From: David Gibson <david@gibson.dropbear.id.au>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "Greg Kurz" <groug@kaod.org>,
qemu-ppc@nongnu.org, "Cédric Le Goater" <clg@kaod.org>,
"Nicholas Piggin" <npiggin@gmail.com>,
qemu-devel@nongnu.org
Subject: Re: [EXTERNAL] [PATCH 2/2] target/ppc: Fix ISA v3.0 (POWER9) slbia implementation
Date: Thu, 19 Mar 2020 16:22:06 +1100 [thread overview]
Message-ID: <20200319052206.GG628315@umbus.fritz.box> (raw)
In-Reply-To: <c534dd84f3e8509b7d8f1e844e48ee0dfaa3c420.camel@kernel.crashing.org>
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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
out please.
--
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_!
http://www.ozlabs.org/~dgibson
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next prev parent reply other threads:[~2020-03-19 5:31 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-18 4:41 [PATCH 1/2] target/ppc: Fix slbia TLB invalidation gap Nicholas Piggin
2020-03-18 4:41 ` [PATCH 2/2] target/ppc: Fix ISA v3.0 (POWER9) slbia implementation Nicholas Piggin
2020-03-18 17:08 ` [EXTERNAL] " Cédric Le Goater
2020-03-18 20:46 ` Benjamin Herrenschmidt
2020-03-19 2:42 ` Nicholas Piggin
2020-03-19 5:22 ` David Gibson [this message]
2020-03-18 16:45 ` [EXTERNAL] [PATCH 1/2] target/ppc: Fix slbia TLB invalidation gap Cédric Le Goater
2020-03-19 2:24 ` Nicholas Piggin
2020-03-18 16:52 ` Greg Kurz
2020-03-19 5:20 ` David Gibson
2020-03-19 5:19 ` David Gibson
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