Re: [Xen-devel] [PATCH v7 11/19] x86/VPMU: Interface for setting PMU mode and flags

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 06.06.14 at 19:40, <boris.ostrovsky@xxxxxxxxxx> wrote:
> --- a/xen/arch/x86/x86_64/compat/entry.S
> +++ b/xen/arch/x86/x86_64/compat/entry.S
> @@ -417,6 +417,8 @@ ENTRY(compat_hypercall_table)
>          .quad do_domctl
>          .quad compat_kexec_op
>          .quad do_tmem_op
> +        .quad do_ni_hypercall           /* reserved for XenClient */
> +        .quad do_xenpmu_op              /* 40 */
>          .rept __HYPERVISOR_arch_0-((.-compat_hypercall_table)/8)
>          .quad compat_ni_hypercall
>          .endr
> @@ -465,6 +467,8 @@ ENTRY(compat_hypercall_args_table)
>          .byte 1 /* do_domctl                */
>          .byte 2 /* compat_kexec_op          */
>          .byte 1 /* do_tmem_op               */
> +        .byte 0 /* reserved for XenClient   */
> +        .byte 2 /* do_xenpmu_op             */  /* 40 */
>          .rept __HYPERVISOR_arch_0-(.-compat_hypercall_args_table)
>          .byte 0 /* compat_ni_hypercall      */
>          .endr

I'm pretty certain I said on an earlier version of the patch series
already: If you use the same handler for native and compat mode
hypercalls, you should add structure layout verification (see the ?
entries in xen/include/xlat.lst and how what they produce is being
used in various places). And the fact that the interface structure
contains a handle already makes clear that this check will fail - I
don't think there's  a way around having at least a thin compat
mode wrapper here.

Jan


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