From: Avi Kivity <avi@redhat.com>
To: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>,
qemu-devel <qemu-devel@nongnu.org>, kvm <kvm@vger.kernel.org>,
qemu-stable <qemu-stable@nongnu.org>
Subject: Re: [Qemu-devel] [PATCH] KVM: i8254: Clean up limit constant
Date: Mon, 11 Jun 2012 14:18:40 +0300 [thread overview]
Message-ID: <4FD5D410.9030707@redhat.com> (raw)
In-Reply-To: <4FD5C89D.2010408@siemens.com>
On 06/11/2012 01:29 PM, Jan Kiszka wrote:
> On 2012-06-11 12:07, Avi Kivity wrote:
>> On 06/06/2012 05:28 PM, Jan Kiszka wrote:
>>> Due to a offset between the clock used to generate the in-kernel
>>> count_load_time (CLOCK_MONOTONIC) and the clock used for processing this
>>> in userspace (vm_clock), reading back the output of PIT channel 2 via
>>> port 0x61 was broken. One use cases that suffered from it was the CPU
>>> frequency calibration of SeaBIOS, which also affected IDE/AHCI timeouts.
>>>
>>> This fixes it by calibrating the offset between both clocks on
>>> kvm_pit_get and adjusting the kernel value before saving it in the
>>> userspace state. As the calibration only works while the vm_clock is
>>> running, we cache the in-kernel state across stopped phases.
>>
>> Applied, thanks.
>>
>>> + clock_offset = LLONG_MAX;
>>
>> INT64_MAX would me more strictly correct, but in practice it makes no
>> difference.
>
> Was looking for this, just not long enough. Need to print some cheat
> sheet. However, let's clean this up immediately:
>
> ---8<---
>
> clock_offset is int64_t.
>
Thanks, folded.
--
error compiling committee.c: too many arguments to function
prev parent reply other threads:[~2012-06-11 11:18 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-06 14:28 [Qemu-devel] [PATCH uq/master] kvm: i8254: Fix conversion of in-kernel to userspace state Jan Kiszka
2012-06-11 10:07 ` Avi Kivity
2012-06-11 10:29 ` [Qemu-devel] [PATCH] KVM: i8254: Clean up limit constant Jan Kiszka
2012-06-11 11:18 ` Avi Kivity [this message]
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