From: Mark Rutland <mark.rutland@arm.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Jan Kiszka <jan.kiszka@siemens.com>,
RT <linux-rt-users@vger.kernel.org>,
maz@kernel.org
Subject: Re: arm64: kvm + RT
Date: Tue, 5 Oct 2021 11:54:49 +0100 [thread overview]
Message-ID: <20211005105449.GC1664@C02TD0UTHF1T.local> (raw)
In-Reply-To: <87h7dvg5mz.ffs@tglx>
On Tue, Oct 05, 2021 at 11:52:52AM +0200, Thomas Gleixner wrote:
> 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.
I think that was dealt with as of mainline commits:
* e1c6b9e1669e44fb ("entry: KVM: Allow use of generic KVM entry w/o full generic support")
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e1c6b9e1669e44fb7f9688e34e460b759e3b9187
* 6caa5812e2d126a0 ("KVM: arm64: Use generic KVM xfer to guest work function")
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=6caa5812e2d126a0aa8a17816c1ba6f0a0c2b309
... unless I'm missing something.
Mark.
next prev parent reply other threads:[~2021-10-05 10:54 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-04 17:54 arm64: kvm + RT Jan Kiszka
2021-10-05 9:52 ` Thomas Gleixner
2021-10-05 10:01 ` Jan Kiszka
2021-10-05 10:54 ` Mark Rutland [this message]
2021-10-06 0:05 ` Thomas Gleixner
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