[Qemu-devel] [PATCH 2/7] PPC64: Implement large pages

[Alexander Graf]

The current SLB/PTE code does not support large pages, which are
required by Linux, as it boots up with the kernel regions up as large.

This patch implements large page support, so we can run Linux.

Signed-off-by: Alexander Graf <address@hidden>
---
 target-ppc/cpu.h    |    1 +
 target-ppc/helper.c |   78 +++++++++++++++++++++++++++++++-------------------
 2 files changed, 49 insertions(+), 30 deletions(-)

diff --git a/target-ppc/cpu.h b/target-ppc/cpu.h
index f53be5a..c88f81b 100644
--- a/target-ppc/cpu.h
+++ b/target-ppc/cpu.h
@@ -675,6 +675,7 @@ struct CPUPPCState {
 typedef struct mmu_ctx_t mmu_ctx_t;
 struct mmu_ctx_t {
     target_phys_addr_t raddr;      /* Real address              */
+    target_phys_addr_t eaddr;      /* Effective address         */
     int prot;                      /* Protection bits           */
     target_phys_addr_t pg_addr[2]; /* PTE tables base addresses */
     target_ulong ptem;             /* Virtual segment ID | API  */
diff --git a/target-ppc/helper.c b/target-ppc/helper.c
index 9461daf..0fa87dc 100644
--- a/target-ppc/helper.c
+++ b/target-ppc/helper.c
@@ -582,7 +582,8 @@ static always_inline int get_bat (CPUState *env, mmu_ctx_t 
*ctx,
 
 /* PTE table lookup */
 static always_inline int _find_pte (mmu_ctx_t *ctx, int is_64b, int h,
-                                    int rw, int type)
+                                    int rw, int type,
+                                    int target_page_bits)
 {
     target_ulong base, pte0, pte1;
     int i, good = -1;
@@ -594,7 +595,14 @@ static always_inline int _find_pte (mmu_ctx_t *ctx, int 
is_64b, int h,
 #if defined(TARGET_PPC64)
         if (is_64b) {
             pte0 = ldq_phys(base + (i * 16));
-            pte1 =  ldq_phys(base + (i * 16) + 8);
+            pte1 = ldq_phys(base + (i * 16) + 8);
+
+            /* We have a TLB that saves 4K pages, so let's
+             * split a huge page to 4k chunks */
+            if (target_page_bits != TARGET_PAGE_BITS)
+                pte1 |= (ctx->eaddr & (( 1 << target_page_bits ) - 1))
+                        & TARGET_PAGE_MASK;
+
             r = pte64_check(ctx, pte0, pte1, h, rw, type);
             LOG_MMU("Load pte from " ADDRX " => " ADDRX " " ADDRX
                         " %d %d %d " ADDRX "\n",
@@ -658,27 +666,30 @@ static always_inline int _find_pte (mmu_ctx_t *ctx, int 
is_64b, int h,
     return ret;
 }
 
-static always_inline int find_pte32 (mmu_ctx_t *ctx, int h, int rw, int type)
+static always_inline int find_pte32 (mmu_ctx_t *ctx, int h, int rw,
+                                     int type, int target_page_bits)
 {
-    return _find_pte(ctx, 0, h, rw, type);
+    return _find_pte(ctx, 0, h, rw, type, target_page_bits);
 }
 
 #if defined(TARGET_PPC64)
-static always_inline int find_pte64 (mmu_ctx_t *ctx, int h, int rw, int type)
+static always_inline int find_pte64 (mmu_ctx_t *ctx, int h, int rw,
+                                     int type, int target_page_bits)
 {
-    return _find_pte(ctx, 1, h, rw, type);
+    return _find_pte(ctx, 1, h, rw, type, target_page_bits);
 }
 #endif
 
 static always_inline int find_pte (CPUState *env, mmu_ctx_t *ctx,
-                                   int h, int rw, int type)
+                                   int h, int rw, int type,
+                                   int target_page_bits)
 {
 #if defined(TARGET_PPC64)
     if (env->mmu_model & POWERPC_MMU_64)
-        return find_pte64(ctx, h, rw, type);
+        return find_pte64(ctx, h, rw, type, target_page_bits);
 #endif
 
-    return find_pte32(ctx, h, rw, type);
+    return find_pte32(ctx, h, rw, type, target_page_bits);
 }
 
 #if defined(TARGET_PPC64)
@@ -694,7 +705,8 @@ static always_inline void slb_invalidate (uint64_t *slb64)
 
 static always_inline int slb_lookup (CPUPPCState *env, target_ulong eaddr,
                                      target_ulong *vsid,
-                                     target_ulong *page_mask, int *attr)
+                                     target_ulong *page_mask, int *attr,
+                                     int *target_page_bits)
 {
     target_phys_addr_t sr_base;
     target_ulong mask;
@@ -714,19 +726,16 @@ static always_inline int slb_lookup (CPUPPCState *env, 
target_ulong eaddr,
                     PRIx32 "\n", __func__, n, sr_base, tmp64, tmp);
         if (slb_is_valid(tmp64)) {
             /* SLB entry is valid */
-            switch (tmp64 & 0x0000000006000000ULL) {
-            case 0x0000000000000000ULL:
-                /* 256 MB segment */
-                mask = 0xFFFFFFFFF0000000ULL;
-                break;
-            case 0x0000000002000000ULL:
-                /* 1 TB segment */
+            if (tmp & 0x8) {
+                /* 1 TB Segment */
                 mask = 0xFFFF000000000000ULL;
-                break;
-            case 0x0000000004000000ULL:
-            case 0x0000000006000000ULL:
-                /* Reserved => segment is invalid */
-                continue;
+                if (target_page_bits)
+                    *target_page_bits = 24; // XXX 16M pages?
+            } else {
+                /* 256MB Segment */
+                mask = 0xFFFFFFFFF0000000ULL;
+                if (target_page_bits)
+                    *target_page_bits = TARGET_PAGE_BITS;
             }
             if ((eaddr & mask) == (tmp64 & mask)) {
                 /* SLB match */
@@ -777,7 +786,7 @@ void ppc_slb_invalidate_one (CPUPPCState *env, uint64_t T0)
     int attr;
     int n;
 
-    n = slb_lookup(env, T0, &vsid, &page_mask, &attr);
+    n = slb_lookup(env, T0, &vsid, &page_mask, &attr, NULL);
     if (n >= 0) {
         sr_base = env->spr[SPR_ASR];
         sr_base += 12 * n;
@@ -871,20 +880,22 @@ static always_inline int get_segment (CPUState *env, 
mmu_ctx_t *ctx,
 #if defined(TARGET_PPC64)
     int attr;
 #endif
-    int ds, vsid_sh, sdr_sh, pr;
+    int ds, vsid_sh, sdr_sh, pr, target_page_bits;
     int ret, ret2;
 
     pr = msr_pr;
 #if defined(TARGET_PPC64)
     if (env->mmu_model & POWERPC_MMU_64) {
         LOG_MMU("Check SLBs\n");
-        ret = slb_lookup(env, eaddr, &vsid, &page_mask, &attr);
+        ret = slb_lookup(env, eaddr, &vsid, &page_mask, &attr,
+                         &target_page_bits);
         if (ret < 0)
             return ret;
         ctx->key = ((attr & 0x40) && (pr != 0)) ||
             ((attr & 0x80) && (pr == 0)) ? 1 : 0;
         ds = 0;
-        ctx->nx = attr & 0x20 ? 1 : 0;
+        ctx->nx = attr & 0x10 ? 1 : 0;
+        ctx->eaddr = eaddr;
         vsid_mask = 0x00003FFFFFFFFF80ULL;
         vsid_sh = 7;
         sdr_sh = 18;
@@ -903,6 +914,7 @@ static always_inline int get_segment (CPUState *env, 
mmu_ctx_t *ctx,
         vsid_sh = 6;
         sdr_sh = 16;
         sdr_mask = 0xFFC0;
+        target_page_bits = TARGET_PAGE_BITS;
         LOG_MMU("Check segment v=" ADDRX " %d " ADDRX
                     " nip=" ADDRX " lr=" ADDRX " ir=%d dr=%d pr=%d %d t=%d\n",
                     eaddr, (int)(eaddr >> 28), sr, env->nip,
@@ -918,7 +930,7 @@ static always_inline int get_segment (CPUState *env, 
mmu_ctx_t *ctx,
             /* Page address translation */
             /* Primary table address */
             sdr = env->sdr1;
-            pgidx = (eaddr & page_mask) >> TARGET_PAGE_BITS;
+            pgidx = (eaddr & page_mask) >> target_page_bits;
 #if defined(TARGET_PPC64)
             if (env->mmu_model & POWERPC_MMU_64) {
                 htab_mask = 0x0FFFFFFF >> (28 - (sdr & 0x1F));
@@ -944,7 +956,12 @@ static always_inline int get_segment (CPUState *env, 
mmu_ctx_t *ctx,
 #if defined(TARGET_PPC64)
             if (env->mmu_model & POWERPC_MMU_64) {
                 /* Only 5 bits of the page index are used in the AVPN */
-                ctx->ptem = (vsid << 12) | ((pgidx >> 4) & 0x0F80);
+                if (target_page_bits > 23) {
+                    ctx->ptem = (vsid << 12) |
+                                ((pgidx << (target_page_bits - 16)) & 0xF80);
+                } else {
+                    ctx->ptem = (vsid << 12) | ((pgidx >> 4) & 0x0F80);
+                }
             } else
 #endif
             {
@@ -962,7 +979,7 @@ static always_inline int get_segment (CPUState *env, 
mmu_ctx_t *ctx,
                             " pg_addr=" PADDRX "\n",
                             sdr, vsid, pgidx, hash, ctx->pg_addr[0]);
                 /* Primary table lookup */
-                ret = find_pte(env, ctx, 0, rw, type);
+                ret = find_pte(env, ctx, 0, rw, type, target_page_bits);
                 if (ret < 0) {
                     /* Secondary table lookup */
                     if (eaddr != 0xEFFFFFFF)
@@ -970,7 +987,8 @@ static always_inline int get_segment (CPUState *env, 
mmu_ctx_t *ctx,
                                 "api=" ADDRX " hash=" PADDRX
                                 " pg_addr=" PADDRX "\n",
                                 sdr, vsid, pgidx, hash, ctx->pg_addr[1]);
-                    ret2 = find_pte(env, ctx, 1, rw, type);
+                    ret2 = find_pte(env, ctx, 1, rw, type,
+                                    target_page_bits);
                     if (ret2 != -1)
                         ret = ret2;
                 }
-- 
1.6.0.2