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>

2 files changed, 34 insertions, 0 deletions

diff --git a/include/xen/interface/xen.h b/include/xen/interface/xen.h
index e9d4501d1f5e..167071c290b3 100644
--- a/include/xen/interface/xen.h
+++ b/include/xen/interface/xen.h
@@ -113,6 +113,7 @@
 #define VIRQ_MEM_EVENT  10 /* G. (DOM0) A memory event has occured           */
 #define VIRQ_XC_RESERVED 11 /* G. Reserved for XenClient                     */
 #define VIRQ_ENOMEM     12 /* G. (DOM0) Low on heap memory       */
+#define VIRQ_XENPMU     13  /* PMC interrupt                                 */
 
 /* Architecture-specific VIRQ definitions. */
 #define VIRQ_ARCH_0    16
diff --git a/include/xen/interface/xenpmu.h b/include/xen/interface/xenpmu.h
index eac1b498b89f..ca42301949b5 100644
--- a/include/xen/interface/xenpmu.h
+++ b/include/xen/interface/xenpmu.h
@@ -56,4 +56,37 @@ struct xen_pmu_params {
  */
 #define XENPMU_FEATURE_INTEL_BTS  1
 
+/*
+ * Shared PMU data between hypervisor and PV(H) domains.
+ *
+ * The hypervisor fills out this structure during PMU interrupt and sends an
+ * interrupt to appropriate VCPU.
+ * Architecture-independent fields of xen_pmu_data are WO for the hypervisor
+ * and RO for the guest but some fields in xen_pmu_arch can be writable
+ * by both the hypervisor and the guest (see arch-$arch/pmu.h).
+ */
+struct xen_pmu_data {
+	/* Interrupted VCPU */
+	uint32_t vcpu_id;
+
+	/*
+	 * Physical processor on which the interrupt occurred. On non-privileged
+	 * guests set to vcpu_id;
+	 */
+	uint32_t pcpu_id;
+
+	/*
+	 * Domain that was interrupted. On non-privileged guests set to
+	 * DOMID_SELF.
+	 * On privileged guests can be DOMID_SELF, DOMID_XEN, or, when in
+	 * XENPMU_MODE_ALL mode, domain ID of another domain.
+	 */
+	domid_t  domain_id;
+
+	uint8_t pad[6];
+
+	/* Architecture-specific information */
+	struct xen_pmu_arch pmu;
+};
+
 #endif /* __XEN_PUBLIC_XENPMU_H__ */