linux-kernel - [PATCH v2 7/7] iommu/vt-d: Differentiate relaxable and non relaxable RMRRs

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Date:   Thu, 16 May 2019 10:47:20 +0200
From:   Eric Auger <eric.auger@...hat.com>
To:     eric.auger.pro@...il.com, eric.auger@...hat.com, joro@...tes.org,
        iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
        dwmw2@...radead.org, lorenzo.pieralisi@....com,
        robin.murphy@....com, will.deacon@....com, hanjun.guo@...aro.org,
        sudeep.holla@....com
Cc:     alex.williamson@...hat.com, shameerali.kolothum.thodi@...wei.com
Subject: [PATCH v2 7/7] iommu/vt-d: Differentiate relaxable and non relaxable RMRRs

Now we have a new IOMMU_RESV_DIRECT_RELAXABLE reserved memory
region type, let's report USB and GFX RMRRs as relaxable ones.

This allows to have a finer reporting at IOMMU API level of
reserved memory regions. This will be exploitable by VFIO to
define the usable IOVA range and detect potential conflicts
between the guest physical address space and host reserved
regions.

Signed-off-by: Eric Auger <eric.auger@...hat.com>
---
 drivers/iommu/intel-iommu.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index a36604f4900f..af1d65fdedfc 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -5493,7 +5493,9 @@ static void intel_iommu_get_resv_regions(struct device *device,
 	for_each_rmrr_units(rmrr) {
 		for_each_active_dev_scope(rmrr->devices, rmrr->devices_cnt,
 					  i, i_dev) {
+			struct pci_dev *pdev = to_pci_dev(device);
 			struct iommu_resv_region *resv;
+			enum iommu_resv_type type;
 			size_t length;
 
 			if (i_dev != device &&
@@ -5501,9 +5503,13 @@ static void intel_iommu_get_resv_regions(struct device *device,
 				continue;
 
 			length = rmrr->end_address - rmrr->base_address + 1;
+
+			type = (pdev &&
+				(IS_USB_DEVICE(pdev) || IS_GFX_DEVICE(pdev))) ?
+				IOMMU_RESV_DIRECT_RELAXABLE : IOMMU_RESV_DIRECT;
+
 			resv = iommu_alloc_resv_region(rmrr->base_address,
-						       length, prot,
-						       IOMMU_RESV_DIRECT,
+						       length, prot, type,
 						       GFP_ATOMIC);
 			if (!resv)
 				break;
-- 
2.20.1