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    SubjectRe: [PATCH 4.19 041/361] x86/speculation: Enable cross-hyperthread spectre v2 STIBP mitigation
    On Wed, Nov 21, 2018 at 09:47:48AM -0800, Tim Chen wrote:
    > On 11/21/2018 05:56 AM, Greg Kroah-Hartman wrote:
    > > On Wed, Nov 21, 2018 at 02:21:15PM +0100, Jiri Kosina wrote:
    > >> On Sun, 11 Nov 2018, Greg Kroah-Hartman wrote:
    > >>
    > >>> 4.19-stable review patch. If anyone has any objections, please let me know.
    > >>
    > >> Greg, please drop this patch from all -stable for now. Version that
    > >> wouldn't have such performance impact is being worked on.
    > >
    > > Is it reverted in Linus's tree? If not, then anything that comes "later
    > > on" will not apply here, right?
    > >
    > > I see the thread asking about this, but I got really conflicting
    > > messages here, and now it's in all of the latest releases, and no
    > > testing seems to have uncovered issues. Is it just a "slow down"
    > > problem?
    >
    > Greg,
    >
    > It could be a big slow down in excess of 20% for some applications.
    > And cross sibling Spectre v2 attack is quite hard to pull off.
    >
    > So till we have the accompanying patchset that only apply STIBP on processes
    > that really need it instead of universally, it should be withheld from
    > stable.

    Ok, now reverted, thanks.

    greg k-h

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