Re: [Xen-devel] [PATCH V3] x86/monitor: Disallow setting mem_access_emulate_each_rep when vm_event is NULL

[Tamas K Lengyel]

On Tue, May 3, 2016 at 2:18 AM, Razvan Cojocaru 
wrote:

> On 05/03/2016 11:14 AM, Jan Beulich wrote:
>  On 29.04.16 at 18:12,  wrote:
> >> On 04/09/16 08:54, Razvan Cojocaru wrote:
> >>> It is meaningless (and potentially dangerous - see
> hvmemul_virtual_to_linear())
> >>> to set mem_access_emulate_each_rep before xc_monitor_enable() (which
> allocates
> >>> vcpu->arch.vm_event) has been called, so return an error from the
> >>> XEN_DOMCTL_MONITOR_OP_EMULATE_EACH_REP hypercall when that is the case.
> >>>
> >>> Signed-off-by: Razvan Cojocaru 
> >>> Reviewed-by: Andrew Cooper 
> >>>
> >>> ---
> >>> Changes since V2:
> >>>  - Updated the if() condition as recommended by Andrew Cooper.
> >>>  - Added Andrew Cooper's Reviewed-by.
> >>> ---
> >>>  xen/include/asm-x86/monitor.h | 16 +---
> >>>  1 file changed, 13 insertions(+), 3 deletions(-)
> >>>
> >>> diff --git a/xen/include/asm-x86/monitor.h
> b/xen/include/asm-x86/monitor.h
> >>> index 0954b59..d367099 100644
> >>> --- a/xen/include/asm-x86/monitor.h
> >>> +++ b/xen/include/asm-x86/monitor.h
> >>> @@ -32,19 +32,29 @@
> >>>  static inline
> >>>  int arch_monitor_domctl_op(struct domain *d, struct
> xen_domctl_monitor_op *mop)
> >>>  {
> >>> +int rc = 0;
> >>> +
> >>>  switch ( mop->op )
> >>>  {
> >>>  case XEN_DOMCTL_MONITOR_OP_EMULATE_EACH_REP:
> >>>  domain_pause(d);
> >>> -d->arch.mem_access_emulate_each_rep = !!mop->event;
> >>> +/*
> >>> + * Enabling mem_access_emulate_each_rep without a vm_event
> subscriber
> >>> + * is meaningless.
> >>> + */
> >>> +if ( d->max_vcpus && d->vcpu[0] && d->vcpu[0]->arch.vm_event )
> >>> +d->arch.mem_access_emulate_each_rep = !!mop->event;
> >>> +else
> >>> +rc = -EINVAL;
> >>> +
> >>>  domain_unpause(d);
> >>>  break;
> >>>
> >>>  default:
> >>> -return -EOPNOTSUPP;
> >>> +rc = -EOPNOTSUPP;
> >>>  }
> >>>
> >>> -return 0;
> >>> +return rc;
> >>>  }
> >>>
> >>>  int arch_monitor_domctl_event(struct domain *d,
> >>
> >> According to the previous list discussion with Andrew Cooper, this fix
> >> might be considered for the 4.7 release, so CC-ing Wei for a release
> >> ack, as suggested.
> >
> > Even if - without the pending ./MAINTAINERS adjustment - not
> > formally required, I don't understand why you didn't Cc Tamas on
> > this patch. I don't think this should go in without his ack.
>
> Of course, I was under the impression that he was in the recipients list
> (I let scripts/maintaners.pl do the work and didn't pay much attention
> to its output).
>
> By all means.
>

The maintainers file wasn't covering this header properly. Fixed in my
other patch-set.

Acked-by: Tamas K Lengyel 
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Re: [Xen-devel] [PATCH V3] x86/monitor: Disallow setting mem_access_emulate_each_rep when vm_event is NULL

[Razvan Cojocaru]

On 05/03/2016 11:14 AM, Jan Beulich wrote:
 On 29.04.16 at 18:12,  wrote:
>> On 04/09/16 08:54, Razvan Cojocaru wrote:
>>> It is meaningless (and potentially dangerous - see 
>>> hvmemul_virtual_to_linear())
>>> to set mem_access_emulate_each_rep before xc_monitor_enable() (which 
>>> allocates
>>> vcpu->arch.vm_event) has been called, so return an error from the
>>> XEN_DOMCTL_MONITOR_OP_EMULATE_EACH_REP hypercall when that is the case.
>>>
>>> Signed-off-by: Razvan Cojocaru 
>>> Reviewed-by: Andrew Cooper 
>>>
>>> ---
>>> Changes since V2:
>>>  - Updated the if() condition as recommended by Andrew Cooper.
>>>  - Added Andrew Cooper's Reviewed-by.
>>> ---
>>>  xen/include/asm-x86/monitor.h | 16 +---
>>>  1 file changed, 13 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/xen/include/asm-x86/monitor.h b/xen/include/asm-x86/monitor.h
>>> index 0954b59..d367099 100644
>>> --- a/xen/include/asm-x86/monitor.h
>>> +++ b/xen/include/asm-x86/monitor.h
>>> @@ -32,19 +32,29 @@
>>>  static inline
>>>  int arch_monitor_domctl_op(struct domain *d, struct xen_domctl_monitor_op 
>>> *mop)
>>>  {
>>> +int rc = 0;
>>> +
>>>  switch ( mop->op )
>>>  {
>>>  case XEN_DOMCTL_MONITOR_OP_EMULATE_EACH_REP:
>>>  domain_pause(d);
>>> -d->arch.mem_access_emulate_each_rep = !!mop->event;
>>> +/*
>>> + * Enabling mem_access_emulate_each_rep without a vm_event 
>>> subscriber
>>> + * is meaningless.
>>> + */
>>> +if ( d->max_vcpus && d->vcpu[0] && d->vcpu[0]->arch.vm_event )
>>> +d->arch.mem_access_emulate_each_rep = !!mop->event;
>>> +else
>>> +rc = -EINVAL;
>>> +
>>>  domain_unpause(d);
>>>  break;
>>>  
>>>  default:
>>> -return -EOPNOTSUPP;
>>> +rc = -EOPNOTSUPP;
>>>  }
>>>  
>>> -return 0;
>>> +return rc;
>>>  }
>>>  
>>>  int arch_monitor_domctl_event(struct domain *d,
>>
>> According to the previous list discussion with Andrew Cooper, this fix
>> might be considered for the 4.7 release, so CC-ing Wei for a release
>> ack, as suggested.
> 
> Even if - without the pending ./MAINTAINERS adjustment - not
> formally required, I don't understand why you didn't Cc Tamas on
> this patch. I don't think this should go in without his ack.

Of course, I was under the impression that he was in the recipients list
(I let scripts/maintaners.pl do the work and didn't pay much attention
to its output).

By all means.


Thanks,
Razvan

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Re: [Xen-devel] [PATCH V3] x86/monitor: Disallow setting mem_access_emulate_each_rep when vm_event is NULL

[Jan Beulich]

>>> On 29.04.16 at 18:12,  wrote:
> On 04/09/16 08:54, Razvan Cojocaru wrote:
>> It is meaningless (and potentially dangerous - see 
>> hvmemul_virtual_to_linear())
>> to set mem_access_emulate_each_rep before xc_monitor_enable() (which 
>> allocates
>> vcpu->arch.vm_event) has been called, so return an error from the
>> XEN_DOMCTL_MONITOR_OP_EMULATE_EACH_REP hypercall when that is the case.
>> 
>> Signed-off-by: Razvan Cojocaru 
>> Reviewed-by: Andrew Cooper 
>> 
>> ---
>> Changes since V2:
>>  - Updated the if() condition as recommended by Andrew Cooper.
>>  - Added Andrew Cooper's Reviewed-by.
>> ---
>>  xen/include/asm-x86/monitor.h | 16 +---
>>  1 file changed, 13 insertions(+), 3 deletions(-)
>> 
>> diff --git a/xen/include/asm-x86/monitor.h b/xen/include/asm-x86/monitor.h
>> index 0954b59..d367099 100644
>> --- a/xen/include/asm-x86/monitor.h
>> +++ b/xen/include/asm-x86/monitor.h
>> @@ -32,19 +32,29 @@
>>  static inline
>>  int arch_monitor_domctl_op(struct domain *d, struct xen_domctl_monitor_op 
>> *mop)
>>  {
>> +int rc = 0;
>> +
>>  switch ( mop->op )
>>  {
>>  case XEN_DOMCTL_MONITOR_OP_EMULATE_EACH_REP:
>>  domain_pause(d);
>> -d->arch.mem_access_emulate_each_rep = !!mop->event;
>> +/*
>> + * Enabling mem_access_emulate_each_rep without a vm_event 
>> subscriber
>> + * is meaningless.
>> + */
>> +if ( d->max_vcpus && d->vcpu[0] && d->vcpu[0]->arch.vm_event )
>> +d->arch.mem_access_emulate_each_rep = !!mop->event;
>> +else
>> +rc = -EINVAL;
>> +
>>  domain_unpause(d);
>>  break;
>>  
>>  default:
>> -return -EOPNOTSUPP;
>> +rc = -EOPNOTSUPP;
>>  }
>>  
>> -return 0;
>> +return rc;
>>  }
>>  
>>  int arch_monitor_domctl_event(struct domain *d,
> 
> According to the previous list discussion with Andrew Cooper, this fix
> might be considered for the 4.7 release, so CC-ing Wei for a release
> ack, as suggested.

Even if - without the pending ./MAINTAINERS adjustment - not
formally required, I don't understand why you didn't Cc Tamas on
this patch. I don't think this should go in without his ack.

Jan


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Re: [Xen-devel] [PATCH V3] x86/monitor: Disallow setting mem_access_emulate_each_rep when vm_event is NULL

[Wei Liu]

On Fri, Apr 29, 2016 at 07:12:47PM +0300, Razvan Cojocaru wrote:
> On 04/09/16 08:54, Razvan Cojocaru wrote:
> > It is meaningless (and potentially dangerous - see 
> > hvmemul_virtual_to_linear())
> > to set mem_access_emulate_each_rep before xc_monitor_enable() (which 
> > allocates
> > vcpu->arch.vm_event) has been called, so return an error from the
> > XEN_DOMCTL_MONITOR_OP_EMULATE_EACH_REP hypercall when that is the case.
> > 
> > Signed-off-by: Razvan Cojocaru 
> > Reviewed-by: Andrew Cooper 

Release-acked-by: Wei Liu 

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Re: [Xen-devel] [PATCH V3] x86/monitor: Disallow setting mem_access_emulate_each_rep when vm_event is NULL

[Razvan Cojocaru]

On 04/09/16 08:54, Razvan Cojocaru wrote:
> It is meaningless (and potentially dangerous - see 
> hvmemul_virtual_to_linear())
> to set mem_access_emulate_each_rep before xc_monitor_enable() (which allocates
> vcpu->arch.vm_event) has been called, so return an error from the
> XEN_DOMCTL_MONITOR_OP_EMULATE_EACH_REP hypercall when that is the case.
> 
> Signed-off-by: Razvan Cojocaru 
> Reviewed-by: Andrew Cooper 
> 
> ---
> Changes since V2:
>  - Updated the if() condition as recommended by Andrew Cooper.
>  - Added Andrew Cooper's Reviewed-by.
> ---
>  xen/include/asm-x86/monitor.h | 16 +---
>  1 file changed, 13 insertions(+), 3 deletions(-)
> 
> diff --git a/xen/include/asm-x86/monitor.h b/xen/include/asm-x86/monitor.h
> index 0954b59..d367099 100644
> --- a/xen/include/asm-x86/monitor.h
> +++ b/xen/include/asm-x86/monitor.h
> @@ -32,19 +32,29 @@
>  static inline
>  int arch_monitor_domctl_op(struct domain *d, struct xen_domctl_monitor_op 
> *mop)
>  {
> +int rc = 0;
> +
>  switch ( mop->op )
>  {
>  case XEN_DOMCTL_MONITOR_OP_EMULATE_EACH_REP:
>  domain_pause(d);
> -d->arch.mem_access_emulate_each_rep = !!mop->event;
> +/*
> + * Enabling mem_access_emulate_each_rep without a vm_event subscriber
> + * is meaningless.
> + */
> +if ( d->max_vcpus && d->vcpu[0] && d->vcpu[0]->arch.vm_event )
> +d->arch.mem_access_emulate_each_rep = !!mop->event;
> +else
> +rc = -EINVAL;
> +
>  domain_unpause(d);
>  break;
>  
>  default:
> -return -EOPNOTSUPP;
> +rc = -EOPNOTSUPP;
>  }
>  
> -return 0;
> +return rc;
>  }
>  
>  int arch_monitor_domctl_event(struct domain *d,

Hello,

According to the previous list discussion with Andrew Cooper, this fix
might be considered for the 4.7 release, so CC-ing Wei for a release
ack, as suggested.


Thanks,
Razvan

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[Xen-devel] [PATCH V3] x86/monitor: Disallow setting mem_access_emulate_each_rep when vm_event is NULL

[Razvan Cojocaru]

It is meaningless (and potentially dangerous - see hvmemul_virtual_to_linear())
to set mem_access_emulate_each_rep before xc_monitor_enable() (which allocates
vcpu->arch.vm_event) has been called, so return an error from the
XEN_DOMCTL_MONITOR_OP_EMULATE_EACH_REP hypercall when that is the case.

Signed-off-by: Razvan Cojocaru 
Reviewed-by: Andrew Cooper 

---
Changes since V2:
 - Updated the if() condition as recommended by Andrew Cooper.
 - Added Andrew Cooper's Reviewed-by.
---
 xen/include/asm-x86/monitor.h | 16 +---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/xen/include/asm-x86/monitor.h b/xen/include/asm-x86/monitor.h
index 0954b59..d367099 100644
--- a/xen/include/asm-x86/monitor.h
+++ b/xen/include/asm-x86/monitor.h
@@ -32,19 +32,29 @@
 static inline
 int arch_monitor_domctl_op(struct domain *d, struct xen_domctl_monitor_op *mop)
 {
+int rc = 0;
+
 switch ( mop->op )
 {
 case XEN_DOMCTL_MONITOR_OP_EMULATE_EACH_REP:
 domain_pause(d);
-d->arch.mem_access_emulate_each_rep = !!mop->event;
+/*
+ * Enabling mem_access_emulate_each_rep without a vm_event subscriber
+ * is meaningless.
+ */
+if ( d->max_vcpus && d->vcpu[0] && d->vcpu[0]->arch.vm_event )
+d->arch.mem_access_emulate_each_rep = !!mop->event;
+else
+rc = -EINVAL;
+
 domain_unpause(d);
 break;
 
 default:
-return -EOPNOTSUPP;
+rc = -EOPNOTSUPP;
 }
 
-return 0;
+return rc;
 }
 
 int arch_monitor_domctl_event(struct domain *d,
-- 
1.9.1


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