Re: [PATCH v6 18/29] KVM: x86: Use nr_memslot_pages to avoid traversing the memslots array

[Maciej S. Szmigiero]

On 01.12.2021 03:21, Sean Christopherson wrote:
> On Tue, Nov 30, 2021, Maciej S. Szmigiero wrote:
> > From: "Maciej S. Szmigiero" <maciej.szmigiero@xxxxxxxxxx>
> >
> > There is no point in recalculating from scratch the total number of pages
> > in all memslots each time a memslot is created or deleted.  Use KVM's
> > cached nr_memslot_pages to compute the default max number of MMU pages.
> >
> > Note that even with nr_memslot_pages capped at ULONG_MAX we can't safely
> > multiply it by KVM_PERMILLE_MMU_PAGES (20) since this operation can
> > possibly overflow an unsigned long variable.
> >
> > Write this "* 20 / 1000" operation as "/ 50" instead to avoid such
> > overflow.
> >
> > Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@xxxxxxxxxx>
> > [sean: use common KVM field and rework changelog accordingly]
> > Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
>
> My SoB can definitely be dropped for this one, just consider it review feedback
> that happened to have an SoB attached.
>
> Reviewed-by: Sean Christopherson <seanjc@xxxxxxxxxx>

...and on this one, too.

Thanks,
Maciej