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-rw-r--r--target/i386/tcg/sysemu/excp_helper.c17
1 files changed, 14 insertions, 3 deletions
diff --git a/target/i386/tcg/sysemu/excp_helper.c b/target/i386/tcg/sysemu/excp_helper.c
index 8fb05b1f53..8cb0d80177 100644
--- a/target/i386/tcg/sysemu/excp_helper.c
+++ b/target/i386/tcg/sysemu/excp_helper.c
@@ -150,6 +150,7 @@ static bool mmu_translate(CPUX86State *env, const TranslateParams *in,
     uint32_t pkr;
     int page_size;
     int error_code;
+    int prot;
 
  restart_all:
     rsvd_mask = ~MAKE_64BIT_MASK(0, env_archcpu(env)->phys_bits);
@@ -298,7 +299,7 @@ static bool mmu_translate(CPUX86State *env, const TranslateParams *in,
         /* combine pde and pte nx, user and rw protections */
         ptep &= pte ^ PG_NX_MASK;
         page_size = 4096;
-    } else {
+    } else if (pg_mode) {
         /*
          * Page table level 2
          */
@@ -343,6 +344,15 @@ static bool mmu_translate(CPUX86State *env, const TranslateParams *in,
         ptep &= pte | PG_NX_MASK;
         page_size = 4096;
         rsvd_mask = 0;
+    } else {
+        /*
+         * No paging (real mode), let's tentatively resolve the address as 1:1
+         * here, but conditionally still perform an NPT walk on it later.
+         */
+        page_size = 0x40000000;
+        paddr = in->addr;
+        prot = PAGE_READ | PAGE_WRITE | PAGE_EXEC;
+        goto stage2;
     }
 
 do_check_protect:
@@ -358,7 +368,7 @@ do_check_protect_pse36:
         goto do_fault_protect;
     }
 
-    int prot = 0;
+    prot = 0;
     if (!is_mmu_index_smap(in->mmu_idx) || !(ptep & PG_USER_MASK)) {
         prot |= PAGE_READ;
         if ((ptep & PG_RW_MASK) || !(is_user || (pg_mode & PG_MODE_WP))) {
@@ -420,6 +430,7 @@ do_check_protect_pse36:
 
     /* merge offset within page */
     paddr = (pte & PG_ADDRESS_MASK & ~(page_size - 1)) | (addr & (page_size - 1));
+ stage2:
 
     /*
      * Note that NPT is walked (for both paging structures and final guest
@@ -562,7 +573,7 @@ static bool get_physical_address(CPUX86State *env, vaddr addr,
             addr = (uint32_t)addr;
         }
 
-        if (likely(env->cr[0] & CR0_PG_MASK)) {
+        if (likely(env->cr[0] & CR0_PG_MASK || use_stage2)) {
             in.cr3 = env->cr[3];
             in.mmu_idx = mmu_idx;
             in.ptw_idx = use_stage2 ? MMU_NESTED_IDX : MMU_PHYS_IDX;