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| author | Nadav Amit <namit@cs.technion.ac.il> | 2014-11-02 12:54:47 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2014-11-05 14:36:58 +0300 |
| commit | d29b9d7ed76c0b961603ca692b8a562556a20212 (patch) | |
| tree | 73703f51dcce80a433eb6e628f59258896e2319b /arch/x86 | |
| parent | bc79a3179a1da387d730af81ce857d481915efdb (diff) | |
| download | linux-d29b9d7ed76c0b961603ca692b8a562556a20212.tar.xz | |
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.c | 8 |
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: |