RE: [PATCH v13 5/5] x86/sgx: Enable automatic SVN updates for SGX enclaves

[Reshetova, Elena]

> -----Original Message-----
> From: Huang, Kai <kai.huang@xxxxxxxxx>
> Sent: Wednesday, August 13, 2025 2:08 PM
> To: Reshetova, Elena <elena.reshetova@xxxxxxxxx>; Hansen, Dave
> <dave.hansen@xxxxxxxxx>
> Cc: seanjc@xxxxxxxxxx; mingo@xxxxxxxxxx; Scarlata, Vincent R
> <vincent.r.scarlata@xxxxxxxxx>; x86@xxxxxxxxxx; jarkko@xxxxxxxxxx;
> Annapurve, Vishal <vannapurve@xxxxxxxxxx>; linux-kernel@xxxxxxxxxxxxxxx;
> Mallick, Asit K <asit.k.mallick@xxxxxxxxx>; Aktas, Erdem
> <erdemaktas@xxxxxxxxxx>; Cai, Chong <chongc@xxxxxxxxxx>; Bondarevska,
> Nataliia <bondarn@xxxxxxxxxx>; linux-sgx@xxxxxxxxxxxxxxx; Raynor, Scott
> <scott.raynor@xxxxxxxxx>
> Subject: Re: [PATCH v13 5/5] x86/sgx: Enable automatic SVN updates for SGX
> enclaves
> 
> >
> > Note: while in such cases the underlying crypto assets are regenrated, it
> 							     ^
> 							     regenerated
> 
> 

Thank you for catching this! Will fix. 

> [...]
> 
> > +/* Mutex to ensure no concurrent EPC accesses during EUPDATESVN */
> > +static DEFINE_MUTEX(sgx_svn_lock);
> > +
> >  int sgx_inc_usage_count(void)
> >  {
> > +	int ret;
> > +
> > +	guard(mutex)(&sgx_svn_lock);
> > +
> > +	if (sgx_usage_count++ == 0) {
> > +		ret = sgx_update_svn();
> > +		if (ret)
> > +			sgx_usage_count--;
> > +		return ret;
> > +	}
> > +
> 
> To me, I would prefer:
> 
> int sgx_inc_usage_count(void)
> {
> 	guard(mutex)(&sgx_svn_lock);
> 
> 	if (!sgx_usage_count) {
> 		int ret = sgx_update_svn();
> 		if (ret)
> 			return ret;
> 	}
> 
> 	sgx_usage_count++;
> 
> 	return 0;
> }

I can change to this version, but functionality-wise
it is equal. 

Best Regards,
Elena.