On 08/08/2024 14:31, Duan, Zhenzhong wrote:
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> On 8/6/2024 2:35 PM, CLEMENT MATHIEU--DRIF wrote:
>>
>> On 05/08/2024 08:27, Zhenzhong Duan wrote:
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>>> is safe.
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>>>
>>> Add an new element scalable_mode in IntelIOMMUState to mark scalable
>>> modern mode, this element will be exposed as an intel_iommu property
>>> finally.
>>>
>>> For now, it's only a placehholder and used for address width
>>> compatibility check and block host device passthrough until nesting
>>> is supported.
>>>
>>> Signed-off-by: Yi Liu <yi.l....@intel.com>
>>> Signed-off-by: Zhenzhong Duan <zhenzhong.d...@intel.com>
>>> ---
>>> include/hw/i386/intel_iommu.h | 1 +
>>> hw/i386/intel_iommu.c | 12 +++++++++---
>>> 2 files changed, 10 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/include/hw/i386/intel_iommu.h
>>> b/include/hw/i386/intel_iommu.h
>>> index 1eb05c29fc..788ed42477 100644
>>> --- a/include/hw/i386/intel_iommu.h
>>> +++ b/include/hw/i386/intel_iommu.h
>>> @@ -262,6 +262,7 @@ struct IntelIOMMUState {
>>>
>>> bool caching_mode; /* RO - is cap CM enabled? */
>>> bool scalable_mode; /* RO - is Scalable Mode
>>> supported? */
>>> + bool scalable_modern; /* RO - is modern SM supported? */
>>> bool snoop_control; /* RO - is SNP filed
>>> supported? */
>>>
>>> dma_addr_t root; /* Current root table pointer */
>>> diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
>>> index e3465fc27d..c1382a5651 100644
>>> --- a/hw/i386/intel_iommu.c
>>> +++ b/hw/i386/intel_iommu.c
>>> @@ -3872,7 +3872,13 @@ static bool vtd_check_hiod(IntelIOMMUState
>>> *s, HostIOMMUDevice *hiod,
>>> return false;
>>> }
>>>
>>> - return true;
>>> + if (!s->scalable_modern) {
>>> + /* All checks requested by VTD non-modern mode pass */
>>> + return true;
>>> + }
>>> +
>>> + error_setg(errp, "host device is unsupported in scalable modern
>>> mode yet");
>>> + return false;
>>> }
>>>
>>> static bool vtd_dev_set_iommu_device(PCIBus *bus, void *opaque,
>>> int devfn,
>>> @@ -4262,9 +4268,9 @@ static bool vtd_decide_config(IntelIOMMUState
>>> *s, Error **errp)
>>> }
>>> }
>>>
>>> - /* Currently only address widths supported are 39 and 48 bits */
>>> if ((s->aw_bits != VTD_HOST_AW_39BIT) &&
>>> - (s->aw_bits != VTD_HOST_AW_48BIT)) {
>>> + (s->aw_bits != VTD_HOST_AW_48BIT) &&
>>> + !s->scalable_modern) {
>> Why does scalable_modern allow to use a value other than 39 or 48?
>> Is it safe?
>
> The check for scalable_modern is in patch14:
>
> if ((s->aw_bits != VTD_HOST_AW_48BIT) && s->scalable_modern) {
>
> error_setg(errp, "Supported values for aw-bits are: %d",
> VTD_HOST_AW_48BIT);
>
> return false;
>
> }
>
> Let me know if you prefer to move it in this patch.
Yes, you are right, it would be better to move the check here.
But I think the first check should also fail even when scalable_modern
is enabled because values other than 39 and 48 are not supported at all,
whatever the mode.
Then, we should check if the value is valid for scalable_modern mode.
Thanks
>cmd
>
> Thanks
>
> Zhenzhong
>
