RE: [PATCH v3 09/20] intel_iommu: Introduce two helpers vtd_as_from/to_iommu_pasid_locked
>-Original Message-
>From: Eric Auger
>Subject: Re: [PATCH v3 09/20] intel_iommu: Introduce two helpers
>vtd_as_from/to_iommu_pasid_locked
>
>Hi Zhenzhong,
>
>On 7/8/25 1:05 PM, 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
>> ---
>> 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 15f4393d6f..38e7f7b7be 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 int vtd_as_to_iommu_pasid_locked(VTDAddressSpace *vtd_as,
>> +uint32_t *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;
>you need to retrieve the ce only if vtd_as->pasid. So this can be moved
>to the conditional block below.
Good idea! Will do.
Thanks
Zhenzhong
Re: [PATCH v3 09/20] intel_iommu: Introduce two helpers vtd_as_from/to_iommu_pasid_locked
Hi Zhenzhong,
On 7/8/25 1:05 PM, 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
> ---
> 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 15f4393d6f..38e7f7b7be 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 int vtd_as_to_iommu_pasid_locked(VTDAddressSpace *vtd_as,
> +uint32_t *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;
you need to retrieve the ce only if vtd_as->pasid. So this can be moved
to the conditional block below.
> +}
> +}
> +
> +/* 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)
> {
With that addressed,
Reviewed-by: Eric Auger
Eric
[PATCH v3 09/20] intel_iommu: Introduce two helpers vtd_as_from/to_iommu_pasid_locked
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
---
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 15f4393d6f..38e7f7b7be 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 int vtd_as_to_iommu_pasid_locked(VTDAddressSpace *vtd_as,
+uint32_t *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;
+}
+}
+
+/* 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)
{
--
2.47.1
