VT-d: generalize and correct "iommu=no-igfx" handling

Linux'es supposedly equivalent "intel_iommu=igfx_off" deals with any
graphics devices (not just Intel ones) while at the same time limiting
the effect to IOMMUs covering only graphics devices. Keying the decision
to leave translation disabled for an IOMMU to merely a magic SBDF tuple
was wrong in the first place - systems may very well have non-graphics
devices at 0000:00:02.0 (ordinary root ports commonly live there, for
example). Any use of igd_drhd_address (and hence is_igd_drhd()) needs
further qualification.

Introduce a new "graphics only" field in struct acpi_drhd_unit and set
it according to device scope parsing outcome. Replace the bad use of
is_igd_drhd() in iommu_enable_translation() by use of this new field.

While adding the new field also convert the adjacent include_all one to
"bool".

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Release-Acked-by: Ian Jackson <iwj@xenproject.org>

diff --git a/docs/misc/xen-command-line.pandoc b/docs/misc/xen-command-line.pandoc
index b1f7978aa44cf167cc90c0dfc92ca62e3f443b91..f7797ea233f90a39a844a6b92f1f34b2f22a4698 100644 (file)
--- a/docs/misc/xen-command-line.pandoc
+++ b/docs/misc/xen-command-line.pandoc
@@ -1494,8 +1494,8 @@ The following options are specific to Intel VT-d hardware:
     version 6 and greater as Registered-Based Invalidation isn't supported
     by them.
 
-*   The `igfx` boolean is active by default, and controls whether the IOMMU in
-    front of an Intel Graphics Device is enabled or not.
+*   The `igfx` boolean is active by default, and controls whether IOMMUs in
+    front of solely graphics devices get enabled or not.
 
     It is intended as a debugging mechanism for graphics issues, and to be
     similar to Linux's `intel_iommu=igfx_off` option.  If specifying `no-igfx`

diff --git a/xen/drivers/passthrough/vtd/dmar.c b/xen/drivers/passthrough/vtd/dmar.c
index 36d909b06df6d332f8770b1553368814d48d6018..d5ee3675998b58da8aac5c5472f7387987889dc9 100644 (file)
--- a/xen/drivers/passthrough/vtd/dmar.c
+++ b/xen/drivers/passthrough/vtd/dmar.c
@@ -315,6 +315,7 @@ static int __init acpi_parse_dev_scope(
     struct acpi_drhd_unit *drhd = type == DMAR_TYPE ?
         container_of(scope, struct acpi_drhd_unit, scope) : NULL;
     int depth, cnt, didx = 0, ret;
+    bool gfx_only = false;
 
     if ( (cnt = scope_device_count(start, end)) < 0 )
         return cnt;
@@ -324,6 +325,8 @@ static int __init acpi_parse_dev_scope(
         scope->devices = xzalloc_array(u16, cnt);
         if ( !scope->devices )
             return -ENOMEM;
+
+        gfx_only = drhd && !drhd->include_all;
     }
     scope->devices_cnt = cnt;
 
@@ -354,6 +357,7 @@ static int __init acpi_parse_dev_scope(
                        acpi_scope->bus, sec_bus, sub_bus);
 
             dmar_scope_add_buses(scope, sec_bus, sub_bus);
+            gfx_only = false;
             break;
 
         case ACPI_DMAR_SCOPE_TYPE_HPET:
@@ -374,6 +378,8 @@ static int __init acpi_parse_dev_scope(
                 acpi_hpet_unit->dev = path->dev;
                 acpi_hpet_unit->func = path->fn;
                 list_add(&acpi_hpet_unit->list, &drhd->hpet_list);
+
+                gfx_only = false;
             }
 
             break;
@@ -388,6 +394,12 @@ static int __init acpi_parse_dev_scope(
                 if ( (seg == 0) && (bus == 0) && (path->dev == 2) &&
                      (path->fn == 0) )
                     igd_drhd_address = drhd->address;
+
+                if ( gfx_only &&
+                     pci_conf_read8(PCI_SBDF(seg, bus, path->dev, path->fn),
+                                    PCI_CLASS_DEVICE + 1) != 0x03
+                                    /* PCI_BASE_CLASS_DISPLAY */ )
+                    gfx_only = false;
             }
 
             break;
@@ -408,6 +420,8 @@ static int __init acpi_parse_dev_scope(
                 acpi_ioapic_unit->ioapic.bdf.dev = path->dev;
                 acpi_ioapic_unit->ioapic.bdf.func = path->fn;
                 list_add(&acpi_ioapic_unit->list, &drhd->ioapic_list);
+
+                gfx_only = false;
             }
 
             break;
@@ -417,11 +431,15 @@ static int __init acpi_parse_dev_scope(
                 printk(XENLOG_WARNING VTDPREFIX "Unknown scope type %#x\n",
                        acpi_scope->entry_type);
             start += acpi_scope->length;
+            gfx_only = false;
             continue;
         }
         scope->devices[didx++] = PCI_BDF(bus, path->dev, path->fn);
         start += acpi_scope->length;
-   }
+    }
+
+    if ( drhd && gfx_only )
+        drhd->gfx_only = true;
 
     ret = 0;
 

diff --git a/xen/drivers/passthrough/vtd/dmar.h b/xen/drivers/passthrough/vtd/dmar.h
index a44820a5e77657ed90b275a98cca52cb9c6564e2..a1f2353a511f4f432494cd0d318ae9531a6c9001 100644 (file)
--- a/xen/drivers/passthrough/vtd/dmar.h
+++ b/xen/drivers/passthrough/vtd/dmar.h
@@ -62,7 +62,8 @@ struct acpi_drhd_unit {
     struct list_head list;
     u64    address;                     /* register base address of the unit */
     u16    segment;
-    u8     include_all:1;
+    bool   include_all:1;
+    bool   gfx_only:1;
     struct vtd_iommu *iommu;
     struct list_head ioapic_list;
     struct list_head hpet_list;

diff --git a/xen/drivers/passthrough/vtd/iommu.c b/xen/drivers/passthrough/vtd/iommu.c
index 0519dfc9e72f63f35b78241a2480c4d6ce9a6a88..137aea2c92f889e1a848774a9b10b708ae4de6d3 100644 (file)
--- a/xen/drivers/passthrough/vtd/iommu.c
+++ b/xen/drivers/passthrough/vtd/iommu.c
@@ -751,7 +751,7 @@ static void iommu_enable_translation(struct acpi_drhd_unit *drhd)
     unsigned long flags;
     struct vtd_iommu *iommu = drhd->iommu;
 
-    if ( is_igd_drhd(drhd) )
+    if ( drhd->gfx_only )
     {
         if ( !iommu_igfx )
         {