Re: [PATCH v3 2/4] KVM: Add unified KVM_GET/SET_VCPU_STATE IOCTL

[Avi Kivity <avi@redhat.com>]

On 11/02/2009 06:20 PM, Jan Kiszka wrote:
> Add a new IOCTL pair to retrieve or set the VCPU state in one chunk.
> More precisely, the IOCTL is able to process a list of substates to be
> read or written. This list is easily extensible without breaking the
> existing ABI, thus we will no longer have to add new IOCTLs when we
> discover a missing VCPU state field or want to support new hardware
> features.
>
> This patch establishes the generic infrastructure for KVM_GET/
> SET_VCPU_STATE, introduces KVM_CHECK_VCPU_STATES to query supported
> substates, and adds support for the generic substates REGS, SREGS, FPU,
> and MP. To avoid code duplication, the entry point for the corresponding
> original IOCTLs are converted to make use of the new infrastructure
> internally, too.
>
> +
> +struct kvm_vcpu_substate {
> +	__u32 type;	/* KVM_VCPU_STATE_* or KVM_$(ARCH)_VCPU_STATE_* */
> +	__u32 pad;
> +	__s64 offset;	/* payload offset to kvm_vcpu_state in bytes */
> +};
>    

64-bit offset is a bit too much, and can't be made to work on 32-bit 
hosts.  Also, why signed?  it's begging for trouble.

-- 
error compiling committee.c: too many arguments to function