• Dave Martin's avatar
    KVM: arm64/sve: Clean up UAPI register ID definitions · 8ae6efdd
    Dave Martin authored
    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 the UAPI
    header.
    
    Fixes: e1c9c983 ("KVM: arm64/sve: Add SVE support to register access ioctl interface")
    Suggested-by: default avatarAndrew Jones <drjones@redhat.com>
    Signed-off-by: default avatarDave Martin <Dave.Martin@arm.com>
    Reviewed-by: default avatarAndrew Jones <drjones@redhat.com>
    Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
    8ae6efdd
guest.c 21.6 KB