Re: [PATCH v2 1/5] x86: Add helper variables and functions to hold VMCSINFO

[Avi Kivity <avi-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

On 05/16/2012 10:52 AM, zhangyanfei wrote:
> This patch provides a set of variables to hold the VMCSINFO and also
> some helper functions to help fill the VMCSINFO.

Need to document the format.


> +void vmcsinfo_append_id(u32 id)
> +{
> +	size_t r;
> +
> +	r = sizeof(id);
> +	if (r + vmcsinfo_size > vmcsinfo_max_size)
> +		return;
> +
> +	memcpy(&vmcsinfo_data[vmcsinfo_size], &id, r);
> +	vmcsinfo_size += r;
> +}
> +EXPORT_SYMBOL_GPL(vmcsinfo_append_id);
> +
> +void vmcsinfo_append_field(u32 field, u64 offset)

Why u64?  It's guaranteed to fit within a page.

> +{
> +	size_t r;
> +
> +	r = sizeof(field) + sizeof(offset);
> +	if (r + vmcsinfo_size > vmcsinfo_max_size)
> +		return;
> +
> +	memcpy(&vmcsinfo_data[vmcsinfo_size], &field, sizeof(field));
> +	vmcsinfo_size += sizeof(field);
> +	memcpy(&vmcsinfo_data[vmcsinfo_size], &offset, sizeof(offset));
> +	vmcsinfo_size += sizeof(offset);

Instead of this vmcsinfo_data, how about a struct with fields for the
revision ID and field count, and an array for the fields?  Should be a
lot simpler.

> +}
> +EXPORT_SYMBOL_GPL(vmcsinfo_append_field);
> +
> +unsigned long paddr_vmcsinfo_note(void)
> +{
> +	return __pa((unsigned long)(char *)&vmcsinfo_note);
> +}
> 


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