[RFC PATCH v3 2/4] x86: Separate emulation context initialization in a separate function

Mohammed Gamal
2010-08-15T21:47:23Z

The code for initializing the emulation context is duplicated at two
locations (emulate_instruction() and kvm_task_switch()). Separate it
in a separate function and call it from there.

Signed-off-by: Mohammed Gamal <m.gamal005@gmail.com>
---
arch/x86/kvm/x86.c | 54 ++++++++++++++++++++++++---------------------------
1 files changed, 25 insertions(+), 29 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 1722d37..f24e594 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3936,6 +3936,28 @@ static void inject_emulated_exception(struct kvm_vcpu *vcpu)
kvm_queue_exception(vcpu, ctxt->exception);
}

+static void init_emulate_ctxt(struct kvm_vcpu *vcpu)
+{
+ struct decode_cache *c = &vcpu->arch.emulate_ctxt.decode;
+ int cs_db, cs_l;
+
+ cache_all_regs(vcpu);
+
+ kvm_x86_ops->get_cs_db_l_bits(vcpu, &cs_db, &cs_l);
+
+ vcpu->arch.emulate_ctxt.vcpu = vcpu;
+ vcpu->arch.emulate_ctxt.eflags = kvm_x86_ops->get_rflags(vcpu);
+ vcpu->arch.emulate_ctxt.eip = kvm_rip_read(vcpu);
+ vcpu->arch.emulate_ctxt.mode =
+ (!is_protmode(vcpu)) ? X86EMUL_MODE_REAL :
+ (vcpu->arch.emulate_ctxt.eflags & X86_EFLAGS_VM)
+ ? X86EMUL_MODE_VM86 : cs_l
+ ? X86EMUL_MODE_PROT64 : cs_db
+ ? X86EMUL_MODE_PROT32 : X86EMUL_MODE_PROT16;
+ memset(c, 0, sizeof(struct decode_cache));
+ memcpy(c->regs, vcpu->arch.regs, sizeof c->regs);
+}
+
static int handle_emulation_failure(struct kvm_vcpu *vcpu)
{
++vcpu->stat.insn_emulation_fail;
@@ -3992,20 +4014,7 @@ int emulate_instruction(struct kvm_vcpu *vcpu,
cache_all_regs(vcpu);

if (!(emulation_type & EMULTYPE_NO_DECODE)) {
- int cs_db, cs_l;
- kvm_x86_ops->get_cs_db_l_bits(vcpu, &cs_db, &cs_l);
-
- vcpu->arch.emulate_ctxt.vcpu = vcpu;
- vcpu->arch.emulate_ctxt.eflags = kvm_x86_ops->get_rflags(vcpu);
- vcpu->arch.emulate_ctxt.eip = kvm_rip_read(vcpu);
- vcpu->arch.emulate_ctxt.mode =
- (!is_protmode(vcpu)) ? X86EMUL_MODE_REAL :
- (vcpu->arch.emulate_ctxt.eflags & X86_EFLAGS_VM)
- ? X86EMUL_MODE_VM86 : cs_l
- ? X86EMUL_MODE_PROT64 : cs_db
- ? X86EMUL_MODE_PROT32 : X86EMUL_MODE_PROT16;
- memset(c, 0, sizeof(struct decode_cache));
- memcpy(c->regs, vcpu->arch.regs, sizeof c->regs);
+ init_emulate_ctxt(vcpu);
vcpu->arch.emulate_ctxt.interruptibility = 0;
vcpu->arch.emulate_ctxt.exception = -1;
vcpu->arch.emulate_ctxt.perm_ok = false;
@@ -5064,22 +5073,9 @@ int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int reason,
bool has_error_code, u32 error_code)
{
struct decode_cache *c = &vcpu->arch.emulate_ctxt.decode;
- int cs_db, cs_l, ret;
- cache_all_regs(vcpu);
-
- kvm_x86_ops->get_cs_db_l_bits(vcpu, &cs_db, &cs_l);
+ int ret;

- vcpu->arch.emulate_ctxt.vcpu = vcpu;
- vcpu->arch.emulate_ctxt.eflags = kvm_x86_ops->get_rflags(vcpu);
- vcpu->arch.emulate_ctxt.eip = kvm_rip_read(vcpu);
- vcpu->arch.emulate_ctxt.mode =
- (!is_protmode(vcpu)) ? X86EMUL_MODE_REAL :
- (vcpu->arch.emulate_ctxt.eflags & X86_EFLAGS_VM)
- ? X86EMUL_MODE_VM86 : cs_l
- ? X86EMUL_MODE_PROT64 : cs_db
- ? X86EMUL_MODE_PROT32 : X86EMUL_MODE_PROT16;
- memset(c, 0, sizeof(struct decode_cache));
- memcpy(c->regs, vcpu->arch.regs, sizeof c->regs);
+ init_emulate_ctxt(vcpu);

ret = emulator_task_switch(&vcpu->arch.emulate_ctxt,
tss_selector, reason, has_error_code,
--
1.7.0.4