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Diffstat (limited to 'arch/powerpc/kvm/book3s_64_mmu_hv.c')
-rw-r--r--arch/powerpc/kvm/book3s_64_mmu_hv.c18
1 files changed, 18 insertions, 0 deletions
diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index bd2dcfbf00cd..be7bc070eae5 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -442,6 +442,24 @@ int kvmppc_hv_emulate_mmio(struct kvm_run *run, struct kvm_vcpu *vcpu,
u32 last_inst;
/*
+ * Fast path - check if the guest physical address corresponds to a
+ * device on the FAST_MMIO_BUS, if so we can avoid loading the
+ * instruction all together, then we can just handle it and return.
+ */
+ if (is_store) {
+ int idx, ret;
+
+ idx = srcu_read_lock(&vcpu->kvm->srcu);
+ ret = kvm_io_bus_write(vcpu, KVM_FAST_MMIO_BUS, (gpa_t) gpa, 0,
+ NULL);
+ srcu_read_unlock(&vcpu->kvm->srcu, idx);
+ if (!ret) {
+ kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
+ return RESUME_GUEST;
+ }
+ }
+
+ /*
* If we fail, we just return to the guest and try executing it again.
*/
if (kvmppc_get_last_inst(vcpu, INST_GENERIC, &last_inst) !=