On Fri, Apr 12, 2019 at 05:28:09PM +0100, Dave Martin wrote:
> Currently, the SVE register ID macros are not all defined in the
> same way, and advertise the fact that FFR maps onto the nonexistent
> predicate register P16. This is really just for kernel
> convenience, and may lead userspace into bad habits.
>
> Instead, this patch masks the ID macro arguments so that
> architecturally invalid register numbers will not be passed through
> any more, and uses a literal KVM_REG_ARM64_SVE_FFR_BASE macro to
> define KVM_REG_ARM64_SVE_FFR(), similarly to the way the _ZREG()
> and _PREG() macros are defined.
>
> Rather than plugging in magic numbers for the number of Z- and P-
> registers and the maximum possible number of register slices, this
> patch provides definitions for those too. Userspace is going to
> need them in any case, and it makes sense for them to come from
> <uapi/asm/kvm.h>.
>
> sve_reg_to_region() uses convenience constants that are defined in
> a different way, and also makes use of the fact that the FFR IDs
> are really contiguous with the P15 IDs, so this patch retains the
> existing convenience constants in guest.c, supplemented with a
> couple of sanity checks to check for consistency with with the UAPI
s/with with/with/
> header.
>
> Fixes: e1c9c98345b3 ("KVM: arm64/sve: Add SVE support to register access ioctl interface")
> Suggested-by: Andrew Jones <drjones@xxxxxxxxxx>
> Signed-off-by: Dave Martin <Dave.Martin@xxxxxxx>
> ---
> arch/arm64/include/uapi/asm/kvm.h | 32 +++++++++++++++++++++++---------
> arch/arm64/kvm/guest.c | 9 +++++++++
> 2 files changed, 32 insertions(+), 9 deletions(-)
>
Reviewed-by: Andrew Jones <drjones@xxxxxxxxxx>
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