Re: [Xen-devel] [PATCH v2 13/25] arm/altp2m: Make p2m_restore_state ready for altp2m.

[Sergej Proskurin <proskurin@xxxxxxxxxxxxx>]

Hi Julien,


On 08/04/2016 01:55 PM, Julien Grall wrote:
> Hello,
>
> On 01/08/16 18:10, Sergej Proskurin wrote:
>> This commit adapts the function "p2m_restore_state" in a way that the
>> currently active altp2m table is considered during state restoration.
>>
>> Signed-off-by: Sergej Proskurin <proskurin@xxxxxxxxxxxxx>
>> ---
>> Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
>> Cc: Julien Grall <julien.grall@xxxxxxx>
>> ---
>>  xen/arch/arm/p2m.c           | 4 +++-
>>  xen/include/asm-arm/altp2m.h | 3 +++
>>  2 files changed, 6 insertions(+), 1 deletion(-)
>>
>> diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
>> index 8afea11..bcad51f 100644
>> --- a/xen/arch/arm/p2m.c
>> +++ b/xen/arch/arm/p2m.c
>> @@ -115,7 +115,9 @@ void p2m_save_state(struct vcpu *p)
>>  void p2m_restore_state(struct vcpu *n)
>>  {
>>      register_t hcr;
>> -    struct p2m_domain *p2m = &n->domain->arch.p2m;
>> +    struct domain *d = n->domain;
>> +    struct p2m_domain *p2m = unlikely(altp2m_active(d)) ?
>> +                             altp2m_get_altp2m(n) : p2m_get_hostp2m(d);
>
> This seems to be a common idiom in multiple place. I would like to see
> a helper for this.

Ok.

>
> However, I think this could be avoided if you store a pointer to the
> p2m directly in arch_vcpu.
>

This answers my question in the previous patch (patch #12). It would
definitely make thinks easier in some cases. I will check if we can do
it without too much troubles.

>>
>>      if ( is_idle_vcpu(n) )
>>          return;
>> diff --git a/xen/include/asm-arm/altp2m.h b/xen/include/asm-arm/altp2m.h
>> index 790bb33..a6496b7 100644
>> --- a/xen/include/asm-arm/altp2m.h
>> +++ b/xen/include/asm-arm/altp2m.h
>> @@ -49,6 +49,9 @@ void altp2m_teardown(struct domain *d);
>>  void altp2m_vcpu_initialise(struct vcpu *v);
>>  void altp2m_vcpu_destroy(struct vcpu *v);
>>
>> +/* Get current alternate p2m table. */
>> +struct p2m_domain *altp2m_get_altp2m(struct vcpu *v);
>> +
>
> This should be added in the patch where the function was added (i.e
> patch #8).
>

Ok.

>>  /* Switch alternate p2m for entire domain */
>>  int altp2m_switch_domain_altp2m_by_id(struct domain *d,
>>                                        unsigned int idx);
>>
>

Best regards,
~Sergej


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