[v9,1/6] domain: introduce XEN_DOMCTL_CDF_iommu flag
diff mbox series

Message ID 20190912111744.40410-2-paul.durrant@citrix.com
State Superseded
Headers show
Series
  • add per-domain IOMMU control
Related show

Commit Message

Paul Durrant Sept. 12, 2019, 11:17 a.m. UTC
This patch introduces a common domain creation flag to determine whether
the domain is permitted to make use of the IOMMU. Currently the flag is
always set for both dom0 and any domU created by libxl if the IOMMU is
globally enabled (i.e. iommu_enabled == 1). sanitise_domain_config() is
modified to reject the flag if !iommu_enabled.

A new helper function, is_iommu_enabled(), is added to test the flag and
iommu_domain_init() will return immediately if !is_iommu_enabled(). This is
slightly different to the previous behaviour based on !iommu_enabled where
the call to arch_iommu_domain_init() was made regardless, however it appears
that this call was only necessary to initialize the dt_devices list for ARM
such that iommu_release_dt_devices() can be called unconditionally by
domain_relinquish_resources(). Adding a simple check of is_iommu_enabled()
into iommu_release_dt_devices() keeps this unconditional call working.

No functional change should be observed with this patch applied.

Subsequent patches will allow the toolstack to control whether use of the
IOMMU is enabled for a domain.

NOTE: The introduction of the is_iommu_enabled() helper function might
      seem excessive but its use is expected to increase with subsequent
      patches. Also, having iommu_domain_init() bail before calling
      arch_iommu_domain_init() is not strictly necessary, but I think the
      consequent addition of the call to is_iommu_enabled() in
      iommu_release_dt_devices() makes the code clearer.

Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Reviewed-by: "Roger Pau Monné" <roger.pau@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Christian Lindig <christian.lindig@citrix.com>
---
Cc: David Scott <dave@recoil.org>
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Wei Liu <wl@xen.org>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: George Dunlap <George.Dunlap@eu.citrix.com>
Cc: Julien Grall <julien.grall@arm.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Tim Deegan <tim@xen.org>
Cc: Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>

Previously part of series https://lists.xenproject.org/archives/html/xen-devel/2019-07/msg02267.html

v9:
 - Fix oversight in ARM's arch_sanitise_domain_config() to tolerate setting
   of XEN_DOMCTL_CDF_iommu

v7:
 - Add a check to verify that the toolstack has not set XEN_DOMCTL_CDF_iommu
 - Add missing ocaml binding changes

v6:
 - Remove the toolstack parts as there's no nice method of testing whether
   the IOMMU is enabled in an architecture-neutral way

v5:
 - Move is_iommu_enabled() check into iommu_domain_init()
 - Reject XEN_DOMCTL_CDF_iommu in sanitise_domain_config() if !iommu_enabled
 - Use evaluate_nospec() in defintion of is_iommu_enabled()
---
 tools/ocaml/libs/xc/xenctrl.ml        |  1 +
 tools/ocaml/libs/xc/xenctrl.mli       |  1 +
 xen/arch/arm/domain.c                 |  7 +++++--
 xen/arch/arm/setup.c                  |  3 +++
 xen/arch/x86/setup.c                  |  3 +++
 xen/common/domain.c                   |  9 ++++++++-
 xen/common/domctl.c                   | 13 +++++++++++++
 xen/drivers/passthrough/device_tree.c |  3 +++
 xen/drivers/passthrough/iommu.c       |  6 +++---
 xen/include/public/domctl.h           |  5 ++++-
 xen/include/xen/sched.h               |  5 +++++
 11 files changed, 49 insertions(+), 7 deletions(-)

Patch
diff mbox series

diff --git a/tools/ocaml/libs/xc/xenctrl.ml b/tools/ocaml/libs/xc/xenctrl.ml
index bfb3d8e181..eaf009f0f9 100644
--- a/tools/ocaml/libs/xc/xenctrl.ml
+++ b/tools/ocaml/libs/xc/xenctrl.ml
@@ -63,6 +63,7 @@  type domain_create_flag =
 	| CDF_S3_INTEGRITY
 	| CDF_OOS_OFF
 	| CDF_XS_DOMAIN
+	| CDF_IOMMU
 
 type domctl_create_config =
 {
diff --git a/tools/ocaml/libs/xc/xenctrl.mli b/tools/ocaml/libs/xc/xenctrl.mli
index 8bc36ec8f6..e0636de23a 100644
--- a/tools/ocaml/libs/xc/xenctrl.mli
+++ b/tools/ocaml/libs/xc/xenctrl.mli
@@ -56,6 +56,7 @@  type domain_create_flag =
   | CDF_S3_INTEGRITY
   | CDF_OOS_OFF
   | CDF_XS_DOMAIN
+  | CDF_IOMMU
 
 type domctl_create_config = {
   ssidref: int32;
diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index a9c4113c26..ae13e47e86 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -608,9 +608,12 @@  int arch_sanitise_domain_config(struct xen_domctl_createdomain *config)
 {
     unsigned int max_vcpus;
 
-    if ( config->flags != (XEN_DOMCTL_CDF_hvm | XEN_DOMCTL_CDF_hap) )
+    /* HVM and HAP must be set. IOMMU may or may not be */
+    if ( (config->flags & ~XEN_DOMCTL_CDF_iommu) !=
+         (XEN_DOMCTL_CDF_hvm | XEN_DOMCTL_CDF_hap) )
     {
-        dprintk(XENLOG_INFO, "Unsupported configuration %#x\n", config->flags);
+        dprintk(XENLOG_INFO, "Unsupported configuration %#x\n",
+                config->flags);
         return -EINVAL;
     }
 
diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 1b303bde34..ad101784e6 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -961,6 +961,9 @@  void __init start_xen(unsigned long boot_phys_offset,
     dom0_cfg.arch.tee_type = tee_get_type();
     dom0_cfg.max_vcpus = dom0_max_vcpus();
 
+    if ( iommu_enabled )
+        dom0_cfg.flags |= XEN_DOMCTL_CDF_iommu;
+
     dom0 = domain_create(0, &dom0_cfg, true);
     if ( IS_ERR(dom0) || (alloc_dom0_vcpu0(dom0) == NULL) )
         panic("Error creating domain 0\n");
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 27981adc0b..dec60d0301 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -1732,6 +1732,9 @@  void __init noreturn __start_xen(unsigned long mbi_p)
     }
     dom0_cfg.max_vcpus = dom0_max_vcpus();
 
+    if ( iommu_enabled )
+        dom0_cfg.flags |= XEN_DOMCTL_CDF_iommu;
+
     /* Create initial domain 0. */
     dom0 = domain_create(get_initial_domain_id(), &dom0_cfg, !pv_shim);
     if ( IS_ERR(dom0) || (alloc_dom0_vcpu0(dom0) == NULL) )
diff --git a/xen/common/domain.c b/xen/common/domain.c
index 09917b2885..4681f29c8b 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -301,7 +301,8 @@  static int sanitise_domain_config(struct xen_domctl_createdomain *config)
                            XEN_DOMCTL_CDF_hap |
                            XEN_DOMCTL_CDF_s3_integrity |
                            XEN_DOMCTL_CDF_oos_off |
-                           XEN_DOMCTL_CDF_xs_domain) )
+                           XEN_DOMCTL_CDF_xs_domain |
+                           XEN_DOMCTL_CDF_iommu) )
     {
         dprintk(XENLOG_INFO, "Unknown CDF flags %#x\n", config->flags);
         return -EINVAL;
@@ -320,6 +321,12 @@  static int sanitise_domain_config(struct xen_domctl_createdomain *config)
         return -EINVAL;
     }
 
+    if ( (config->flags & XEN_DOMCTL_CDF_iommu) && !iommu_enabled )
+    {
+        dprintk(XENLOG_INFO, "IOMMU is not enabled\n");
+        return -EINVAL;
+    }
+
     return arch_sanitise_domain_config(config);
 }
 
diff --git a/xen/common/domctl.c b/xen/common/domctl.c
index 6e6e9b9866..5dcfe3c8f6 100644
--- a/xen/common/domctl.c
+++ b/xen/common/domctl.c
@@ -515,6 +515,19 @@  long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t) u_domctl)
             rover = dom;
         }
 
+        /*
+         * For now, make sure the createdomain IOMMU flag is set if the
+         * IOMMU is enabled. When the flag comes under toolstack control
+         * this can go away.
+         */
+        if ( op->u.createdomain.flags & XEN_DOMCTL_CDF_iommu )
+        {
+            ASSERT_UNREACHABLE();
+            return -EINVAL;
+        }
+        if ( iommu_enabled )
+            op->u.createdomain.flags |= XEN_DOMCTL_CDF_iommu;
+
         d = domain_create(dom, &op->u.createdomain, false);
         if ( IS_ERR(d) )
         {
diff --git a/xen/drivers/passthrough/device_tree.c b/xen/drivers/passthrough/device_tree.c
index b6eaae7283..d32b172664 100644
--- a/xen/drivers/passthrough/device_tree.c
+++ b/xen/drivers/passthrough/device_tree.c
@@ -119,6 +119,9 @@  int iommu_release_dt_devices(struct domain *d)
     struct dt_device_node *dev, *_dev;
     int rc;
 
+    if ( !is_iommu_enabled(d) )
+        return 0;
+
     list_for_each_entry_safe(dev, _dev, &hd->dt_devices, domain_list)
     {
         rc = iommu_deassign_dt_device(d, dev);
diff --git a/xen/drivers/passthrough/iommu.c b/xen/drivers/passthrough/iommu.c
index b82f778479..f42402bc92 100644
--- a/xen/drivers/passthrough/iommu.c
+++ b/xen/drivers/passthrough/iommu.c
@@ -151,6 +151,9 @@  int iommu_domain_init(struct domain *d)
     struct domain_iommu *hd = dom_iommu(d);
     int ret = 0;
 
+    if ( !is_iommu_enabled(d) )
+        return 0;
+
 #ifdef CONFIG_NUMA
     hd->node = NUMA_NO_NODE;
 #endif
@@ -159,9 +162,6 @@  int iommu_domain_init(struct domain *d)
     if ( ret )
         return ret;
 
-    if ( !iommu_enabled )
-        return 0;
-
     hd->platform_ops = iommu_get_ops();
     return hd->platform_ops->init(d);
 }
diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h
index 77f546cbb8..1b3176adb5 100644
--- a/xen/include/public/domctl.h
+++ b/xen/include/public/domctl.h
@@ -64,9 +64,12 @@  struct xen_domctl_createdomain {
  /* Is this a xenstore domain? */
 #define _XEN_DOMCTL_CDF_xs_domain     4
 #define XEN_DOMCTL_CDF_xs_domain      (1U<<_XEN_DOMCTL_CDF_xs_domain)
+ /* Should this domain be permitted to use the IOMMU? */
+#define _XEN_DOMCTL_CDF_iommu         5
+#define XEN_DOMCTL_CDF_iommu          (1U<<_XEN_DOMCTL_CDF_iommu)
 
 /* Max XEN_DOMCTL_CDF_* constant.  Used for ABI checking. */
-#define XEN_DOMCTL_CDF_MAX XEN_DOMCTL_CDF_xs_domain
+#define XEN_DOMCTL_CDF_MAX XEN_DOMCTL_CDF_iommu
 
     uint32_t flags;
 
diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
index e3601c1935..2d17c84915 100644
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -983,6 +983,11 @@  static inline bool is_xenstore_domain(const struct domain *d)
     return d->options & XEN_DOMCTL_CDF_xs_domain;
 }
 
+static inline bool is_iommu_enabled(const struct domain *d)
+{
+    return evaluate_nospec(d->options & XEN_DOMCTL_CDF_iommu);
+}
+
 extern bool sched_smt_power_savings;
 
 extern enum cpufreq_controller {