From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Ellerman Date: Wed, 29 Jan 2020 05:17:26 +0000 Subject: Re: [PATCH v3] powerpc/mm: Remove kvm radix prefetch workaround for Power9 DD2.2 Message-Id: <486sDl09qNz9sRh@ozlabs.org> List-Id: In-Reply-To: <20191206031722.25781-1-jniethe5@gmail.com> References: <20191206031722.25781-1-jniethe5@gmail.com> In-Reply-To: <20191206031722.25781-1-jniethe5@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Jordan Niethe , linuxppc-dev@lists.ozlabs.org, kvm-ppc@vger.kernel.org Cc: Jordan Niethe , oohall@gmail.com On Fri, 2019-12-06 at 03:17:22 UTC, Jordan Niethe wrote: > Commit a25bd72badfa ("powerpc/mm/radix: Workaround prefetch issue with > KVM") introduced a number of workarounds as coming out of a guest with > the mmu enabled would make the cpu would start running in hypervisor > state with the PID value from the guest. The cpu will then start > prefetching for the hypervisor with that PID value. > > In Power9 DD2.2 the cpu behaviour was modified to fix this. When > accessing Quadrant 0 in hypervisor mode with LPID != 0 prefetching will > not be performed. This means that we can get rid of the workarounds for > Power9 DD2.2 and later revisions. Add a new cpu feature > CPU_FTR_P9_RADIX_PREFETCH_BUG to indicate if the workarounds are needed. > > Signed-off-by: Jordan Niethe Applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/736bcdd3a9fc672af33fb83230ecd0570ec38ec6 cheers