linux-kernel - Re: [PATCH v5 04/11] iommu/vt-d: Add helper to setup pasid nested translation

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Date:   Fri, 13 Oct 2023 20:48:19 +0800
From:   Baolu Lu <baolu.lu@...ux.intel.com>
To:     Yi Liu <yi.l.liu@...el.com>, "Tian, Kevin" <kevin.tian@...el.com>,
        "joro@...tes.org" <joro@...tes.org>,
        "alex.williamson@...hat.com" <alex.williamson@...hat.com>,
        "jgg@...dia.com" <jgg@...dia.com>,
        "robin.murphy@....com" <robin.murphy@....com>
Cc:     baolu.lu@...ux.intel.com, "cohuck@...hat.com" <cohuck@...hat.com>,
        "eric.auger@...hat.com" <eric.auger@...hat.com>,
        "nicolinc@...dia.com" <nicolinc@...dia.com>,
        "kvm@...r.kernel.org" <kvm@...r.kernel.org>,
        "mjrosato@...ux.ibm.com" <mjrosato@...ux.ibm.com>,
        "chao.p.peng@...ux.intel.com" <chao.p.peng@...ux.intel.com>,
        "yi.y.sun@...ux.intel.com" <yi.y.sun@...ux.intel.com>,
        "peterx@...hat.com" <peterx@...hat.com>,
        "jasowang@...hat.com" <jasowang@...hat.com>,
        "shameerali.kolothum.thodi@...wei.com" 
        <shameerali.kolothum.thodi@...wei.com>,
        "lulu@...hat.com" <lulu@...hat.com>,
        "suravee.suthikulpanit@....com" <suravee.suthikulpanit@....com>,
        "iommu@...ts.linux.dev" <iommu@...ts.linux.dev>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-kselftest@...r.kernel.org" <linux-kselftest@...r.kernel.org>,
        "Duan, Zhenzhong" <zhenzhong.duan@...el.com>,
        "Martins, Joao" <joao.m.martins@...cle.com>,
        Jacob Pan <jacob.jun.pan@...ux.intel.com>
Subject: Re: [PATCH v5 04/11] iommu/vt-d: Add helper to setup pasid nested
 translation

On 2023/10/13 20:40, Yi Liu wrote:
>>
>>> +        return -EINVAL;
>>> +    }
>>> +
>>> +    if ((s1_cfg->flags & IOMMU_VTD_S1_SRE) && !ecap_srs(iommu-
>>>> ecap)) {
>>> +        pr_err_ratelimited("No supervisor request support on %s\n",
>>> +                   iommu->name);
>>> +        return -EINVAL;
>>> +    }
>>> +
>>> +    if ((s1_cfg->flags & IOMMU_VTD_S1_EAFE) && !ecap_eafs(iommu-
>>>> ecap)) {
>>> +        pr_err_ratelimited("No extended access flag support
>>> on %s\n",
>>> +                   iommu->name);
>>> +        return -EINVAL;
>>> +    }
>>> +
>>> +    spin_lock(&iommu->lock);
>>> +    pte = intel_pasid_get_entry(dev, pasid);
>>> +    if (!pte) {
>>> +        spin_unlock(&iommu->lock);
>>> +        return -ENODEV;
>>> +    }
>>> +    if (pasid_pte_is_present(pte)) {
>>> +        spin_unlock(&iommu->lock);
>>> +        return -EBUSY;
>>> +    }
>>> +
>>> +    pasid_clear_entry(pte);
>>> +
>>> +    if (s1_cfg->addr_width == ADDR_WIDTH_5LEVEL)
>>> +        pasid_set_flpm(pte, 1);
>>> +
>>> +    pasid_set_flptr(pte, (uintptr_t)s1_gpgd);
>>> +
>>> +    if (s1_cfg->flags & IOMMU_VTD_S1_SRE) {
>>> +        pasid_set_sre(pte);
>>> +        if (s1_cfg->flags & IOMMU_VTD_S1_WPE)
>>> +            pasid_set_wpe(pte);
>>> +    }
>>> +
>>> +    if (s1_cfg->flags & IOMMU_VTD_S1_EAFE)
>>> +        pasid_set_eafe(pte);
>>> +
>>> +    if (s2_domain->force_snooping)
>>> +        pasid_set_pgsnp(pte);
>>> +
>>> +    pasid_set_slptr(pte, virt_to_phys(pgd));
>>> +    pasid_set_fault_enable(pte);
>>> +    pasid_set_domain_id(pte, did);
>>> +    pasid_set_address_width(pte, s2_domain->agaw);
>>> +    pasid_set_page_snoop(pte, !!ecap_smpwc(iommu->ecap));
>>> +    pasid_set_translation_type(pte, PASID_ENTRY_PGTT_NESTED);
>>> +    pasid_set_present(pte);
>>> +    spin_unlock(&iommu->lock);
>>
>> All changes within iommu->lock are specific to the device specific
>> PASID entry. Probably this is one potential cleanup TODO to
>> use a per-device lock instead.
> 
> yeah, a separate cleanup. is it, @Baolu?

Sure. I'd like to take some time to consider this further. Please keep
it as-is for the time being.

Best regards,
baolu