From: Pavel Hrdina <phrdina@redhat.com>
Date: Mon, 16 Feb 2026 08:12:02 +0000 (+0100)
Subject: qemu: Move IOMMUFD validation to qemu_validate
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0c1af67be554d4daa2facfb647ce6e9914da2f06;p=thirdparty%2Flibvirt.git

qemu: Move IOMMUFD validation to qemu_validate

Fail early if kernel doesn't support IOMMUFD.

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
---

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 8554191503..2f9fdc04ad 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -2649,6 +2649,7 @@ virInitctlSetRunLevel;
 
 # util/viriommufd.h
 virIOMMUFDSetRLimitMode;
+virIOMMUFDSupported;
 
 # util/viriscsi.h
 virISCSIConnectionLogin;
diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index c3f681f1dd..fd400ae8a6 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -7694,13 +7694,7 @@ qemuProcessOpenIommuFd(virDomainObj *vm)
     VIR_DEBUG("Opening IOMMU FD for domain %s", vm->def->name);
 
     if ((fd = open(VIR_IOMMU_DEV_PATH, O_RDWR | O_CLOEXEC)) < 0) {
-        if (errno == ENOENT) {
-            virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
-                           _("IOMMU FD support requires /dev/iommu device"));
-        } else {
-            virReportSystemError(errno, "%s",
-                                 _("cannot open /dev/iommu"));
-        }
+        virReportSystemError(errno, "%s", _("cannot open /dev/iommu"));
         return -1;
     }
 
diff --git a/src/qemu/qemu_validate.c b/src/qemu/qemu_validate.c
index 18700b5a9b..16dd5fef1a 100644
--- a/src/qemu/qemu_validate.c
+++ b/src/qemu/qemu_validate.c
@@ -27,6 +27,7 @@
 #include "qemu_process.h"
 #include "domain_conf.h"
 #include "virbitmap.h"
+#include "viriommufd.h"
 #include "virlog.h"
 #include "virutil.h"
 
@@ -2729,6 +2730,12 @@ qemuValidateDomainDeviceDefHostdev(const virDomainHostdevDef *hostdev,
                                        _("IOMMUFD is not supported by this version of qemu"));
                         return -1;
                     }
+
+                    if (!virIOMMUFDSupported()) {
+                        virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                                       _("IOMMUFD is not supported by host kernel"));
+                        return -1;
+                    }
                 }
             }
 
diff --git a/src/util/viriommufd.c b/src/util/viriommufd.c
index 5af097683d..44b30029a5 100644
--- a/src/util/viriommufd.c
+++ b/src/util/viriommufd.c
@@ -88,3 +88,16 @@ int virIOMMUFDSetRLimitMode(int fd G_GNUC_UNUSED,
 }
 
 #endif
+
+/**
+ * virIOMMUFDSupported:
+ *
+ * Check the presence of IOMMU device.
+ *
+ * Retruns: true if it exists, false otherwise
+ */
+bool
+virIOMMUFDSupported(void)
+{
+    return virFileExists(VIR_IOMMU_DEV_PATH);
+}
diff --git a/src/util/viriommufd.h b/src/util/viriommufd.h
index ebecfe3633..ec6be9fa66 100644
--- a/src/util/viriommufd.h
+++ b/src/util/viriommufd.h
@@ -23,3 +23,5 @@
 #define VIR_IOMMU_DEV_PATH "/dev/iommu"
 
 int virIOMMUFDSetRLimitMode(int fd, bool processAccounting);
+
+bool virIOMMUFDSupported(void);