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.
I don't really understand the iommu_pasid terminology. Either it is a
pasid passed through the PCI transaction or it is the default pasid
found in rid2passid ce field. So that's a pasid both ways ;-) can't you
simply call it pasid.
> +{
> + VTDContextCacheEntry *cc_entry = &vtd_as->context_cache_entry;
> + IntelIOMMUState *s = vtd_as->iommu_state;
> + uint8_t bus_num = pci_bus_num(vtd_as->bus);
> + uint8_t devfn = vtd_as->devfn;
> + VTDContextEntry ce;
> + int ret;
> +
> + if (cc_entry->context_cache_gen == s->context_cache_gen) {
> + ce = cc_entry->context_entry;
> + } else {
> + ret = vtd_dev_to_context_entry(s, bus_num, devfn, &ce);
> + if (ret) {
> + return ret;
> + }
> + }
if the above pattern is used at many locations I still think it may be
valuable to have a _locked helper.
> +
> + /* 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;
why target? can't you name it key instead?
> + 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 */
same here
> +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)
> {
Thanks
Eric
