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Subject[RFC PATCH v2 4/6] KVM: emulate: clean up initializations in init_decode_cache
Date
A lot of initializations are unnecessary as they get set to
appropriate values before actually being used. Optimize
placement of fields in x86_emulate_ctxt

Signed-off-by: Bandan Das <bsd@redhat.com>
---
arch/x86/include/asm/kvm_emulate.h | 20 +++++++++++---------
arch/x86/kvm/emulate.c | 7 ++-----
2 files changed, 13 insertions(+), 14 deletions(-)

diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h
index ad4cca8..d2ec45d 100644
--- a/arch/x86/include/asm/kvm_emulate.h
+++ b/arch/x86/include/asm/kvm_emulate.h
@@ -315,30 +315,32 @@ struct x86_emulate_ctxt {
u8 opcode_len;
u8 b;
u8 intercept;
- u8 lock_prefix;
- u8 rep_prefix;
u8 op_bytes;
u8 ad_bytes;
- u8 rex_prefix;
struct operand src;
struct operand src2;
struct operand dst;
- bool has_seg_override;
- u8 seg_override;
- u64 d;
int (*execute)(struct x86_emulate_ctxt *ctxt);
int (*check_perm)(struct x86_emulate_ctxt *ctxt);
+ bool has_seg_override;
+ bool rip_relative;
+ u8 rex_prefix;
+ u8 lock_prefix;
+ u8 rep_prefix;
+ u8 seg_override;
+ /* bitmaps of registers in _regs[] that can be read */
+ u32 regs_valid;
+ /* bitmaps of registers in _regs[] that have been written */
+ u32 regs_dirty;
/* modrm */
u8 modrm;
u8 modrm_mod;
u8 modrm_reg;
u8 modrm_rm;
u8 modrm_seg;
- bool rip_relative;
+ u64 d;
unsigned long _eip;
struct operand memop;
- u32 regs_valid; /* bitmaps of registers in _regs[] that can be read */
- u32 regs_dirty; /* bitmaps of registers in _regs[] that have been written */
/* Fields above regs are cleared together. */
unsigned long _regs[NR_VCPU_REGS];
struct operand *memopp;
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 9cbaba2..5517dd2 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -4550,14 +4550,11 @@ static int fastop(struct x86_emulate_ctxt *ctxt, void (*fop)(struct fastop *))

void init_decode_cache(struct x86_emulate_ctxt *ctxt)
{
- memset(&ctxt->opcode_len, 0,
- (void *)&ctxt->_regs - (void *)&ctxt->opcode_len);
+ memset(&ctxt->has_seg_override, 0,
+ (void *)&ctxt->modrm - (void *)&ctxt->has_seg_override);

- ctxt->fetch.start = 0;
- ctxt->fetch.end = 0;
ctxt->io_read.pos = 0;
ctxt->io_read.end = 0;
- ctxt->mem_read.pos = 0;
ctxt->mem_read.end = 0;
}

--
1.8.3.1


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