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Re: [Xen-devel] [PATCH] x86/xstate: don't clobber or leak state when using XSAVES

On Mon, Apr 25, 2016 at 01:07:54AM -0600, Jan Beulich wrote:
> Commit 4d27280572 ("x86/xsaves: fix overwriting between non-lazy/lazy
> xsaves") switched to always saving full state when using compacted
> format (which is the only one XSAVES allows). It didn't, however, also
> adjust the restore side: In order to save full state, we also need to
> make sure we always load full state, or else the subject vCPU's state
> would get clobbered by that of the vCPU which happened to last have in
> use the respective component(s).
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
> ---
> As to inclusion in 4.7: This is a fiy to a _latent_ bug, i.e. not one
> currently exposed (since XSTATE_XSAVES_ONLY is zero right now).
> Nevertheless I think we should avoid releasing code with such an issue.

I agree. Subject to review from Andrew / Shuai:

Release-acked-by: Wei Liu <wei.liu2@xxxxxxxxxx>

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