Re: [Xen-devel] [PATCH V3 16/29] x86/vvtd: decode interrupt attribute from IRTE

[Chao Gao <chao.gao@xxxxxxxxx>]

On Thu, Oct 19, 2017 at 03:39:44PM +0100, Roger Pau Monné wrote:
>On Thu, Sep 21, 2017 at 11:01:57PM -0400, Lan Tianyu wrote:
>> From: Chao Gao <chao.gao@xxxxxxxxx>
>> 
>> Without interrupt remapping, interrupt attributes can be extracted from
>> msi message or IOAPIC RTE. However, with interrupt remapping enabled,
>> the attributes are enclosed in the associated IRTE. This callback is
>> for cases in which the caller wants to acquire interrupt attributes, for
>> example:
>> 1. vioapic_get_vector(). With vIOMMU, the RTE may don't contain vector.
>                                                    ^ not
>> 2. perform EOI which is always based on the interrupt vector.
>> 
>> Signed-off-by: Chao Gao <chao.gao@xxxxxxxxx>
>> Signed-off-by: Lan Tianyu <tianyu.lan@xxxxxxxxx>
>> ---
>> v3:
>>  - add example cases in which we will use this function.
>> ---
>>  xen/drivers/passthrough/vtd/vvtd.c | 23 ++++++++++++++++++++++-
>>  1 file changed, 22 insertions(+), 1 deletion(-)
>> 
>> diff --git a/xen/drivers/passthrough/vtd/vvtd.c 
>> b/xen/drivers/passthrough/vtd/vvtd.c
>> index 90c00f5..5e22ace 100644
>> --- a/xen/drivers/passthrough/vtd/vvtd.c
>> +++ b/xen/drivers/passthrough/vtd/vvtd.c
>> @@ -516,6 +516,26 @@ static int vvtd_handle_irq_request(struct domain *d,
>>                           irte.remap.tm);
>>  }
>>  
>> +static int vvtd_get_irq_info(struct domain *d,
>> +                             struct arch_irq_remapping_request *irq,
>> +                             struct arch_irq_remapping_info *info)
>> +{
>> +    int ret;
>> +    struct iremap_entry irte;
>> +    struct vvtd *vvtd = domain_vvtd(d);
>
>I've realized that some of the helpers perform a if (!vvtd ) return
>check, while others don't (like this one). Are some handlers expected
>to be called without a vIOMMU?

No. I forgot to check the existence of a vIOMMU here.

Thanks
chao


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