xen/PMU: Initialization code for Xen PMU

Map shared data structure that will hold CPU registers, VPMU context,
V/PCPU IDs of the CPU interrupted by PMU interrupt. Hypervisor fills
this information in its handler and passes it to the guest for further
processing.

Set up PMU VIRQ.

Now that perf infrastructure will assume that PMU is available on a PV
guest we need to be careful and make sure that accesses via RDPMC
instruction don't cause fatal traps by the hypervisor. Provide a nop
RDPMC handler.

For the same reason avoid issuing a warning on a write to APIC's LVTPC.

Both of these will be made functional in later patches.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>

1 files changed, 11 insertions, 1 deletions

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 373dbc9810d1..19072f91a8e2 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -84,6 +84,7 @@
 #include "mmu.h"
 #include "smp.h"
 #include "multicalls.h"
+#include "pmu.h"
 
 EXPORT_SYMBOL_GPL(hypercall_page);
 
@@ -1082,6 +1083,11 @@ static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high)
 	return ret;
 }
 
+unsigned long long xen_read_pmc(int counter)
+{
+	return 0;
+}
+
 void xen_setup_shared_info(void)
 {
 	if (!xen_feature(XENFEAT_auto_translated_physmap)) {
@@ -1216,7 +1222,7 @@ static const struct pv_cpu_ops xen_cpu_ops __initconst = {
 	.write_msr = xen_write_msr_safe,
 
 	.read_tsc = native_read_tsc,
-	.read_pmc = native_read_pmc,
+	.read_pmc = xen_read_pmc,
 
 	.read_tscp = native_read_tscp,
 
@@ -1267,6 +1273,10 @@ static const struct pv_apic_ops xen_apic_ops __initconst = {
 static void xen_reboot(int reason)
 {
 	struct sched_shutdown r = { .reason = reason };
+	int cpu;
+
+	for_each_online_cpu(cpu)
+		xen_pmu_finish(cpu);
 
 	if (HYPERVISOR_sched_op(SCHEDOP_shutdown, &r))
 		BUG();