KVM: Separate emulation context initialization in a separate function

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>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 25 insertions, 29 deletions

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 768197a34d3e..c0004eb354d3 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3931,6 +3931,28 @@ 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;
@@ -3987,20 +4009,7 @@ 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;
@@ -5052,22 +5061,9 @@ 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,