ppc/hash64: Add proper real mode translation support

This adds proper support for translating real mode addresses based
on the combination of HV and LPCR bits. This handles HRMOR offset
for hypervisor real mode, and both RMA and VRMA modes for guest
real mode. PAPR mode adjusts the offsets appropriately to match the
RMA used in TCG, but we need to limit to the max supported by the
implementation (16G).

This includes some fixes by Cédric Le Goater <clg@kaod.org>

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[dwg: Adjusted for differences in my version of the prereq patches]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

4 files changed, 174 insertions, 10 deletions

diff --git a/target-ppc/cpu.h b/target-ppc/cpu.h
index af73bced9f..2666a3f80d 100644
--- a/target-ppc/cpu.h
+++ b/target-ppc/cpu.h
@@ -1047,6 +1047,8 @@ struct CPUPPCState {
     uint64_t insns_flags2;
 #if defined(TARGET_PPC64)
     struct ppc_segment_page_sizes sps;
+    ppc_slb_t vrma_slb;
+    target_ulong rmls;
     bool ci_large_pages;
 #endif
 
diff --git a/target-ppc/mmu-hash64.c b/target-ppc/mmu-hash64.c
index 7c1b169676..7f314442ca 100644
--- a/target-ppc/mmu-hash64.c
+++ b/target-ppc/mmu-hash64.c
@@ -681,11 +681,52 @@ int ppc_hash64_handle_mmu_fault(PowerPCCPU *cpu, vaddr eaddr,
 
     assert((rwx == 0) || (rwx == 1) || (rwx == 2));
 
+    /* Note on LPCR usage: 970 uses HID4, but our special variant
+     * of store_spr copies relevant fields into env->spr[SPR_LPCR].
+     * Similarily we filter unimplemented bits when storing into
+     * LPCR depending on the MMU version. This code can thus just
+     * use the LPCR "as-is".
+     */
+
     /* 1. Handle real mode accesses */
     if (((rwx == 2) && (msr_ir == 0)) || ((rwx != 2) && (msr_dr == 0))) {
-        /* Translation is off */
-        /* In real mode the top 4 effective address bits are ignored */
+        /* Translation is supposedly "off"  */
+        /* In real mode the top 4 effective address bits are (mostly) ignored */
         raddr = eaddr & 0x0FFFFFFFFFFFFFFFULL;
+
+        /* In HV mode, add HRMOR if top EA bit is clear */
+        if (msr_hv || !env->has_hv_mode) {
+            if (!(eaddr >> 63)) {
+                raddr |= env->spr[SPR_HRMOR];
+            }
+        } else {
+            /* Otherwise, check VPM for RMA vs VRMA */
+            if (env->spr[SPR_LPCR] & LPCR_VPM0) {
+                slb = &env->vrma_slb;
+                if (slb->sps) {
+                    goto skip_slb_search;
+                }
+                /* Not much else to do here */
+                cs->exception_index = POWERPC_EXCP_MCHECK;
+                env->error_code = 0;
+                return 1;
+            } else if (raddr < env->rmls) {
+                /* RMA. Check bounds in RMLS */
+                raddr |= env->spr[SPR_RMOR];
+            } else {
+                /* The access failed, generate the approriate interrupt */
+                if (rwx == 2) {
+                    ppc_hash64_set_isi(cs, env, 0x08000000);
+                } else {
+                    dsisr = 0x08000000;
+                    if (rwx == 1) {
+                        dsisr |= 0x02000000;
+                    }
+                    ppc_hash64_set_dsi(cs, env, eaddr, dsisr);
+                }
+                return 1;
+            }
+        }
         tlb_set_page(cs, eaddr & TARGET_PAGE_MASK, raddr & TARGET_PAGE_MASK,
                      PAGE_READ | PAGE_WRITE | PAGE_EXEC, mmu_idx,
                      TARGET_PAGE_SIZE);
@@ -694,7 +735,6 @@ int ppc_hash64_handle_mmu_fault(PowerPCCPU *cpu, vaddr eaddr,
 
     /* 2. Translation is on, so look up the SLB */
     slb = slb_lookup(cpu, eaddr);
-
     if (!slb) {
         if (rwx == 2) {
             cs->exception_index = POWERPC_EXCP_ISEG;
@@ -707,6 +747,8 @@ int ppc_hash64_handle_mmu_fault(PowerPCCPU *cpu, vaddr eaddr,
         return 1;
     }
 
+skip_slb_search:
+
     /* 3. Check for segment level no-execute violation */
     if ((rwx == 2) && (slb->vsid & SLB_VSID_N)) {
         ppc_hash64_set_isi(cs, env, 0x10000000);
@@ -789,18 +831,37 @@ hwaddr ppc_hash64_get_phys_page_debug(PowerPCCPU *cpu, target_ulong addr)
 {
     CPUPPCState *env = &cpu->env;
     ppc_slb_t *slb;
-    hwaddr pte_offset;
+    hwaddr pte_offset, raddr;
     ppc_hash_pte64_t pte;
     unsigned apshift;
 
+    /* Handle real mode */
     if (msr_dr == 0) {
         /* In real mode the top 4 effective address bits are ignored */
-        return addr & 0x0FFFFFFFFFFFFFFFULL;
-    }
+        raddr = addr & 0x0FFFFFFFFFFFFFFFULL;
 
-    slb = slb_lookup(cpu, addr);
-    if (!slb) {
-        return -1;
+        /* In HV mode, add HRMOR if top EA bit is clear */
+        if ((msr_hv || !env->has_hv_mode) && !(addr >> 63)) {
+            return raddr | env->spr[SPR_HRMOR];
+        }
+
+        /* Otherwise, check VPM for RMA vs VRMA */
+        if (env->spr[SPR_LPCR] & LPCR_VPM0) {
+            slb = &env->vrma_slb;
+            if (!slb->sps) {
+                return -1;
+            }
+        } else if (raddr < env->rmls) {
+            /* RMA. Check bounds in RMLS */
+            return raddr | env->spr[SPR_RMOR];
+        } else {
+            return -1;
+        }
+    } else {
+        slb = slb_lookup(cpu, addr);
+        if (!slb) {
+            return -1;
+        }
     }
 
     pte_offset = ppc_hash64_htab_lookup(cpu, slb, addr, &pte, &apshift);
@@ -846,6 +907,90 @@ void ppc_hash64_tlb_flush_hpte(PowerPCCPU *cpu,
     tlb_flush(CPU(cpu), 1);
 }
 
+void ppc_hash64_update_rmls(CPUPPCState *env)
+{
+    uint64_t lpcr = env->spr[SPR_LPCR];
+
+    /*
+     * This is the full 4 bits encoding of POWER8. Previous
+     * CPUs only support a subset of these but the filtering
+     * is done when writing LPCR
+     */
+    switch ((lpcr & LPCR_RMLS) >> LPCR_RMLS_SHIFT) {
+    case 0x8: /* 32MB */
+        env->rmls = 0x2000000ull;
+        break;
+    case 0x3: /* 64MB */
+        env->rmls = 0x4000000ull;
+        break;
+    case 0x7: /* 128MB */
+        env->rmls = 0x8000000ull;
+        break;
+    case 0x4: /* 256MB */
+        env->rmls = 0x10000000ull;
+        break;
+    case 0x2: /* 1GB */
+        env->rmls = 0x40000000ull;
+        break;
+    case 0x1: /* 16GB */
+        env->rmls = 0x400000000ull;
+        break;
+    default:
+        /* What to do here ??? */
+        env->rmls = 0;
+    }
+}
+
+void ppc_hash64_update_vrma(CPUPPCState *env)
+{
+    const struct ppc_one_seg_page_size *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 ? */
+    lpcr = env->spr[SPR_LPCR];
+    if (!(lpcr & LPCR_VPM0)) {
+        return;
+    }
+
+    /* Make one up. Mostly ignore the ESID which will not be
+     * needed for translation
+     */
+    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 struct ppc_one_seg_page_size *sps1 = &env->sps.sps[i];
+
+        if (!sps1->page_shift) {
+            break;
+        }
+
+        if ((vsid & SLB_VSID_LLP_MASK) == sps1->slb_enc) {
+            sps = sps1;
+            break;
+        }
+    }
+
+    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;
+}
+
 void helper_store_lpcr(CPUPPCState *env, target_ulong val)
 {
     uint64_t lpcr = 0;
@@ -901,4 +1046,6 @@ void helper_store_lpcr(CPUPPCState *env, target_ulong val)
         ;
     }
     env->spr[SPR_LPCR] = lpcr;
+    ppc_hash64_update_rmls(env);
+    ppc_hash64_update_vrma(env);
 }
diff --git a/target-ppc/mmu-hash64.h b/target-ppc/mmu-hash64.h
index 154a306997..3a7476b30a 100644
--- a/target-ppc/mmu-hash64.h
+++ b/target-ppc/mmu-hash64.h
@@ -18,6 +18,8 @@ void ppc_hash64_tlb_flush_hpte(PowerPCCPU *cpu,
                                target_ulong pte0, target_ulong pte1);
 unsigned ppc_hash64_hpte_page_shift_noslb(PowerPCCPU *cpu,
                                           uint64_t pte0, uint64_t pte1);
+void ppc_hash64_update_vrma(CPUPPCState *env);
+void ppc_hash64_update_rmls(CPUPPCState *env);
 #endif
 
 /*
@@ -36,6 +38,7 @@ unsigned ppc_hash64_hpte_page_shift_noslb(PowerPCCPU *cpu,
 #define SLB_VSID_B_256M         0x0000000000000000ULL
 #define SLB_VSID_B_1T           0x4000000000000000ULL
 #define SLB_VSID_VSID           0x3FFFFFFFFFFFF000ULL
+#define SLB_VSID_VRMA           (0x0001FFFFFF000000ULL | SLB_VSID_B_1T)
 #define SLB_VSID_PTEM           (SLB_VSID_B | SLB_VSID_VSID)
 #define SLB_VSID_KS             0x0000000000000800ULL
 #define SLB_VSID_KP             0x0000000000000400ULL
diff --git a/target-ppc/translate_init.c b/target-ppc/translate_init.c
index a06bf50b65..8f257fb74a 100644
--- a/target-ppc/translate_init.c
+++ b/target-ppc/translate_init.c
@@ -8791,11 +8791,19 @@ void cpu_ppc_set_papr(PowerPCCPU *cpu)
     /* Set emulated LPCR to not send interrupts to hypervisor. Note that
      * under KVM, the actual HW LPCR will be set differently by KVM itself,
      * the settings below ensure proper operations with TCG in absence of
-     * a real hypervisor
+     * a real hypervisor.
+     *
+     * Clearing VPM0 will also cause us to use RMOR in mmu-hash64.c for
+     * real mode accesses, which thankfully defaults to 0 and isn't
+     * accessible in guest mode.
      */
     lpcr->default_value &= ~(LPCR_VPM0 | LPCR_VPM1 | LPCR_ISL | LPCR_KBV);
     lpcr->default_value |= LPCR_LPES0 | LPCR_LPES1;
 
+    /* Set RMLS to the max (ie, 16G) */
+    lpcr->default_value &= ~LPCR_RMLS;
+    lpcr->default_value |= 1ull << LPCR_RMLS_SHIFT;
+
     /* P7 and P8 has slightly different PECE bits, mostly because P8 adds
      * bit 47 and 48 which are reserved on P7. Here we set them all, which
      * will work as expected for both implementations
@@ -8811,6 +8819,10 @@ void cpu_ppc_set_papr(PowerPCCPU *cpu)
     /* Set a full AMOR so guest can use the AMR as it sees fit */
     env->spr[SPR_AMOR] = amor->default_value = 0xffffffffffffffffull;
 
+    /* Update some env bits based on new LPCR value */
+    ppc_hash64_update_rmls(env);
+    ppc_hash64_update_vrma(env);
+
     /* Tell KVM that we're in PAPR mode */
     if (kvm_enabled()) {
         kvmppc_set_papr(cpu);