Re: [Xen-devel] [PATCH v2 2/5] x86/domain: Initialise vcpu debug registers correctly

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Mon, Oct 15, 2018 at 11:36:17AM +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
> be asserted, even though a debug exception from a transaction hasn't actually
> been observed.
> 
> Introduce arch_vcpu_regs_init() to set various architectural defaults, and
> reuse this in the hvm_vcpu_reset_state() path.
> 
> Architecturally, %edx's init state contains the processors model information,
> and 0xf looks to be a remnant of the old Intel processors.  We clearly have no
> software which cares, seeing as it is wrong for the last decade's worth of
> Intel hardware and for all other vendors, so lets use the value 0 for
> simplicity.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>

Reviewed-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>

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