IOMMU: iommu_intremap is x86-only

Provide a #define for other cases; it didn't seem worthwhile to me to
introduce an IOMMU_INTREMAP Kconfig option at this point.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Paul Durrant <paul@xen.org>

docs/misc/xen-command-line.pandoc

@@ -1299,6 +1299,8 @@ boolean (e.g. `iommu=no`) can override this and leave the IOMMUs disabled.
     generation of IOMMUs only supported DMA remapping, and Interrupt Remapping
     appeared in the second generation.
 
+    This option is only valid on x86.
+
 *   The `intpost` boolean controls the Posted Interrupt sub-feature.  In
     combination with APIC acceleration (VT-x APICV, SVM AVIC), the IOMMU can
     be configured to deliver interrupts from assigned PCI devices directly

xen/drivers/passthrough/iommu.c

@@ -35,7 +35,6 @@ bool __read_mostly iommu_quarantine = true;
 bool_t __read_mostly iommu_igfx = 1;
 bool_t __read_mostly iommu_snoop = 1;
 bool_t __read_mostly iommu_qinval = 1;
-enum iommu_intremap __read_mostly iommu_intremap = iommu_intremap_full;
 bool_t __read_mostly iommu_crash_disable;
 
 static bool __hwdom_initdata iommu_hwdom_none;
@@ -90,8 +89,10 @@ static int __init parse_iommu_param(const char *s)
             iommu_snoop = val;
         else if ( (val = parse_boolean("qinval", s, ss)) >= 0 )
             iommu_qinval = val;
+#ifndef iommu_intremap
         else if ( (val = parse_boolean("intremap", s, ss)) >= 0 )
             iommu_intremap = val ? iommu_intremap_full : iommu_intremap_off;
+#endif
         else if ( (val = parse_boolean("intpost", s, ss)) >= 0 )
             iommu_intpost = val;
 #ifdef CONFIG_KEXEC
@@ -474,8 +475,11 @@ int __init iommu_setup(void)
         rc = iommu_hardware_setup();
         iommu_enabled = (rc == 0);
     }
+
+#ifndef iommu_intremap
     if ( !iommu_enabled )
         iommu_intremap = iommu_intremap_off;
+#endif
 
     if ( (force_iommu && !iommu_enabled) ||
          (force_intremap && !iommu_intremap) )
@@ -500,7 +504,9 @@ int __init iommu_setup(void)
         printk(" - Dom0 mode: %s\n",
                iommu_hwdom_passthrough ? "Passthrough" :
                iommu_hwdom_strict ? "Strict" : "Relaxed");
+#ifndef iommu_intremap
         printk("Interrupt remapping %sabled\n", iommu_intremap ? "en" : "dis");
+#endif
         tasklet_init(&iommu_pt_cleanup_tasklet, iommu_free_pagetables, NULL);
     }
 
@@ -558,7 +564,9 @@ void iommu_crash_shutdown(void)
     if ( iommu_enabled )
         iommu_get_ops()->crash_shutdown();
     iommu_enabled = iommu_intpost = 0;
+#ifndef iommu_intremap
     iommu_intremap = iommu_intremap_off;
+#endif
 }
 
 int iommu_get_reserved_device_memory(iommu_grdm_t *func, void *ctxt)

xen/drivers/passthrough/x86/iommu.c

@@ -27,6 +27,8 @@
 const struct iommu_init_ops *__initdata iommu_init_ops;
 struct iommu_ops __read_mostly iommu_ops;
 
+enum iommu_intremap __read_mostly iommu_intremap = iommu_intremap_full;
+
 int __init iommu_hardware_setup(void)
 {
     struct IO_APIC_route_entry **ioapic_entries = NULL;

xen/include/xen/iommu.h

@@ -55,21 +55,24 @@ static inline bool_t dfn_eq(dfn_t x, dfn_t y)
 extern bool_t iommu_enable, iommu_enabled;
 extern bool force_iommu, iommu_quarantine, iommu_verbose, iommu_igfx;
 extern bool_t iommu_snoop, iommu_qinval, iommu_intpost;
+
+#ifdef CONFIG_X86
 extern enum __packed iommu_intremap {
    /*
     * In order to allow traditional boolean uses of the iommu_intremap
     * variable, the "off" value has to come first (yielding a value of zero).
     */
    iommu_intremap_off,
-#ifdef CONFIG_X86
    /*
     * Interrupt remapping enabled, but only able to generate interrupts
     * with an 8-bit APIC ID.
     */
    iommu_intremap_restricted,
-#endif
    iommu_intremap_full,
 } iommu_intremap;
+#else
+# define iommu_intremap false
+#endif
 
 #if defined(CONFIG_IOMMU_FORCE_PT_SHARE)
 #define iommu_hap_pt_share true