From: Paolo Bonzini <pbonzini@redhat.com>
To: James Hogan <james.hogan@imgtec.com>
Cc: Gleb Natapov <gleb@kernel.org>,
kvm@vger.kernel.org, Ralf Baechle <ralf@linux-mips.org>,
linux-mips@linux-mips.org, David Daney <david.daney@cavium.com>,
Sanjay Lal <sanjayl@kymasys.com>
Subject: Re: [PATCH 14/21] MIPS: KVM: Add nanosecond count bias KVM register
Date: Mon, 28 Apr 2014 14:01:20 +0200 [thread overview]
Message-ID: <535E4310.10308@redhat.com> (raw)
In-Reply-To: <1398439204-26171-15-git-send-email-james.hogan@imgtec.com>
Il 25/04/2014 17:19, James Hogan ha scritto:
> Expose the KVM guest CP0_Count bias (from the monotonic kernel time) to
> userland in nanosecond units via a new KVM_REG_MIPS_COUNT_BIAS register
> accessible with the KVM_{GET,SET}_ONE_REG ioctls. This gives userland
> control of the bias so that it can exactly match its own monotonic time.
>
> The nanosecond bias is stored separately from the raw bias used
> internally (since nanoseconds isn't a convenient or efficient unit for
> various timer calculations), and is recalculated each time the raw count
> bias is altered. The raw count bias used in CP0_Count determination is
> recalculated when the nanosecond bias is altered via the KVM_SET_ONE_REG
> ioctl.
>
> Signed-off-by: James Hogan <james.hogan@imgtec.com>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Gleb Natapov <gleb@kernel.org>
> Cc: kvm@vger.kernel.org
> Cc: Ralf Baechle <ralf@linux-mips.org>
> Cc: linux-mips@linux-mips.org
> Cc: David Daney <david.daney@cavium.com>
> Cc: Sanjay Lal <sanjayl@kymasys.com>
If it is possible and not too hairy to use a raw value in userspace
(together with KVM_REG_MIPS_COUNT_HZ), please do it---my suggestions
were just that, a suggestion. Otherwise, the patch looks good.
Paolo
next prev parent reply other threads:[~2014-04-28 12:37 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
2014-04-28 12:01 ` Paolo Bonzini [this message]
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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