From: robin.murphy@arm•com (Robin Murphy)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 2/2] kvmtool/arm: Add option to override Generic Timer frequency
Date: Wed, 18 Dec 2013 13:44:09 +0000 [thread overview]
Message-ID: <52B1A6A9.1030107@arm.com> (raw)
In-Reply-To: <308D5B7E-5BDA-4984-9448-EAD8B5D699CF@suse.de>
On 17/12/13 20:39, Alexander Graf wrote:
>
> On 17.12.2013, at 19:31, Robin Murphy <robin.murphy@arm•com> wrote:
>
>> Some platforms have secure firmware which does not correctly set the
>> CNTFRQ register on boot, preventing the use of the Generic Timer.
>> This patch allows mirroring the necessary host workaround by specifying
>> the clock-frequency property in the guest DT.
>>
>> This should only be considered a means of KVM bring-up on such systems,
>> such that vendors may be convinced to properly implement their firmware
>> to support the virtualisation capabilities of their hardware.
>>
>> Signed-off-by: Robin Murphy <robin.murphy@arm•com>
>> Acked-by: Will Deacon <will.deacon@arm•com>
>
> How does it encourage a vendor to properly implement their firmware if there's a workaround?
>
>
> Alex
>
>
Hi Alex,
In short, by enabling the users to create the demand. Yes, like any
workaround there's potential for abuse, but having *something* that
makes it work is the difference between "I want virtualisation"[1] and
"Dear vendor, I've tried virtualisation on your chip/board and it's
great, but it tells me I need new firmware, where do I get that?"
Having the specs tell them what to do clearly isn't sufficient, so let's
give the integrators and consumers incentive to shout at them too. The
sooner proper support is commonplace and we can deprecate
clock-frequency hacks altogether, the better.
Robin.
[1]
http://www.theregister.co.uk/2013/12/12/virtualisation_on_mobile_phones_is_coming/
next prev parent reply other threads:[~2013-12-18 13:44 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-17 18:31 [PATCH 0/2] kvmtool: Enable overriding Generic Timer frequency Robin Murphy
2013-12-17 18:31 ` [PATCH 1/2] kvmtool: Support unsigned int options Robin Murphy
2013-12-17 18:31 ` [PATCH 2/2] kvmtool/arm: Add option to override Generic Timer frequency Robin Murphy
2013-12-17 20:39 ` Alexander Graf
2013-12-18 13:44 ` Robin Murphy [this message]
2013-12-18 14:07 ` Alexander Graf
2013-12-18 16:11 ` Robin Murphy
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