x86/IOMMU: abstract Intel-specific iommu_{en,dis}able_x2apic_IR()

Introduce respective elements in struct iommu_init_ops as well as a
pointer to the main ops structure.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

xen/arch/x86/apic.c

@@ -510,7 +510,7 @@ static void resume_x2apic(void)
     mask_8259A();
     mask_IO_APIC_setup(ioapic_entries);
 
-    iommu_enable_x2apic_IR();
+    iommu_enable_x2apic();
     __enable_x2apic();
 
     restore_IO_APIC_setup(ioapic_entries);
@@ -720,7 +720,7 @@ int lapic_suspend(void)
 
     local_irq_save(flags);
     disable_local_APIC();
-    iommu_disable_x2apic_IR();
+    iommu_disable_x2apic();
     local_irq_restore(flags);
     return 0;
 }
@@ -924,7 +924,7 @@ void __init x2apic_bsp_setup(void)
     mask_8259A();
     mask_IO_APIC_setup(ioapic_entries);
 
-    switch ( iommu_enable_x2apic_IR() )
+    switch ( iommu_enable_x2apic() )
     {
     case 0:
         break;

xen/drivers/passthrough/vtd/extern.h

@@ -35,6 +35,8 @@ void print_vtd_entries(struct iommu *iommu, int bus, int devfn, u64 gmfn);
 keyhandler_fn_t vtd_dump_iommu_info;
 
 bool intel_iommu_supports_eim(void);
+int intel_iommu_enable_eim(void);
+void intel_iommu_disable_eim(void);
 
 int enable_qinval(struct iommu *iommu);
 void disable_qinval(struct iommu *iommu);

xen/drivers/passthrough/vtd/intremap.c

@@ -887,23 +887,13 @@ out:
  * This function is used to enable Interrupt remapping when
  * enable x2apic
  */
-int iommu_enable_x2apic_IR(void)
+int intel_iommu_enable_eim(void)
 {
     struct acpi_drhd_unit *drhd;
     struct iommu *iommu;
 
-    if ( system_state < SYS_STATE_active )
-    {
-        if ( !intel_iommu_supports_eim() )
-            return -EOPNOTSUPP;
-
-        if ( !platform_supports_x2apic() )
-            return -ENXIO;
-
-        iommu_ops = intel_iommu_ops;
-    }
-    else if ( !x2apic_enabled )
-        return -EOPNOTSUPP;
+    if ( system_state < SYS_STATE_active && !platform_supports_x2apic() )
+        return -ENXIO;
 
     for_each_drhd_unit ( drhd )
     {
@@ -948,17 +938,13 @@ int iommu_enable_x2apic_IR(void)
 }
 
 /*
- * This function is used to disable Interrutp remapping when
+ * This function is used to disable Interrupt remapping when
  * suspend local apic
  */
-void iommu_disable_x2apic_IR(void)
+void intel_iommu_disable_eim(void)
 {
     struct acpi_drhd_unit *drhd;
 
-    /* x2apic_enabled implies iommu_supports_eim(). */
-    if ( !x2apic_enabled )
-        return;
-
     for_each_drhd_unit ( drhd )
         disable_intremap(drhd->iommu);
 

xen/drivers/passthrough/vtd/iommu.c

@@ -2720,6 +2720,8 @@ const struct iommu_ops __initconstrel intel_iommu_ops = {
     .free_page_table = iommu_free_page_table,
     .reassign_device = reassign_device_ownership,
     .get_device_group_id = intel_iommu_group_id,
+    .enable_x2apic = intel_iommu_enable_eim,
+    .disable_x2apic = intel_iommu_disable_eim,
     .update_ire_from_apic = io_apic_write_remap_rte,
     .update_ire_from_msi = msi_msg_write_remap_rte,
     .read_apic_from_ire = io_apic_read_remap_rte,
@@ -2736,6 +2738,7 @@ const struct iommu_ops __initconstrel intel_iommu_ops = {
 };
 
 const struct iommu_init_ops __initconstrel intel_iommu_init_ops = {
+    .ops = &intel_iommu_ops,
     .setup = vtd_setup,
     .supports_x2apic = intel_iommu_supports_eim,
 };

xen/drivers/passthrough/x86/iommu.c

@@ -26,6 +26,24 @@
 const struct iommu_init_ops *__initdata iommu_init_ops;
 struct iommu_ops __read_mostly iommu_ops;
 
+int iommu_enable_x2apic(void)
+{
+    if ( system_state < SYS_STATE_active )
+    {
+        if ( !iommu_supports_x2apic() )
+            return -EOPNOTSUPP;
+
+        iommu_ops = *iommu_init_ops->ops;
+    }
+    else if ( !x2apic_enabled )
+        return -EOPNOTSUPP;
+
+    if ( !iommu_ops.enable_x2apic )
+        return -EOPNOTSUPP;
+
+    return iommu_ops.enable_x2apic();
+}
+
 void iommu_update_ire_from_apic(
     unsigned int apic, unsigned int reg, unsigned int value)
 {

xen/include/asm-x86/apic.h

@@ -25,7 +25,6 @@ enum apic_mode {
 };
 
 extern u8 apic_verbosity;
-extern bool x2apic_enabled;
 extern bool directed_eoi_enabled;
 
 void check_x2apic_preenabled(void);

xen/include/asm-x86/apicdef.h

@@ -126,4 +126,6 @@
 
 #define MAX_IO_APICS 128
 
+extern bool x2apic_enabled;
+
 #endif

xen/include/asm-x86/iommu.h

@@ -17,6 +17,7 @@
 #include <xen/errno.h>
 #include <xen/list.h>
 #include <xen/spinlock.h>
+#include <asm/apicdef.h>
 #include <asm/processor.h>
 #include <asm/hvm/vmx/vmcs.h>
 
@@ -65,6 +66,7 @@ static inline const struct iommu_ops *iommu_get_ops(void)
 }
 
 struct iommu_init_ops {
+    const struct iommu_ops *ops;
     int (*setup)(void);
     bool (*supports_x2apic)(void);
 };
@@ -96,8 +98,13 @@ static inline bool iommu_supports_x2apic(void)
            : false;
 }
 
-int iommu_enable_x2apic_IR(void);
-void iommu_disable_x2apic_IR(void);
+int iommu_enable_x2apic(void);
+
+static inline void iommu_disable_x2apic(void)
+{
+    if ( x2apic_enabled && iommu_ops.disable_x2apic )
+        iommu_ops.disable_x2apic();
+}
 
 extern bool untrusted_msi;
 

xen/include/xen/iommu.h

@@ -216,11 +216,16 @@ struct iommu_ops {
                                     unsigned int *flags);
 
     void (*free_page_table)(struct page_info *);
+
 #ifdef CONFIG_X86
+    int (*enable_x2apic)(void);
+    void (*disable_x2apic)(void);
+
     void (*update_ire_from_apic)(unsigned int apic, unsigned int reg, unsigned int value);
     unsigned int (*read_apic_from_ire)(unsigned int apic, unsigned int reg);
     int (*setup_hpet_msi)(struct msi_desc *);
 #endif /* CONFIG_X86 */
+
     int __must_check (*suspend)(void);
     void (*resume)(void);
     void (*share_p2m)(struct domain *d);