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Subject[RFC PATCH v2 6/6] KVM: emulate: remove memopp and rip_relative
Date
Move typecast on "out of range value" of mem.ea to
decode_modrm. rip_relative is only set in decode_modrm,
change it to a local var

Signed-off-by: Bandan Das <bsd@redhat.com>
---
arch/x86/include/asm/kvm_emulate.h | 2 --
arch/x86/kvm/emulate.c | 18 +++++++-----------
2 files changed, 7 insertions(+), 13 deletions(-)

diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h
index 08a7696..813254b 100644
--- a/arch/x86/include/asm/kvm_emulate.h
+++ b/arch/x86/include/asm/kvm_emulate.h
@@ -322,7 +322,6 @@ struct x86_emulate_ctxt {
struct operand dst;
int (*execute)(struct x86_emulate_ctxt *ctxt);
int (*check_perm)(struct x86_emulate_ctxt *ctxt);
- bool rip_relative;
u8 rex_prefix;
u8 lock_prefix;
u8 rep_prefix;
@@ -342,7 +341,6 @@ struct x86_emulate_ctxt {
struct operand memop;
/* Fields above regs are cleared together. */
unsigned long _regs[NR_VCPU_REGS];
- struct operand *memopp;
struct fetch_cache fetch;
struct read_cache io_read;
struct read_cache mem_read;
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index b8affac..fcdf5b7 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -1053,6 +1053,7 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt,
int index_reg, base_reg, scale;
int rc = X86EMUL_CONTINUE;
ulong modrm_ea = 0;
+ bool rip_relative = false;

index_reg = (ctxt->rex_prefix << 2) & 8; /* REX.X */
base_reg = (ctxt->rex_prefix << 3) & 8; /* REG.B */
@@ -1155,7 +1156,7 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt,
modrm_ea += reg_read(ctxt, index_reg) << scale;
} else if ((ctxt->modrm_rm & 7) == 5 && ctxt->modrm_mod == 0) {
if (ctxt->mode == X86EMUL_MODE_PROT64)
- ctxt->rip_relative = 1;
+ rip_relative = true;
} else {
base_reg = ctxt->modrm_rm;
modrm_ea += reg_read(ctxt, base_reg);
@@ -1175,6 +1176,9 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt,
}
}
op->addr.mem.ea = modrm_ea;
+ ctxt->memop.addr.mem.ea = (u32)ctxt->memop.addr.mem.ea;
+ if (rip_relative)
+ ctxt->memop.addr.mem.ea += ctxt->_eip;
done:
return rc;
}
@@ -4088,7 +4092,6 @@ static int decode_operand(struct x86_emulate_ctxt *ctxt, struct operand *op,
ctxt->memop.bytes = (ctxt->d & ByteOp) ? 1 : ctxt->op_bytes;
mem_common:
*op = ctxt->memop;
- ctxt->memopp = op;
if (ctxt->d & BitOp)
fetch_bit_operand(ctxt);
op->orig_val = op->val;
@@ -4240,7 +4243,6 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len)
struct opcode opcode;

ctxt->memop.type = OP_NONE;
- ctxt->memopp = NULL;
ctxt->_eip = ctxt->eip;
ctxt->fetch.start = ctxt->_eip;
ctxt->fetch.end = ctxt->fetch.start + insn_len;
@@ -4441,9 +4443,6 @@ done_prefixes:

ctxt->memop.addr.mem.seg = ctxt->seg_override;

- if (ctxt->memop.type == OP_MEM && ctxt->ad_bytes != 8)
- ctxt->memop.addr.mem.ea = (u32)ctxt->memop.addr.mem.ea;
-
/*
* Decode and fetch the source operand: register, memory
* or immediate.
@@ -4464,9 +4463,6 @@ done_prefixes:
rc = decode_operand(ctxt, &ctxt->dst, (ctxt->d >> DstShift) & OpMask);

done:
- if (ctxt->memopp && ctxt->memopp->type == OP_MEM && ctxt->rip_relative)
- ctxt->memopp->addr.mem.ea += ctxt->_eip;
-
return (rc != X86EMUL_CONTINUE) ? EMULATION_FAILED : EMULATION_OK;
}

@@ -4541,8 +4537,8 @@ static int fastop(struct x86_emulate_ctxt *ctxt, void (*fop)(struct fastop *))

void init_decode_cache(struct x86_emulate_ctxt *ctxt)
{
- memset(&ctxt->rip_relative, 0,
- (void *)&ctxt->modrm - (void *)&ctxt->rip_relative);
+ memset(&ctxt->rex_prefix, 0,
+ (void *)&ctxt->modrm - (void *)&ctxt->rex_prefix);

ctxt->io_read.pos = 0;
ctxt->io_read.end = 0;
--
1.8.3.1


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