The value it returns may change from true to false in case
iommu_enable_x2apic() fails and, as a side effect, clears iommu_intremap
(as can happen at least on AMD). Latch the return value from the first
invocation to replace the second one.
Signed-off-by: Jan Beulich <jbeul...@suse.com>
---
v2: New.
--- a/xen/arch/x86/apic.c
+++ b/xen/arch/x86/apic.c
@@ -865,6 +865,7 @@ void x2apic_ap_setup(void)
void __init x2apic_bsp_setup(void)
{
struct IO_APIC_route_entry **ioapic_entries = NULL;
+ bool iommu_x2apic;
const char *orig_name;
if ( !cpu_has_x2apic )
@@ -880,7 +881,8 @@ void __init x2apic_bsp_setup(void)
printk("x2APIC: Already enabled by BIOS: Ignoring cmdline disable.\n");
}
- if ( iommu_supports_x2apic() )
+ iommu_x2apic = iommu_supports_x2apic();
+ if ( iommu_x2apic )
{
if ( (ioapic_entries = alloc_ioapic_entries()) == NULL )
{
@@ -933,8 +935,11 @@ void __init x2apic_bsp_setup(void)
printk("Switched to APIC driver %s\n", genapic.name);
restore_out:
- /* iommu_x2apic_enabled cannot be used here in the error case. */
- if ( iommu_supports_x2apic() )
+ /*
+ * iommu_x2apic_enabled and iommu_supports_x2apic() cannot be used here
+ * in the error case.
+ */
+ if ( iommu_x2apic )
{
/*
* NB: do not use raw mode when restoring entries if the iommu has
