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author | Halil Pasic <pasic@linux.ibm.com> | 2021-08-27 15:54:29 +0300 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-09-15 11:02:34 +0300 |
commit | f8c655627a1d79c00ee33866bed46de60f1d2bcf (patch) | |
tree | 2bb58818b3fd63c4e888439f2b52c1feb6f0b26b /arch/s390/include/asm | |
parent | 9d52658ef6ebd387ad0c32f09061dee32a7cc92b (diff) | |
download | linux-f8c655627a1d79c00ee33866bed46de60f1d2bcf.tar.xz |
KVM: s390: index kvm->arch.idle_mask by vcpu_idx
commit a3e03bc1368c1bc16e19b001fc96dc7430573cc8 upstream.
While in practice vcpu->vcpu_idx == vcpu->vcp_id is often true, it may
not always be, and we must not rely on this. Reason is that KVM decides
the vcpu_idx, userspace decides the vcpu_id, thus the two might not
match.
Currently kvm->arch.idle_mask is indexed by vcpu_id, which implies
that code like
for_each_set_bit(vcpu_id, kvm->arch.idle_mask, online_vcpus) {
vcpu = kvm_get_vcpu(kvm, vcpu_id);
do_stuff(vcpu);
}
is not legit. Reason is that kvm_get_vcpu expects an vcpu_idx, not an
vcpu_id. The trouble is, we do actually use kvm->arch.idle_mask like
this. To fix this problem we have two options. Either use
kvm_get_vcpu_by_id(vcpu_id), which would loop to find the right vcpu_id,
or switch to indexing via vcpu_idx. The latter is preferable for obvious
reasons.
Let us make switch from indexing kvm->arch.idle_mask by vcpu_id to
indexing it by vcpu_idx. To keep gisa_int.kicked_mask indexed by the
same index as idle_mask lets make the same change for it as well.
Fixes: 1ee0bc559dc3 ("KVM: s390: get rid of local_int array")
Signed-off-by: Halil Pasic <pasic@linux.ibm.com>
Reviewed-by: Christian Bornträger <borntraeger@de.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: <stable@vger.kernel.org> # 3.15+
Link: https://lore.kernel.org/r/20210827125429.1912577-1-pasic@linux.ibm.com
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/s390/include/asm')
-rw-r--r-- | arch/s390/include/asm/kvm_host.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h index 161a9e12bfb8..630eab0fa176 100644 --- a/arch/s390/include/asm/kvm_host.h +++ b/arch/s390/include/asm/kvm_host.h @@ -957,6 +957,7 @@ struct kvm_arch{ atomic64_t cmma_dirty_pages; /* subset of available cpu features enabled by user space */ DECLARE_BITMAP(cpu_feat, KVM_S390_VM_CPU_FEAT_NR_BITS); + /* indexed by vcpu_idx */ DECLARE_BITMAP(idle_mask, KVM_MAX_VCPUS); struct kvm_s390_gisa_interrupt gisa_int; struct kvm_s390_pv pv; |