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| author | David Hildenbrand <dahi@linux.vnet.ibm.com> | 2015-09-29 16:27:24 +0200 |
|---|---|---|
| committer | Christian Borntraeger <borntraeger@de.ibm.com> | 2015-10-13 15:50:34 +0200 |
| commit | 5a3d883a59b3fe8dc8775c7a79200a5b11a6761e (patch) | |
| tree | a1b60ce1821f86e3a6fc30e32ba3228d5525f6f6 /arch/s390 | |
| parent | KVM: s390: correctly handle injection of pgm irqs and per events (diff) | |
| download | linux-5a3d883a59b3fe8dc8775c7a79200a5b11a6761e.tar.xz linux-5a3d883a59b3fe8dc8775c7a79200a5b11a6761e.zip | |
KVM: s390: switch to get_tod_clock() and fix STP sync races
Nobody except early.c makes use of store_tod_clock() to handle the
cc. So if we would get a cc != 0, we would be in more trouble.
Let's replace all users with get_tod_clock(). Returning a cc
on an ioctl sounded strange either way.
We can now also easily move the get_tod_clock() call into the
preempt_disable() section. This is in fact necessary to make the
STP sync work as expected. Otherwise the host TOD could change
and we would end up with a wrong epoch calculation.
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Diffstat (limited to 'arch/s390')
| -rw-r--r-- | arch/s390/kvm/kvm-s390.c | 18 | ||||
| -rw-r--r-- | arch/s390/kvm/priv.c | 8 |
2 files changed, 6 insertions, 20 deletions
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 0a67c40eece9..a0907795f31d 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -523,19 +523,14 @@ static int kvm_s390_set_tod_low(struct kvm *kvm, struct kvm_device_attr *attr) { struct kvm_vcpu *cur_vcpu; unsigned int vcpu_idx; - u64 host_tod, gtod; - int r; + u64 gtod; if (copy_from_user(>od, (void __user *)attr->addr, sizeof(gtod))) return -EFAULT; - r = store_tod_clock(&host_tod); - if (r) - return r; - mutex_lock(&kvm->lock); preempt_disable(); - kvm->arch.epoch = gtod - host_tod; + kvm->arch.epoch = gtod - get_tod_clock(); kvm_s390_vcpu_block_all(kvm); kvm_for_each_vcpu(vcpu_idx, cur_vcpu, kvm) cur_vcpu->arch.sie_block->epoch = kvm->arch.epoch; @@ -581,15 +576,10 @@ static int kvm_s390_get_tod_high(struct kvm *kvm, struct kvm_device_attr *attr) static int kvm_s390_get_tod_low(struct kvm *kvm, struct kvm_device_attr *attr) { - u64 host_tod, gtod; - int r; - - r = store_tod_clock(&host_tod); - if (r) - return r; + u64 gtod; preempt_disable(); - gtod = host_tod + kvm->arch.epoch; + gtod = get_tod_clock() + kvm->arch.epoch; preempt_enable(); if (copy_to_user((void __user *)attr->addr, >od, sizeof(gtod))) return -EFAULT; diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c index 4d21dc4d1a84..b253de5b8945 100644 --- a/arch/s390/kvm/priv.c +++ b/arch/s390/kvm/priv.c @@ -34,7 +34,7 @@ static int handle_set_clock(struct kvm_vcpu *vcpu) { struct kvm_vcpu *cpup; - s64 hostclk, val; + s64 val; int i, rc; ar_t ar; u64 op2; @@ -49,15 +49,11 @@ static int handle_set_clock(struct kvm_vcpu *vcpu) if (rc) return kvm_s390_inject_prog_cond(vcpu, rc); - if (store_tod_clock(&hostclk)) { - kvm_s390_set_psw_cc(vcpu, 3); - return 0; - } VCPU_EVENT(vcpu, 3, "SCK: setting guest TOD to 0x%llx", val); - val = (val - hostclk) & ~0x3fUL; mutex_lock(&vcpu->kvm->lock); preempt_disable(); + val = (val - get_tod_clock()) & ~0x3fUL; kvm_for_each_vcpu(i, cpup, vcpu->kvm) cpup->arch.sie_block->epoch = val; preempt_enable(); |