Re: [Xen-devel] [PATCH] hvm/monitor: fix usage of the control register mask

[Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx>]

On 02/16/2018 02:18 PM, Roger Pau Monne wrote:
> Previous usage is not correct and would prevent certain updates from
> being notified to the monitor client.
> 
> For example if (value ^ old) == (PGE | PSE) and mask == PGE this
> update would not be notified.
> 
> Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
> ---
> Cc: Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx>
> Cc: Tamas K Lengyel <tamas@xxxxxxxxxxxxx>
> Cc: Jan Beulich <jbeulich@xxxxxxxx>
> Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> ---
>  xen/arch/x86/hvm/monitor.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/xen/arch/x86/hvm/monitor.c b/xen/arch/x86/hvm/monitor.c
> index 131b85209f..04665c5f6c 100644
> --- a/xen/arch/x86/hvm/monitor.c
> +++ b/xen/arch/x86/hvm/monitor.c
> @@ -39,7 +39,7 @@ bool hvm_monitor_cr(unsigned int index, unsigned long 
> value, unsigned long old)
>      if ( (ad->monitor.write_ctrlreg_enabled & ctrlreg_bitmask) &&
>           (!(ad->monitor.write_ctrlreg_onchangeonly & ctrlreg_bitmask) ||
>            value != old) &&
> -         (!((value ^ old) & ad->monitor.write_ctrlreg_mask[index])) )
> +         ((value ^ old) & ~ad->monitor.write_ctrlreg_mask[index]) )
>      {
>          bool sync = ad->monitor.write_ctrlreg_sync & ctrlreg_bitmask;

Acked-by: Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx>


Thanks,
Razvan

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