Re: [PATCH 2/2] x86/svmdebug: Print sev and sev_es vmcb bits

[Vaishali Thakkar <vaishali.thakkar@xxxxxxxxxx>]

On 3/8/24 00:34, Andrew Cooper wrote:
> On 07/03/2024 9:40 pm, Vaishali Thakkar wrote:
> > diff --git a/xen/arch/x86/hvm/svm/svmdebug.c b/xen/arch/x86/hvm/svm/svmdebug.c
> > index 24358c6eea..f54b426fb3 100644
> > --- a/xen/arch/x86/hvm/svm/svmdebug.c
> > +++ b/xen/arch/x86/hvm/svm/svmdebug.c
> > @@ -53,6 +53,8 @@ void svm_vmcb_dump(const char *from, const struct vmcb_struct 
> > *vmcb)
> >              vmcb->exitinfo1, vmcb->exitinfo2);
> >       printk("np_ctrl = %#"PRIx64" guest_asid = %#x\n",
> >              vmcb_get_np_ctrl(vmcb), vmcb_get_guest_asid(vmcb));
> > +    printk("sev = %d sev_es = %d\n",
> > +           vmcb_get_sev(vmcb), vmcb_get_sev_es(vmcb));
> Hmm.  These are covered by the previous line printing all of np_ctrl.
> What about rearranging the previous line to be something like:
>
> printk("asid: %#x, np_ctrl: %#"PRIx64" -%s%s%s\n",
>      vmcb->_asid, vmcb->_np_ctrl,
>      vmcb->_np ? " NP" : "",
>      vmcb->_sev ? " SEV" : "",
>      ...);
>
> This is more compact (things like "guest" in "guest asid" is entirely
> redundant), and provides both the raw _np_ctrl field and a bit-by-bit
> decode on the same line, rather than having different parts of the info
> on different lines and bools written out in longhand?
Good point. Will change it in the revised v2.

> See xen/arch/x86/spec_ctrl.c: print_details() for a rather more complete
> example of this style of printk() rendering for bits, including how to
> tabulate it for better readability.
Thanks for pointing to the reference.

> ~Andrew