[Qemu-devel] [PULL 04/11] target-i386: fix segment flags for SMM and VM86 mode

[Paolo Bonzini <pbonzini@redhat.com>]

With the next patch, these need to be correct or VM86 tasks
have the wrong CPL.  The flags are basically what the Intel VMX
documentation say is mandatory for entry into a VM86 guest.

For consistency, SMM ought to have the same flags except with
CPL=0.

Tested-by: Kevin O'Connor <kevin@koconnor.net>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 bsd-user/main.c          |  2 +-
 linux-user/main.c        |  2 +-
 target-i386/gdbstub.c    |  4 +++-
 target-i386/seg_helper.c | 11 ++++++++---
 target-i386/smm_helper.c | 24 ++++++++++++++++++------
 5 files changed, 31 insertions(+), 12 deletions(-)

diff --git a/bsd-user/main.c b/bsd-user/main.c
index 4ba61da..0e8c26c 100644
--- a/bsd-user/main.c
+++ b/bsd-user/main.c
@@ -1004,7 +1004,7 @@ int main(int argc, char **argv)
 
 #if defined(TARGET_I386)
     env->cr[0] = CR0_PG_MASK | CR0_WP_MASK | CR0_PE_MASK;
-    env->hflags |= HF_PE_MASK;
+    env->hflags |= HF_PE_MASK | HF_CPL_MASK;
     if (env->features[FEAT_1_EDX] & CPUID_SSE) {
         env->cr[4] |= CR4_OSFXSR_MASK;
         env->hflags |= HF_OSFXSR_MASK;
diff --git a/linux-user/main.c b/linux-user/main.c
index 882186e..3e21024 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -4052,7 +4052,7 @@ int main(int argc, char **argv, char **envp)
 
 #if defined(TARGET_I386)
     env->cr[0] = CR0_PG_MASK | CR0_WP_MASK | CR0_PE_MASK;
-    env->hflags |= HF_PE_MASK;
+    env->hflags |= HF_PE_MASK | HF_CPL_MASK;
     if (env->features[FEAT_1_EDX] & CPUID_SSE) {
         env->cr[4] |= CR4_OSFXSR_MASK;
         env->hflags |= HF_OSFXSR_MASK;
diff --git a/target-i386/gdbstub.c b/target-i386/gdbstub.c
index d34e535..19fe9ad 100644
--- a/target-i386/gdbstub.c
+++ b/target-i386/gdbstub.c
@@ -127,9 +127,11 @@ static int x86_cpu_gdb_load_seg(X86CPU *cpu, int sreg, uint8_t *mem_buf)
         target_ulong base;
 
         if (!(env->cr[0] & CR0_PE_MASK) || (env->eflags & VM_MASK)) {
+            int dpl = (env->eflags & VM_MASK) ? 3 : 0;
             base = selector << 4;
             limit = 0xffff;
-            flags = 0;
+            flags = DESC_P_MASK | DESC_S_MASK | DESC_W_MASK |
+                    DESC_A_MASK | (dpl << DESC_DPL_SHIFT);
         } else {
             if (!cpu_x86_get_descr_debug(env, selector, &base, &limit,
                                          &flags)) {
diff --git a/target-i386/seg_helper.c b/target-i386/seg_helper.c
index cc7eadf..6f7efee 100644
--- a/target-i386/seg_helper.c
+++ b/target-i386/seg_helper.c
@@ -88,8 +88,10 @@ static inline void load_seg_cache_raw_dt(SegmentCache *sc, uint32_t e1,
 static inline void load_seg_vm(CPUX86State *env, int seg, int selector)
 {
     selector &= 0xffff;
-    cpu_x86_load_seg_cache(env, seg, selector,
-                           (selector << 4), 0xffff, 0);
+
+    cpu_x86_load_seg_cache(env, seg, selector, (selector << 4), 0xffff,
+                           DESC_P_MASK | DESC_S_MASK | DESC_W_MASK |
+                           DESC_A_MASK | (3 << DESC_DPL_SHIFT));
 }
 
 static inline void get_ss_esp_from_tss(CPUX86State *env, uint32_t *ss_ptr,
@@ -2465,9 +2467,12 @@ void helper_verw(CPUX86State *env, target_ulong selector1)
 void cpu_x86_load_seg(CPUX86State *env, int seg_reg, int selector)
 {
     if (!(env->cr[0] & CR0_PE_MASK) || (env->eflags & VM_MASK)) {
+        int dpl = (env->eflags & VM_MASK) ? 3 : 0;
         selector &= 0xffff;
         cpu_x86_load_seg_cache(env, seg_reg, selector,
-                               (selector << 4), 0xffff, 0);
+                               (selector << 4), 0xffff,
+                               DESC_P_MASK | DESC_S_MASK | DESC_W_MASK |
+                               DESC_A_MASK | (dpl << DESC_DPL_SHIFT));
     } else {
         helper_load_seg(env, seg_reg, selector);
     }
diff --git a/target-i386/smm_helper.c b/target-i386/smm_helper.c
index 4841d53..517f3b0 100644
--- a/target-i386/smm_helper.c
+++ b/target-i386/smm_helper.c
@@ -171,12 +171,24 @@ void do_smm_enter(X86CPU *cpu)
     CC_OP = CC_OP_EFLAGS;
 
     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);
-    cpu_x86_load_seg_cache(env, R_ES, 0, 0, 0xffffffff, 0);
-    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);
+                           0xffffffff,
+                           DESC_P_MASK | DESC_S_MASK | DESC_W_MASK |
+                           DESC_A_MASK);
+    cpu_x86_load_seg_cache(env, R_DS, 0, 0, 0xffffffff,
+                           DESC_P_MASK | DESC_S_MASK | DESC_W_MASK |
+                           DESC_A_MASK);
+    cpu_x86_load_seg_cache(env, R_ES, 0, 0, 0xffffffff,
+                           DESC_P_MASK | DESC_S_MASK | DESC_W_MASK |
+                           DESC_A_MASK);
+    cpu_x86_load_seg_cache(env, R_SS, 0, 0, 0xffffffff,
+                           DESC_P_MASK | DESC_S_MASK | DESC_W_MASK |
+                           DESC_A_MASK);
+    cpu_x86_load_seg_cache(env, R_FS, 0, 0, 0xffffffff,
+                           DESC_P_MASK | DESC_S_MASK | DESC_W_MASK |
+                           DESC_A_MASK);
+    cpu_x86_load_seg_cache(env, R_GS, 0, 0, 0xffffffff,
+                           DESC_P_MASK | DESC_S_MASK | DESC_W_MASK |
+                           DESC_A_MASK);
 }
 
 void helper_rsm(CPUX86State *env)
-- 
1.8.3.1