From: Oliver Upton <oliver.upton@linux.dev>
To: Marc Zyngier <maz@kernel.org>
Cc: kvmarm@lists.linux.dev, kvm@vger.kernel.org,
James Morse <james.morse@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Zenghui Yu <yuzenghui@huawei.com>
Subject: Re: [PATCH 0/3] KVM: arm64: Load the stage-2 MMU from vcpu_load() for VHE
Date: Fri, 6 Oct 2023 18:11:30 +0000 [thread overview]
Message-ID: <ZSBN0nAKANRHsxll@linux.dev> (raw)
In-Reply-To: <86y1gfn67v.wl-maz@kernel.org>
Hey Marc,
On Fri, Oct 06, 2023 at 04:03:32PM +0100, Marc Zyngier wrote:
> On Fri, 06 Oct 2023 14:33:04 +0100,
> Marc Zyngier <maz@kernel.org> wrote:
>
> Still talking to myself! :D
Seems like you had a good bit of fun :)
> >
> > However, this isn't enough.
> >
> > [ 63.450113] Oh crap 400000435c001 vs 3000004430001
> >
> > So there are situations where we end-up with the wrong VTTBR, rather
> > than the wrong VMID, which is even worse. Haven't worked out the
> > scenario yet, but it apparently involves being preempted by a vcpu
> > from a different VM and not doing the right thing.
>
> Actually, no. It is the MMU notifiers kicking in and performing TLB
> invalidation for a guest while we're in the context of another. The
> joy of running 4 large VMs on a box with 2GB of RAM, basically running
> from swap.
Whelp, looks like my self-rule of no patches on the list after midnight
is in force again. Clearly this was all quite gently tested, thanks for
being the guinea pig.
> There's the sum of my hacks, which keeps the box alive.
Thanks! I'll roll it into v2 so we have something that actually works.
--
Thanks,
Oliver
prev parent reply other threads:[~2023-10-06 18:11 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-06 9:35 [PATCH 0/3] KVM: arm64: Load the stage-2 MMU from vcpu_load() for VHE Oliver Upton
2023-10-06 9:35 ` [PATCH 1/3] KVM: arm64: Don't zero VTTBR in __tlb_switch_to_host() Oliver Upton
2023-10-06 9:41 ` Oliver Upton
2023-10-06 9:35 ` [PATCH 2/3] KVM: arm64: Rename helpers for VHE vCPU load/put Oliver Upton
2023-10-06 22:06 ` kernel test robot
2023-10-06 9:36 ` [PATCH 3/3] KVM: arm64: Load the stage-2 MMU context in kvm_vcpu_load_vhe() Oliver Upton
2023-10-06 11:13 ` [PATCH 0/3] KVM: arm64: Load the stage-2 MMU from vcpu_load() for VHE Marc Zyngier
2023-10-06 12:34 ` Marc Zyngier
2023-10-06 13:33 ` Marc Zyngier
2023-10-06 15:03 ` Marc Zyngier
2023-10-06 18:11 ` Oliver Upton [this message]
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