Re: [RFC PATCH V2 10/18] drivers: hv: Decrypt percpu hvcall input arg page in sev-snp enlightened guest

[Tianyu Lan]

On 12/9/2022 5:52 AM, Dexuan Cui wrote:
> > @@ -134,6 +136,16 @@ int hv_common_cpu_init(unsigned int cpu)
> >   	if (!(*inputarg))
> >   		return -ENOMEM;
> >
> > +	if (hv_isolation_type_en_snp()) {
> > +		ret = set_memory_decrypted((unsigned long)*inputarg, 1);
> Is it possible hv_root_partition==1 here? If yes, the pgcount is 2.
Hi Dexuan:
	Thanks for review. So far, root partition doesn't support sev 
enlightened guest and so here assume pgcount is always 1. We may use 
pgcount variable here instead of the number.

> > +		if (ret) {
> > +			kfree(*inputarg);
> > +			return ret;
> > +		}
> > +
> > +		memset(*inputarg, 0x00, PAGE_SIZE);
> > +	}
> > +
> >   	if (hv_root_partition) {
> >   		outputarg = (void **)this_cpu_ptr(hyperv_pcpu_output_arg);
> >   		*outputarg = (char *)(*inputarg) + HV_HYP_PAGE_SIZE;
> > @@ -168,6 +180,9 @@ int hv_common_cpu_die(unsigned int cpu)
> >
> >   	local_irq_restore(flags);
> >
> > +	if (hv_isolation_type_en_snp())
> > +		set_memory_encrypted((unsigned long)mem, 1);
> If set_memory_encrypted() fails, we should not free the 'mem'.

Good point. Will update in the next version.