Re: [PATCH v1 4/7] x86/vmx: add do_vmtrace_op

[Jan Beulich <jbeulich@xxxxxxxx>]

On 18.06.2020 17:25, Michał Leszczyński wrote:
> ----- 16 cze 2020 o 19:23, Roger Pau Monné roger.pau@xxxxxxxxxx napisał(a):
>> On Tue, Jun 16, 2020 at 05:22:06PM +0200, Michał Leszczyński wrote:
>>> --- a/xen/include/public/hvm/hvm_op.h
>>> +++ b/xen/include/public/hvm/hvm_op.h
>>> @@ -382,6 +382,33 @@ struct xen_hvm_altp2m_op {
>>>  typedef struct xen_hvm_altp2m_op xen_hvm_altp2m_op_t;
>>>  DEFINE_XEN_GUEST_HANDLE(xen_hvm_altp2m_op_t);
>>>  
>>> +/* HVMOP_vmtrace: Perform VM tracing related operation */
>>> +#define HVMOP_vmtrace 26
>>> +
>>> +#define HVMOP_VMTRACE_INTERFACE_VERSION 0x00000001
>>> +
>>> +struct xen_hvm_vmtrace_op {
>>> +    /* IN variable */
>>> +    uint32_t version;   /* HVMOP_VMTRACE_INTERFACE_VERSION */
>>> +    uint32_t cmd;
>>> +/* Enable/disable external vmtrace for given domain */
>>> +#define HVMOP_vmtrace_ipt_enable      1
>>> +#define HVMOP_vmtrace_ipt_disable     2
>>> +#define HVMOP_vmtrace_ipt_get_buf     3
>>> +#define HVMOP_vmtrace_ipt_get_offset  4
>>> +    domid_t domain;
>>
>> You are missing a padding field here AFAICT.
> 
> 
> Could you point out what is the purpose of this padding field and what should 
> be the size in this case? It's pretty unclear to me.

In the public interface we aim at making all padding explicit.

Also, as a general remark: Please trim your replies.

Jan