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-rw-r--r--arch/x86/hyperv/hv_apic.c20
1 files changed, 15 insertions, 5 deletions
diff --git a/arch/x86/hyperv/hv_apic.c b/arch/x86/hyperv/hv_apic.c
index 5c056b8aebef..e01078e93dd3 100644
--- a/arch/x86/hyperv/hv_apic.c
+++ b/arch/x86/hyperv/hv_apic.c
@@ -260,11 +260,21 @@ void __init hv_apic_init(void)
}
if (ms_hyperv.hints & HV_X64_APIC_ACCESS_RECOMMENDED) {
- pr_info("Hyper-V: Using MSR based APIC access\n");
+ pr_info("Hyper-V: Using enlightened APIC (%s mode)",
+ x2apic_enabled() ? "x2apic" : "xapic");
+ /*
+ * With x2apic, architectural x2apic MSRs are equivalent to the
+ * respective synthetic MSRs, so there's no need to override
+ * the apic accessors. The only exception is
+ * hv_apic_eoi_write, because it benefits from lazy EOI when
+ * available, but it works for both xapic and x2apic modes.
+ */
apic_set_eoi_write(hv_apic_eoi_write);
- apic->read = hv_apic_read;
- apic->write = hv_apic_write;
- apic->icr_write = hv_apic_icr_write;
- apic->icr_read = hv_apic_icr_read;
+ if (!x2apic_enabled()) {
+ apic->read = hv_apic_read;
+ apic->write = hv_apic_write;
+ apic->icr_write = hv_apic_icr_write;
+ apic->icr_read = hv_apic_icr_read;
+ }
}
}