Hi Eric, >-----Original Message----- >From: Eric Auger <eric.au...@redhat.com> >Subject: Re: [PATCH v2 09/19] intel_iommu: Introduce two helpers >vtd_as_from/to_iommu_pasid_locked > >Hi Zhenzhong, > >On 7/7/25 5:12 AM, Duan, Zhenzhong wrote: >> Hi Eric, >> >>> -----Original Message----- >>> From: Duan, Zhenzhong >>> Subject: RE: [PATCH v2 09/19] intel_iommu: Introduce two helpers >>> vtd_as_from/to_iommu_pasid_locked >>> >>> >>> >>>> -----Original Message----- >>>> From: Eric Auger <eric.au...@redhat.com> >>>> Subject: Re: [PATCH v2 09/19] intel_iommu: Introduce two helpers >>>> vtd_as_from/to_iommu_pasid_locked >>>> >>>> Hi Zhenzhong, >>>> >>>> On 6/20/25 9:18 AM, Zhenzhong Duan wrote: >>>>> PCI device supports two request types, Requests-without-PASID and >>>>> Requests-with-PASID. Requests-without-PASID doesn't include a PASID >TLP >>>>> prefix, IOMMU fetches rid_pasid from context entry and use it as >>> IOMMU's >>>>> pasid to index pasid table. >>>>> >>>>> So we need to translate between PCI's pasid and IOMMU's pasid >specially >>>>> for Requests-without-PASID, e.g., PCI_NO_PASID(-1) <-> rid_pasid. >>>>> For Requests-with-PASID, PCI's pasid and IOMMU's pasid are same >value. >>>>> >>>>> vtd_as_from_iommu_pasid_locked() translates from BDF+iommu_pasid >to >>>> vtd_as >>>>> which contains PCI's pasid vtd_as->pasid. >>>>> >>>>> vtd_as_to_iommu_pasid_locked() translates from BDF+vtd_as->pasid to >>>> iommu_pasid. >>>>> Signed-off-by: Zhenzhong Duan <zhenzhong.d...@intel.com> >>>>> --- >>>>> hw/i386/intel_iommu.c | 58 >>>> +++++++++++++++++++++++++++++++++++++++++++ >>>>> 1 file changed, 58 insertions(+) >>>>> >>>>> diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c >>>>> index 9d4adc9458..8948b8370f 100644 >>>>> --- a/hw/i386/intel_iommu.c >>>>> +++ b/hw/i386/intel_iommu.c >>>>> @@ -1602,6 +1602,64 @@ static int >>>> vtd_dev_to_context_entry(IntelIOMMUState *s, uint8_t bus_num, >>>>> return 0; >>>>> } >>>>> >>>>> +static inline int vtd_as_to_iommu_pasid_locked(VTDAddressSpace >>> *vtd_as, >>>>> + uint32_t >>> *pasid) >>>> Is it meaningful to use inline here and below? Below I guess you do so >>>> to avoid "defined but not used" compilation error but I don't think it >>>> should stay as is. >>> Yes, that's the only reason I define the both inline. >>> Do you have other suggestions to avoid compilation error if not use inline? >> I find I am not clear on above comments yet, do you just want to remove >inline flag? >> Maybe merging the two helpers to other patches using them to avoid inline? >In the past what I did in such situation consisted in introducing a >declaration of the static function before its definition and when the >actual user is introduced, in a subsequent patch, remove the spurious >declaration. >Now, reading >https://www.reddit.com/r/cpp_questions/comments/15kfije/how_to_decide >_if_a_function_should_be_inline_or/, >maybe adding the inline here is not a problem given the compiler may or >may not inline the function.
Thanks for the link, this refreshes my understanding to inline. BRs, Zhenzhong
