Re: [PATCH V2 03/14] x86/set_memory: Add x86_set_memory_enc static call support

Dave Hansen
2021-08-04T19:27:26Z

On 8/4/21 11:44 AM, Tianyu Lan wrote:
> +static int default_set_memory_enc(unsigned long addr, int numpages, bool enc);
> +DEFINE_STATIC_CALL(x86_set_memory_enc, default_set_memory_enc);
> +
> #define CPA_FLUSHTLB 1
> #define CPA_ARRAY 2
> #define CPA_PAGES_ARRAY 4
> @@ -1981,6 +1985,11 @@ int set_memory_global(unsigned long addr, int numpages)
> }
>
> static int __set_memory_enc_dec(unsigned long addr, int numpages, bool enc)
> +{
> + return static_call(x86_set_memory_enc)(addr, numpages, enc);
> +}
> +
> +static int default_set_memory_enc(unsigned long addr, int numpages, bool enc)
> {
> struct cpa_data cpa;
> int ret;

It doesn't make a lot of difference to add this infrastructure and then
ignore it for the existing in-tree user:

> static int __set_memory_enc_dec(unsigned long addr, int numpages, bool enc)
> {
> struct cpa_data cpa;
> int ret;
>
> /* Nothing to do if memory encryption is not active */
> if (!mem_encrypt_active())
> return 0;

Shouldn't the default be to just "return 0"? Then on
mem_encrypt_active() systems, do the bulk of what is in
__set_memory_enc_dec() today.