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Re: [EXTERNAL] [PATCH 2/2] target/ppc: Fix ISA v3.0 (POWER9) slbia imple
Re: [EXTERNAL] [PATCH 2/2] target/ppc: Fix ISA v3.0 (POWER9) slbia implementation
Thu, 19 Mar 2020 16:22:06 +1100
On Thu, Mar 19, 2020 at 07:46:54AM +1100, Benjamin Herrenschmidt wrote:
> On Wed, 2020-03-18 at 18:08 +0100, Cédric Le Goater wrote:
> > On 3/18/20 5:41 AM, Nicholas Piggin wrote:
> > > Linux using the hash MMU ("disable_radix" command line) on a POWER9
> > > machine quickly hits translation bugs due to using v3.0 slbia
> > > features that are not implemented in TCG. Add them.
> > I checked the ISA books and this looks OK but you are also modifying
> > slbie.
> For the same reason, I believe slbie needs to invalidate caches even if
> the entry isn't present.
> The kernel will under some circumstances overwrite SLB entries without
> invalidating (because the translation itself isn't invalid, it's just
> that the SLB is full, so anything cached in the ERAT is still
> technically ok).
> However, when those things get really invalidated, they need to be
> taken out, even if they no longer have a corresponding SLB entry.
Right, the slbie change is certainly correct, but it doesn't match
what the commit message says this is doing. Nick, can you split that
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
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