Re: [PATCH 00/35 v5] PTI support for x32

From: Joerg Roedel
Date: Mon Apr 16 2018 - 12:02:02 EST


Hi Linus,

On Mon, Apr 16, 2018 at 08:32:46AM -0700, Linus Torvalds wrote:
> Also, it would be nice to have performance numbers,

Here are some numbers I gathered for Ingo on v2 of the patch-set:

https://marc.info/?l=linux-kernel&m=151844711432661&w=2

I don't think they significantly changed, but I can measure them again
if needed.

Besides those, what other numbers/tests are you interested in?

> and check that the global page issues are at least fixed on 32-bit
> too, since we screwed that up on x86-64 initially.
>
> On x86-32, the global pages are likely a bigger deal since there's no PCID.

Okay, I verify if there are any global bits left in the page-tables.
According to the PTDUMP_X86 the cpu_entry_area is mapped with G=1 (which
should be fine?) and another 4M range in the kernel mapping. I need to
check what that is.

Thanks,

Joerg


>
> Linus