[Xen-devel] [PATCH v2] iommu: setup inclusive mappings before enabling iommu

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

Or else it can lead to freezes when enabling the iommu on certain
Intel hardware:

[...]
(XEN) ELF: addresses:
(XEN)     virt_base        = 0xffffffff80000000
(XEN)     elf_paddr_offset = 0x0
(XEN)     virt_offset      = 0xffffffff80000000
(XEN)     virt_kstart      = 0xffffffff81000000
(XEN)     virt_kend        = 0xffffffff82953000
(XEN)     virt_entry       = 0xffffffff8274e180
(XEN)     p2m_base         = 0x8000000000
(XEN)  Xen  kernel: 64-bit, lsb, compat32
(XEN)  Dom0 kernel: 64-bit, PAE, lsb, paddr 0x1000000 -> 0x295300
<freeze>

This restores the behavior before commit 66a9274cc3435 that changed
the order and enabled the iommu without having the inclusive mappings
setup.

Note that on AMD hardware the order is also changed to add inclusive
mappings before adding any devices.

Reported-by: Dario Faggioli <dfaggioli@xxxxxxxx>
Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
Cc: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
Cc: Brian Woods <brian.woods@xxxxxxx>
Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Cc: Julien Grall <julien.grall@xxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Kevin Tian <kevin.tian@xxxxxxxxx>
Cc: Dario Faggioli <dfaggioli@xxxxxxxx>
---
 xen/drivers/passthrough/amd/pci_amd_iommu.c |  2 ++
 xen/drivers/passthrough/arm/smmu.c          |  2 ++
 xen/drivers/passthrough/iommu.c             | 10 ----------
 xen/drivers/passthrough/vtd/iommu.c         |  2 ++
 xen/drivers/passthrough/x86/iommu.c         |  8 ++++++++
 5 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/xen/drivers/passthrough/amd/pci_amd_iommu.c 
b/xen/drivers/passthrough/amd/pci_amd_iommu.c
index 330f9ce386..4a633ca940 100644
--- a/xen/drivers/passthrough/amd/pci_amd_iommu.c
+++ b/xen/drivers/passthrough/amd/pci_amd_iommu.c
@@ -300,6 +300,8 @@ static void __hwdom_init amd_iommu_hwdom_init(struct domain 
*d)
                                         IOMMU_MMIO_REGION_LENGTH - 1)) )
             BUG();
 
+    /* Make sure workarounds are applied (if needed) before adding devices. */
+    arch_iommu_hwdom_init(d);
     setup_hwdom_pci_devices(d, amd_iommu_add_device);
 }
 
diff --git a/xen/drivers/passthrough/arm/smmu.c 
b/xen/drivers/passthrough/arm/smmu.c
index 43ece42a50..8f91807b1b 100644
--- a/xen/drivers/passthrough/arm/smmu.c
+++ b/xen/drivers/passthrough/arm/smmu.c
@@ -2736,6 +2736,8 @@ static void __hwdom_init arm_smmu_iommu_hwdom_init(struct 
domain *d)
                printk(XENLOG_WARNING
                "map-reserved dom0-iommu option is not supported on ARM\n");
        iommu_hwdom_reserved = 0;
+
+       arch_iommu_hwdom_init(d);
 }
 
 static void arm_smmu_iommu_domain_teardown(struct domain *d)
diff --git a/xen/drivers/passthrough/iommu.c b/xen/drivers/passthrough/iommu.c
index ee3f523fdf..ae6cf2f0ff 100644
--- a/xen/drivers/passthrough/iommu.c
+++ b/xen/drivers/passthrough/iommu.c
@@ -238,16 +238,6 @@ void __hwdom_init iommu_hwdom_init(struct domain *d)
     }
 
     hd->platform_ops->hwdom_init(d);
-
-    ASSERT(iommu_hwdom_inclusive != -1 && iommu_hwdom_inclusive != -1);
-    if ( iommu_hwdom_inclusive && !is_pv_domain(d) )
-    {
-        printk(XENLOG_WARNING
-               "IOMMU inclusive mappings are only supported on PV Dom0\n");
-        iommu_hwdom_inclusive = 0;
-    }
-
-    arch_iommu_hwdom_init(d);
 }
 
 void iommu_teardown(struct domain *d)
diff --git a/xen/drivers/passthrough/vtd/iommu.c 
b/xen/drivers/passthrough/vtd/iommu.c
index adc70f205a..bb422ec58c 100644
--- a/xen/drivers/passthrough/vtd/iommu.c
+++ b/xen/drivers/passthrough/vtd/iommu.c
@@ -1313,6 +1313,8 @@ static void __hwdom_init intel_iommu_hwdom_init(struct 
domain *d)
 
     setup_hwdom_pci_devices(d, setup_hwdom_device);
     setup_hwdom_rmrr(d);
+    /* Make sure workarounds are applied before enabling the IOMMU(s). */
+    arch_iommu_hwdom_init(d);
 
     if ( iommu_flush_all() )
         printk(XENLOG_WARNING VTDPREFIX
diff --git a/xen/drivers/passthrough/x86/iommu.c 
b/xen/drivers/passthrough/x86/iommu.c
index 47a078272a..b7c8b5be41 100644
--- a/xen/drivers/passthrough/x86/iommu.c
+++ b/xen/drivers/passthrough/x86/iommu.c
@@ -210,6 +210,14 @@ void __hwdom_init arch_iommu_hwdom_init(struct domain *d)
 
     BUG_ON(!is_hardware_domain(d));
 
+    ASSERT(iommu_hwdom_inclusive != -1 && iommu_hwdom_inclusive != -1);
+    if ( iommu_hwdom_inclusive && !is_pv_domain(d) )
+    {
+        printk(XENLOG_WARNING
+               "IOMMU inclusive mappings are only supported on PV Dom0\n");
+        iommu_hwdom_inclusive = 0;
+    }
+
     if ( iommu_hwdom_passthrough )
         return;
 
-- 
2.18.0


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