Hi Jacob,
On 5/13/19 6:41 PM, Jacob Pan wrote:
> On Mon, 13 May 2019 09:13:01 +0200
> Eric Auger <[email protected]> wrote:
>
>> When reading the vtd specification and especially the
>> Reserved Memory Region Reporting Structure chapter,
>> it is not obvious a device scope element cannot be a
>> PCI-PCI bridge, in which case all downstream ports are
>> likely to access the reserved memory region. Let's handle
>> this case in device_has_rmrr.
>>
>> Fixes: ea2447f700ca ("intel-iommu: Prevent devices with RMRRs from
>> being placed into SI Domain")
>>
>> Signed-off-by: Eric Auger <[email protected]>
>> ---
>> drivers/iommu/intel-iommu.c | 32 +++++++++++++++++++++++---------
>> 1 file changed, 23 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
>> index e2134b13c9ae..89d82a1d50b1 100644
>> --- a/drivers/iommu/intel-iommu.c
>> +++ b/drivers/iommu/intel-iommu.c
>> @@ -736,12 +736,31 @@ static int iommu_dummy(struct device *dev)
>> return dev->archdata.iommu == DUMMY_DEVICE_DOMAIN_INFO;
>> }
>>
>> +static bool
>> +is_downstream_to_pci_bridge(struct device *deva, struct device *devb)
>> +{
>> + struct pci_dev *pdeva, *pdevb;
>> +
> is there a more illustrative name for these. i guess deva is is the
> bridge dev?
deva is the candidate PCI device likely to belong to the PCI
sub-hierarchy of devb (the candidate bridge).
My concern about the naming was that they are not necessarily a pci
device or a bridge. But at least I can add a comment or rename according
to your suggestion ;-)
>> + if (!dev_is_pci(deva) || !dev_is_pci(devb))
>> + return false;
>> +
>> + pdeva = to_pci_dev(deva);
>> + pdevb = to_pci_dev(devb);
>> +
>> + if (pdevb->subordinate &&
>> + pdevb->subordinate->number <= pdeva->bus->number &&
>> + pdevb->subordinate->busn_res.end >= pdeva->bus->number)
>> + return true;
>> +
>> + return false;
>> +>> +
> this seems to be a separate cleanup patch.
I can split into 2 patches: introduction of this helper and its usage in
device_to_iommu and second patch using it in iommu_has_rmrr.
>> static struct intel_iommu *device_to_iommu(struct device *dev, u8
>> *bus, u8 *devfn) {
>> struct dmar_drhd_unit *drhd = NULL;
>> struct intel_iommu *iommu;
>> struct device *tmp;
>> - struct pci_dev *ptmp, *pdev = NULL;
>> + struct pci_dev *pdev = NULL;
>> u16 segment = 0;
>> int i;
>>
>> @@ -787,13 +806,7 @@ static struct intel_iommu
>> *device_to_iommu(struct device *dev, u8 *bus, u8 *devf goto out;
>> }
>>
>> - if (!pdev || !dev_is_pci(tmp))
>> - continue;
>> -
>> - ptmp = to_pci_dev(tmp);
>> - if (ptmp->subordinate &&
>> - ptmp->subordinate->number <=
>> pdev->bus->number &&
>> - ptmp->subordinate->busn_res.end >=
>> pdev->bus->number)
>> + if (is_downstream_to_pci_bridge(dev, tmp))
>> goto got_pdev;
>> }
>>
>> @@ -2886,7 +2899,8 @@ static bool device_has_rmrr(struct device *dev)
>> */
>> for_each_active_dev_scope(rmrr->devices,
>> rmrr->devices_cnt, i, tmp)
>> - if (tmp == dev) {
>> + if (tmp == dev ||
>> + is_downstream_to_pci_bridge(dev, tmp)) {
>> rcu_read_unlock();
>> return true;
>> }
>
> [Jacob Pan]
>
Thanks
Eric
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