From: Pavel Fedin <p.fedin@samsung.com>
To: 'Marc Zyngier' <marc.zyngier@arm.com>
Cc: kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org,
'Christoffer Dall' <christoffer.dall@linaro.org>
Subject: RE: [RFC] Handling CP15 timer without in-kernel irqchip
Date: Fri, 02 Oct 2015 13:33:14 +0300 [thread overview]
Message-ID: <00d601d0fcfd$bf3d3790$3db7a6b0$@samsung.com> (raw)
In-Reply-To: <20151002112224.73e46be1@arm.com>
Hello!
> - How do you find out that your guest is Linux?
Yes, i agree. No way. And it's not host kernel's job anyway.
> - How do you ensure that the guest will not require the virtual timer?
Agree again. Except device tree, no way. If the guest has its own hardcoded assumptions, it's
doomed. (*)
> - Who is going to maintain this new ABI that would exist for the sole
> benefit of broken hardware?
The ABI is simple, just one more exit code. And it's not only for broken hardware. It is quite
legitimate thing to have GICv3 without v2 backwards compatibility.
> - What is wrong with exposing another, memory mapped timer and remove
> the architected timer entirely?
Well... qemu guys don't want to remove CP15, i already proposed it, and it was very simple thing to
do. :) But, again, this is also device-tree-based, the same concern applies as to (*).
Kind regards,
Pavel Fedin
Expert Engineer
Samsung Electronics Research center Russia
next prev parent reply other threads:[~2015-10-02 10:33 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-02 7:28 [RFC] Handling CP15 timer without in-kernel irqchip Pavel Fedin
2015-10-02 9:30 ` Paolo Bonzini
2015-10-02 9:41 ` Pavel Fedin
2015-10-02 9:58 ` Peter Maydell
2015-10-02 10:05 ` Paolo Bonzini
2015-10-02 10:16 ` Peter Maydell
2015-10-02 10:18 ` Paolo Bonzini
2015-10-02 10:22 ` Pavel Fedin
2015-10-02 10:23 ` Peter Maydell
2015-10-02 10:18 ` Pavel Fedin
2015-10-02 10:22 ` Marc Zyngier
2015-10-02 10:33 ` Pavel Fedin [this message]
2015-10-02 14:54 ` Pavel Fedin
2015-10-02 20:26 ` Christoffer Dall
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