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authorNadav Amit <namit@cs.technion.ac.il>2014-11-02 11:54:47 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2014-11-05 12:36:58 +0100
commitd29b9d7ed76c0b961603ca692b8a562556a20212 (patch)
tree73703f51dcce80a433eb6e628f59258896e2319b /arch/x86
parentbc79a3179a1da387d730af81ce857d481915efdb (diff)
KVM: x86: Fix uninitialized op->type for some immediate values
The emulator could reuse an op->type from a previous instruction for some immediate values. If it mistakenly considers the operands as memory operands, it will performs a memory read and overwrite op->val. Consider for instance the ROR instruction - src2 (the number of times) would be read from memory instead of being used as immediate. Mark every immediate operand as such to avoid this problem. Cc: stable@vger.kernel.org Fixes: c44b4c6ab80eef3a9c52c7b3f0c632942e6489aa Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/kvm/emulate.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 5edf088ca51e..9f8a2faf5040 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -4287,6 +4287,7 @@ static int decode_operand(struct x86_emulate_ctxt *ctxt, struct operand *op,
fetch_register_operand(op);
break;
case OpCL:
+ op->type = OP_IMM;
op->bytes = 1;
op->val = reg_read(ctxt, VCPU_REGS_RCX) & 0xff;
break;
@@ -4294,6 +4295,7 @@ static int decode_operand(struct x86_emulate_ctxt *ctxt, struct operand *op,
rc = decode_imm(ctxt, op, 1, true);
break;
case OpOne:
+ op->type = OP_IMM;
op->bytes = 1;
op->val = 1;
break;
@@ -4352,21 +4354,27 @@ static int decode_operand(struct x86_emulate_ctxt *ctxt, struct operand *op,
ctxt->memop.bytes = ctxt->op_bytes + 2;
goto mem_common;
case OpES:
+ op->type = OP_IMM;
op->val = VCPU_SREG_ES;
break;
case OpCS:
+ op->type = OP_IMM;
op->val = VCPU_SREG_CS;
break;
case OpSS:
+ op->type = OP_IMM;
op->val = VCPU_SREG_SS;
break;
case OpDS:
+ op->type = OP_IMM;
op->val = VCPU_SREG_DS;
break;
case OpFS:
+ op->type = OP_IMM;
op->val = VCPU_SREG_FS;
break;
case OpGS:
+ op->type = OP_IMM;
op->val = VCPU_SREG_GS;
break;
case OpImplicit: