From mboxrd@z Thu Jan  1 00:00:00 1970
From: Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: kvm-unit-test failed to complete
Date: Thu, 30 Jul 2015 15:32:33 +0200
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Cc: Christoffer Dall <cdall@cs.columbia.edu>, kvm@vger.kernel.org,
	Christoffer Dall <christofferdall@christofferdall.dk>
To: Bandan Das <bsd@redhat.com>, Shih-Wei Li <shihwei@cs.columbia.edu>
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On 30/07/2015 06:41, Bandan Das wrote:
> 
> diff --git a/x86/cstart64.S b/x86/cstart64.S
> index 8d0d95d..8d5ee2d 100644
> --- a/x86/cstart64.S
> +++ b/x86/cstart64.S
> @@ -213,7 +213,11 @@ idt_descr:
>  
>  load_tss:
>         lidtq idt_descr
> -       mov $0, %eax
> +       mov $0x10, %eax
> +       mov %ax, %ds
> +       mov %ax, %es
> +       mov %ax, %fs
> +       mov %ax, %gs
>         mov %ax, %ss
>         mov $(APIC_DEFAULT_PHYS_BASE + APIC_ID), %eax
>         mov (%rax), %eax
> 
> Paolo, what is the purpose of initializing %gs and %fs ? It seems if I comment
> out "mov %ax, %gs", the test works.

Oh, you're right!  setup_percpu_area writes the GS base.  Also the 0x10
selector is the same between the 32-bit and 64-bit GDT, so it should be
okay to remove the whole sequence of moves (from mov $0, %eax to mov
%ax, %ss).

Paolo