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From:   Thomas Gleixner <tglx@linutronix.de>
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To:     Jan Kiszka <jan.kiszka@siemens.com>,
        RT <linux-rt-users@vger.kernel.org>
Subject: Re: arm64: kvm + RT
In-Reply-To: <c640276e-77ca-f895-715e-053bae754f89@siemens.com>
Date:   Tue, 05 Oct 2021 11:52:52 +0200
Message-ID: <87h7dvg5mz.ffs@tglx>
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Jan,

On Mon, Oct 04 2021 at 19:54, Jan Kiszka wrote:
> what's the state of getting kvm working (again?) along RT? Seems
> HAVE_POSIX_CPU_TIMERS_TASK_WORK is in conflict with KVM but a
> precondition for RT on recent kernels. What's the story behind that?

the ARM64 KVM implementation is incorrect vs. TIF handling before
VMENTER which breaks the posix cpu timers task work assumptions and also
violates a few other expectations. AFAICT the arm64 folks are working on
that, but you have to ask them directly what the state of this is.

Thanks,

        tglx