From: Paolo Bonzini <pbonzini@redhat.com>
To: James Hogan <james.hogan@imgtec.com>,
David Daney <ddaney.cavm@gmail.com>,
David Daney <david.daney@cavium.com>,
Andreas Herrmann <andreas.herrmann@caviumnetworks.com>
Cc: linux-mips@linux-mips.org, Gleb Natapov <gleb@kernel.org>,
kvm@vger.kernel.org, Ralf Baechle <ralf@linux-mips.org>,
Sanjay Lal <sanjayl@kymasys.com>,
qemu-devel <qemu-devel@nongnu.org>
Subject: Re: [PATCH 14/21] MIPS: KVM: Add nanosecond count bias KVM register
Date: Wed, 28 May 2014 18:24:04 +0200 [thread overview]
Message-ID: <53860DA4.9020703@redhat.com> (raw)
In-Reply-To: <5385F0E4.1080207@imgtec.com>
Il 28/05/2014 16:21, James Hogan ha scritto:
> The implementation in QEMU that I've settled upon makes do with just
> COUNT_CTL and COUNT_RESUME, but with a slight kernel modification so
> that COUNT_RESUME is writeable (to any positive monotonic nanosecond
> value <= now). It works fairly cleanly and correctly even with stopping
> and starting VM clock (gdb, stop/cont, savevm/loadvm, live migration),
> to match the behaviour of the existing mips cpu timer emulation, so I
> plan to drop this bias patch, and will post a v2 patchset soon with just
> a few modifications.
It makes sense to have writable registers in the emulator, even if they
are read-only in real hardware. We also do that for x86, FWIW.
So the idea looks okay to me.
Paolo
next prev parent reply other threads:[~2014-05-28 16:24 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-25 15:19 [PATCH 00/21] MIPS: KVM: Fixes and guest timer rewrite James Hogan
2014-04-25 15:19 ` [PATCH 01/21] MIPS: KVM: Allocate at least 16KB for exception handlers James Hogan
2014-04-25 15:19 ` [PATCH 02/21] MIPS: KVM: Use local_flush_icache_range to fix RI on XBurst James Hogan
2014-04-25 15:19 ` [PATCH 03/21] MIPS: KVM: Use tlb_write_random James Hogan
2014-04-25 15:19 ` [PATCH 04/21] MIPS: KVM: Fix CP0_EBASE KVM register id James Hogan
2014-04-25 16:36 ` David Daney
2014-04-25 19:22 ` James Hogan
2014-04-25 15:19 ` [PATCH 05/21] MIPS: KVM: Add CP0_EPC KVM register access James Hogan
2014-04-25 16:44 ` David Daney
2014-04-25 20:29 ` James Hogan
2014-04-25 21:45 ` David Daney
2014-04-25 15:19 ` [PATCH 06/21] MIPS: KVM: Move KVM_{GET,SET}_ONE_REG definitions into kvm_host.h James Hogan
2014-04-25 15:19 ` [PATCH 07/21] MIPS: KVM: Add CP0_Count/Compare KVM register access James Hogan
2014-04-25 15:19 ` [PATCH 08/21] MIPS: KVM: Deliver guest interrupts after local_irq_disable() James Hogan
2014-04-25 15:19 ` [PATCH 09/21] MIPS: KVM: Fix timer race modifying guest CP0_Cause James Hogan
2014-04-25 16:55 ` David Daney
2014-04-25 20:42 ` James Hogan
2014-04-25 15:19 ` [PATCH 10/21] MIPS: KVM: Migrate hrtimer to follow VCPU James Hogan
2014-04-25 15:19 ` [PATCH 11/21] MIPS: KVM: Rewrite count/compare timer emulation James Hogan
2014-04-25 17:00 ` David Daney
2014-04-25 21:05 ` James Hogan
2014-04-25 15:19 ` [PATCH 12/21] MIPS: KVM: Override guest kernel timer frequency directly James Hogan
2014-04-25 15:19 ` [PATCH 13/21] MIPS: KVM: Add master disable count interface James Hogan
2014-04-25 15:19 ` [PATCH 14/21] MIPS: KVM: Add nanosecond count bias KVM register James Hogan
2014-04-25 17:27 ` David Daney
2014-04-25 22:34 ` James Hogan
2014-04-26 9:37 ` Paolo Bonzini
2014-05-28 14:21 ` James Hogan
2014-05-28 16:24 ` Paolo Bonzini [this message]
2014-04-28 12:01 ` Paolo Bonzini
2014-04-28 15:17 ` James Hogan
2014-04-28 15:42 ` Paolo Bonzini
2014-04-25 15:19 ` [PATCH 15/21] MIPS: KVM: Add count frequency " James Hogan
2014-04-25 15:19 ` [PATCH 16/21] MIPS: KVM: Make kvm_mips_comparecount_{func,wakeup} static James Hogan
2014-04-25 15:20 ` [PATCH 17/21] MIPS: KVM: Whitespace fixes in kvm_mips_callbacks James Hogan
2014-04-25 15:20 ` [PATCH 18/21] MIPS: KVM: Fix kvm_debug bit-rottage James Hogan
2014-04-25 15:20 ` [PATCH 19/21] MIPS: KVM: Remove ifdef DEBUG around kvm_debug James Hogan
2014-04-25 15:20 ` [PATCH 20/21] MIPS: KVM: Quieten kvm_info() logging James Hogan
2014-04-25 15:20 ` [PATCH 21/21] MIPS: KVM: Remove redundant NULL checks before kfree() James Hogan
2014-04-28 12:02 ` [PATCH 00/21] MIPS: KVM: Fixes and guest timer rewrite Paolo Bonzini
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