Re: [PATCH v4 4/7] iommu/vt-d: Use pci_real_dma_dev() for mapping

[Derrick, Jonathan]

Good catch. Thanks Baolu.
Will do v5 fixing this and Christoph's nit

On Tue, 2020-01-21 at 09:06 +0800, Lu Baolu wrote:
> Hi,
> 
> On 1/18/20 12:27 AM, Jon Derrick wrote:
> > The PCI device may have a DMA requester on another bus, such as VMD
> > subdevices needing to use the VMD endpoint. This case requires the real
> > DMA device when mapping to IOMMU.
> > 
> > Signed-off-by: Jon Derrick
> > ---
> >   drivers/iommu/intel-iommu.c | 9 +
> >   1 file changed, 9 insertions(+)
> > 
> > diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> > index 0c8d81f..01a1b0f 100644
> > --- a/drivers/iommu/intel-iommu.c
> > +++ b/drivers/iommu/intel-iommu.c
> > @@ -782,6 +782,8 @@ static struct intel_iommu *device_to_iommu(struct 
> > device *dev, u8 *bus, u8 *devf
> > return NULL;
> >   #endif
> >   
> > +   pdev = pci_real_dma_dev(dev);
> 
> This isn't correct. It will result in a compiling error when bisect.
> 
> Best regards,
> baolu
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Re: [PATCH v4 4/7] iommu/vt-d: Use pci_real_dma_dev() for mapping

[Lu Baolu]

Hi,

On 1/18/20 12:27 AM, Jon Derrick wrote:

The PCI device may have a DMA requester on another bus, such as VMD
subdevices needing to use the VMD endpoint. This case requires the real
DMA device when mapping to IOMMU.

Signed-off-by: Jon Derrick
---
  drivers/iommu/intel-iommu.c | 9 +
  1 file changed, 9 insertions(+)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 0c8d81f..01a1b0f 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -782,6 +782,8 @@ static struct intel_iommu *device_to_iommu(struct device 
*dev, u8 *bus, u8 *devf
return NULL;
  #endif
  
+		pdev = pci_real_dma_dev(dev);


This isn't correct. It will result in a compiling error when bisect.

Best regards,
baolu
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Re: [PATCH v4 4/7] iommu/vt-d: Use pci_real_dma_dev() for mapping

[Christoph Hellwig]

On Fri, Jan 17, 2020 at 09:27:26AM -0700, Jon Derrick wrote:
> + if (dev_is_pci(dev)) {
> + struct pci_dev *pdev;
> +
> + pdev = pci_real_dma_dev(to_pci_dev(dev));
> + dev = >dev;

I think this could be simplified to

if (dev_is_pci(dev))
dev = _real_dma_dev(to_pci_dev(dev)->dev;

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[PATCH v4 4/7] iommu/vt-d: Use pci_real_dma_dev() for mapping

[Jon Derrick]

The PCI device may have a DMA requester on another bus, such as VMD
subdevices needing to use the VMD endpoint. This case requires the real
DMA device when mapping to IOMMU.

Signed-off-by: Jon Derrick 
---
 drivers/iommu/intel-iommu.c | 9 +
 1 file changed, 9 insertions(+)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 0c8d81f..01a1b0f 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -782,6 +782,8 @@ static struct intel_iommu *device_to_iommu(struct device 
*dev, u8 *bus, u8 *devf
return NULL;
 #endif
 
+   pdev = pci_real_dma_dev(dev);
+
/* VFs aren't listed in scope tables; we need to look up
 * the PF instead to find the IOMMU. */
pf_pdev = pci_physfn(pdev);
@@ -2428,6 +2430,13 @@ static struct dmar_domain *find_domain(struct device 
*dev)
 dev->archdata.iommu == DUMMY_DEVICE_DOMAIN_INFO))
return NULL;
 
+   if (dev_is_pci(dev)) {
+   struct pci_dev *pdev;
+
+   pdev = pci_real_dma_dev(to_pci_dev(dev));
+   dev = >dev;
+   }
+
/* No lock here, assumes no domain exit in normal case */
info = dev->archdata.iommu;
if (likely(info))
-- 
1.8.3.1

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