Re: [PATCH v5 18/20] intel_iommu: Introduce a property x-flts for scalable modern mode

[CLEMENT MATHIEU--DRIF]

On 09/12/2024 07:24, Jason Wang wrote:
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> email comes from a known sender and you know the content is safe.
>
>
> On Mon, Dec 9, 2024 at 2:15 PM CLEMENT MATHIEU--DRIF
> <clement.mathieu--drif@eviden.com> wrote:
>>
>>
>> On 09/12/2024 04:13, Jason Wang wrote:
>>> Caution: External email. Do not open attachments or click links, unless 
>>> this email comes from a known sender and you know the content is safe.
>>>
>>>
>>> On Wed, Dec 4, 2024 at 2:14 PM CLEMENT MATHIEU--DRIF
>>> <clement.mathieu--drif@eviden.com> wrote:
>>>>
>>>>
>>>> On 04/12/2024 04:34, Jason Wang wrote:
>>>>> Caution: External email. Do not open attachments or click links, unless 
>>>>> this email comes from a known sender and you know the content is safe.
>>>>>
>>>>>
>>>>> On Mon, Nov 11, 2024 at 4:39 PM Zhenzhong Duan <zhenzhong.duan@intel.com> 
>>>>> wrote:
>>>>>> Intel VT-d 3.0 introduces scalable mode, and it has a bunch of 
>>>>>> capabilities
>>>>>> related to scalable mode translation, thus there are multiple 
>>>>>> combinations.
>>>>>>
>>>>>> This vIOMMU implementation wants to simplify it with a new property 
>>>>>> "x-flts".
>>>>>> When enabled in scalable mode, first stage translation also known as 
>>>>>> scalable
>>>>>> modern mode is supported. When enabled in legacy mode, throw out error.
>>>>>>
>>>>>> With scalable modern mode exposed to user, also accurate the pasid entry
>>>>>> check in vtd_pe_type_check().
>>>>>>
>>>>>> Suggested-by: Jason Wang <jasowang@redhat.com>
>>>>>> Signed-off-by: Yi Liu <yi.l.liu@intel.com>
>>>>>> Signed-off-by: Yi Sun <yi.y.sun@linux.intel.com>
>>>>>> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
>>>>>> ---
>>>>>>     hw/i386/intel_iommu_internal.h |  2 ++
>>>>>>     hw/i386/intel_iommu.c          | 28 +++++++++++++++++++---------
>>>>>>     2 files changed, 21 insertions(+), 9 deletions(-)
>>>>>>
>>>>>> diff --git a/hw/i386/intel_iommu_internal.h 
>>>>>> b/hw/i386/intel_iommu_internal.h
>>>>>> index 2c977aa7da..e8b211e8b0 100644
>>>>>> --- a/hw/i386/intel_iommu_internal.h
>>>>>> +++ b/hw/i386/intel_iommu_internal.h
>>>>>> @@ -195,6 +195,7 @@
>>>>>>     #define VTD_ECAP_PASID              (1ULL << 40)
>>>>>>     #define VTD_ECAP_SMTS               (1ULL << 43)
>>>>>>     #define VTD_ECAP_SLTS               (1ULL << 46)
>>>>>> +#define VTD_ECAP_FLTS               (1ULL << 47)
>>>>>>
>>>>>>     /* CAP_REG */
>>>>>>     /* (offset >> 4) << 24 */
>>>>>> @@ -211,6 +212,7 @@
>>>>>>     #define VTD_CAP_SLLPS               ((1ULL << 34) | (1ULL << 35))
>>>>>>     #define VTD_CAP_DRAIN_WRITE         (1ULL << 54)
>>>>>>     #define VTD_CAP_DRAIN_READ          (1ULL << 55)
>>>>>> +#define VTD_CAP_FS1GP               (1ULL << 56)
>>>>>>     #define VTD_CAP_DRAIN               (VTD_CAP_DRAIN_READ | 
>>>>>> VTD_CAP_DRAIN_WRITE)
>>>>>>     #define VTD_CAP_CM                  (1ULL << 7)
>>>>>>     #define VTD_PASID_ID_SHIFT          20
>>>>>> diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
>>>>>> index b921793c3a..a7a81aebee 100644
>>>>>> --- a/hw/i386/intel_iommu.c
>>>>>> +++ b/hw/i386/intel_iommu.c
>>>>>> @@ -803,16 +803,18 @@ static inline bool 
>>>>>> vtd_is_fl_level_supported(IntelIOMMUState *s, uint32_t level)
>>>>>>     }
>>>>>>
>>>>>>     /* Return true if check passed, otherwise false */
>>>>>> -static inline bool vtd_pe_type_check(X86IOMMUState *x86_iommu,
>>>>>> -                                     VTDPASIDEntry *pe)
>>>>>> +static inline bool vtd_pe_type_check(IntelIOMMUState *s, VTDPASIDEntry 
>>>>>> *pe)
>>>>>>     {
>>>>>>         switch (VTD_PE_GET_TYPE(pe)) {
>>>>>> -    case VTD_SM_PASID_ENTRY_SLT:
>>>>>> -        return true;
>>>>>> -    case VTD_SM_PASID_ENTRY_PT:
>>>>>> -        return x86_iommu->pt_supported;
>>>>>>         case VTD_SM_PASID_ENTRY_FLT:
>>>>>> +        return !!(s->ecap & VTD_ECAP_FLTS);
>>>>>> +    case VTD_SM_PASID_ENTRY_SLT:
>>>>>> +        return !!(s->ecap & VTD_ECAP_SLTS);
>>>>>>         case VTD_SM_PASID_ENTRY_NESTED:
>>>>>> +        /* Not support NESTED page table type yet */
>>>>>> +        return false;
>>>>>> +    case VTD_SM_PASID_ENTRY_PT:
>>>>>> +        return !!(s->ecap & VTD_ECAP_PT);
>>>>>>         default:
>>>>>>             /* Unknown type */
>>>>>>             return false;
>>>>>> @@ -861,7 +863,6 @@ static int 
>>>>>> vtd_get_pe_in_pasid_leaf_table(IntelIOMMUState *s,
>>>>>>         uint8_t pgtt;
>>>>>>         uint32_t index;
>>>>>>         dma_addr_t entry_size;
>>>>>> -    X86IOMMUState *x86_iommu = X86_IOMMU_DEVICE(s);
>>>>>>
>>>>>>         index = VTD_PASID_TABLE_INDEX(pasid);
>>>>>>         entry_size = VTD_PASID_ENTRY_SIZE;
>>>>>> @@ -875,7 +876,7 @@ static int 
>>>>>> vtd_get_pe_in_pasid_leaf_table(IntelIOMMUState *s,
>>>>>>         }
>>>>>>
>>>>>>         /* Do translation type check */
>>>>>> -    if (!vtd_pe_type_check(x86_iommu, pe)) {
>>>>>> +    if (!vtd_pe_type_check(s, pe)) {
>>>>>>             return -VTD_FR_PASID_TABLE_ENTRY_INV;
>>>>>>         }
>>>>>>
>>>>>> @@ -3827,6 +3828,7 @@ static Property vtd_properties[] = {
>>>>>>                           VTD_HOST_ADDRESS_WIDTH),
>>>>>>         DEFINE_PROP_BOOL("caching-mode", IntelIOMMUState, caching_mode, 
>>>>>> FALSE),
>>>>>>         DEFINE_PROP_BOOL("x-scalable-mode", IntelIOMMUState, 
>>>>>> scalable_mode, FALSE),
>>>>>> +    DEFINE_PROP_BOOL("x-flts", IntelIOMMUState, scalable_modern, FALSE),
>>>>>>         DEFINE_PROP_BOOL("snoop-control", IntelIOMMUState, 
>>>>>> snoop_control, false),
>>>>>>         DEFINE_PROP_BOOL("x-pasid-mode", IntelIOMMUState, pasid, false),
>>>>>>         DEFINE_PROP_BOOL("dma-drain", IntelIOMMUState, dma_drain, true),
>>>>>> @@ -4558,7 +4560,10 @@ static void vtd_cap_init(IntelIOMMUState *s)
>>>>>>         }
>>>>>>
>>>>>>         /* TODO: read cap/ecap from host to decide which cap to be 
>>>>>> exposed. */
>>>>>> -    if (s->scalable_mode) {
>>>>>> +    if (s->scalable_modern) {
>>>>>> +        s->ecap |= VTD_ECAP_SMTS | VTD_ECAP_FLTS;
>>>>>> +        s->cap |= VTD_CAP_FS1GP;
>>>>>> +    } else if (s->scalable_mode) {
>>>>>>             s->ecap |= VTD_ECAP_SMTS | VTD_ECAP_SRS | VTD_ECAP_SLTS;
>>>>>>         }
>>>>>>
>>>>>> @@ -4737,6 +4742,11 @@ static bool vtd_decide_config(IntelIOMMUState *s, 
>>>>>> Error **errp)
>>>>>>             }
>>>>>>         }
>>>>>>
>>>>>> +    if (!s->scalable_mode && s->scalable_modern) {
>>>>>> +        error_setg(errp, "Legacy mode: not support x-flts=on");
>>>>> This seems to be wired, should we say "scalable mode is needed for
>>>>> scalable modern mode"?
>>>> Hi Jason,
>>>>
>>>> We agreed to use the following sentence: "x-flts is only available in
>>>> scalable mode"
>>>>
>>>> Does it look goot to you?
>>> Better but if we add more features to the scalable modern, we need to
>>> change the error message here.
>> Hi Jason
>>
>> Maybe the weirdness comes from the fact that x-flts on the command line
>> is mapped to scalable_modern in the code?
> Yes, actually the code checks if scalable mode is enabled if scalable
> modern is enabled. But this is inconsistent with the error message
> (though x-flts was implied there probably).

Would you rename s->scalable_modern to s->flts?

>
> Thanks
>
>
>> Thanks
>>   >cmd
>>
>>> Thanks
>>>
>>>> Thanks
>>>> cmd
>>>>
>>>>>> +        return false;
>>>>>> +    }
>>>>>> +
>>>>>>         if (!s->scalable_modern && s->aw_bits != VTD_HOST_AW_39BIT &&
>>>>>>             s->aw_bits != VTD_HOST_AW_48BIT) {
>>>>>>             error_setg(errp, "%s mode: supported values for aw-bits are: 
>>>>>> %d, %d",
>>>>>> --
>>>>>> 2.34.1
>>>>>>
>>>>> Thanks
>>>>>