@@ -49,6 +49,7 @@
#include <asm/mtrr.h>
#include <asm/smp.h>
#include <asm/mce.h>
+#include <asm/kvm_para.h>
unsigned int num_processors;
@@ -1361,52 +1362,74 @@ void enable_x2apic(void)
}
#endif /* CONFIG_X86_X2APIC */
-void __init enable_IR_x2apic(void)
+int __init enable_IR(void)
{
#ifdef CONFIG_INTR_REMAP
int ret;
- unsigned long flags;
- struct IO_APIC_route_entry **ioapic_entries = NULL;
ret = dmar_table_init();
if (ret) {
pr_debug("dmar_table_init() failed with %d:\n", ret);
- goto ir_failed;
+ return 0;
}
if (!intr_remapping_supported()) {
pr_debug("intr-remapping not supported\n");
- goto ir_failed;
+ return 0;
}
-
if (!x2apic_preenabled && skip_ioapic_setup) {
pr_info("Skipped enabling intr-remap because of skipping "
"io-apic setup\n");
- return;
+ return 0;
}
+ if (enable_intr_remapping(x2apic_supported()))
+ return 0;
+
+ pr_info("Enabled Interrupt-remapping\n");
+
+ return 1;
+
+#endif
+ return 0;
+}
+
+void __init enable_IR_x2apic(void)
+{
+ unsigned long flags;
+ struct IO_APIC_route_entry **ioapic_entries = NULL;
+ int ret, x2apic_enabled = 0;
+
ioapic_entries = alloc_ioapic_entries();
if (!ioapic_entries) {
- pr_info("Allocate ioapic_entries failed: %d\n", ret);
- goto end;
+ pr_info("Allocate ioapic_entries failed\n");
+ goto out;
}
ret = save_IO_APIC_setup(ioapic_entries);
if (ret) {
pr_info("Saving IO-APIC state failed: %d\n", ret);
- goto end;
+ goto out;
}
local_irq_save(flags);
- mask_IO_APIC_setup(ioapic_entries);
mask_8259A();
+ mask_IO_APIC_setup(ioapic_entries);
- ret = enable_intr_remapping(x2apic_supported());
- if (ret)
- goto end_restore;
+ ret = enable_IR();
+ if (!ret) {
+ /* IR is required if x2apic is enabled by BIOS even
+ * when running in kvm since this indicates present
+ * of APIC ID > 255 */
+ if (max_physical_apicid > 255 || !kvm_para_available())
+ goto nox2apic;
+ /* without IR all CPUs can be addressed by IOAPIC/MSI
+ * only in physical mode */
+ x2apic_phys = 1;
+ }
- pr_info("Enabled Interrupt-remapping\n");
+ x2apic_enabled = 1;
if (x2apic_supported() && !x2apic_mode) {
x2apic_mode = 1;
@@ -1414,41 +1437,30 @@ void __init enable_IR_x2apic(void)
pr_info("Enabled x2apic\n");
}
-end_restore:
- if (ret)
- /*
- * IR enabling failed
- */
+nox2apic:
+ if (!ret) /* IR enabling failed */
restore_IO_APIC_setup(ioapic_entries);
-
unmask_8259A();
local_irq_restore(flags);
-end:
+out:
if (ioapic_entries)
free_ioapic_entries(ioapic_entries);
- if (!ret)
+ if (x2apic_enabled)
return;
-ir_failed:
- if (x2apic_preenabled)
+ if (x2apic_preenabled) {
+#ifdef CONFIG_INTR_REMAP
panic("x2apic enabled by bios. But IR enabling failed");
- else if (cpu_has_x2apic)
- pr_info("Not enabling x2apic,Intr-remapping\n");
#else
- if (!cpu_has_x2apic)
- return;
-
- if (x2apic_preenabled)
panic("x2apic enabled prior OS handover,"
- " enable CONFIG_X86_X2APIC, CONFIG_INTR_REMAP");
+ " enable CONFIG_X86_X2APIC, CONFIG_INTR_REMAP");
#endif
-
- return;
+ } else if (cpu_has_x2apic)
+ pr_info("Not enabling x2apic,Intr-remapping\n");
}
-
#ifdef CONFIG_X86_64
/*
* Detect and enable local APICs on non-SMP boards.
@@ -50,11 +50,11 @@ static struct apic *apic_probe[] __initdata = {
void __init default_setup_apic_routing(void)
{
#ifdef CONFIG_X86_X2APIC
- if (x2apic_mode && (apic != &apic_x2apic_phys &&
+ if (x2apic_mode
#ifdef CONFIG_X86_UV
- apic != &apic_x2apic_uv_x &&
+ && apic != &apic_x2apic_uv_x
#endif
- apic != &apic_x2apic_cluster)) {
+ ) {
if (x2apic_phys)
apic = &apic_x2apic_phys;
else
KVM would like to provide x2APIC interface to a guest without emulating interrupt remapping device. The reason KVM prefers guest to use x2APIC is that x2APIC interface is better virtualizable and provides better performance than mmio xAPIC interface: - msr exits are faster than mmio (no page table walk, emulation) - no need to read back ICR to look at the busy bit - one 64 bit ICR write instead of two 32 bit writes - shared code with the Hyper-V paravirt interface Included patch changes x2APIC enabling logic to enable it even if IR initialization failed, but kernel runs under KVM and no apic id is greater than 255 (if there is one spec requires BIOS to move to x2apic mode before starting an OS). Signed-off-by: Gleb Natapov <gleb@redhat.com> Acked-by: Suresh Siddha <suresh.b.siddha@intel.com> --- This is based on x86 tree commit 5b9eea3e7 with checkpatch complains fixed. -- Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html