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Re: [Xen-devel] [PATCH for-4.11 v2 1/3] x86/HVM: don't cause #NM to be raised in Xen

> From: Jan Beulich [mailto:JBeulich@xxxxxxxx]
> Sent: Tuesday, June 26, 2018 2:36 PM
> The changes for XSA-267 did not touch management of CR0.TS for HVM
> guests. In fully eager mode this bit should never be set when
> respective vCPU-s are active, or else hvmemul_get_fpu() might leave it
> wrongly set, leading to #NM in hypervisor context.
> {svm,vmx}_enter() and {svm,vmx}_fpu_dirty_intercept() become
> unreachable
> this way. Explicit {svm,vmx}_fpu_leave() invocations need to be guarded
> now.
> With no CR0.TS management necessary in fully eager mode, there's also no
> need anymore to intercept #NM.
> Reported-by: Charles Arnold <carnold@xxxxxxxx>
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>

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