target/i386: only include bits in pg_mode if they are not ignored

LA57/PKE/PKS is only relevant in 64-bit mode, and NXE is only relevant if
PAE is in use.  Since there is code that checks PG_MODE_LA57 to determine
the canonicality of addresses, make sure that the bit is not set by
mistake in 32-bit mode.  While it would not be a problem because 32-bit
addresses by definition fit in both 48-bit and 57-bit address spaces,
it is nicer if get_pg_mode() actually returns whether a feature is enabled,
and it allows a few simplifications in the page table walker.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/target/i386/tcg/sysemu/excp_helper.c b/target/i386/tcg/sysemu/excp_helper.c
index 5627772e7c32edfa2512e1b0e537c8b6c612838d..6f1fbe667b7fcfb838d051f8f81ce343ab2884f0 100644 (file)
--- a/target/i386/tcg/sysemu/excp_helper.c
+++ b/target/i386/tcg/sysemu/excp_helper.c
@@ -25,32 +25,35 @@
 int get_pg_mode(CPUX86State *env)
 {
     int pg_mode = 0;
+    if (!(env->cr[0] & CR0_PG_MASK)) {
+        return 0;
+    }
     if (env->cr[0] & CR0_WP_MASK) {
         pg_mode |= PG_MODE_WP;
     }
     if (env->cr[4] & CR4_PAE_MASK) {
         pg_mode |= PG_MODE_PAE;
+        if (env->efer & MSR_EFER_NXE) {
+            pg_mode |= PG_MODE_NXE;
+        }
     }
     if (env->cr[4] & CR4_PSE_MASK) {
         pg_mode |= PG_MODE_PSE;
     }
-    if (env->cr[4] & CR4_PKE_MASK) {
-        pg_mode |= PG_MODE_PKE;
-    }
-    if (env->cr[4] & CR4_PKS_MASK) {
-        pg_mode |= PG_MODE_PKS;
-    }
     if (env->cr[4] & CR4_SMEP_MASK) {
         pg_mode |= PG_MODE_SMEP;
     }
-    if (env->cr[4] & CR4_LA57_MASK) {
-        pg_mode |= PG_MODE_LA57;
-    }
     if (env->hflags & HF_LMA_MASK) {
         pg_mode |= PG_MODE_LMA;
-    }
-    if (env->efer & MSR_EFER_NXE) {
-        pg_mode |= PG_MODE_NXE;
+        if (env->cr[4] & CR4_PKE_MASK) {
+            pg_mode |= PG_MODE_PKE;
+        }
+        if (env->cr[4] & CR4_PKS_MASK) {
+            pg_mode |= PG_MODE_PKS;
+        }
+        if (env->cr[4] & CR4_LA57_MASK) {
+            pg_mode |= PG_MODE_LA57;
+        }
     }
     return pg_mode;
 }
@@ -279,9 +282,7 @@ do_check_protect_pse36:
         *prot |= PAGE_EXEC;
     }
 
-    if (!(pg_mode & PG_MODE_LMA)) {
-        pkr = 0;
-    } else if (ptep & PG_USER_MASK) {
+    if (ptep & PG_USER_MASK) {
         pkr = pg_mode & PG_MODE_PKE ? env->pkru : 0;
     } else {
         pkr = pg_mode & PG_MODE_PKS ? env->pkrs : 0;
@@ -344,8 +345,7 @@ do_check_protect_pse36:
     if (is_user)
         error_code |= PG_ERROR_U_MASK;
     if (is_write1 == 2 &&
-        (((pg_mode & PG_MODE_NXE) && (pg_mode & PG_MODE_PAE)) ||
-         (pg_mode & PG_MODE_SMEP)))
+        ((pg_mode & PG_MODE_NXE) || (pg_mode & PG_MODE_SMEP)))
         error_code |= PG_ERROR_I_D_MASK;
     return error_code;
 }