From: Marc Zyngier <marc.zyngier@arm.com>
To: Christoffer Dall <cdall@linaro.org>
Cc: kvm@vger.kernel.org, Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 06/10] KVM: arm/arm64: Only clean the dcache on translation fault
Date: Tue, 17 Oct 2017 10:34:15 +0100 [thread overview]
Message-ID: <210cf2dc-2566-a29b-637e-901f3dcc80b6@arm.com> (raw)
In-Reply-To: <20171016200811.GH1845@lvm>
On 16/10/17 21:08, Christoffer Dall wrote:
> On Mon, Oct 09, 2017 at 04:20:28PM +0100, Marc Zyngier wrote:
>> The only case where we actually need to perform a dache maintenance
>> is when we map the page for the first time, and subsequent permission
>> faults do not require cache maintenance. Let's make it conditional
>> on not being a permission fault (and thus a translation fault).
>
> Why do we actually need to do any dcache maintenance when faulting in a
> page?
>
> Is this for the case when the stage 1 MMU is disabled, or to support
> guest mappings using uncached attributes?
These are indeed the two cases that require cleaning the dcache to PoC.
> Can we do better, for example
> by only flushing the cache if the guest MMU is disabled?
The guest MMU being disabled is easy. But the uncached mapping is much
trickier, and would involve parsing the guest page tables. Not something
I'm really eager to implement.
>
> Beyond that:
>
> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Thanks!
M.
--
Jazz is not dead. It just smells funny...
next prev parent reply other threads:[~2017-10-17 9:33 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-09 15:20 [PATCH 00/10] arm/arm64: KVM: limit icache invalidation to prefetch aborts Marc Zyngier
2017-10-09 15:20 ` [PATCH 01/10] KVM: arm/arm64: Split dcache/icache flushing Marc Zyngier
2017-10-16 20:07 ` Christoffer Dall
2017-10-17 8:57 ` Marc Zyngier
2017-10-17 14:28 ` Christoffer Dall
2017-10-17 14:41 ` Marc Zyngier
2017-10-16 21:35 ` Roy Franz (Cavium)
2017-10-17 6:44 ` Christoffer Dall
2017-10-09 15:20 ` [PATCH 02/10] arm64: KVM: Add invalidate_icache_range helper Marc Zyngier
2017-10-16 20:08 ` Christoffer Dall
2017-10-19 16:47 ` Will Deacon
2017-10-20 13:41 ` Marc Zyngier
2017-10-09 15:20 ` [PATCH 03/10] arm: KVM: Add optimized PIPT icache flushing Marc Zyngier
2017-10-16 20:07 ` Christoffer Dall
2017-10-17 9:26 ` Marc Zyngier
2017-10-17 14:34 ` Christoffer Dall
2017-10-09 15:20 ` [PATCH 04/10] arm64: KVM: PTE/PMD S2 XN bit definition Marc Zyngier
2017-10-16 20:07 ` Christoffer Dall
2017-10-09 15:20 ` [PATCH 05/10] KVM: arm/arm64: Limit icache invalidation to prefetch aborts Marc Zyngier
2017-10-16 20:08 ` Christoffer Dall
2017-10-09 15:20 ` [PATCH 06/10] KVM: arm/arm64: Only clean the dcache on translation fault Marc Zyngier
2017-10-16 20:08 ` Christoffer Dall
2017-10-17 9:34 ` Marc Zyngier [this message]
2017-10-17 14:36 ` Christoffer Dall
2017-10-17 14:52 ` Marc Zyngier
2017-10-09 15:20 ` [PATCH 07/10] KVM: arm/arm64: Preserve Exec permission across R/W permission faults Marc Zyngier
2017-10-16 20:08 ` Christoffer Dall
2017-10-17 11:22 ` Marc Zyngier
2017-10-17 14:46 ` Christoffer Dall
2017-10-17 15:04 ` Marc Zyngier
2017-10-09 15:20 ` [PATCH 08/10] KVM: arm/arm64: Drop vcpu parameter from coherent_{d,i}cache_guest_page Marc Zyngier
2017-10-16 20:08 ` Christoffer Dall
2017-10-09 15:20 ` [PATCH 09/10] KVM: arm/arm64: Detangle kvm_mmu.h from kvm_hyp.h Marc Zyngier
2017-10-16 20:08 ` Christoffer Dall
2017-10-09 15:20 ` [PATCH 10/10] arm: KVM: Use common implementation for all flushes to PoC Marc Zyngier
2017-10-16 20:06 ` Christoffer Dall
2017-10-17 12:40 ` Marc Zyngier
2017-10-17 14:48 ` Christoffer Dall
2017-10-16 20:59 ` [PATCH 00/10] arm/arm64: KVM: limit icache invalidation to prefetch aborts Christoffer Dall
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=210cf2dc-2566-a29b-637e-901f3dcc80b6@arm.com \
--to=marc.zyngier@arm.com \
--cc=catalin.marinas@arm.com \
--cc=cdall@linaro.org \
--cc=kvm@vger.kernel.org \
--cc=kvmarm@lists.cs.columbia.edu \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=will.deacon@arm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox