[PATCH v7 23/23] [DO NOT MERGE] arm64: Cope with CPUs stuck in VHE mode

Marc Zyngier maz at kernel.org
Mon Feb 22 04:47:06 EST 2021

Hi Jonathan,

On 2021-02-22 09:35, Jonathan Neuschäfer wrote:
> Hi,
> On Mon, Feb 08, 2021 at 09:57:32AM +0000, Marc Zyngier wrote:
>> It seems that the CPU known as Apple M1 has the terrible habit
>> of being stuck with HCR_EL2.E2H==1, in violation of the architecture.
> Minor nitpick from the sideline: The M1 SoC has two kinds of CPU in it
> (Icestorm and Firestorm), which makes "CPU known as Apple M1" a bit
> imprecise.

Fair enough. How about something along the lines of:
"At least some of the CPUs integrated in the Apple M1 SoC have
  the terrible habit..."

> In practicality it seems unlikely though, that Icestorm and Firestorm
> act differently with regards to the code in this patch.

This is my hunch as well. And if they did, it shouldn't be a big deal:
the "architecture compliant" CPUs would simply transition via EL1
as expected, and join their buggy friends running at EL2 slightly later.


Jazz is not dead. It just smells funny...

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