From: Jack Lange <jacklange@cs.pitt.edu>
Date: Fri, 9 Sep 2011 20:13:18 +0000 (-0400)
Subject: more decoder fixes to handle incorrect long mode register decoding
X-Git-Url: http://v3vee.org/palacios/gitweb/gitweb.cgi?p=palacios.git;a=commitdiff_plain;h=284cd2cc7083fbb37293bf5e2638aeadd366807f

more decoder fixes to handle incorrect long mode register decoding
---

diff --git a/palacios/include/palacios/vmm_decoder.h b/palacios/include/palacios/vmm_decoder.h
index 767fe25..03c5edb 100644
--- a/palacios/include/palacios/vmm_decoder.h
+++ b/palacios/include/palacios/vmm_decoder.h
@@ -216,11 +216,18 @@ static inline addr_t get_addr_linear(struct guest_info * info, addr_t addr, stru
 	    return addr + seg->base;
 	    break;
 
-	case LONG:
+	case LONG: {
+	    uint64_t seg_base = 0;
+
 	    // In long mode the segment bases are disregarded (forced to 0), unless using 
 	    // FS or GS, then the base addresses are added
-	    return addr + seg->base;
 
+	    if (seg) {
+		seg_base = seg->base;
+	    }
+
+	    return addr + seg_base;
+	}
 	case LONG_16_COMPAT:
 	default:
 	    PrintError("Unsupported CPU Mode: %d\n", info->cpu_mode);
diff --git a/palacios/include/palacios/vmm_instr_decoder.h b/palacios/include/palacios/vmm_instr_decoder.h
index 3fe838b..6e33c46 100644
--- a/palacios/include/palacios/vmm_instr_decoder.h
+++ b/palacios/include/palacios/vmm_instr_decoder.h
@@ -1017,23 +1017,24 @@ int decode_rm_operand64(struct guest_info * core, uint8_t * modrm_instr,
 	}
     
 
-	/* 
-	   Segments should be ignored 
-	   // get appropriate segment
-	   if (instr->prefixes.cs_override) {
-	   seg = &(core->segments.cs);
-	   } else if (instr->prefixes.es_override) {
-	   seg = &(core->segments.es);
-	   } else if (instr->prefixes.ss_override) {
-	   seg = &(core->segments.ss);
-	   } else if (instr->prefixes.fs_override) {
-	   seg = &(core->segments.fs);
-	   } else if (instr->prefixes.gs_override) {
-	   seg = &(core->segments.gs);
-	   } else {
-	   seg = &(core->segments.ds);
-	   }
-	*/
+	
+	//Segments should be ignored 
+	// get appropriate segment
+
+	if (instr->prefixes.cs_override) {
+	    seg = &(core->segments.cs);
+	} else if (instr->prefixes.es_override) {
+	    seg = &(core->segments.es);
+	} else if (instr->prefixes.ss_override) {
+	    seg = &(core->segments.ss);
+	} else if (instr->prefixes.fs_override) {
+	    seg = &(core->segments.fs);
+	} else if (instr->prefixes.gs_override) {
+	    seg = &(core->segments.gs);
+	} else {
+	    seg = &(core->segments.ds);
+	}
+	
 
 	operand->operand = ADDR_MASK(get_addr_linear(core, base_addr, seg), 
 				     get_addr_width(core, instr));
@@ -1061,7 +1062,7 @@ static int decode_rm_operand(struct guest_info * core,
 	case REAL:
 	    return decode_rm_operand16(core, instr_ptr, instr, operand, reg_code);
 	case LONG:
-	    if (instr->prefixes.rex_op_size) {
+	    if (instr->prefixes.rex) {
 		return decode_rm_operand64(core, instr_ptr, instr, operand, reg_code);
 	    }
 	case PROTECTED: