From: "Roger Pau Monné" <roger.pau@citrix.com>
To: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: <xen-devel@lists.xenproject.org>, <iwj@xenproject.org>,
<wl@xen.org>, <anthony.perard@citrix.com>, <jbeulich@suse.com>,
<andrew.cooper3@citrix.com>, <jun.nakajima@intel.com>,
<kevin.tian@intel.com>
Subject: Re: [PATCH v2 1/4] xl: Add support for ignore_msrs option
Date: Thu, 18 Feb 2021 11:42:18 +0100 [thread overview]
Message-ID: <YC5EitRCZB+VCeCC@Air-de-Roger> (raw)
In-Reply-To: <1611182952-9941-2-git-send-email-boris.ostrovsky@oracle.com>
On Wed, Jan 20, 2021 at 05:49:09PM -0500, Boris Ostrovsky wrote:
> This option allows guest administrator specify what should happen when
> guest accesses an MSR which is not explicitly emulated by the hypervisor.
>
> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> ---
> docs/man/xl.cfg.5.pod.in | 20 +++++++++++++++++++-
> tools/libs/light/libxl_types.idl | 7 +++++++
> tools/xl/xl_parse.c | 7 +++++++
> 3 files changed, 33 insertions(+), 1 deletion(-)
>
> diff --git a/docs/man/xl.cfg.5.pod.in b/docs/man/xl.cfg.5.pod.in
> index c8e017f950de..96ce97c42cab 100644
> --- a/docs/man/xl.cfg.5.pod.in
> +++ b/docs/man/xl.cfg.5.pod.in
> @@ -2044,7 +2044,25 @@ Do not provide a VM generation ID.
> See also "Virtual Machine Generation ID" by Microsoft:
> L<https://docs.microsoft.com/en-us/windows/win32/hyperv_v2/virtual-machine-generation-identifier>
>
> -=back
> +=over
> +
> +=item B<ignore_msrs="STRING">
> +
> +Determine hypervisor behavior on accesses to MSRs that are not emulated by the hypervisor.
> +
> +=over 4
> +
> +=item B<never>
> +
> +Issue a warning to the log and #GP to the guest. This is default.
> +
> +=item B<silent>
> +
> +MSR reads return 0, MSR writes are ignored. No warnings to the log.
> +
> +=item B<verbose>
> +
> +Similar to B<silent> but a warning is written.
Would it make sense to allow for this option to be more fine-grained
in the future?
Not that you need to implement the full thing now, but maybe we could
have something like:
"
=item B<ignore_msrs=[ "MSR_RANGE, "MSR_RANGE", ..]>
Specify a list of MSR ranges that will be ignored by the hypervisor:
reads will return zeros and writes will be discarded without raising a
#GP.
Each MSR_RANGE is given in hexadecimal format and may be a range, e.g.
c00102f0-c00102f1 (inclusive), or a single MSR, e.g. c00102f1.
"
Then you can print the messages in the hypervisor using a guest log
level and modify it on demand in order to get more verbose output?
I don't think selecting whether the messages are printed or not from
xl is that helpful as the same could be achieved using guest_loglvl.
Also I think it will be fine to only implement:
ignore_msrs=[ "0-ffffffff" ]
Right now and return an error for any other combination, so that we
can get something in soon and expand it later.
Thanks, Roger.
next prev parent reply other threads:[~2021-02-18 10:42 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-20 22:49 [PATCH v2 0/4] Permit fault-less access to non-emulated MSRs Boris Ostrovsky
2021-01-20 22:49 ` [PATCH v2 1/4] xl: Add support for ignore_msrs option Boris Ostrovsky
2021-01-21 14:56 ` Wei Liu
2021-01-21 22:43 ` Boris Ostrovsky
2021-01-22 9:52 ` Julien Grall
2021-01-22 18:28 ` Boris Ostrovsky
2021-01-22 18:33 ` Julien Grall
2021-01-22 18:39 ` Boris Ostrovsky
2021-01-22 20:42 ` Julien Grall
2021-02-18 10:42 ` Roger Pau Monné [this message]
2021-02-18 11:54 ` Jan Beulich
2021-02-18 15:52 ` Roger Pau Monné
2021-02-18 15:57 ` Jan Beulich
2021-02-19 14:50 ` Boris Ostrovsky
2021-02-22 10:24 ` Roger Pau Monné
2021-02-22 10:33 ` Jan Beulich
2021-01-20 22:49 ` [PATCH v2 2/4] x86: Introduce MSR_UNHANDLED Boris Ostrovsky
2021-01-22 11:51 ` Jan Beulich
2021-01-22 18:56 ` Boris Ostrovsky
2021-02-02 17:01 ` Boris Ostrovsky
2021-02-18 10:51 ` Roger Pau Monné
2021-02-19 14:56 ` Boris Ostrovsky
2021-02-22 11:08 ` Roger Pau Monné
2021-02-22 21:19 ` Boris Ostrovsky
2021-02-23 7:57 ` Jan Beulich
2021-02-23 9:34 ` Roger Pau Monné
2021-02-23 10:15 ` Jan Beulich
2021-02-23 12:17 ` Roger Pau Monné
2021-02-23 13:23 ` Jan Beulich
2021-02-23 15:39 ` Boris Ostrovsky
2021-02-23 16:10 ` Jan Beulich
2021-02-23 18:00 ` Roger Pau Monné
2021-02-23 16:11 ` Roger Pau Monné
2021-02-23 16:40 ` Boris Ostrovsky
2021-02-23 18:02 ` Roger Pau Monné
2021-02-23 18:45 ` Boris Ostrovsky
2021-01-20 22:49 ` [PATCH v2 3/4] x86: Allow non-faulting accesses to non-emulated MSRs if policy permits this Boris Ostrovsky
2021-01-22 12:51 ` Jan Beulich
2021-01-22 19:52 ` Boris Ostrovsky
2021-01-25 10:22 ` Jan Beulich
2021-01-25 18:42 ` Boris Ostrovsky
2021-01-26 9:05 ` Jan Beulich
2021-01-26 16:02 ` Boris Ostrovsky
2021-01-26 16:35 ` Jan Beulich
2021-02-18 11:24 ` Roger Pau Monné
2021-02-18 11:57 ` Jan Beulich
2021-02-18 15:53 ` Roger Pau Monné
2021-01-20 22:49 ` [PATCH v2 4/4] tools/libs: Apply MSR policy to a guest Boris Ostrovsky
2021-01-21 14:58 ` Wei Liu
2021-01-22 9:56 ` Julien Grall
2021-01-22 18:35 ` Boris Ostrovsky
2021-02-18 11:48 ` Roger Pau Monné
2021-02-19 14:57 ` Boris Ostrovsky
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