xen/acpi: ACPI PAD driver

PAD is acpi Processor Aggregator Device which provides a control point
that enables the platform to perform specific processor configuration
and control that applies to all processors in the platform.

This patch is to implement Xen acpi pad logic. When running under Xen
virt platform, native pad driver would not work. Instead Xen pad driver,
a self-contained and thin logic level, would take over acpi pad logic.

When acpi pad notify OSPM, xen pad logic intercept and parse _PUR object
to get the expected idle cpu number, and then hypercall to hypervisor.
Xen hypervisor would then do the rest work, say, core parking, to idle
specific number of cpus on its own policy.

Signed-off-by: Jan Beulich <JBeulich@suse.com>
Signed-off-by: Liu Jinsong <jinsong.liu@intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

2 files changed, 32 insertions, 0 deletions

diff --git a/include/xen/interface/platform.h b/include/xen/interface/platform.h
index 4755b5fac9c7..5e36932ab407 100644
--- a/include/xen/interface/platform.h
+++ b/include/xen/interface/platform.h
@@ -324,6 +324,22 @@ struct xenpf_cpu_ol {
 };
 DEFINE_GUEST_HANDLE_STRUCT(xenpf_cpu_ol);
 
+/*
+ * CMD 58 and 59 are reserved for cpu hotadd and memory hotadd,
+ * which are already occupied at Xen hypervisor side.
+ */
+#define XENPF_core_parking     60
+struct xenpf_core_parking {
+        /* IN variables */
+#define XEN_CORE_PARKING_SET   1
+#define XEN_CORE_PARKING_GET   2
+        uint32_t type;
+        /* IN variables:  set cpu nums expected to be idled */
+        /* OUT variables: get cpu nums actually be idled */
+        uint32_t idle_nums;
+};
+DEFINE_GUEST_HANDLE_STRUCT(xenpf_core_parking);
+
 struct xen_platform_op {
         uint32_t cmd;
         uint32_t interface_version; /* XENPF_INTERFACE_VERSION */
@@ -341,6 +357,7 @@ struct xen_platform_op {
                 struct xenpf_set_processor_pminfo set_pminfo;
                 struct xenpf_pcpuinfo          pcpu_info;
                 struct xenpf_cpu_ol            cpu_ol;
+                struct xenpf_core_parking      core_parking;
                 uint8_t                        pad[128];
         } u;
 };
diff --git a/include/xen/interface/version.h b/include/xen/interface/version.h
index 7ff6498679a3..96d8d3deea6b 100644
--- a/include/xen/interface/version.h
+++ b/include/xen/interface/version.h
@@ -63,4 +63,19 @@ struct xen_feature_info {
 /* arg == xen_domain_handle_t. */
 #define XENVER_guest_handle 8
 
+/* Check if running on Xen version (major, minor) or later */
+static inline bool
+xen_running_on_version_or_later(unsigned int major, unsigned int minor)
+{
+        unsigned int version;
+
+        if (!xen_domain())
+                return false;
+
+        version = HYPERVISOR_xen_version(XENVER_version, NULL);
+        if ((((version >> 16) == major) && ((version & 0xffff) >= minor)) ||
+                ((version >> 16) > major))
+                return true;
+        return false;
+}
 #endif /* __XEN_PUBLIC_VERSION_H__ */