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author | Eugene (jno) Dvurechenski <jno@linux.vnet.ibm.com> | 2015-04-22 18:08:39 +0200 |
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committer | Christian Borntraeger <borntraeger@de.ibm.com> | 2015-11-30 12:47:08 +0100 |
commit | 5e0443152367ab9fef597a41a4e09a32df2bf887 (patch) | |
tree | 143843125470e817394a2854c380baf9030c56e8 /arch/s390/kvm/gaccess.c | |
parent | 7d43bafcff17c7fb07270999d3cf002f1ed6bd3f (diff) | |
download | linux-stable-5e0443152367ab9fef597a41a4e09a32df2bf887.tar.gz linux-stable-5e0443152367ab9fef597a41a4e09a32df2bf887.tar.bz2 linux-stable-5e0443152367ab9fef597a41a4e09a32df2bf887.zip |
KVM: s390: Introduce switching code
This patch adds code that performs transparent switch to Extended
SCA on addition of 65th VCPU in a VM. Disposal of ESCA is added too.
The entier ESCA functionality, however, is still not enabled.
The enablement will be provided in a separate patch.
This patch also uses read/write lock protection of SCA and its subfields for
possible disposal at the BSCA-to-ESCA transition. While only Basic SCA needs such
a protection (for the swap), any SCA access is now guarded.
Signed-off-by: Eugene (jno) Dvurechenski <jno@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Diffstat (limited to 'arch/s390/kvm/gaccess.c')
-rw-r--r-- | arch/s390/kvm/gaccess.c | 30 |
1 files changed, 23 insertions, 7 deletions
diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c index 06f7edb3770d..d30db40437dc 100644 --- a/arch/s390/kvm/gaccess.c +++ b/arch/s390/kvm/gaccess.c @@ -259,10 +259,14 @@ struct aste { int ipte_lock_held(struct kvm_vcpu *vcpu) { - union ipte_control *ic = kvm_s390_get_ipte_control(vcpu->kvm); + if (vcpu->arch.sie_block->eca & 1) { + int rc; - if (vcpu->arch.sie_block->eca & 1) - return ic->kh != 0; + read_lock(&vcpu->kvm->arch.sca_lock); + rc = kvm_s390_get_ipte_control(vcpu->kvm)->kh != 0; + read_unlock(&vcpu->kvm->arch.sca_lock); + return rc; + } return vcpu->kvm->arch.ipte_lock_count != 0; } @@ -274,16 +278,20 @@ static void ipte_lock_simple(struct kvm_vcpu *vcpu) vcpu->kvm->arch.ipte_lock_count++; if (vcpu->kvm->arch.ipte_lock_count > 1) goto out; +retry: + read_lock(&vcpu->kvm->arch.sca_lock); ic = kvm_s390_get_ipte_control(vcpu->kvm); do { old = READ_ONCE(*ic); - while (old.k) { + if (old.k) { + read_unlock(&vcpu->kvm->arch.sca_lock); cond_resched(); - old = READ_ONCE(*ic); + goto retry; } new = old; new.k = 1; } while (cmpxchg(&ic->val, old.val, new.val) != old.val); + read_unlock(&vcpu->kvm->arch.sca_lock); out: mutex_unlock(&vcpu->kvm->arch.ipte_mutex); } @@ -296,12 +304,14 @@ static void ipte_unlock_simple(struct kvm_vcpu *vcpu) vcpu->kvm->arch.ipte_lock_count--; if (vcpu->kvm->arch.ipte_lock_count) goto out; + read_lock(&vcpu->kvm->arch.sca_lock); ic = kvm_s390_get_ipte_control(vcpu->kvm); do { old = READ_ONCE(*ic); new = old; new.k = 0; } while (cmpxchg(&ic->val, old.val, new.val) != old.val); + read_unlock(&vcpu->kvm->arch.sca_lock); wake_up(&vcpu->kvm->arch.ipte_wq); out: mutex_unlock(&vcpu->kvm->arch.ipte_mutex); @@ -311,23 +321,28 @@ static void ipte_lock_siif(struct kvm_vcpu *vcpu) { union ipte_control old, new, *ic; +retry: + read_lock(&vcpu->kvm->arch.sca_lock); ic = kvm_s390_get_ipte_control(vcpu->kvm); do { old = READ_ONCE(*ic); - while (old.kg) { + if (old.kg) { + read_unlock(&vcpu->kvm->arch.sca_lock); cond_resched(); - old = READ_ONCE(*ic); + goto retry; } new = old; new.k = 1; new.kh++; } while (cmpxchg(&ic->val, old.val, new.val) != old.val); + read_unlock(&vcpu->kvm->arch.sca_lock); } static void ipte_unlock_siif(struct kvm_vcpu *vcpu) { union ipte_control old, new, *ic; + read_lock(&vcpu->kvm->arch.sca_lock); ic = kvm_s390_get_ipte_control(vcpu->kvm); do { old = READ_ONCE(*ic); @@ -336,6 +351,7 @@ static void ipte_unlock_siif(struct kvm_vcpu *vcpu) if (!new.kh) new.k = 0; } while (cmpxchg(&ic->val, old.val, new.val) != old.val); + read_unlock(&vcpu->kvm->arch.sca_lock); if (!new.kh) wake_up(&vcpu->kvm->arch.ipte_wq); } |