smm: unify SMM handlers

The next patch will add shared code between the initial handler for
SMBASE relocation and the actual SMI handler.  Combine the code of
the two handlers for simplicity.

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

diff --git a/src/fw/smm.c b/src/fw/smm.c
index eccef881c40a83f7f643f5c2e7b403ef43c3af1a..f486c781c855746e51b3e69666e1e55e4bb19761 100644 (file)
--- a/src/fw/smm.c
+++ b/src/fw/smm.c
@@ -17,13 +17,17 @@
 #include "util.h" // smm_setup
 #include "x86.h" // wbinvd
 
-extern u8 smm_relocation_start, smm_relocation_end;
+extern u8 smm_code_start, smm_code_end;
+
 ASM32FLAT(
-    ".global smm_relocation_start, smm_relocation_end\n"
+    ".global smm_code_start, smm_code_end\n"
     "  .code16gcc\n"
+    "smm_code_start:\n"
+    "  mov %cs, %ax\n"
+    "  cmp $0xa000, %ax\n"
+    "  je smm_exit\n"
 
     /* code to relocate SMBASE to 0xa0000 */
-    "smm_relocation_start:\n"
     "  movl $" __stringify(BUILD_SMM_INIT_ADDR) " + 0x7efc, %ebx\n"
     "  addr32 movb (%ebx), %al\n"  /* revision ID to see if x86_64 or x86 */
     "  cmpb $0x64, %al\n"
@@ -39,16 +43,7 @@ ASM32FLAT(
     "  movb $0x00, %al\n"
     "  movw $" __stringify(PORT_SMI_STATUS) ", %dx\n"
     "  outb %al, %dx\n"
-    "  rsm\n"
-    "smm_relocation_end:\n"
-    "  .code32\n"
-    );
-
-extern u8 smm_code_start, smm_code_end;
-ASM32FLAT(
-    ".global smm_code_start, smm_code_end\n"
-    "  .code16gcc\n"
-    "smm_code_start:\n"
+    "smm_exit:\n"
     "  rsm\n"
     "smm_code_end:\n"
     "  .code32\n"
@@ -60,9 +55,9 @@ smm_save_and_copy(void)
     /* save original memory content */
     memcpy((void *)BUILD_SMM_ADDR, (void *)BUILD_SMM_INIT_ADDR, BUILD_SMM_SIZE);
 
-    /* copy the SMM relocation code */
-    memcpy((void *)BUILD_SMM_INIT_ADDR, &smm_relocation_start,
-           &smm_relocation_end - &smm_relocation_start);
+    /* copy the SMM code, which will relocate itself on the first execution */
+    memcpy((void *)BUILD_SMM_INIT_ADDR, &smm_code_start,
+           &smm_code_end - &smm_code_start);
 }
 
 static void