3 changed files with 22 additions and 38 deletions.
46 changes: 15 additions & 31 deletions arch/s390/kvm/kvm-s390.c
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Original file line number Diff line number Diff line change
Expand Up @@ -928,12 +928,9 @@ static int kvm_s390_set_tod_ext(struct kvm *kvm, struct kvm_device_attr *attr)
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);
Expand All @@ -958,13 +955,14 @@ static int kvm_s390_set_tod_high(struct kvm *kvm, struct kvm_device_attr *attr)

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;
}

Expand Down Expand Up @@ -3048,8 +3046,8 @@ static int kvm_s390_handle_requests(struct kvm_vcpu *vcpu)
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;
Expand All @@ -3061,10 +3059,12 @@ void kvm_s390_set_tod_clock_ext(struct kvm *kvm,
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) {
Expand All @@ -3077,22 +3077,6 @@ void kvm_s390_set_tod_clock_ext(struct kvm *kvm,
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);
}

/**
* kvm_arch_fault_in_page - fault-in guest page if necessary
* @vcpu: The corresponding virtual cpu
Expand Down
5 changes: 2 additions & 3 deletions arch/s390/kvm/kvm-s390.h
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Original file line number Diff line number Diff line change
Expand Up @@ -281,9 +281,8 @@ int kvm_s390_handle_sigp(struct kvm_vcpu *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);
Expand Down
9 changes: 5 additions & 4 deletions arch/s390/kvm/priv.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -85,9 +85,10 @@ int kvm_s390_handle_e3(struct kvm_vcpu *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;

vcpu->stat.instruction_sck++;

Expand All @@ -97,12 +98,12 @@ static int handle_set_clock(struct kvm_vcpu *vcpu)
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;
Expand Down

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