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Message-ID: <31bb1d1e-22ac-e576-110d-4e13fb822167@huawei.com>
Date: Thu, 16 Feb 2023 20:10:33 +0800
From: Nanyong Sun <sunnanyong@...wei.com>
To: Jason Wang <jasowang@...hat.com>, <joro@...tes.org>,
<will@...nel.org>, <robin.murphy@....com>, <mst@...hat.com>
CC: <iommu@...ts.linux.dev>, <linux-kernel@...r.kernel.org>,
<kvm@...r.kernel.org>, <virtualization@...ts.linux-foundation.org>,
<netdev@...r.kernel.org>, <wangrong68@...wei.com>
Subject: Re: [PATCH v2] vhost/vdpa: Add MSI translation tables to iommu for
software-managed MSI
On 2023/2/16 12:43, Jason Wang wrote:
>
> 在 2023/2/7 20:08, Nanyong Sun 写道:
>> From: Rong Wang <wangrong68@...wei.com>
>>
>> Once enable iommu domain for one device, the MSI
>> translation tables have to be there for software-managed MSI.
>> Otherwise, platform with software-managed MSI without an
>> irq bypass function, can not get a correct memory write event
>> from pcie, will not get irqs.
>> The solution is to obtain the MSI phy base address from
>> iommu reserved region, and set it to iommu MSI cookie,
>> then translation tables will be created while request irq.
>>
>> Change log
>> ----------
>>
>> v1->v2:
>> - add resv iotlb to avoid overlap mapping.
>>
>> Signed-off-by: Rong Wang <wangrong68@...wei.com>
>> Signed-off-by: Nanyong Sun <sunnanyong@...wei.com>
>> ---
>> drivers/iommu/iommu.c | 1 +
>> drivers/vhost/vdpa.c | 59 ++++++++++++++++++++++++++++++++++++++++---
>> 2 files changed, 57 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
>> index 5f6a85aea501..af9c064ad8b2 100644
>> --- a/drivers/iommu/iommu.c
>> +++ b/drivers/iommu/iommu.c
>> @@ -2623,6 +2623,7 @@ void iommu_get_resv_regions(struct device *dev,
>> struct list_head *list)
>> if (ops->get_resv_regions)
>> ops->get_resv_regions(dev, list);
>> }
>> +EXPORT_SYMBOL(iommu_get_resv_regions);
>> /**
>> * iommu_put_resv_regions - release resered regions
>> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
>> index ec32f785dfde..a58979da8acd 100644
>> --- a/drivers/vhost/vdpa.c
>> +++ b/drivers/vhost/vdpa.c
>> @@ -49,6 +49,7 @@ struct vhost_vdpa {
>> struct completion completion;
>> struct vdpa_device *vdpa;
>> struct hlist_head as[VHOST_VDPA_IOTLB_BUCKETS];
>> + struct vhost_iotlb resv_iotlb;
>
>
> Nit: it might be better to rename this as resv_regions.
>
Agree, and will do that in version3
>
>> struct device dev;
>> struct cdev cdev;
>> atomic_t opened;
>> @@ -216,6 +217,8 @@ static int vhost_vdpa_reset(struct vhost_vdpa *v)
>> v->in_batch = 0;
>> + vhost_iotlb_reset(&v->resv_iotlb);
>> +
>> return vdpa_reset(vdpa);
>> }
>> @@ -1013,6 +1016,10 @@ static int
>> vhost_vdpa_process_iotlb_update(struct vhost_vdpa *v,
>> msg->iova + msg->size - 1 > v->range.last)
>> return -EINVAL;
>> + if (vhost_iotlb_itree_first(&v->resv_iotlb, msg->iova,
>> + msg->iova + msg->size - 1))
>> + return -EINVAL;
>> +
>> if (vhost_iotlb_itree_first(iotlb, msg->iova,
>> msg->iova + msg->size - 1))
>> return -EEXIST;
>> @@ -1103,6 +1110,45 @@ static ssize_t
>> vhost_vdpa_chr_write_iter(struct kiocb *iocb,
>> return vhost_chr_write_iter(dev, from);
>> }
>> +static int vhost_vdpa_resv_iommu_region(struct iommu_domain
>> *domain, struct device *dma_dev,
>> + struct vhost_iotlb *resv_iotlb)
>> +{
>> + struct list_head dev_resv_regions;
>> + phys_addr_t resv_msi_base = 0;
>> + struct iommu_resv_region *region;
>> + int ret = 0;
>> + bool with_sw_msi = false;
>> + bool with_hw_msi = false;
>> +
>> + INIT_LIST_HEAD(&dev_resv_regions);
>> + iommu_get_resv_regions(dma_dev, &dev_resv_regions);
>> +
>> + list_for_each_entry(region, &dev_resv_regions, list) {
>> + ret = vhost_iotlb_add_range_ctx(resv_iotlb, region->start,
>> + region->start + region->length - 1,
>> + 0, 0, NULL);
>> + if (ret) {
>> + vhost_iotlb_reset(resv_iotlb);
>> + break;
>> + }
>> +
>> + if (region->type == IOMMU_RESV_MSI)
>> + with_hw_msi = true;
>> +
>> + if (region->type == IOMMU_RESV_SW_MSI) {
>> + resv_msi_base = region->start;
>> + with_sw_msi = true;
>> + }
>> + }
>> +
>> + if (!ret && !with_hw_msi && with_sw_msi)
>> + ret = iommu_get_msi_cookie(domain, resv_msi_base);
>> +
>> + iommu_put_resv_regions(dma_dev, &dev_resv_regions);
>> +
>> + return ret;
>> +}
>
>
> As discussed in v1, I still prefer to factor out the common logic and
> move them to iommu.c. It helps to simplify the future bug fixing and
> enhancement.
Ok, will do that in version3
>
>
>> +
>> static int vhost_vdpa_alloc_domain(struct vhost_vdpa *v)
>> {
>> struct vdpa_device *vdpa = v->vdpa;
>> @@ -1128,11 +1174,16 @@ static int vhost_vdpa_alloc_domain(struct
>> vhost_vdpa *v)
>> ret = iommu_attach_device(v->domain, dma_dev);
>> if (ret)
>> - goto err_attach;
>> + goto err_alloc_domain;
>> - return 0;
>> + ret = vhost_vdpa_resv_iommu_region(v->domain, dma_dev,
>> &v->resv_iotlb);
>> + if (ret)
>> + goto err_attach_device;
>> -err_attach:
>> + return 0;
>> +err_attach_device:
>> + iommu_detach_device(v->domain, dma_dev);
>> +err_alloc_domain:
>> iommu_domain_free(v->domain);
>> return ret;
>> }
>> @@ -1385,6 +1436,8 @@ static int vhost_vdpa_probe(struct vdpa_device
>> *vdpa)
>> goto err;
>> }
>> + vhost_iotlb_init(&v->resv_iotlb, 0, 0);
>> +
>> r = dev_set_name(&v->dev, "vhost-vdpa-%u", minor);
>> if (r)
>> goto err;
>
>
> We need clean resv_iotlb during release().
I added vhost_iotlb_reset in vhost_vdpa_reset, so will clean while call vhost_vdpa_release() and vhost_vdpa_open().
>
> Other looks good.
>
> Thanks
>
> .
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