From: Wei Liu <wl@xen.org>
To: "Roger Pau Monné" <roger.pau@citrix.com>
Cc: Wei Liu <wl@xen.org>,
xen-devel@lists.xenproject.org,
Andrew Cooper <andrew.cooper3@citrix.com>,
Ian Jackson <iwj@xenproject.org>,
Anthony PERARD <anthony.perard@citrix.com>
Subject: Re: [PATCH v2 15/21] libs/guest: obtain a compatible cpu policy from two input ones
Date: Wed, 21 Apr 2021 16:42:37 +0000 [thread overview]
Message-ID: <20210421164237.im72bpddu52oruzw@liuwe-devbox-debian-v2> (raw)
In-Reply-To: <YIAL+bTKvPsAfM2a@Air-de-Roger>
On Wed, Apr 21, 2021 at 01:26:49PM +0200, Roger Pau Monné wrote:
> On Wed, Apr 21, 2021 at 10:22:39AM +0000, Wei Liu wrote:
> > On Tue, Apr 13, 2021 at 04:01:33PM +0200, Roger Pau Monne wrote:
> > > Introduce a helper to obtain a compatible cpu policy based on two
> > > input cpu policies. Currently this is done by and'ing all CPUID leaves
> > > and MSR entries, except for MSR_ARCH_CAPABILITIES which has the RSBA
> > > bit or'ed.
> > >
> >
> > I thought canonical source for compatibility was to be put into the
> > hypervisor, thus all this functionality would be in the hypervisor. Am I
> > misremembering?
>
> Andrew said something similar on v1, but I'm not able to figure how
> this would be used by the hypervisor.
>
> It's my understating that the toolstack will attempt to generate a CPU
> policy and forward it to the hypervisor, which will either accept or
> reject it based on the capabilities of the system. I'm not sure I see
> why we would need to give the hypervisor two policies in order to
> generate a resulting compatible one - it should all be done by the
> toolstack AFAICT.
>
> If there's a use case for this being in the hypervisor I'm happy to
> add it there, but so far I haven't been able to come up with one
> myself, and hence I don't see the need to make the code available.
I have no opinion here. Just wanted to get on the same page.
Thanks for the explanation.
Wei.
>
> Thanks, Roger.
next prev parent reply other threads:[~2021-04-21 16:42 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-13 14:01 [PATCH v2 00/21] libs/guest: new CPUID/MSR interface Roger Pau Monne
2021-04-13 14:01 ` [PATCH v2 01/21] libxl: don't ignore the return value from xc_cpuid_apply_policy Roger Pau Monne
2021-04-28 15:13 ` Anthony PERARD
2021-04-13 14:01 ` [PATCH v2 02/21] libs/guest: rename xc_get_cpu_policy_size to xc_cpu_policy_get_size Roger Pau Monne
2021-04-13 14:01 ` [PATCH v2 03/21] libs/guest: introduce xc_cpu_policy_t Roger Pau Monne
2021-04-13 14:01 ` [PATCH v2 04/21] libs/guest: introduce helper to fetch a system cpu policy Roger Pau Monne
2021-04-14 13:28 ` Jan Beulich
2021-04-13 14:01 ` [PATCH v2 05/21] libs/guest: introduce helper to fetch a domain " Roger Pau Monne
2021-04-13 14:01 ` [PATCH v2 06/21] libs/guest: introduce helper to serialize a " Roger Pau Monne
2021-04-13 14:01 ` [PATCH v2 07/21] tools: switch existing users of xc_get_{system,domain}_cpu_policy Roger Pau Monne
2021-04-13 14:01 ` [PATCH v2 08/21] libs/guest: introduce a helper to apply a cpu policy to a domain Roger Pau Monne
2021-04-13 14:01 ` [PATCH v2 09/21] libs/guest: allow fetching a specific CPUID leaf from a cpu policy Roger Pau Monne
2021-04-13 14:01 ` [PATCH v2 10/21] tests/cpu-policy: add sorted MSR test Roger Pau Monne
2021-04-13 14:01 ` [PATCH v2 11/21] libs/guest: allow fetching a specific MSR entry from a cpu policy Roger Pau Monne
2021-04-13 14:01 ` [PATCH v2 12/21] libs/guest: allow updating a cpu policy CPUID data Roger Pau Monne
2021-04-13 14:01 ` [PATCH v2 13/21] libs/guest: allow updating a cpu policy MSR data Roger Pau Monne
2021-04-13 14:01 ` [PATCH v2 14/21] libs/guest: introduce helper to check cpu policy compatibility Roger Pau Monne
2021-04-14 13:36 ` Jan Beulich
2021-04-22 8:22 ` Roger Pau Monné
2021-04-22 8:31 ` Jan Beulich
2021-04-13 14:01 ` [PATCH v2 15/21] libs/guest: obtain a compatible cpu policy from two input ones Roger Pau Monne
2021-04-14 13:49 ` Jan Beulich
2021-04-22 9:42 ` Roger Pau Monné
2021-04-22 9:58 ` Jan Beulich
2021-04-22 10:34 ` Roger Pau Monné
2021-04-22 10:48 ` Jan Beulich
2021-04-22 10:56 ` Roger Pau Monné
2021-04-22 11:05 ` Jan Beulich
2021-04-22 11:37 ` Roger Pau Monné
2021-04-22 11:42 ` Jan Beulich
2021-04-22 12:07 ` Roger Pau Monné
2021-04-22 12:08 ` Jan Beulich
2021-04-21 10:22 ` Wei Liu
2021-04-21 11:26 ` Roger Pau Monné
2021-04-21 16:42 ` Wei Liu [this message]
2021-04-13 14:01 ` [PATCH v2 16/21] libs/guest: make a cpu policy compatible with older Xen versions Roger Pau Monne
2021-04-13 14:01 ` [PATCH v2 17/21] libs/guest: introduce helper set cpu topology in cpu policy Roger Pau Monne
2021-04-13 14:01 ` [PATCH v2 18/21] libs/guest: rework xc_cpuid_xend_policy Roger Pau Monne
2021-04-13 14:01 ` [PATCH v2 19/21] libs/guest: apply a featureset into a cpu policy Roger Pau Monne
2021-04-13 14:01 ` [PATCH v2 20/21] libs/{light,guest}: implement xc_cpuid_apply_policy in libxl Roger Pau Monne
2021-04-28 16:19 ` Anthony PERARD
2021-04-13 14:01 ` [PATCH v2 21/21] libs/guest: (re)move xc_cpu_policy_apply_cpuid Roger Pau Monne
2021-04-28 16:45 ` Anthony PERARD
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