KVM: PPC: Book3S PR: Fix proto-VSID calculations

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>
Signed-off-by: Alexander Graf <agraf@suse.de>

1 files changed, 2 insertions, 2 deletions

diff --git a/arch/powerpc/kvm/book3s_64_mmu_host.c b/arch/powerpc/kvm/book3s_64_mmu_host.c
index 3a9a1aceb14f..2c6e7ee8be34 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);