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From: "Roger Pau Monné" <roger.pau@citrix.com>
To: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Xen-devel <xen-devel@lists.xenproject.org>,
	Jan Beulich <JBeulich@suse.com>, Wei Liu <wl@xen.org>,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	Ian Jackson <iwj@xenproject.org>
Subject: Re: [PATCH 1/3] Revert "x86/msr: drop compatibility #GP handling in guest_{rd,wr}msr()"
Date: Wed, 17 Mar 2021 09:40:42 +0100	[thread overview]
Message-ID: <YFHAiv5VOK1wFcs2@Air-de-Roger> (raw)
In-Reply-To: <20210316161844.1658-2-andrew.cooper3@citrix.com>

On Tue, Mar 16, 2021 at 04:18:42PM +0000, Andrew Cooper wrote:
> In hindsight, this was a poor move.  Some of these MSRs require probing for,
> causing unhelpful spew into xl dmesg, as well as spew from unit tests
> explicitly checking behaviour.
> 
> This restores behaviour close to that of Xen 4.14.

I think it might be worth adding that guest access to those MSRs will
now always trigger a #GP, even when msr_relaxed is used. This is
however fine, as that's not a regression when compared to older Xen
versions, where access to the MSRs also trigger a #GP
unconditionally.

I assume the wrmsr side is added so that when using msr_relaxed Xen
also injects a #GP for writes to those MSRs, as it would do for
reads?

Thanks, Roger.


  parent reply	other threads:[~2021-03-17  8:41 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-16 16:18 [PATCH for-4.15 0/3] x86/msr: Fixes for XSA-351 Andrew Cooper
2021-03-16 16:18 ` [PATCH 1/3] Revert "x86/msr: drop compatibility #GP handling in guest_{rd,wr}msr()" Andrew Cooper
2021-03-16 16:58   ` Jan Beulich
2021-03-19 12:59     ` Andrew Cooper
2021-03-19 13:56       ` Jan Beulich
2021-03-19 14:03         ` Andrew Cooper
2021-03-17  8:40   ` Roger Pau Monné [this message]
2021-03-17 13:37   ` Ian Jackson
2021-03-17 13:45     ` Andrew Cooper
2021-03-17 14:46       ` Ian Jackson
2021-03-17 15:06         ` Roger Pau Monné
2021-03-17 15:15           ` Ian Jackson
2021-03-26 14:25             ` [PATCH for-4.15 0/3] x86/msr: Fixes for XSA-351 [and 1 more messages] Ian Jackson
2021-03-26 14:30               ` Ian Jackson
2021-03-29  8:58                 ` Roger Pau Monné
2021-03-18  9:37         ` [PATCH 1/3] Revert "x86/msr: drop compatibility #GP handling in guest_{rd,wr}msr()" Jan Beulich
2021-03-18  9:35     ` Jan Beulich
2021-03-19 13:11       ` Andrew Cooper
2021-03-16 16:18 ` [PATCH 2/3] x86/msr: Forward port XSA-351 changes from 4.14 Andrew Cooper
2021-03-17  8:52   ` Roger Pau Monné
2021-03-19 13:19     ` Andrew Cooper
2021-03-16 16:18 ` [PATCH 3/3] x86/msr: Fix Solaris and turbostat following XSA-351 Andrew Cooper
2021-03-16 16:56   ` Roger Pau Monné
2021-03-16 17:45     ` Boris Ostrovsky
2021-03-16 21:20     ` Andrew Cooper
2021-03-17  8:32       ` Roger Pau Monné
2021-03-19 13:23         ` Andrew Cooper
2021-03-17  9:26   ` Jan Beulich
2021-03-26 15:08 ` [PATCH for-4.15 v1.1 1/3] Revert "x86/msr: drop compatibility #GP handling in guest_{rd,wr}msr()" Jan Beulich
2021-03-26 15:13   ` Ian Jackson

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