Date: Tue, 17 Sep 2013 16:06:07 +0000 (UTC) From: Neel Natu <neel@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r255638 - head/sys/amd64/vmm Message-ID: <201309171606.r8HG67Ot032544@svn.freebsd.org>
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Author: neel Date: Tue Sep 17 16:06:07 2013 New Revision: 255638 URL: http://svnweb.freebsd.org/changeset/base/255638 Log: Fix a bug in decoding an instruction that has an SIB byte as well as an immediate operand. The presence of an SIB byte in decoding the ModR/M field would cause 'imm_bytes' to not be set to the correct value. Fix this by initializing 'imm_bytes' independent of the ModR/M decoding. Reported by: grehan@ Approved by: re@ Modified: head/sys/amd64/vmm/vmm_instruction_emul.c Modified: head/sys/amd64/vmm/vmm_instruction_emul.c ============================================================================== --- head/sys/amd64/vmm/vmm_instruction_emul.c Tue Sep 17 15:19:26 2013 (r255637) +++ head/sys/amd64/vmm/vmm_instruction_emul.c Tue Sep 17 16:06:07 2013 (r255638) @@ -701,12 +701,6 @@ decode_modrm(struct vie *vie) break; } - /* Figure out immediate operand size (if any) */ - if (vie->op.op_flags & VIE_OP_F_IMM) - vie->imm_bytes = 4; - else if (vie->op.op_flags & VIE_OP_F_IMM8) - vie->imm_bytes = 1; - done: vie_advance(vie); @@ -822,6 +816,12 @@ decode_immediate(struct vie *vie) int32_t signed32; } u; + /* Figure out immediate operand size (if any) */ + if (vie->op.op_flags & VIE_OP_F_IMM) + vie->imm_bytes = 4; + else if (vie->op.op_flags & VIE_OP_F_IMM8) + vie->imm_bytes = 1; + if ((n = vie->imm_bytes) == 0) return (0);
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