[Qemu-devel] [PATCHv3 2/4] Set eflags and cr0 prior to calling cpu_x86_load_seg_cache() in smm_helper.c.

[Kevin O'Connor]

On Wed, Apr 30, 2014 at 09:54:10AM -0700, Richard Henderson wrote:
> On 04/29/2014 01:38 PM, Kevin O'Connor wrote:
> >      cpu_load_eflags(env, 0, ~(CC_O | CC_S | CC_Z | CC_A | CC_P | CC_C |
> >                                DF_MASK));
> >      env->eip = 0x00008000;
> > +    cpu_x86_update_cr0(env,
> > +                       env->cr[0] & ~(CR0_PE_MASK | CR0_EM_MASK | 
> > CR0_TS_MASK |
> > +                                      CR0_PG_MASK));
> > +    cpu_x86_update_cr4(env, 0);
> > +    env->dr[7] = 0x00000400;
> > +    CC_OP = CC_OP_EFLAGS;
> 
> Please place the CC_OP update immediately after cpu_load_eflags.

Sure - see below.  Paolo, if this conflicts with your work, you can
use the previous version of this patch.

-Kevin


>From 12abb36264ac441444d21efa382bacc9f8b657ca Mon Sep 17 00:00:00 2001
Message-Id: <address@hidden>
In-Reply-To: <address@hidden>
References: <address@hidden>
From: Kevin O'Connor <address@hidden>
Date: Tue, 29 Apr 2014 11:19:06 -0400
Subject: [PATCH 2/4] Set eflags and cr0 prior to calling
 cpu_x86_load_seg_cache() in smm_helper.c.
To: address@hidden

The cpu_x86_load_seg_cache() function inspects cr0 and eflags, so make
sure all changes to eflags and cr0 are done prior to loading the
segment caches.

Signed-off-by: Kevin O'Connor <address@hidden>
---
 target-i386/smm_helper.c | 34 +++++++++++++++++-----------------
 1 file changed, 17 insertions(+), 17 deletions(-)

diff --git a/target-i386/smm_helper.c b/target-i386/smm_helper.c
index 35901c9..5b36f3f 100644
--- a/target-i386/smm_helper.c
+++ b/target-i386/smm_helper.c
@@ -162,7 +162,14 @@ void do_smm_enter(X86CPU *cpu)
 #endif
     cpu_load_eflags(env, 0, ~(CC_O | CC_S | CC_Z | CC_A | CC_P | CC_C |
                               DF_MASK));
+    CC_OP = CC_OP_EFLAGS;
     env->eip = 0x00008000;
+    cpu_x86_update_cr0(env,
+                       env->cr[0] & ~(CR0_PE_MASK | CR0_EM_MASK | CR0_TS_MASK |
+                                      CR0_PG_MASK));
+    cpu_x86_update_cr4(env, 0);
+    env->dr[7] = 0x00000400;
+
     cpu_x86_load_seg_cache(env, R_CS, (env->smbase >> 4) & 0xffff, env->smbase,
                            0xffffffff, 0);
     cpu_x86_load_seg_cache(env, R_DS, 0, 0, 0xffffffff, 0);
@@ -170,13 +177,6 @@ void do_smm_enter(X86CPU *cpu)
     cpu_x86_load_seg_cache(env, R_SS, 0, 0, 0xffffffff, 0);
     cpu_x86_load_seg_cache(env, R_FS, 0, 0, 0xffffffff, 0);
     cpu_x86_load_seg_cache(env, R_GS, 0, 0, 0xffffffff, 0);
-
-    cpu_x86_update_cr0(env,
-                       env->cr[0] & ~(CR0_PE_MASK | CR0_EM_MASK | CR0_TS_MASK |
-                                      CR0_PG_MASK));
-    cpu_x86_update_cr4(env, 0);
-    env->dr[7] = 0x00000400;
-    CC_OP = CC_OP_EFLAGS;
 }
 
 void helper_rsm(CPUX86State *env)
@@ -191,16 +191,6 @@ void helper_rsm(CPUX86State *env)
 #ifdef TARGET_X86_64
     cpu_load_efer(env, ldq_phys(cs->as, sm_state + 0x7ed0));
 
-    for (i = 0; i < 6; i++) {
-        offset = 0x7e00 + i * 16;
-        cpu_x86_load_seg_cache(env, i,
-                               lduw_phys(cs->as, sm_state + offset),
-                               ldq_phys(cs->as, sm_state + offset + 8),
-                               ldl_phys(cs->as, sm_state + offset + 4),
-                               (lduw_phys(cs->as, sm_state + offset + 2) &
-                                0xf0ff) << 8);
-    }
-
     env->gdt.base = ldq_phys(cs->as, sm_state + 0x7e68);
     env->gdt.limit = ldl_phys(cs->as, sm_state + 0x7e64);
 
@@ -238,6 +228,16 @@ void helper_rsm(CPUX86State *env)
     cpu_x86_update_cr3(env, ldl_phys(cs->as, sm_state + 0x7f50));
     cpu_x86_update_cr0(env, ldl_phys(cs->as, sm_state + 0x7f58));
 
+    for (i = 0; i < 6; i++) {
+        offset = 0x7e00 + i * 16;
+        cpu_x86_load_seg_cache(env, i,
+                               lduw_phys(cs->as, sm_state + offset),
+                               ldq_phys(cs->as, sm_state + offset + 8),
+                               ldl_phys(cs->as, sm_state + offset + 4),
+                               (lduw_phys(cs->as, sm_state + offset + 2) &
+                                0xf0ff) << 8);
+    }
+
     val = ldl_phys(cs->as, sm_state + 0x7efc); /* revision ID */
     if (val & 0x20000) {
         env->smbase = ldl_phys(cs->as, sm_state + 0x7f00) & ~0x7fff;
-- 
1.9.0