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From: Wei Liu <wei.liu@kernel.org>
To: Praveen Kumar <kumarpraveen@linux.microsoft.com>
Cc: Wei Liu <wei.liu@kernel.org>,
	Linux on Hyper-V List <linux-hyperv@vger.kernel.org>,
	virtualization@lists.linux-foundation.org,
	Linux Kernel List <linux-kernel@vger.kernel.org>,
	Michael Kelley <mikelley@microsoft.com>,
	Vineeth Pillai <viremana@linux.microsoft.com>,
	Sunil Muthuswamy <sunilmut@microsoft.com>,
	Nuno Das Neves <nunodasneves@linux.microsoft.com>,
	pasha.tatashin@soleen.com, "K. Y. Srinivasan" <kys@microsoft.com>,
	Haiyang Zhang <haiyangz@microsoft.com>,
	Stephen Hemminger <sthemmin@microsoft.com>,
	Dexuan Cui <decui@microsoft.com>
Subject: Re: [RFC v1 8/8] mshv: add vfio bridge device
Date: Tue, 10 Aug 2021 10:52:11 +0000	[thread overview]
Message-ID: <20210810105211.zzaamjqmcq3jecmn@liuwe-devbox-debian-v2> (raw)
In-Reply-To: <b400d536-632e-9212-a06d-6e41af8a6fe5@linux.microsoft.com>

On Wed, Aug 04, 2021 at 12:57:03AM +0530, Praveen Kumar wrote:
> On 09-07-2021 17:13, Wei Liu wrote:
> > +
> > +static int mshv_vfio_set_group(struct mshv_device *dev, long attr, u64 arg)
> > +{
> > +	struct mshv_vfio *mv = dev->private;
> > +	struct vfio_group *vfio_group;
> > +	struct mshv_vfio_group *mvg;
> > +	int32_t __user *argp = (int32_t __user *)(unsigned long)arg;
> > +	struct fd f;
> > +	int32_t fd;
> > +	int ret;
> > +
> > +	switch (attr) {
> > +	case MSHV_DEV_VFIO_GROUP_ADD:
> > +		if (get_user(fd, argp))
> > +			return -EFAULT;
> > +
> > +		f = fdget(fd);
> > +		if (!f.file)
> > +			return -EBADF;
> > +
> > +		vfio_group = mshv_vfio_group_get_external_user(f.file);
> > +		fdput(f);
> > +
> > +		if (IS_ERR(vfio_group))
> > +			return PTR_ERR(vfio_group);
> > +
> > +		mutex_lock(&mv->lock);
> > +
> > +		list_for_each_entry(mvg, &mv->group_list, node) {
> > +			if (mvg->vfio_group == vfio_group) {
> > +				mutex_unlock(&mv->lock);
> > +				mshv_vfio_group_put_external_user(vfio_group);
> > +				return -EEXIST;
> > +			}
> > +		}
> > +
> > +		mvg = kzalloc(sizeof(*mvg), GFP_KERNEL_ACCOUNT);
> > +		if (!mvg) {
> > +			mutex_unlock(&mv->lock);
> > +			mshv_vfio_group_put_external_user(vfio_group);
> > +			return -ENOMEM;
> > +		}
> > +
> > +		list_add_tail(&mvg->node, &mv->group_list);
> > +		mvg->vfio_group = vfio_group;
> > +
> > +		mutex_unlock(&mv->lock);
> > +
> > +		return 0;
> > +
> > +	case MSHV_DEV_VFIO_GROUP_DEL:
> > +		if (get_user(fd, argp))
> > +			return -EFAULT;
> > +
> > +		f = fdget(fd);
> > +		if (!f.file)
> > +			return -EBADF;
> 
> Can we move these both checks above switch statement and do fdput
> accordingly under both case statement accordingly?

Fair point. This can be done, albeit at the cost of having a rather
different code structure.

I was waiting to see if we should somehow merge this with KVM's
implementation so the code was deliberately kept close. If there is no
further comment I can of course make the change you suggested.

> 
> > +
> > +		ret = -ENOENT;
> > +
> > +		mutex_lock(&mv->lock);
> > +
> > +		list_for_each_entry(mvg, &mv->group_list, node) {
> > +			if (!mshv_vfio_external_group_match_file(mvg->vfio_group,
> > +								 f.file))
> > +				continue;
> > +
> > +			list_del(&mvg->node);
> > +			mshv_vfio_group_put_external_user(mvg->vfio_group);
> > +			kfree(mvg);
> > +			ret = 0;
> > +			break;
> > +		}
> > +
> > +		mutex_unlock(&mv->lock);
> > +
> > +		fdput(f);
> > +
> > +		return ret;
> > +	}
> > +
> > +	return -ENXIO;
> > +}
> > +
> > +static int mshv_vfio_set_attr(struct mshv_device *dev,
> > +			      struct mshv_device_attr *attr)
> > +{
> > +	switch (attr->group) {
> > +	case MSHV_DEV_VFIO_GROUP:
> > +		return mshv_vfio_set_group(dev, attr->attr, attr->addr);
> > +	}
> > +
> > +	return -ENXIO;
> > +}
> > +
> > +static int mshv_vfio_has_attr(struct mshv_device *dev,
> > +			      struct mshv_device_attr *attr)
> > +{
> > +	switch (attr->group) {
> > +	case MSHV_DEV_VFIO_GROUP:
> > +		switch (attr->attr) {
> > +		case MSHV_DEV_VFIO_GROUP_ADD:
> > +		case MSHV_DEV_VFIO_GROUP_DEL:
> > +			return 0;
> > +		}
> > +
> > +		break;
> 
> do we need this break statement ? If not, lets remove it.

Will do.

Wei.

      reply	other threads:[~2021-08-10 10:52 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-09 11:43 [RFC v1 0/8] MSHV: add PV-IOMMU driver Wei Liu
2021-07-09 11:43 ` [RFC v1 1/8] x86/hyperv: export hv_build_pci_dev_id Wei Liu
2021-07-09 11:43 ` [RFC v1 2/8] asm-generic/hyperv: add device domain definitions Wei Liu
2021-07-09 11:43 ` [RFC v1 3/8] intel/vt-d: make DMAR table parsing code more flexible Wei Liu
2021-07-09 12:56   ` Robin Murphy
2021-07-09 13:42     ` Wei Liu
2021-07-09 11:43 ` [RFC v1 4/8] intel/vt-d: export intel_iommu_get_resv_regions Wei Liu
2021-07-09 14:17   ` Lu Baolu
2021-07-09 14:21     ` Wei Liu
2021-07-09 11:43 ` [RFC v1 5/8] mshv: add paravirtualized IOMMU support Wei Liu
2021-08-03 18:40   ` Praveen Kumar
2021-08-03 21:47     ` Wei Liu
2021-08-04  6:43       ` Praveen Kumar
2021-08-10 10:46         ` Wei Liu
2021-07-09 11:43 ` [RFC v1 6/8] mshv: command line option to skip devices in PV-IOMMU Wei Liu
2021-07-09 12:46   ` Robin Murphy
2021-07-09 13:34     ` Wei Liu
2021-08-03 18:50   ` Praveen Kumar
2021-08-03 21:56     ` Wei Liu
2021-08-04  7:03       ` Praveen Kumar
2021-08-10 10:04         ` Wei Liu
2021-07-09 11:43 ` [RFC v1 7/8] mshv: implement in-kernel device framework Wei Liu
2021-07-09 13:02   ` Matthew Wilcox
2021-07-09 13:50     ` Wei Liu
2021-07-09 15:32       ` Matthew Wilcox
2021-07-09 16:27         ` Wei Liu
2021-07-09 16:38           ` Matthew Wilcox
2021-07-09 19:14             ` Wei Liu
2021-07-09 19:48               ` Matthew Wilcox
2021-07-09 20:11                 ` Wei Liu
2021-08-03 19:12   ` Praveen Kumar
2021-08-03 22:04     ` Wei Liu
2021-07-09 11:43 ` [RFC v1 8/8] mshv: add vfio bridge device Wei Liu
2021-08-03 19:27   ` Praveen Kumar
2021-08-10 10:52     ` Wei Liu [this message]

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