[Xen-devel] [PATCH v2 06/13] iommu: Add extra use_iommu argument to iommu_domain_init()

[Oleksandr Tyshchenko <olekstysh@xxxxxxxxx>]

From: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>

The presence of this flag lets us know that the guest domain has statically
assigned devices which will most likely be used for passthrough
and as the result the IOMMU is expected to be used for this domain.

Taking into the account this hint when dealing with non-shared IOMMUs
we can populate IOMMU page tables before hand avoid going through
the list of pages at the first assigned device.
As this flag doesn't cover hotplug case, we will continue to populate
IOMMU page tables on the fly.

Extend corresponding platform callback with extra argument as well and
pass thought incoming flag to the IOMMU drivers followed by updating
"d->need_iommu" flag for any domains. But, it must be an additional logic before
updating this flag for hardware domains which the next patch is introducing.

As iommu_domain_init() is called with "use_iommu" flag being forced
to false for now, no functional change is intended for both ARM and x86.

Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
CC: Jan Beulich <jbeulich@xxxxxxxx>
CC: Julien Grall <julien.grall@xxxxxxx>
CC: Stefano Stabellini <sstabellini@xxxxxxxxxx>
CC: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CC: Kevin Tian <kevin.tian@xxxxxxxxx>
CC: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>

---
   Changes in v1:
      - Clarify patch subject/description.
      - s/bool_t/bool/

   Changes in v2:
      - Extend "init" callback with extra argument too.
      - Clarify patch description.
      - Add maintainers in CC
---
 xen/arch/arm/domain.c                       |  2 +-
 xen/arch/x86/domain.c                       |  2 +-
 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/include/xen/iommu.h                     |  4 ++--
 7 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index 76310ed..ec19310 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -569,7 +569,7 @@ int arch_domain_create(struct domain *d, unsigned int 
domcr_flags,
     ASSERT(config != NULL);
 
     /* p2m_init relies on some value initialized by the IOMMU subsystem */
-    if ( (rc = iommu_domain_init(d)) != 0 )
+    if ( (rc = iommu_domain_init(d, false)) != 0 )
         goto fail;
 
     if ( (rc = p2m_init(d)) != 0 )
diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
index d7e6992..1ffe76c 100644
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -641,7 +641,7 @@ int arch_domain_create(struct domain *d, unsigned int 
domcr_flags,
         if ( (rc = init_domain_irq_mapping(d)) != 0 )
             goto fail;
 
-        if ( (rc = iommu_domain_init(d)) != 0 )
+        if ( (rc = iommu_domain_init(d, false)) != 0 )
             goto fail;
     }
     spin_lock_init(&d->arch.e820_lock);
diff --git a/xen/drivers/passthrough/amd/pci_amd_iommu.c 
b/xen/drivers/passthrough/amd/pci_amd_iommu.c
index fe744d2..2491e8c 100644
--- a/xen/drivers/passthrough/amd/pci_amd_iommu.c
+++ b/xen/drivers/passthrough/amd/pci_amd_iommu.c
@@ -261,7 +261,7 @@ static int get_paging_mode(unsigned long entries)
     return level;
 }
 
-static int amd_iommu_domain_init(struct domain *d)
+static int amd_iommu_domain_init(struct domain *d, bool use_iommu)
 {
     struct domain_iommu *hd = dom_iommu(d);
 
diff --git a/xen/drivers/passthrough/arm/smmu.c 
b/xen/drivers/passthrough/arm/smmu.c
index e828308..652b58c 100644
--- a/xen/drivers/passthrough/arm/smmu.c
+++ b/xen/drivers/passthrough/arm/smmu.c
@@ -2705,7 +2705,7 @@ static int arm_smmu_reassign_dev(struct domain *s, struct 
domain *t,
        return 0;
 }
 
-static int arm_smmu_iommu_domain_init(struct domain *d)
+static int arm_smmu_iommu_domain_init(struct domain *d, bool use_iommu)
 {
        struct arm_smmu_xen_domain *xen_domain;
 
diff --git a/xen/drivers/passthrough/iommu.c b/xen/drivers/passthrough/iommu.c
index 3e9e4c3..19c87d1 100644
--- a/xen/drivers/passthrough/iommu.c
+++ b/xen/drivers/passthrough/iommu.c
@@ -129,7 +129,7 @@ static void __init parse_iommu_param(char *s)
     } while ( ss );
 }
 
-int iommu_domain_init(struct domain *d)
+int iommu_domain_init(struct domain *d, bool use_iommu)
 {
     struct domain_iommu *hd = dom_iommu(d);
     int ret = 0;
@@ -142,7 +142,13 @@ int iommu_domain_init(struct domain *d)
         return 0;
 
     hd->platform_ops = iommu_get_ops();
-    return hd->platform_ops->init(d);
+    ret = hd->platform_ops->init(d, use_iommu);
+    if ( ret )
+        return ret;
+
+    d->need_iommu = use_iommu;
+
+    return 0;
 }
 
 static void __hwdom_init check_hwdom_reqs(struct domain *d)
diff --git a/xen/drivers/passthrough/vtd/iommu.c 
b/xen/drivers/passthrough/vtd/iommu.c
index b4e8c89..45d1f36 100644
--- a/xen/drivers/passthrough/vtd/iommu.c
+++ b/xen/drivers/passthrough/vtd/iommu.c
@@ -1277,7 +1277,7 @@ void __init iommu_free(struct acpi_drhd_unit *drhd)
         agaw = 64;                              \
     agaw; })
 
-static int intel_iommu_domain_init(struct domain *d)
+static int intel_iommu_domain_init(struct domain *d, bool use_iommu)
 {
     dom_iommu(d)->arch.agaw = width_to_agaw(DEFAULT_DOMAIN_ADDRESS_WIDTH);
 
diff --git a/xen/include/xen/iommu.h b/xen/include/xen/iommu.h
index 3297998..f4d489e 100644
--- a/xen/include/xen/iommu.h
+++ b/xen/include/xen/iommu.h
@@ -56,7 +56,7 @@ int iommu_setup(void);
 int iommu_add_device(struct pci_dev *pdev);
 int iommu_enable_device(struct pci_dev *pdev);
 int iommu_remove_device(struct pci_dev *pdev);
-int iommu_domain_init(struct domain *d);
+int iommu_domain_init(struct domain *d, bool use_iommu);
 void iommu_hwdom_init(struct domain *d);
 void iommu_domain_destroy(struct domain *d);
 int deassign_device(struct domain *d, u16 seg, u8 bus, u8 devfn);
@@ -155,7 +155,7 @@ struct page_info;
 typedef int iommu_grdm_t(xen_pfn_t start, xen_ulong_t nr, u32 id, void *ctxt);
 
 struct iommu_ops {
-    int (*init)(struct domain *d);
+    int (*init)(struct domain *d, bool use_iommu);
     void (*hwdom_init)(struct domain *d);
     int (*add_device)(u8 devfn, device_t *dev);
     int (*enable_device)(device_t *dev);
-- 
2.7.4


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