[PATCH v4 11/12] target/ppc: Streamline construction of VRMA SLB entry

[David Gibson <david@gibson.dropbear.id.au>]

When in VRMA mode (i.e. a guest thinks it has the MMU off, but the
hypervisor is still applying translation) we use a special SLB entry,
rather than looking up an SLBE by address as we do when guest translation
is on.

We build that special entry in ppc_hash64_update_vrma() along with some
logic for handling some non-VRMA cases.  Split the actual build of the
VRMA SLBE into a separate helper and streamline it a bit.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 target/ppc/mmu-hash64.c | 78 ++++++++++++++++++++---------------------
 1 file changed, 38 insertions(+), 40 deletions(-)

diff --git a/target/ppc/mmu-hash64.c b/target/ppc/mmu-hash64.c
index 203a41cca1..5ce7cc8359 100644
--- a/target/ppc/mmu-hash64.c
+++ b/target/ppc/mmu-hash64.c
@@ -791,6 +791,39 @@ static target_ulong rmls_limit(PowerPCCPU *cpu)
     }
 }
 
+static int build_vrma_slbe(PowerPCCPU *cpu, ppc_slb_t *slb)
+{
+    CPUPPCState *env = &cpu->env;
+    target_ulong lpcr = env->spr[SPR_LPCR];
+    uint32_t vrmasd = (lpcr & LPCR_VRMASD) >> LPCR_VRMASD_SHIFT;
+    target_ulong vsid = SLB_VSID_VRMA | ((vrmasd << 4) & SLB_VSID_LLP_MASK);
+    int i;
+
+    /*
+     * Make one up. Mostly ignore the ESID which will not be needed
+     * for translation
+     */
+    for (i = 0; i < PPC_PAGE_SIZES_MAX_SZ; i++) {
+        const PPCHash64SegmentPageSizes *sps = &cpu->hash64_opts->sps[i];
+
+        if (!sps->page_shift) {
+            break;
+        }
+
+        if ((vsid & SLB_VSID_LLP_MASK) == sps->slb_enc) {
+            slb->esid = SLB_ESID_V;
+            slb->vsid = vsid;
+            slb->sps = sps;
+            return 0;
+        }
+    }
+
+    error_report("Bad page size encoding in LPCR[VRMASD]; LPCR=0x"
+                 TARGET_FMT_lx"\n", lpcr);
+
+    return -1;
+}
+
 int ppc_hash64_handle_mmu_fault(PowerPCCPU *cpu, vaddr eaddr,
                                 int rwx, int mmu_idx)
 {
@@ -1046,53 +1079,18 @@ void ppc_hash64_tlb_flush_hpte(PowerPCCPU *cpu, target_ulong ptex,
 static void ppc_hash64_update_vrma(PowerPCCPU *cpu)
 {
     CPUPPCState *env = &cpu->env;
-    const PPCHash64SegmentPageSizes *sps = NULL;
-    target_ulong esid, vsid, lpcr;
     ppc_slb_t *slb = &env->vrma_slb;
-    uint32_t vrmasd;
-    int i;
-
-    /* First clear it */
-    slb->esid = slb->vsid = 0;
-    slb->sps = NULL;
 
     /* Is VRMA enabled ? */
     if (ppc_hash64_use_vrma(env)) {
-        return;
-    }
-
-    /*
-     * Make one up. Mostly ignore the ESID which will not be needed
-     * for translation
-     */
-    lpcr = env->spr[SPR_LPCR];
-    vsid = SLB_VSID_VRMA;
-    vrmasd = (lpcr & LPCR_VRMASD) >> LPCR_VRMASD_SHIFT;
-    vsid |= (vrmasd << 4) & (SLB_VSID_L | SLB_VSID_LP);
-    esid = SLB_ESID_V;
-
-    for (i = 0; i < PPC_PAGE_SIZES_MAX_SZ; i++) {
-        const PPCHash64SegmentPageSizes *sps1 = &cpu->hash64_opts->sps[i];
-
-        if (!sps1->page_shift) {
-            break;
-        }
-
-        if ((vsid & SLB_VSID_LLP_MASK) == sps1->slb_enc) {
-            sps = sps1;
-            break;
+        if (build_vrma_slbe(cpu, slb) == 0) {
+            return;
         }
     }
 
-    if (!sps) {
-        error_report("Bad page size encoding esid 0x"TARGET_FMT_lx
-                     " vsid 0x"TARGET_FMT_lx, esid, vsid);
-        return;
-    }
-
-    slb->vsid = vsid;
-    slb->esid = esid;
-    slb->sps = sps;
+    /* Otherwise, clear it to indicate error */
+    slb->esid = slb->vsid = 0;
+    slb->sps = NULL;
 }
 
 void ppc_store_lpcr(PowerPCCPU *cpu, target_ulong val)
-- 
2.24.1