Intel IOMMU Suspend/Resume Support - Interrupt Remapping

This patch enables suspend/resume for interrupt remapping. During suspend,
interrupt remapping is disabled. When resume, interrupt remapping is enabled
again.

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

1 files changed, 62 insertions, 8 deletions

diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 85eb8e100818..098ec84b8c00 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -1304,6 +1304,7 @@ void __init enable_IR_x2apic(void)
 #ifdef CONFIG_INTR_REMAP
         int ret;
         unsigned long flags;
+        struct IO_APIC_route_entry **ioapic_entries = NULL;
 
         if (!cpu_has_x2apic)
                 return;
@@ -1334,17 +1335,23 @@ void __init enable_IR_x2apic(void)
                 return;
         }
 
-        ret = save_IO_APIC_setup();
+        ioapic_entries = alloc_ioapic_entries();
+        if (!ioapic_entries) {
+                pr_info("Allocate ioapic_entries failed: %d\n", ret);
+                goto end;
+        }
+
+        ret = save_IO_APIC_setup(ioapic_entries);
         if (ret) {
                 pr_info("Saving IO-APIC state failed: %d\n", ret);
                 goto end;
         }
 
         local_irq_save(flags);
-        mask_IO_APIC_setup();
+        mask_IO_APIC_setup(ioapic_entries);
         mask_8259A();
 
-        ret = enable_intr_remapping(1);
+        ret = enable_intr_remapping(EIM_32BIT_APIC_ID);
 
         if (ret && x2apic_preenabled) {
                 local_irq_restore(flags);
@@ -1364,9 +1371,9 @@ end_restore:
                 /*
                  * IR enabling failed
                  */
-                restore_IO_APIC_setup();
+                restore_IO_APIC_setup(ioapic_entries);
         else
-                reinit_intr_remapped_IO_APIC(x2apic_preenabled);
+                reinit_intr_remapped_IO_APIC(x2apic_preenabled, ioapic_entries);
 
         unmask_8259A();
         local_irq_restore(flags);
@@ -1379,6 +1386,8 @@ end:
                         pr_info("Enabled Interrupt-remapping\n");
         } else
                 pr_err("Failed to enable Interrupt-remapping and x2apic\n");
+        if (ioapic_entries)
+                free_ioapic_entries(ioapic_entries);
 #else
         if (!cpu_has_x2apic)
                 return;
@@ -1954,6 +1963,10 @@ static int lapic_suspend(struct sys_device *dev, pm_message_t state)
 
         local_irq_save(flags);
         disable_local_APIC();
+#ifdef CONFIG_INTR_REMAP
+        if (intr_remapping_enabled)
+                disable_intr_remapping();
+#endif
         local_irq_restore(flags);
         return 0;
 }
@@ -1964,15 +1977,41 @@ static int lapic_resume(struct sys_device *dev)
         unsigned long flags;
         int maxlvt;
 
+#ifdef CONFIG_INTR_REMAP
+        int ret;
+        struct IO_APIC_route_entry **ioapic_entries = NULL;
+
         if (!apic_pm_state.active)
                 return 0;
 
-        maxlvt = lapic_get_maxlvt();
-
         local_irq_save(flags);
+        if (x2apic) {
+                ioapic_entries = alloc_ioapic_entries();
+                if (!ioapic_entries) {
+                        WARN(1, "Alloc ioapic_entries in lapic resume failed.");
+                        return -ENOMEM;
+                }
+
+                ret = save_IO_APIC_setup(ioapic_entries);
+                if (ret) {
+                        WARN(1, "Saving IO-APIC state failed: %d\n", ret);
+                        free_ioapic_entries(ioapic_entries);
+                        return ret;
+                }
+
+                mask_IO_APIC_setup(ioapic_entries);
+                mask_8259A();
+                enable_x2apic();
+        }
+#else
+        if (!apic_pm_state.active)
+                return 0;
 
+        local_irq_save(flags);
         if (x2apic)
                 enable_x2apic();
+#endif
+
         else {
                 /*
                  * Make sure the APICBASE points to the right address
@@ -1986,6 +2025,7 @@ static int lapic_resume(struct sys_device *dev)
                 wrmsr(MSR_IA32_APICBASE, l, h);
         }
 
+        maxlvt = lapic_get_maxlvt();
         apic_write(APIC_LVTERR, ERROR_APIC_VECTOR | APIC_LVT_MASKED);
         apic_write(APIC_ID, apic_pm_state.apic_id);
         apic_write(APIC_DFR, apic_pm_state.apic_dfr);
@@ -2009,8 +2049,20 @@ static int lapic_resume(struct sys_device *dev)
         apic_write(APIC_ESR, 0);
         apic_read(APIC_ESR);
 
+#ifdef CONFIG_INTR_REMAP
+        if (intr_remapping_enabled)
+                reenable_intr_remapping(EIM_32BIT_APIC_ID);
+
+        if (x2apic) {
+                unmask_8259A();
+                restore_IO_APIC_setup(ioapic_entries);
+                free_ioapic_entries(ioapic_entries);
+        }
+#endif
+
         local_irq_restore(flags);
 
+
         return 0;
 }
 
@@ -2048,7 +2100,9 @@ static int __init init_lapic_sysfs(void)
                 error = sysdev_register(&device_lapic);
         return error;
 }
-device_initcall(init_lapic_sysfs);
+
+/* local apic needs to resume before other devices access its registers. */
+core_initcall(init_lapic_sysfs);
 
 #else   /* CONFIG_PM */