Re: [Xen-devel] [PATCH RFC] pvh: clearly specify used parameters in vcpu_guest_context

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 15.11.13 at 16:50, Roger Pau Monne <roger.pau@xxxxxxxxxx> wrote:
> --- a/xen/arch/x86/domain.c
> +++ b/xen/arch/x86/domain.c
> @@ -704,9 +704,11 @@ int arch_set_info_guest(
>          /* PVH 32bitfixme */
>          ASSERT(!compat);
>  
> -        if ( c(ctrlreg[1]) || c(ldt_base) || c(ldt_ents) ||
> +        if ( c(ctrlreg[0]) || c(ctrlreg[1]) || c(ctrlreg[2]) ||
> +             c(ctrlreg[4]) || c(ldt_base) || c(ldt_ents) ||

I think it should actually be a bug for the guest to request an
all blank CR0 or CR4. Minimally CR0.PE, CR0.PG, and CR4.PAE
would seem to be a valid requirement to be set.

Apart from that ctrlreg[] is an 8-element array... And I don't
see debugreg[] being verified at all.

>               c(user_regs.cs) || c(user_regs.ss) || c(user_regs.es) ||
>               c(user_regs.ds) || c(user_regs.fs) || c(user_regs.gs) ||
> +             c(kernel_ss) || c(kernel_sp) || c.nat->gs_base_kernel ||

So George and/or Mukesh found it necessary to set
gs_base_kernel, and you rip it out? I'm curious as to what
they're going to say...

> --- a/xen/arch/x86/hvm/vmx/vmx.c
> +++ b/xen/arch/x86/hvm/vmx/vmx.c
> @@ -1492,10 +1492,6 @@ static void vmx_set_info_guest(struct vcpu *v, 
> uint64_t gs_base_kernel)
>          __vmwrite(GUEST_INTERRUPTIBILITY_INFO, intr_shadow);
>      }
>  
> -    /* PVH 32bitfixme */
> -    if ( is_pvh_vcpu(v) )
> -        __vmwrite(GUEST_GS_BASE, gs_base_kernel);

And if you rip it out, then you should remove the now unused
function parameter here again.

Jan


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