| Message ID | 20130622071332.GB2791@iris.ozlabs.ibm.com |
|---|---|
| State | New, archived |
| Headers | show |
diff --git a/arch/powerpc/kvm/book3s_64_mmu_host.c b/arch/powerpc/kvm/book3s_64_mmu_host.c index 3a9a1ac..2c6e7ee 100644 --- a/arch/powerpc/kvm/book3s_64_mmu_host.c +++ b/arch/powerpc/kvm/book3s_64_mmu_host.c @@ -325,9 +325,9 @@ int kvmppc_mmu_init(struct kvm_vcpu *vcpu) return -1; vcpu3s->context_id[0] = err; - vcpu3s->proto_vsid_max = ((vcpu3s->context_id[0] + 1) + vcpu3s->proto_vsid_max = ((u64)(vcpu3s->context_id[0] + 1) << ESID_BITS) - 1; - vcpu3s->proto_vsid_first = vcpu3s->context_id[0] << ESID_BITS; + vcpu3s->proto_vsid_first = (u64)vcpu3s->context_id[0] << ESID_BITS; vcpu3s->proto_vsid_next = vcpu3s->proto_vsid_first; kvmppc_mmu_hpte_init(vcpu);
This makes sure the calculation of the proto-VSIDs used by PR KVM is done with 64-bit arithmetic. Since vcpu3s->context_id[] is int, when we do vcpu3s->context_id[0] << ESID_BITS the shift will be done with 32-bit instructions, possibly leading to significant bits getting lost, as the context id can be up to 524283 and ESID_BITS is 18. To fix this we cast the context id to u64 before shifting. Signed-off-by: Paul Mackerras <paulus@samba.org> --- arch/powerpc/kvm/book3s_64_mmu_host.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)