target-ppc: Update ppc_hash64_store_hpte to support updating in-kernel htab

This support updating htab managed by the hypervisor. Currently we don't have
any user for this feature. This actually bring the store_hpte interface
in-line with the load_hpte one. We may want to use this when we want to
emulate henter hcall in qemu for HV kvm.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
[ folded fix for the "warn_unused_result" build break in
  kvmppc_hash64_write_pte(), Greg Kurz <gkurz@linux.vnet.ibm.com> ]
Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>

1 files changed, 36 insertions, 0 deletions

diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
index e00991920a..b5fff70f09 100644
--- a/target-ppc/kvm.c
+++ b/target-ppc/kvm.c
@@ -1992,3 +1992,39 @@ void kvmppc_hash64_free_pteg(uint64_t token)
     g_free(htab_buf);
     return;
 }
+
+void kvmppc_hash64_write_pte(CPUPPCState *env, target_ulong pte_index,
+                             target_ulong pte0, target_ulong pte1)
+{
+    int htab_fd;
+    struct kvm_get_htab_fd ghf;
+    struct kvm_get_htab_buf hpte_buf;
+
+    ghf.flags = 0;
+    ghf.start_index = 0;     /* Ignored */
+    htab_fd = kvm_vm_ioctl(kvm_state, KVM_PPC_GET_HTAB_FD, &ghf);
+    if (htab_fd < 0) {
+        goto error_out;
+    }
+
+    hpte_buf.header.n_valid = 1;
+    hpte_buf.header.n_invalid = 0;
+    hpte_buf.header.index = pte_index;
+    hpte_buf.hpte[0] = pte0;
+    hpte_buf.hpte[1] = pte1;
+    /*
+     * Write the hpte entry.
+     * CAUTION: write() has the warn_unused_result attribute. Hence we
+     * need to check the return value, even though we do nothing.
+     */
+    if (write(htab_fd, &hpte_buf, sizeof(hpte_buf)) < 0) {
+        goto out_close;
+    }
+
+out_close:
+    close(htab_fd);
+    return;
+
+error_out:
+    return;
+}