>-----Original Message-----
>From: Liu, Yi L <yi.l....@intel.com>
>Subject: Re: [PATCH v1 05/15] intel_iommu: Introduce two helpers
>vtd_as_from/to_iommu_pasid_locked
>
>On 2025/6/6 18:04, Zhenzhong Duan wrote:
>> We already have vtd_find_add_as() to find an AS from BDF+pasid, but this
>> pasid is passed from PCI subsystem. 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.
>
>When reading the first line, it makes me thinking why need the helpers
>since there is already a helper to find. The key is the later part. We need
>to translate the PCI_NO_PASID to ridpasid.
OK, presume you want me to delete first line.
Let me know if you mean not.
Thanks
Zhenzhong
>
>> 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 | 50
>+++++++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 50 insertions(+)
>>
>> diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
>> index 796b71605c..112e09e305 100644
>> --- a/hw/i386/intel_iommu.c
>> +++ b/hw/i386/intel_iommu.c
>> @@ -1617,6 +1617,56 @@ static int
>vtd_as_to_context_entry(VTDAddressSpace *vtd_as, VTDContextEntry *ce)
>> }
>> }
>>
>> +static inline int vtd_as_to_iommu_pasid_locked(VTDAddressSpace *vtd_as,
>> + uint32_t *pasid)
>> +{
>> + VTDContextEntry ce;
>> + int ret;
>> +
>> + ret = vtd_as_to_context_entry(vtd_as, &ce);
>> + if (ret) {
>> + return ret;
>> + }
>> +
>> + /* Translate to iommu pasid if PCI_NO_PASID */
>> + if (vtd_as->pasid == PCI_NO_PASID) {
>> + *pasid = VTD_CE_GET_RID2PASID(&ce);
>> + } else {
>> + *pasid = vtd_as->pasid;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static gboolean vtd_find_as_by_sid_and_iommu_pasid(gpointer key, gpointer
>value,
>> + gpointer user_data)
>> +{
>> + VTDAddressSpace *vtd_as = (VTDAddressSpace *)value;
>> + struct vtd_as_raw_key *target = (struct vtd_as_raw_key *)user_data;
>> + uint16_t sid = PCI_BUILD_BDF(pci_bus_num(vtd_as->bus), vtd_as->devfn);
>> + uint32_t pasid;
>> +
>> + if (vtd_as_to_iommu_pasid_locked(vtd_as, &pasid)) {
>> + return false;
>> + }
>> +
>> + return (pasid == target->pasid) && (sid == target->sid);
>> +}
>> +
>> +/* Translate iommu pasid to vtd_as */
>> +static inline
>> +VTDAddressSpace *vtd_as_from_iommu_pasid_locked(IntelIOMMUState *s,
>> + uint16_t sid, uint32_t
>> pasid)
>> +{
>> + struct vtd_as_raw_key key = {
>> + .sid = sid,
>> + .pasid = pasid
>> + };
>> +
>> + return g_hash_table_find(s->vtd_address_spaces,
>> + vtd_find_as_by_sid_and_iommu_pasid, &key);
>> +}
>> +
>> static int vtd_sync_shadow_page_hook(const IOMMUTLBEvent *event,
>> void *private)
>> {
>
>--
>Regards,
>Yi Liu
