linux-kernel - Re: [PATCH 00/18] KVM: arm64: Support FEAT

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250108123840.GA9197@willie-the-truck>
Date: Wed, 8 Jan 2025 12:38:41 +0000
From: Will Deacon <will@...nel.org>
To: Oliver Upton <oliver.upton@...ux.dev>
Cc: kvmarm@...ts.linux.dev, Marc Zyngier <maz@...nel.org>,
	Joey Gouly <joey.gouly@....com>,
	Suzuki K Poulose <suzuki.poulose@....com>,
	Zenghui Yu <yuzenghui@...wei.com>,
	Mingwei Zhang <mizhang@...gle.com>,
	Colton Lewis <coltonlewis@...gle.com>,
	Raghavendra Rao Ananta <rananta@...gle.com>,
	Catalin Marinas <catalin.marinas@....com>,
	Mark Rutland <mark.rutland@....com>,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 00/18] KVM: arm64: Support FEAT_PMUv3 on Apple hardware

Hi Oliver,

On Tue, Dec 17, 2024 at 01:20:30PM -0800, Oliver Upton wrote:
> One of the interesting features of some Apple M* parts is an IMPDEF trap
> that routes EL1/EL0 accesses of the PMUv3 registers to EL2. This allows
> a hypervisor to emulate an architectural PMUv3 on top of the IMPDEF PMU
> hardware present in the CPU.
> 
> And if you squint, this _might_ look like a CPU erratum :-)
> 
> This series takes advantage of these IMPDEF traps to provide PMUv3 to
> KVM guests. As a starting point, only expose the fixed CPU cycle counter
> and no event counters. Conveniently, this is enough to get Windows
> running as a KVM guest on Apple hardware.
> 
> I've tried to keep the deviation to a minimum by refactoring some of the
> flows used for PMUv3, e.g. computing PMCEID from the arm_pmu bitmap
> instead of reading hardware directly.

What's your plan for this series? I started looking at it and I can take
the first four apple_m1 patches if you like?

Will