Re: [PATCH v5 09/11] x86/domctl: add XEN_DOMCTL_vmtrace_op

[Jan Beulich <jbeulich@xxxxxxxx>]

On 06.07.2020 12:31, Julien Grall wrote:
> On 05/07/2020 19:55, Michał Leszczyński wrote:
>> +/* XEN_DOMCTL_vmtrace_op: Perform VM tracing related operation */
>> +#if defined(__XEN__) || defined(__XEN_TOOLS__)
>> +
>> +struct xen_domctl_vmtrace_op {
>> +    /* IN variable */
>> +    uint32_t cmd;
>> +/* Enable/disable external vmtrace for given domain */
>> +#define XEN_DOMCTL_vmtrace_pt_enable      1
>> +#define XEN_DOMCTL_vmtrace_pt_disable     2
>> +#define XEN_DOMCTL_vmtrace_pt_get_offset  3
>> +    domid_t domain;
> 
> AFAICT, there is a 16-bit implicit padding here and ...
> 
> 
>> +    uint32_t vcpu;
> 
> ... a 32-bit implicit padding here. I would suggest to make
> the two explicit.
> 
> We possibly want to check they are also always zero.

Not just possibly imo - we should.

Jan