Re: [Xen-devel] [PATCH 5/7] x86/shadow: Use the pagewalk reserved bits helpers

[Tim Deegan <tim@xxxxxxx>]

At 14:03 +0000 on 27 Feb (1488204196), Andrew Cooper wrote:
> The shadow logic should never create a shadow of a guest PTE which contains

Nit: a _valid/present_ shadow.

> reserved bits from the guests point of view.  Such a shadowed entry might not
> cause #PF[RSVD] when walked by hardware, thus won't behave architecturally
> from the guests point of view.

The shadow doesn't have to cause #PF(rsvd), any pagefault will do, so
long as the shadow pagefault handler turns it into rsvd.  This patch
uses shadow_l1e_empty(), which doesn't cause #PF(rsvd), and is fine.

Tim.

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