Re: [PATCH v6 4/7] iommu/dma: Move PCI window region reservation back into dma specific path.

[Alex Williamson]

On Tue, 24 Apr 2018 13:16:19 +0000
Shameerali Kolothum Thodi <shameerali.kolothum.thodi@xxxxxxxxxx> wrote:

> Hi Joerg,
> 
> Could you please take a look at this patch and let me know.
> 
> I have rebased this to 4.17-rc1  and added Robin's R-by.
> 
> This series[1] is now pending on this patch as without this it will break few
> ARM platforms[2]. 
> 
> Please take a look and let me know.

Hi Joerg,

Any thoughts on this patch?  Shameer is blocked on this series without
your ack.  We could consider moving this to a separate IOMMU patch, but
then I think we'd need to order our v4.18 pull requests, so there's a
bit of a preference to keep it within this series.  Thanks,

Alex

> [1] https://lkml.org/lkml/2018/4/18/293
> [2] https://lkml.org/lkml/2018/3/14/881
> 
> 
> > -----Original Message-----
> > From: Shameerali Kolothum Thodi
> > Sent: Wednesday, April 18, 2018 12:41 PM
> > To: alex.williamson@xxxxxxxxxx; eric.auger@xxxxxxxxxx;
> > pmorel@xxxxxxxxxxxxxxxxxx
> > Cc: kvm@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; iommu@xxxxxxxxxxxx
> > foundation.org; Linuxarm <linuxarm@xxxxxxxxxx>; John Garry
> > <john.garry@xxxxxxxxxx>; xuwei (O) <xuwei5@xxxxxxxxxx>; Shameerali
> > Kolothum Thodi <shameerali.kolothum.thodi@xxxxxxxxxx>; Joerg Roedel
> > <joro@xxxxxxxxxx>
> > Subject: [PATCH v6 4/7] iommu/dma: Move PCI window region reservation
> > back into dma specific path.
> > 
> > This pretty much reverts commit 273df9635385 ("iommu/dma: Make PCI
> > window reservation generic")  by moving the PCI window region
> > reservation back into the dma specific path so that these regions
> > doesn't get exposed via the IOMMU API interface. With this change,
> > the vfio interface will report only iommu specific reserved regions
> > to the user space.
> > 
> > Cc: Joerg Roedel <joro@xxxxxxxxxx>
> > Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@xxxxxxxxxx>
> > Reviewed-by: Robin Murphy <robin.murphy@xxxxxxx>
> > ---
> >  drivers/iommu/dma-iommu.c | 54 ++++++++++++++++++++++----------------------
> > ---
> >  1 file changed, 25 insertions(+), 29 deletions(-)
> > 
> > diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
> > index f05f3cf..ddcbbdb 100644
> > --- a/drivers/iommu/dma-iommu.c
> > +++ b/drivers/iommu/dma-iommu.c
> > @@ -167,40 +167,16 @@ EXPORT_SYMBOL(iommu_put_dma_cookie);
> >   * @list: Reserved region list from iommu_get_resv_regions()
> >   *
> >   * IOMMU drivers can use this to implement their .get_resv_regions callback
> > - * for general non-IOMMU-specific reservations. Currently, this covers host
> > - * bridge windows for PCI devices and GICv3 ITS region reservation on ACPI
> > - * based ARM platforms that may require HW MSI reservation.
> > + * for general non-IOMMU-specific reservations. Currently, this covers GICv3
> > + * ITS region reservation on ACPI based ARM platforms that may require HW
> > MSI
> > + * reservation.
> >   */
> >  void iommu_dma_get_resv_regions(struct device *dev, struct list_head *list)
> >  {
> > -	struct pci_host_bridge *bridge;
> > -	struct resource_entry *window;
> > -
> > -	if (!is_of_node(dev->iommu_fwspec->iommu_fwnode) &&
> > -		iort_iommu_msi_get_resv_regions(dev, list) < 0)
> > -		return;
> > -
> > -	if (!dev_is_pci(dev))
> > -		return;
> > -
> > -	bridge = pci_find_host_bridge(to_pci_dev(dev)->bus);
> > -	resource_list_for_each_entry(window, &bridge->windows) {
> > -		struct iommu_resv_region *region;
> > -		phys_addr_t start;
> > -		size_t length;
> > -
> > -		if (resource_type(window->res) != IORESOURCE_MEM)
> > -			continue;
> > 
> > -		start = window->res->start - window->offset;
> > -		length = window->res->end - window->res->start + 1;
> > -		region = iommu_alloc_resv_region(start, length, 0,
> > -				IOMMU_RESV_RESERVED);
> > -		if (!region)
> > -			return;
> > +	if (!is_of_node(dev->iommu_fwspec->iommu_fwnode))
> > +		iort_iommu_msi_get_resv_regions(dev, list);
> > 
> > -		list_add_tail(&region->list, list);
> > -	}
> >  }
> >  EXPORT_SYMBOL(iommu_dma_get_resv_regions);
> > 
> > @@ -229,6 +205,23 @@ static int cookie_init_hw_msi_region(struct
> > iommu_dma_cookie *cookie,
> >  	return 0;
> >  }
> > 
> > +static void iova_reserve_pci_windows(struct pci_dev *dev,
> > +		struct iova_domain *iovad)
> > +{
> > +	struct pci_host_bridge *bridge = pci_find_host_bridge(dev->bus);
> > +	struct resource_entry *window;
> > +	unsigned long lo, hi;
> > +
> > +	resource_list_for_each_entry(window, &bridge->windows) {
> > +		if (resource_type(window->res) != IORESOURCE_MEM)
> > +			continue;
> > +
> > +		lo = iova_pfn(iovad, window->res->start - window->offset);
> > +		hi = iova_pfn(iovad, window->res->end - window->offset);
> > +		reserve_iova(iovad, lo, hi);
> > +	}
> > +}
> > +
> >  static int iova_reserve_iommu_regions(struct device *dev,
> >  		struct iommu_domain *domain)
> >  {
> > @@ -238,6 +231,9 @@ static int iova_reserve_iommu_regions(struct device
> > *dev,
> >  	LIST_HEAD(resv_regions);
> >  	int ret = 0;
> > 
> > +	if (dev_is_pci(dev))
> > +		iova_reserve_pci_windows(to_pci_dev(dev), iovad);
> > +
> >  	iommu_get_resv_regions(dev, &resv_regions);
> >  	list_for_each_entry(region, &resv_regions, list) {
> >  		unsigned long lo, hi;
> > --
> > 2.7.4
> >   
>