From: Jack Lange <jacklange@cs.pitt.edu>
Date: Tue, 1 Nov 2011 23:16:12 +0000 (-0400)
Subject: decoder fix for cut/paste bug in rm decoding
X-Git-Url: http://v3vee.org/palacios/gitweb/gitweb.cgi?p=palacios.git;a=commitdiff_plain;h=ce3ab888e2ca5f14a89da45b4dc64122ff1e1050

decoder fix for cut/paste bug in rm decoding
---

diff --git a/palacios/include/palacios/vmm_instr_decoder.h b/palacios/include/palacios/vmm_instr_decoder.h
index 53831c4..ce494e7 100644
--- a/palacios/include/palacios/vmm_instr_decoder.h
+++ b/palacios/include/palacios/vmm_instr_decoder.h
@@ -681,7 +681,6 @@ static int decode_rm_operand32(struct guest_info * core,
 	}
 
 	if (has_sib_byte) {
-	    instr_cursor += 1;
 	    struct sib_byte * sib = (struct sib_byte *)(instr_cursor);
 	    int scale = 0x1 << sib->scale;
 
@@ -736,6 +735,9 @@ static int decode_rm_operand32(struct guest_info * core,
 		case 5:
 		    if (modrm->mod != 0) {
 			base_addr += ADDR_MASK(gprs->rbp, 4);
+		    } else {
+			mod_mode = DISP32;
+			base_addr = 0;
 		    }
 		    break;
 		case 6:
@@ -888,7 +890,6 @@ int decode_rm_operand64(struct guest_info * core, uint8_t * modrm_instr,
 	}
 
 	if (has_sib_byte) {
-	    instr_cursor += 1;
 	    struct sib_byte * sib = (struct sib_byte *)(instr_cursor);
 	    int scale = 0x1 << sib->scale;
 	    uint8_t index_val = sib->index;
@@ -972,6 +973,9 @@ int decode_rm_operand64(struct guest_info * core, uint8_t * modrm_instr,
 		case 5:
 		    if (modrm->mod != 0) {
 			base_addr += gprs->rbp;
+		    } else {
+			mod_mode = DISP32;
+			base_addr = 0;
 		    }
 		    break;
 		case 6: