From: Gleb Natapov Date: Wed, 25 Jul 2012 12:49:42 +0000 (+0300) Subject: KVM: x86 emulator: drop unneeded call to get_segment() X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=99245b507dc3b1b2815d6a6cb4e94a6b7018a24b;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git KVM: x86 emulator: drop unneeded call to get_segment() setup_syscalls_segments() calls get_segment() and than overwrites all but one of the structure fields and this one should also be overwritten anyway, so we can drop call to get_segment() and avoid a couple of vmreads on vmx. Also drop zeroing ss/cs structures since most of the fields are set anyway. Just set those that were not set explicitly. Signed-off-by: Gleb Natapov Signed-off-by: Avi Kivity --- diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 2c5d1e65d9d1..10f0136f50c1 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -2035,12 +2035,6 @@ static void setup_syscalls_segments(struct x86_emulate_ctxt *ctxt, struct desc_struct *cs, struct desc_struct *ss) { - u16 selector; - - memset(cs, 0, sizeof(struct desc_struct)); - ctxt->ops->get_segment(ctxt, &selector, cs, NULL, VCPU_SREG_CS); - memset(ss, 0, sizeof(struct desc_struct)); - cs->l = 0; /* will be adjusted later */ set_desc_base(cs, 0); /* flat segment */ cs->g = 1; /* 4kb granularity */ @@ -2050,6 +2044,7 @@ setup_syscalls_segments(struct x86_emulate_ctxt *ctxt, cs->dpl = 0; /* will be adjusted later */ cs->p = 1; cs->d = 1; + cs->avl = 0; set_desc_base(ss, 0); /* flat segment */ set_desc_limit(ss, 0xfffff); /* 4GB limit */ @@ -2059,6 +2054,8 @@ setup_syscalls_segments(struct x86_emulate_ctxt *ctxt, ss->d = 1; /* 32bit stack segment */ ss->dpl = 0; ss->p = 1; + ss->l = 0; + ss->avl = 0; } static bool vendor_intel(struct x86_emulate_ctxt *ctxt)