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From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Dylanger Daly <dylanger@thegrail.co>, xen-devel@lists.xenproject.org
Cc: Jan Beulich <jbeulich@suse.com>, xen-devel@lists.xen.org
Subject: Re: [PATCH] Add Undervolt MSRs to wrmsr function.
Date: Thu, 18 Apr 2019 10:09:06 +0100	[thread overview]
Message-ID: <53b32c69-b0b4-5441-c8e2-299769eabf8f@citrix.com> (raw)
In-Reply-To: <20190418085634.3629-1-dylanger@thegrail.co>

On 18/04/2019 09:56, Dylanger Daly wrote:
> Giving Laptop Users the ability to Undervolt and change Temp Throttle Limits.
>
> Signed-off-by: Dylanger Daly <dylanger@thegrail.co>

Thankyou for the patch.  Which version of Xen is it against?  It is
fairly old, given that the function you patch has now moved to
arch/x86/pv/emul-priv-op.c.  Furthermore, this is the legacy path, so
the functions this should be added to are guest_{rdmsr,wrmsr}() in
arch/x86/msr.c

What entity is controlling this?

Sadly, there are a number of issues.  You open these MSRs up to
unprivileged domUs, and there is a mismatch between the vcpus/pcpus.

What is the scope of these MSRs?  I guess dom0 is going to write them on
all cores, but as dom0 gets scheduled around, this wont match up with
the pcpus across the host.

~Andrew

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Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel

WARNING: multiple messages have this Message-ID (diff)
From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Dylanger Daly <dylanger@thegrail.co>, <xen-devel@lists.xenproject.org>
Cc: Jan Beulich <jbeulich@suse.com>, xen-devel@lists.xen.org
Subject: Re: [Xen-devel] [PATCH] Add Undervolt MSRs to wrmsr function.
Date: Thu, 18 Apr 2019 10:09:06 +0100	[thread overview]
Message-ID: <53b32c69-b0b4-5441-c8e2-299769eabf8f@citrix.com> (raw)
Message-ID: <20190418090906.qo-l6XkGAx1NKN4X8AtOCdShiAd-jTuJVOwXg1wD8iU@z> (raw)
In-Reply-To: <20190418085634.3629-1-dylanger@thegrail.co>

On 18/04/2019 09:56, Dylanger Daly wrote:
> Giving Laptop Users the ability to Undervolt and change Temp Throttle Limits.
>
> Signed-off-by: Dylanger Daly <dylanger@thegrail.co>

Thankyou for the patch.  Which version of Xen is it against?  It is
fairly old, given that the function you patch has now moved to
arch/x86/pv/emul-priv-op.c.  Furthermore, this is the legacy path, so
the functions this should be added to are guest_{rdmsr,wrmsr}() in
arch/x86/msr.c

What entity is controlling this?

Sadly, there are a number of issues.  You open these MSRs up to
unprivileged domUs, and there is a mismatch between the vcpus/pcpus.

What is the scope of these MSRs?  I guess dom0 is going to write them on
all cores, but as dom0 gets scheduled around, this wont match up with
the pcpus across the host.

~Andrew

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel

  reply	other threads:[~2019-04-18  9:09 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-18  8:56 [PATCH] Add Undervolt MSRs to wrmsr function Dylanger Daly
2019-04-18  8:56 ` [Xen-devel] " Dylanger Daly
2019-04-18  9:09 ` Andrew Cooper [this message]
2019-04-18  9:09   ` Andrew Cooper
2019-04-18  9:19   ` Dylanger Daly
2019-04-18  9:19     ` [Xen-devel] " Dylanger Daly
2019-04-18 11:12     ` Andrew Cooper
2019-04-18 11:12       ` [Xen-devel] " Andrew Cooper
2019-04-18 11:54       ` Dylanger Daly
2019-04-18 11:54         ` [Xen-devel] " Dylanger Daly

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