Re: [Xen-devel] [PATCH 2/6] x86: save GUEST_BNDCFGS on context switch...

[Paul Durrant <Paul.Durrant@xxxxxxxxxx>]

> -----Original Message-----
> From: Jan Beulich [mailto:JBeulich@xxxxxxxx]
> Sent: 08 March 2019 16:43
> To: Paul Durrant <Paul.Durrant@xxxxxxxxxx>
> Cc: Andrew Cooper <Andrew.Cooper3@xxxxxxxxxx>; Roger Pau Monne 
> <roger.pau@xxxxxxxxxx>; Wei Liu
> <wei.liu2@xxxxxxxxxx>; Jun Nakajima <jun.nakajima@xxxxxxxxx>; Kevin Tian 
> <kevin.tian@xxxxxxxxx>; xen-
> devel <xen-devel@xxxxxxxxxxxxxxxxxxxx>
> Subject: Re: [PATCH 2/6] x86: save GUEST_BNDCFGS on context switch...
> 
> >>> On 07.01.19 at 13:02, <paul.durrant@xxxxxxxxxx> wrote:
> > ...to avoid the need for a VMCS reload when the value of MSR_IA32_BNDCFGS is
> > read by the tool-stack.
> 
> Is this a good trade-off? I.e. are tool stack reads at least as frequent as
> context switches?
> 

In the absence of any comment from Andrew on relative cost, I'll drop this.

> Jan
> 


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