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From: Henry Wang <xin.wang2@amd.com>
To: <xen-devel@lists.xenproject.org>
Cc: Henry Wang <xin.wang2@amd.com>,
	Stefano Stabellini <sstabellini@kernel.org>,
	Julien Grall <julien@xen.org>,
	Bertrand Marquis <bertrand.marquis@arm.com>,
	Michal Orzel <michal.orzel@amd.com>,
	"Volodymyr Babchuk" <Volodymyr_Babchuk@epam.com>
Subject: [PATCH v2 3/8] xen/arm, doc: Add a DT property to specify IOMMU for Dom0less domUs
Date: Thu, 16 May 2024 18:03:25 +0800	[thread overview]
Message-ID: <20240516100330.1433265-4-xin.wang2@amd.com> (raw)
In-Reply-To: <20240516100330.1433265-1-xin.wang2@amd.com>

There are some use cases in which the dom0less domUs need to have
the XEN_DOMCTL_CDF_iommu set at the domain construction time. For
example, the dynamic dtbo feature allows the domain to be assigned
a device that is behind the IOMMU at runtime. For these use cases,
we need to have a way to specify the domain will need the IOMMU
mapping at domain construction time.

Introduce a "passthrough" DT property for Dom0less DomUs following
the same entry as the xl.cfg. Currently only provide two options,
i.e. "enable" and "disable". Set the XEN_DOMCTL_CDF_iommu at domain
construction time based on the property.

Signed-off-by: Henry Wang <xin.wang2@amd.com>
---
v2:
- New patch to replace the original patch in v1:
  "[PATCH 03/15] xen/arm: Always enable IOMMU"
---
 docs/misc/arm/device-tree/booting.txt | 13 +++++++++++++
 xen/arch/arm/dom0less-build.c         |  7 +++++--
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/docs/misc/arm/device-tree/booting.txt b/docs/misc/arm/device-tree/booting.txt
index bbd955e9c2..61f9082553 100644
--- a/docs/misc/arm/device-tree/booting.txt
+++ b/docs/misc/arm/device-tree/booting.txt
@@ -260,6 +260,19 @@ with the following properties:
     value specified by Xen command line parameter gnttab_max_maptrack_frames
     (or its default value if unspecified, i.e. 1024) is used.
 
+- passthrough
+
+    A string property specifying whether IOMMU mappings are enabled for the
+    domain and hence whether it will be enabled for passthrough hardware.
+    Possible property values are:
+
+    - "enabled"
+    IOMMU mappings are enabled for the domain.
+
+    - "disabled"
+    IOMMU mappings are disabled for the domain and so hardware may not be
+    passed through. This option is the default if this property is missing.
+
 Under the "xen,domain" compatible node, one or more sub-nodes are present
 for the DomU kernel and ramdisk.
 
diff --git a/xen/arch/arm/dom0less-build.c b/xen/arch/arm/dom0less-build.c
index 74f053c242..1396a102e1 100644
--- a/xen/arch/arm/dom0less-build.c
+++ b/xen/arch/arm/dom0less-build.c
@@ -848,6 +848,7 @@ static int __init construct_domU(struct domain *d,
 void __init create_domUs(void)
 {
     struct dt_device_node *node;
+    const char *dom0less_iommu;
     const struct dt_device_node *cpupool_node,
                                 *chosen = dt_find_node_by_path("/chosen");
 
@@ -895,8 +896,10 @@ void __init create_domUs(void)
             panic("Missing property 'cpus' for domain %s\n",
                   dt_node_name(node));
 
-        if ( dt_find_compatible_node(node, NULL, "multiboot,device-tree") &&
-             iommu_enabled )
+        if ( iommu_enabled &&
+             ((!dt_property_read_string(node, "passthrough", &dom0less_iommu) &&
+               !strcmp(dom0less_iommu, "enabled")) ||
+              dt_find_compatible_node(node, NULL, "multiboot,device-tree")) )
             d_cfg.flags |= XEN_DOMCTL_CDF_iommu;
 
         if ( !dt_property_read_u32(node, "nr_spis", &d_cfg.arch.nr_spis) )
-- 
2.34.1



  parent reply	other threads:[~2024-05-16 10:04 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-05-16 10:03 [PATCH v2 0/8] Remaining patches for dynamic node programming using overlay dtbo Henry Wang
2024-05-16 10:03 ` [PATCH v2 1/8] xen/common/dt-overlay: Fix lock issue when add/remove the device Henry Wang
2024-05-19 10:04   ` Julien Grall
2024-05-16 10:03 ` [PATCH v2 2/8] tools/xl: Correct the help information and exit code of the dt-overlay command Henry Wang
2024-05-20 18:48   ` Jason Andryuk
2024-05-16 10:03 ` Henry Wang [this message]
2024-05-19 10:17   ` [PATCH v2 3/8] xen/arm, doc: Add a DT property to specify IOMMU for Dom0less domUs Julien Grall
2024-05-20  0:41     ` Henry Wang
2024-05-20  1:38       ` Henry Wang
2024-05-20  1:40       ` Henry Wang
2024-05-16 10:03 ` [PATCH v2 4/8] tools/arm: Introduce the "nr_spis" xl config entry Henry Wang
2024-05-20 19:13   ` Jason Andryuk
2024-05-20 23:19     ` Henry Wang
2024-05-16 10:03 ` [PATCH v2 5/8] xen/arm/gic: Allow routing/removing interrupt to running VMs Henry Wang
2024-05-17  6:03   ` Henry Wang
2024-05-19 11:08     ` Julien Grall
2024-05-20  1:01       ` Henry Wang
2024-05-20  9:50         ` Julien Grall
2024-05-21  2:29           ` Stefano Stabellini
2024-05-16 10:03 ` [PATCH v2 6/8] xen/arm: Add XEN_DOMCTL_dt_overlay DOMCTL and related operations Henry Wang
2024-05-16 12:31   ` Jan Beulich
2024-05-17  1:36     ` Henry Wang
2024-05-17  7:11       ` Jan Beulich
2024-05-16 10:03 ` [PATCH v2 7/8] tools: Introduce the "xl dt-overlay {attach,detach}" commands Henry Wang
2024-05-20 19:41   ` Jason Andryuk
2024-05-20 23:21     ` Henry Wang
2024-05-16 10:03 ` [PATCH v2 8/8] docs: Add device tree overlay documentation Henry Wang

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