From e28baeadcf0d657c6b6e849ae1b4faccb4faf326 Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Mon, 20 Feb 2017 08:56:11 -0800 Subject: [PATCH] x86/kvm/vmx: Get rid of segment_base() on 64-bit kernels MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit It was a bit buggy (it didn't list all segment types that needed 64-bit fixups), but the bug was irrelevant because it wasn't called in any interesting context on 64-bit kernels and was only used for data segents on 32-bit kernels. To avoid confusion, make it explicitly 32-bit only. Cc: Thomas Garnier Cc: Jim Mattson Cc: Radim Krčmář Cc: Paolo Bonzini Signed-off-by: Andy Lutomirski Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 3dbbf4e..3ddd723 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -2057,6 +2057,12 @@ static bool update_transition_efer(struct vcpu_vmx *vmx, int efer_offset) } } +#ifdef CONFIG_X86_32 +/* + * On 32-bit kernels, VM exits still load the FS and GS bases from the + * VMCS rather than the segment table. KVM uses this helper to figure + * out the current bases to poke them into the VMCS before entry. + */ static unsigned long segment_base(u16 selector) { struct desc_ptr *gdt = this_cpu_ptr(&host_gdt); @@ -2079,12 +2085,9 @@ static unsigned long segment_base(u16 selector) } d = (struct desc_struct *)(table_base + (selector & ~7)); v = get_desc_base(d); -#ifdef CONFIG_X86_64 - if (d->s == 0 && (d->type == 2 || d->type == 9 || d->type == 11)) - v |= ((unsigned long)((struct ldttss_desc64 *)d)->base3) << 32; -#endif return v; } +#endif static void vmx_save_host_state(struct kvm_vcpu *vcpu) { -- 2.7.4