[PATCH] xen/apic: implement io apic read with hypercall

[Lin Ming <mlin@ss.pku.edu.cn>]

Implements xen_io_apic_read with hypercall, so it returns proper IO-APIC
information instead of fabricated one.

Signed-off-by: Lin Ming <mlin@ss.pku.edu.cn>
---
 arch/x86/xen/apic.c |   16 +++++++++++-----
 1 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/arch/x86/xen/apic.c b/arch/x86/xen/apic.c
index aee16ab..f1f392d 100644
--- a/arch/x86/xen/apic.c
+++ b/arch/x86/xen/apic.c
@@ -1,14 +1,20 @@
 #include <linux/init.h>
 #include <asm/x86_init.h>
+#include <asm/apic.h>
+#include <xen/interface/physdev.h>
+#include <asm/xen/hypercall.h>
 
 unsigned int xen_io_apic_read(unsigned apic, unsigned reg)
 {
-	if (reg == 0x1)
-		return 0x00170020;
-	else if (reg == 0x0)
-		return apic << 24;
+	struct physdev_apic apic_op;
+	int ret;
 
-	return 0xff;
+	apic_op.apic_physbase = mpc_ioapic_addr(apic);
+	apic_op.reg = reg;
+	ret = HYPERVISOR_physdev_op(PHYSDEVOP_apic_read, &apic_op);
+	if (ret)
+		return ret;
+	return apic_op.value;
 }
 
 void __init xen_init_apic(void)
-- 
1.7.2.5