From f4bbd9aaaae23007e4d79536d35a30cbbb11d407 Mon Sep 17 00:00:00 2001 From: Avi Kivity Date: Wed, 20 Aug 2008 15:51:42 +0300 Subject: [PATCH] KVM: Load real mode segments correctly Real mode segments to not reference the GDT or LDT; they simply compute base = selector * 16. Signed-off-by: Avi Kivity --- arch/x86/kvm/x86.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 22edd95712ee..bfc7c332c5d7 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3588,11 +3588,33 @@ static int load_segment_descriptor_to_kvm_desct(struct kvm_vcpu *vcpu, return 0; } +int kvm_load_realmode_segment(struct kvm_vcpu *vcpu, u16 selector, int seg) +{ + struct kvm_segment segvar = { + .base = selector << 4, + .limit = 0xffff, + .selector = selector, + .type = 3, + .present = 1, + .dpl = 3, + .db = 0, + .s = 1, + .l = 0, + .g = 0, + .avl = 0, + .unusable = 0, + }; + kvm_x86_ops->set_segment(vcpu, &segvar, seg); + return 0; +} + int kvm_load_segment_descriptor(struct kvm_vcpu *vcpu, u16 selector, int type_bits, int seg) { struct kvm_segment kvm_seg; + if (!(vcpu->arch.cr0 & X86_CR0_PE)) + return kvm_load_realmode_segment(vcpu, selector, seg); if (load_segment_descriptor_to_kvm_desct(vcpu, selector, &kvm_seg)) return 1; kvm_seg.type |= type_bits; -- 2.39.5