Re: [Xen-devel] [PATCH v2 3/5] tools/dombuilder: Initialise vcpu debug registers correctly

[Wei Liu <wei.liu2@xxxxxxxxxx>]

On Mon, Oct 15, 2018 at 11:36:18AM +0100, Andrew Cooper wrote:
> In particular, initialising %dr6 with the value 0 is buggy, because on
> hardware supporting Transnational Memory, it will cause the sticky RTM bit to

Typo "Transnational"

> be asserted, even though a debug exception from a transaction hasn't actually
> been observed.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
> ---
> CC: Ian Jackson <Ian.Jackson@xxxxxxxxxx>
> CC: Wei Liu <wei.liu2@xxxxxxxxxx>
> CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
> 
> The correct way to do this would be to get/modify/set the vcpu state, but it
> turns out that is impossible for an HVM vcpu which hasn't yet had state set.
> Fixing that is going to take some substantial untangling from implications in
> the migration stream.

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

I haven't checked the manual re the value of dr6, but I trust Jan and
Roger's review on this.

Wei.

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