Re: [PATCH v2 1/9] x86/shadow: replace sh_reset_l3_up_pointers()

[Jan Beulich <jbeulich@xxxxxxxx>]

On 20.01.2023 18:02, George Dunlap wrote:
> On Wed, Jan 11, 2023 at 1:52 PM Jan Beulich <jbeulich@xxxxxxxx> wrote:
> 
>> Rather than doing a separate hash walk (and then even using the vCPU
>> variant, which is to go away), do the up-pointer-clearing right in
>> sh_unpin(), as an alternative to the (now further limited) enlisting on
>> a "free floating" list fragment. This utilizes the fact that such list
>> fragments are traversed only for multi-page shadows (in shadow_free()).
>> Furthermore sh_terminate_list() is a safe guard only anyway, which isn't
>> in use in the common case (it actually does anything only for BIGMEM
>> configurations).
> 
> One thing that seems strange about this patch is that you're essentially
> adding a field to the domain shadow struct in lieu of adding another
> another argument to sh_unpin() (unless the bit is referenced elsewhere in
> subsequent patches, which I haven't reviewed, in part because about half of
> them don't apply cleanly to the current tree).

Well, to me adding another parameter to sh_unpin() would have looked odd;
the new field looks slightly cleaner to me. But changing that is merely a
matter of taste, so if you and e.g. Andrew think that approach was better,
I could switch to that. And no, I don't foresee further uses of the field.

As to half of the patches not applying: Some where already applied out of
order, and others therefore need re-basing slightly. Till now I saw no
reason to re-send the remaining patches just for that.

Jan