From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx> In Intel IOMMU, if the Page Request Queue (PRQ) is full, it will automatically respond to the device with a success message as a keep alive. And when sending the success message, IOMMU will include PASID in the Response Message when the Page Request has a PASID in Request Message and It does not check against the PRG Response PASID requirement of the device before sending the response. Also, If the device receives the PRG response with PASID when its not expecting it then the device behavior is undefined. So enable PASID support only if device expects PASID in PRG response message. Cc: Ashok Raj <ashok.raj@xxxxxxxxx> Cc: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx> Cc: Keith Busch <keith.busch@xxxxxxxxx> Suggested-by: Ashok Raj <ashok.raj@xxxxxxxxx> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx> --- drivers/iommu/intel-iommu.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index 1457f931218e..af2e4a011787 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -1399,7 +1399,8 @@ static void iommu_enable_dev_iotlb(struct device_domain_info *info) undefined. So always enable PASID support on devices which have it, even if we can't yet know if we're ever going to use it. */ - if (info->pasid_supported && !pci_enable_pasid(pdev, info->pasid_supported & ~1)) + if (info->pasid_supported && pci_prg_resp_pasid_required(pdev) && + !pci_enable_pasid(pdev, info->pasid_supported & ~1)) info->pasid_enabled = 1; if (info->pri_supported && !pci_reset_pri(pdev) && !pci_enable_pri(pdev, 32)) -- 2.20.1
