Dave Martin <Dave.Martin@xxxxxxx> writes:
> The Arm SVE architecture defines registers that are up to 2048 bits
> in size (with some possibility of further future expansion).
>
> In order to avoid the need for an excessively large number of
> ioctls when saving and restoring a vcpu's registers, this patch
> adds a #define to make support for individual 2048-bit registers
> through the KVM_{GET,SET}_ONE_REG ioctl interface official. This
> will allow each SVE register to be accessed in a single call.
>
> There are sufficient spare bits in the register id size field for
> this change, so there is no ABI impact providing that
> KVM_GET_REG_LIST does not enumerate any 2048-bit register unless
> userspace explicitly opts in to the relevant architecture-specific
> features.
>
> Signed-off-by: Dave Martin <Dave.Martin@xxxxxxx>
> ---
> include/uapi/linux/kvm.h | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
> index 251be35..7c3c5cc 100644
> --- a/include/uapi/linux/kvm.h
> +++ b/include/uapi/linux/kvm.h
> @@ -1110,6 +1110,7 @@ struct kvm_dirty_tlb {
> #define KVM_REG_SIZE_U256 0x0050000000000000ULL
> #define KVM_REG_SIZE_U512 0x0060000000000000ULL
> #define KVM_REG_SIZE_U1024 0x0070000000000000ULL
> +#define KVM_REG_SIZE_U2048 0x0080000000000000ULL
Yeah OK I guess - but it does make me question if KVM_REG_SIZE_MASK is
part of the ABI because although we have space for another few bits that
is the last one without changing the mask.
Reviewed-by: Alex Bennée <alex.bennee@xxxxxxxxxx>
>
> struct kvm_reg_list {
> __u64 n; /* number of regs */
--
Alex Bennée
_______________________________________________
kvmarm mailing list
kvmarm@xxxxxxxxxxxxxxxxxxxxx
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
