From: Marc Zyngier <maz@kernel.org>
To: michael.reeves077@gmail.com
Cc: Oliver Upton <oupton@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Myria Sarvay <myrialsarvay@gmail.com>,
Yureka Lilian <yureka@cyberchaos.dev>,
Fuad Tabba <fuad.tabba@linux.dev>,
Joey Gouly <joey.gouly@arm.com>,
Steffen Eiden <seiden@linux.ibm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Zenghui Yu <yuzenghui@huawei.com>,
linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev,
Sven Peter <sven@kernel.org>, Janne Grunau <j@jannau.net>,
Neal Gompa <neal@gompa.dev>,
asahi@lists.linux.dev, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] arm64: Apply existing Apple CPU workarounds to M3 and M4
Date: Thu, 08 Oct 2026 14:19:49 +0100 [thread overview]
Message-ID: <86cxtk2utm.wl-maz@kernel.org> (raw)
In-Reply-To: <20261008-apple-m3-m4-kvm-v1-2-7bb4cbf3d63b@gmail.com>
Hi Michael,
On Thu, 08 Oct 2026 13:15:41 +0100,
Michael Reeves via B4 Relay <devnull+michael.reeves077.gmail.com@kernel.org> wrote:
>
> From: Michael Reeves <michael.reeves077@gmail.com>
>
> Add M3, M3 Pro, M3 Max and base M4 to apple_cpus so they receive the
> existing PMU trap and broken SEIS workarounds needed by KVM.
>
How have you established that these CPUs suffer from the same SEIS
erratum? I'm all for working around bugs, but I'd like to make sure
the new fancy stuff is indeed just as broken as the old shit...
For the record, the EDKII build in the QEMU EFI package that was in
part of Debian Bullseye was able to trigger the bug semi reliably
(series of writes to ICC_EOIR1_EL1 for interrupts that were never
active). This happens on handover to the guest kernel.
I can provide the binary (and a few scripts) to test this easily.
Should they have been fixed, we can always create a second
implementation list to cover the PMU.
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
next prev parent reply other threads:[~2026-10-08 13:19 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-08 12:15 [PATCH 0/2] arm64: Add support for Apple M3 and M4 CPUs in KVM Michael Reeves via B4 Relay
2026-10-08 12:15 ` [PATCH 1/2] arm64: Add Apple M3 and M4 CPU part numbers Michael Reeves via B4 Relay
2026-10-08 12:15 ` [PATCH 2/2] arm64: Apply existing Apple CPU workarounds to M3 and M4 Michael Reeves via B4 Relay
2026-10-08 13:19 ` Marc Zyngier [this message]
2026-10-09 0:03 ` Michael Reeves
2026-10-09 8:16 ` Marc Zyngier
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