[xen staging] xen/arm: sci: Don't create a domain with unsatisfied user requests

[patchbot@xxxxxxx]

commit f7b9752dc88c626192d3115ace7585b20a025433
Author:     Michal Orzel <michal.orzel@xxxxxxx>
AuthorDate: Tue May 12 09:52:55 2026 +0200
Commit:     Michal Orzel <michal.orzel@xxxxxxx>
CommitDate: Tue May 12 13:31:01 2026 +0200

    xen/arm: sci: Don't create a domain with unsatisfied user requests
    
    On Arm we stay on the safe side and refuse to create a domain on user
    requests (e.g. via xl.cfg, DT options) that cannot be satisfied due to
    the feature not being compiled in. SCI fall through the crack and does not
    adhere to that i.e. a user request for SCI type other than NONE when
    CONFIG_SCMI_SMC (and thus CONFIG_ARM_SCI) is not set would be silently
    ignored. Fix it by not allowing anything else other than NONE if the
    feature is not enabled.
    
    Fixes: 10e7473d6024 ("xen/arm: scmi-smc: passthrough SCMI SMC to domain, 
single agent")
    Signed-off-by: Michal Orzel <michal.orzel@xxxxxxx>
    Reviewed-by: Luca Fancellu <luca.fancellu@xxxxxxx>
    Reviewed-by: Bertrand Marquis <bertrand.marquis@xxxxxxx>
---
 xen/arch/arm/dom0less-build.c           | 11 +++++++++--
 xen/arch/arm/include/asm/firmware/sci.h |  5 +++++
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/xen/arch/arm/dom0less-build.c b/xen/arch/arm/dom0less-build.c
index 6f73c65e51..52cf788a45 100644
--- a/xen/arch/arm/dom0less-build.c
+++ b/xen/arch/arm/dom0less-build.c
@@ -273,8 +273,7 @@ static int __init domu_dt_sci_parse(struct dt_device_node 
*node,
 
     d_cfg->arch.arm_sci_type = XEN_DOMCTL_CONFIG_ARM_SCI_NONE;
 
-    if ( !IS_ENABLED(CONFIG_ARM_SCI) ||
-         !dt_property_read_bool(node, "xen,sci_type") )
+    if ( !dt_property_read_bool(node, "xen,sci_type") )
         return 0;
 
     ret = dt_property_read_string(node, "xen,sci_type", &sci_type);
@@ -284,7 +283,15 @@ static int __init domu_dt_sci_parse(struct dt_device_node 
*node,
     if ( !strcmp(sci_type, "none") )
         d_cfg->arch.arm_sci_type = XEN_DOMCTL_CONFIG_ARM_SCI_NONE;
     else if ( !strcmp(sci_type, "scmi_smc") )
+    {
+        if ( !IS_ENABLED(CONFIG_SCMI_SMC) )
+        {
+            printk(XENLOG_ERR "xen,sci_type=scmi_smc requested, but 
CONFIG_SCMI_SMC not set\n");
+            return -EINVAL;
+        }
+
         d_cfg->arch.arm_sci_type = XEN_DOMCTL_CONFIG_ARM_SCI_SCMI_SMC;
+    }
     else
     {
         printk(XENLOG_ERR "xen,sci_type in not valid (%s) for domain %s\n",
diff --git a/xen/arch/arm/include/asm/firmware/sci.h 
b/xen/arch/arm/include/asm/firmware/sci.h
index 3500216bc2..485ce211c9 100644
--- a/xen/arch/arm/include/asm/firmware/sci.h
+++ b/xen/arch/arm/include/asm/firmware/sci.h
@@ -148,6 +148,8 @@ int sci_dt_finalize(struct domain *d, void *fdt);
 int sci_assign_dt_device(struct domain *d, struct dt_device_node *dev);
 #else
 
+#include <public/arch-arm.h>
+
 static inline bool sci_domain_is_enabled(struct domain *d)
 {
     return false;
@@ -162,6 +164,9 @@ static inline int sci_domain_init(struct domain *d,
 static inline int
 sci_domain_sanitise_config(struct xen_domctl_createdomain *config)
 {
+    if ( config->arch.arm_sci_type != XEN_DOMCTL_CONFIG_ARM_SCI_NONE )
+        return -EINVAL;
+
     return 0;
 }
 
--
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