Re: [PATCH v19 030/130] KVM: TDX: Add helper functions to print TDX SEAMCALL error

[Huang, Kai]

On Thu, 2024-03-21 at 16:52 -0700, Isaku Yamahata wrote:
> On Thu, Mar 21, 2024 at 12:09:57PM +1300,
> "Huang, Kai" <kai.huang@xxxxxxxxx> wrote:
> 
> > > Does it make sense?
> > > 
> > > void pr_tdx_error(u64 op, u64 error_code)
> > > {
> > >          pr_err_ratelimited("SEAMCALL (0x%016llx) failed: 0x%016llx\n",
> > >                             op, error_code);
> > > }
> > 
> > Should we also have a _ret version?
> > 
> > void pr_seamcall_err(u64 op, u64 err)
> > {
> > 	/* A comment to explain why using the _ratelimited() version? */
> 
> Because KVM can hit successive seamcall erorrs e.g. during desutructing TD,
> (it's unintentional sometimes), ratelimited version is preferred as safe guard.
> For example, SEAMCALL on all or some LPs (TDH_MNG_KEY_FREEID) can fail at the
> same time.  And the number of LPs can be hundreds.

I mean you certainly have a reason to use _ratelimited() version.  My point is
you at least explain it in a comment.

> 
> 
> > 	pr_err_ratelimited(...);
> > }
> > 
> > void pr_seamcall_err_ret(u64 op, u64 err, struct tdx_module_args *arg)
> > {
> > 	pr_err_seamcall(op, err);
> > 	
> > 	pr_err_ratelimited(...);
> > }
> > 
> > (Hmm... if you look at the tdx.c in TDX host, there's similar code there,
> > and again, it was a little bit annoying when I did that..)
> > 
> > Again, if we just use seamcall_ret() for ALL SEAMCALLs except VP.ENTER, we
> > can simply have one..
> 
> What about this?
> 
> void pr_seamcall_err_ret(u64 op, u64 err, struct tdx_module_args *arg)
> {
>         pr_err_ratelimited("SEAMCALL (0x%016llx) failed: 0x%016llx\n",
>                            op, error_code);
>         if (arg)	
>         	pr_err_ratelimited(...);
> }
> 

Fine to me.

Or call pr_seamcall_err() instead.  I don't care too much.