From 7a5b56dfd3a682a51fc84682290d5147872a8e99 Mon Sep 17 00:00:00 2001 From: Avi Kivity Date: Sun, 22 Jun 2008 16:22:51 +0300 Subject: KVM: x86 emulator: lazily evaluate segment registers Instead of prefetching all segment bases before emulation, read them at the last moment. Since most of them are unneeded, we save some cycles on Intel machines where this is a bit expensive. Signed-off-by: Avi Kivity --- arch/x86/kvm/x86.c | 21 --------------------- 1 file changed, 21 deletions(-) (limited to 'arch/x86/kvm/x86.c') diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index d1db5aa5c7f..f726ba79fd3 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2126,27 +2126,6 @@ int emulate_instruction(struct kvm_vcpu *vcpu, ? X86EMUL_MODE_PROT64 : cs_db ? X86EMUL_MODE_PROT32 : X86EMUL_MODE_PROT16; - if (vcpu->arch.emulate_ctxt.mode == X86EMUL_MODE_PROT64) { - vcpu->arch.emulate_ctxt.cs_base = 0; - vcpu->arch.emulate_ctxt.ds_base = 0; - vcpu->arch.emulate_ctxt.es_base = 0; - vcpu->arch.emulate_ctxt.ss_base = 0; - } else { - vcpu->arch.emulate_ctxt.cs_base = - get_segment_base(vcpu, VCPU_SREG_CS); - vcpu->arch.emulate_ctxt.ds_base = - get_segment_base(vcpu, VCPU_SREG_DS); - vcpu->arch.emulate_ctxt.es_base = - get_segment_base(vcpu, VCPU_SREG_ES); - vcpu->arch.emulate_ctxt.ss_base = - get_segment_base(vcpu, VCPU_SREG_SS); - } - - vcpu->arch.emulate_ctxt.gs_base = - get_segment_base(vcpu, VCPU_SREG_GS); - vcpu->arch.emulate_ctxt.fs_base = - get_segment_base(vcpu, VCPU_SREG_FS); - r = x86_decode_insn(&vcpu->arch.emulate_ctxt, &emulate_ops); /* Reject the instructions other than VMCALL/VMMCALL when -- cgit v1.2.3