korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-12-16 23:45:31 +08:00
Code Issues Packages Projects Releases Wiki Activity

KVM: s390: fix SCA related races and double use

Browse Source 
If something goes wrong in kvm_arch_vcpu_create, the VCPU has already
been added to the sca but will never be removed. Trying to create VCPUs
with duplicate ids (e.g. after a failed attempt) is problematic.

Also, when creating multiple VCPUs in parallel, we could theoretically
forget to set the correct SCA when the switch to ESCA happens just
before the VCPU is registered.

Let's add the VCPU to the SCA in kvm_arch_vcpu_postcreate, where we can
be sure that no duplicate VCPU with the same id is around and the VCPU
has already been registered at the VM. We also have to make sure to update
ECB at that point.

Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
This commit is contained in:
David Hildenbrand 2015-10-12 16:27:23 +02:00 committed by Christian Borntraeger
parent 5f3fe620a5
commit 2550882449
1 changed files with 5 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
arch/s390/kvm/kvm-s390.c
View File

@ -1289,6 +1289,7 @@ static void sca_add_vcpu(struct kvm_vcpu *vcpu, struct kvm *kvm,
sca->cpu[id].sda = (__u64) vcpu->arch.sie_block;
vcpu->arch.sie_block->scaoh = (__u32)(((__u64)sca) >> 32);
vcpu->arch.sie_block->scaol = (__u32)(__u64)sca & ~0x3fU;
vcpu->arch.sie_block->ecb2 |= 0x04U;
set_bit_inv(id, (unsigned long *) sca->mcn);
} else {
struct bsca_block *sca = kvm->arch.sca;
@ -1493,8 +1494,11 @@ void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)
vcpu->arch.sie_block->epoch = vcpu->kvm->arch.epoch;
preempt_enable();
mutex_unlock(&vcpu->kvm->lock);
if (!kvm_is_ucontrol(vcpu->kvm))
if (!kvm_is_ucontrol(vcpu->kvm)) {
vcpu->arch.gmap = vcpu->kvm->arch.gmap;
sca_add_vcpu(vcpu, vcpu->kvm, vcpu->vcpu_id);
}
}
static void kvm_s390_vcpu_crypto_setup(struct kvm_vcpu *vcpu)
@ -1558,8 +1562,6 @@ int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
vcpu->arch.sie_block->ecb |= 0x10;
vcpu->arch.sie_block->ecb2 = 8;
if (vcpu->kvm->arch.use_esca)
vcpu->arch.sie_block->ecb2 |= 4;
vcpu->arch.sie_block->eca = 0xC1002000U;
if (sclp.has_siif)
vcpu->arch.sie_block->eca |= 1;
@ -1608,9 +1610,6 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm,
vcpu->arch.sie_block->itdba = (unsigned long) &sie_page->itdb;
vcpu->arch.sie_block->icpua = id;
if (!kvm_is_ucontrol(kvm))
sca_add_vcpu(vcpu, kvm, id);
spin_lock_init(&vcpu->arch.local_int.lock);
vcpu->arch.local_int.float_int = &kvm->arch.float_int;
vcpu->arch.local_int.wq = &vcpu->wq;