Re: [Xen-devel] [PATCH 03/11] x86: Initialise debug registers correctly

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 04.06.18 at 15:59, <andrew.cooper3@xxxxxxxxxx> wrote:
> --- a/xen/arch/x86/domain.c
> +++ b/xen/arch/x86/domain.c
> @@ -322,6 +322,14 @@ void free_vcpu_struct(struct vcpu *v)
>      free_xenheap_page(v);
>  }
>  
> +static void initialise_registers(struct vcpu *v)
> +{
> +    v->arch.user_regs.eflags = X86_EFLAGS_MBS;

If you used ->rflags here, you could (and imo better would) also ...

> @@ -3907,7 +3908,10 @@ void hvm_vcpu_reset_state(struct vcpu *v, uint16_t cs, 
> uint16_t ip)
>      v->arch.user_regs.rflags = X86_EFLAGS_MBS;
>      v->arch.user_regs.rdx = 0x00000f00;
>      v->arch.user_regs.rip = ip;
> -    memset(&v->arch.debugreg, 0, sizeof(v->arch.debugreg));
> +
> +    memset(&v->arch.debugreg, 0, sizeof(v->arch.debugreg) - 16);
> +    v->arch.debugreg[6] = X86_DR6_DEFAULT;
> +    v->arch.debugreg[7] = X86_DR7_DEFAULT;

... call that function from here (dropping the setting of .rflags
visible in context).

If you decide to go that route,
Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>

Jan



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