From: Pavel Fedin <p.fedin@samsung.com>
To: 'Paolo Bonzini' <pbonzini@redhat.com>,
'Peter Maydell' <peter.maydell@linaro.org>
Cc: 'Marc Zyngier' <marc.zyngier@arm.com>,
kvmarm@lists.cs.columbia.edu, 'kvm-devel' <kvm@vger.kernel.org>
Subject: RE: [RFC] Handling CP15 timer without in-kernel irqchip
Date: Fri, 02 Oct 2015 13:18:55 +0300 [thread overview]
Message-ID: <00cc01d0fcfb$bf8994c0$3e9cbe40$@samsung.com> (raw)
In-Reply-To: <560E56DC.6020406@redhat.com>
Hello!
> How do boards other than 'virt' work when emulated without KVM?
Under "emulated without KVM" we normally suppose full software emulation (known in qemu as TCG). In this case CPU code is interpreted, and KVM is not used at all.
Some boards (like vexpress) have own platform-specific timer, so they can work under KVM without CP15 timer. In order to make it working one should either disable CP15 timer in guest .config or remove the node from device tree.
CP15 timer never worked in this configuration (KVM without irqchip).
> It must be possible to emulate the physical timer in QEMU.
Of course it is, and with TCG it works. But we currently cannot use it with KVM because KVM assumes that it emulates all CP15 (or system) registers by itself, and never hands any of them outside.
Kind regards,
Pavel Fedin
Expert Engineer
Samsung Electronics Research center Russia
next prev parent reply other threads:[~2015-10-02 10:18 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 [this message]
2015-10-02 10:22 ` Marc Zyngier
2015-10-02 10:33 ` Pavel Fedin
2015-10-02 14:54 ` Pavel Fedin
2015-10-02 20:26 ` Christoffer Dall
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