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Re: [Xen-devel] [PATCH v5 2/7] x86/xpti: don't flush TLB twice when switching to 64-bit pv context

On 06/04/18 13:21, Andrew Cooper wrote:
> On 06/04/18 08:52, Juergen Gross wrote:
>> When switching to a 64-bit pv context the TLB is flushed twice today:
>> the first time when switching to the new address space in
>> write_ptbase(), the second time when switching to guest mode in
>> restore_to_guest.
>> Limit the first flush to non-global entries in that case.
>> Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
>> Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
> This isn't safe.  If any speculation/prefetching happens into the new
> guest mappings, we will get machine check exceptions.

Okay, I'll drop that patch (it is more or less undone by patch 4


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