From: "Jan Beulich" <JBeulich@suse.com>
To: George Dunlap <dunlapg@umich.edu>
Cc: xen-devel <xen-devel@lists.xenproject.org>
Subject: Re: backporting considerations (Re: [PATCH v9 0/9] xen/x86: various XPTI speedups)
Date: Wed, 16 May 2018 10:01:42 -0600 [thread overview]
Message-ID: <5AFC55E602000078001C35C5@prv1-mh.provo.novell.com> (raw)
In-Reply-To: <CAFLBxZYyspzYvD=hDq8aK5G2OFT+7nGFGE0dTy3hYpirS8uwMg@mail.gmail.com>
>>> On 16.05.18 at 16:53, <dunlapg@umich.edu> wrote:
> On Wed, May 16, 2018 at 3:01 PM, Jan Beulich <JBeulich@suse.com> wrote:
>>>>> On 16.05.18 at 15:18, <dunlapg@umich.edu> wrote:
>>> If the latter, I think the same argument applies: turning on XPTI is a
>>> requirement for many people, and thus represents a pretty hefty
>>> performance regression. While we don't need to backport normal fixes
>>> to security-only releases, we should certainly try to avoid
>>> regressions.
>>
>> I don't think we would have addressed non-security fallout (or other
>> than really severe regressions) from other security patches in the
>> past on security only branches. People caring about performance
>> should upgrade.
>
> If a security patch, when backported to 4.6, broke some fairly
> critical bit of functionality (say, openvswitch support), you would
> oppose a subsequent patch which would fix that regression?
>
> That doesn't seem very reasonable to me. Users shouldn't have to
> choose between being vulnerable to a security issue and losing
> functionality which was working at the last release. Otherwise,
> what's the point of having "security supported" releases?
Note how I did say "or other than really severe regressions". I think
your "fairly critical bit of functionality" falls into exactly that area.
Jan
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next prev parent reply other threads:[~2018-05-16 16:01 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-26 11:33 [PATCH v9 0/9] xen/x86: various XPTI speedups Juergen Gross
2018-04-26 11:33 ` [PATCH v9 1/9] x86/xpti: avoid copying L4 page table contents when possible Juergen Gross
2018-04-26 14:01 ` Tim Deegan
2018-04-26 11:33 ` [PATCH v9 2/9] xen/x86: add a function for modifying cr3 Juergen Gross
2018-04-26 11:33 ` [PATCH v9 3/9] xen/x86: support per-domain flag for xpti Juergen Gross
2018-04-27 7:55 ` Sergey Dyasli
2018-04-27 7:59 ` Juergen Gross
2018-04-27 8:15 ` Jan Beulich
2018-05-04 15:06 ` Wei Liu
2018-04-26 11:33 ` [PATCH v9 4/9] xen/x86: use invpcid for flushing the TLB Juergen Gross
2018-04-26 11:33 ` [PATCH v9 5/9] xen/x86: disable global pages for domains with XPTI active Juergen Gross
2018-04-26 11:33 ` [PATCH v9 6/9] xen/x86: use flag byte for decision whether xen_cr3 is valid Juergen Gross
2018-04-26 11:33 ` [PATCH v9 7/9] xen/x86: convert pv_guest_cr4_to_real_cr4() to a function Juergen Gross
2018-04-26 11:33 ` [PATCH v9 8/9] xen/x86: add some cr3 helpers Juergen Gross
2018-04-26 11:33 ` [PATCH v9 9/9] xen/x86: use PCID feature Juergen Gross
2018-05-01 9:28 ` [PATCH v9 0/9] xen/x86: various XPTI speedups Andrew Cooper
2018-05-02 10:38 ` Juergen Gross
2018-05-03 17:41 ` Andrew Cooper
2018-05-03 18:41 ` Juergen Gross
2018-05-04 14:59 ` Wei Liu
2018-05-16 9:06 ` backporting considerations (Re: [PATCH v9 0/9] xen/x86: various XPTI speedups) Jan Beulich
2018-05-16 13:18 ` George Dunlap
2018-05-16 14:01 ` Jan Beulich
2018-05-16 14:53 ` George Dunlap
2018-05-16 16:01 ` Jan Beulich [this message]
2018-05-16 16:42 ` George Dunlap
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