[PATCH v3 18/19] perf/x86: Provide stubs of KVM helpers for non-Intel CPUs

Sean Christopherson
2019-11-19T03:13:21Z

Provide stubs for perf_guest_get_msrs() and intel_pt_handle_vmx() when
building without support for Intel CPUs, i.e. CPU_SUP_INTEL=n. Lack of
stubs is not currently a problem as the only user, KVM_INTEL, takes a
dependency on CPU_SUP_INTEL=y. Provide the stubs for all CPUs so that
KVM_INTEL can be built for any CPU with compatible hardware support,
e.g. Centuar and Zhaoxin CPUs.

Note, the existing stub for perf_guest_get_msrs() is essentially dead
code as KVM selects CONFIG_PERF_EVENTS, i.e. the only user guarantees
the full implementation is built.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/include/asm/perf_event.h | 22 +++++++++++++++-------
1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h
index ee26e9215f18..29964b0e1075 100644
--- a/arch/x86/include/asm/perf_event.h
+++ b/arch/x86/include/asm/perf_event.h
@@ -322,17 +322,10 @@ struct perf_guest_switch_msr {
u64 host, guest;
};

-extern struct perf_guest_switch_msr *perf_guest_get_msrs(int *nr);
extern void perf_get_x86_pmu_capability(struct x86_pmu_capability *cap);
extern void perf_check_microcode(void);
extern int x86_perf_rdpmc_index(struct perf_event *event);
#else
-static inline struct perf_guest_switch_msr *perf_guest_get_msrs(int *nr)
-{
- *nr = 0;
- return NULL;
-}
-
static inline void perf_get_x86_pmu_capability(struct x86_pmu_capability *cap)
{
memset(cap, 0, sizeof(*cap));
@@ -342,8 +335,23 @@ static inline void perf_events_lapic_init(void) { }
static inline void perf_check_microcode(void) { }
#endif

+#if defined(CONFIG_PERF_EVENTS) && defined(CONFIG_CPU_SUP_INTEL)
+extern struct perf_guest_switch_msr *perf_guest_get_msrs(int *nr);
+#else
+static inline struct perf_guest_switch_msr *perf_guest_get_msrs(int *nr)
+{
+ *nr = 0;
+ return NULL;
+}
+#endif
+
#ifdef CONFIG_CPU_SUP_INTEL
extern void intel_pt_handle_vmx(int on);
+#else
+static inline void intel_pt_handle_vmx(int on)
+{
+
+}
#endif

#if defined(CONFIG_PERF_EVENTS) && defined(CONFIG_CPU_SUP_AMD)
--
2.24.0