Merge tag 'kvm-x86-selftests_6.15-1' of https://github.com/kvm-x86/linux into HEAD

KVM selftests changes for 6.15, part 1

 - Misc cleanups and prep work.

 - Annotate _no_printf() with "printf" so that pr_debug() statements are
   checked by the compiler for default builds (and pr_info() when QUIET).

 - Attempt to whack the last LLC references/misses mole in the Intel PMU
   counters test by adding a data load and doing CLFLUSH{OPT} on the data
   instead of the code being executed.  The theory is that modern Intel CPUs
   have learned new code prefetching tricks that bypass the PMU counters.

 - Fix a flaw in the Intel PMU counters test where it asserts that an event is
   counting correctly without actually knowing what the event counts on the
   underlying hardware.

Author: bonzini

tools/testing/selftests/kvm/access_tracking_perf_test.c

@@ -239,7 +239,7 @@ static void vcpu_thread_main(struct memstress_vcpu_args *vcpu_args)
 		case ITERATION_MARK_IDLE:
 			mark_vcpu_memory_idle(vm, vcpu_args);
 			break;
-		};
+		}
 
 		vcpu_last_completed_iteration[vcpu_idx] = current_iteration;
 	}

tools/testing/selftests/kvm/include/test_util.h

@@ -22,7 +22,7 @@
 
 #define msecs_to_usecs(msec)    ((msec) * 1000ULL)
 
-static inline int _no_printf(const char *format, ...) { return 0; }
+static inline __printf(1, 2) int _no_printf(const char *format, ...) { return 0; }
 
 #ifdef DEBUG
 #define pr_debug(...) printf(__VA_ARGS__)

tools/testing/selftests/kvm/include/x86/processor.h

@@ -183,6 +183,9 @@ struct kvm_x86_cpu_feature {
  * Extended Leafs, a.k.a. AMD defined
  */
 #define	X86_FEATURE_SVM			KVM_X86_CPU_FEATURE(0x80000001, 0, ECX, 2)
+#define	X86_FEATURE_PERFCTR_CORE	KVM_X86_CPU_FEATURE(0x80000001, 0, ECX, 23)
+#define	X86_FEATURE_PERFCTR_NB		KVM_X86_CPU_FEATURE(0x80000001, 0, ECX, 24)
+#define	X86_FEATURE_PERFCTR_LLC		KVM_X86_CPU_FEATURE(0x80000001, 0, ECX, 28)
 #define	X86_FEATURE_NX			KVM_X86_CPU_FEATURE(0x80000001, 0, EDX, 20)
 #define	X86_FEATURE_GBPAGES		KVM_X86_CPU_FEATURE(0x80000001, 0, EDX, 26)
 #define	X86_FEATURE_RDTSCP		KVM_X86_CPU_FEATURE(0x80000001, 0, EDX, 27)
@@ -199,6 +202,8 @@ struct kvm_x86_cpu_feature {
 #define	X86_FEATURE_VGIF		KVM_X86_CPU_FEATURE(0x8000000A, 0, EDX, 16)
 #define X86_FEATURE_SEV			KVM_X86_CPU_FEATURE(0x8000001F, 0, EAX, 1)
 #define X86_FEATURE_SEV_ES		KVM_X86_CPU_FEATURE(0x8000001F, 0, EAX, 3)
+#define	X86_FEATURE_PERFMON_V2		KVM_X86_CPU_FEATURE(0x80000022, 0, EAX, 0)
+#define	X86_FEATURE_LBR_PMC_FREEZE	KVM_X86_CPU_FEATURE(0x80000022, 0, EAX, 2)
 
 /*
  * KVM defined paravirt features.
@@ -285,6 +290,8 @@ struct kvm_x86_cpu_property {
 #define X86_PROPERTY_GUEST_MAX_PHY_ADDR		KVM_X86_CPU_PROPERTY(0x80000008, 0, EAX, 16, 23)
 #define X86_PROPERTY_SEV_C_BIT			KVM_X86_CPU_PROPERTY(0x8000001F, 0, EBX, 0, 5)
 #define X86_PROPERTY_PHYS_ADDR_REDUCTION	KVM_X86_CPU_PROPERTY(0x8000001F, 0, EBX, 6, 11)
+#define X86_PROPERTY_NR_PERFCTR_CORE		KVM_X86_CPU_PROPERTY(0x80000022, 0, EBX, 0, 3)
+#define X86_PROPERTY_NR_PERFCTR_NB		KVM_X86_CPU_PROPERTY(0x80000022, 0, EBX, 10, 15)
 
 #define X86_PROPERTY_MAX_CENTAUR_LEAF		KVM_X86_CPU_PROPERTY(0xC0000000, 0, EAX, 0, 31)
 
@@ -1339,6 +1346,46 @@ static inline void kvm_hypercall_map_gpa_range(uint64_t gpa, uint64_t size,
 	GUEST_ASSERT(!ret);
 }
 
+/*
+ * Execute HLT in an STI interrupt shadow to ensure that a pending IRQ that's
+ * intended to be a wake event arrives *after* HLT is executed.  Modern CPUs,
+ * except for a few oddballs that KVM is unlikely to run on, block IRQs for one
+ * instruction after STI, *if* RFLAGS.IF=0 before STI.  Note, Intel CPUs may
+ * block other events beyond regular IRQs, e.g. may block NMIs and SMIs too.
+ */
+static inline void safe_halt(void)
+{
+	asm volatile("sti; hlt");
+}
+
+/*
+ * Enable interrupts and ensure that interrupts are evaluated upon return from
+ * this function, i.e. execute a nop to consume the STi interrupt shadow.
+ */
+static inline void sti_nop(void)
+{
+	asm volatile ("sti; nop");
+}
+
+/*
+ * Enable interrupts for one instruction (nop), to allow the CPU to process all
+ * interrupts that are already pending.
+ */
+static inline void sti_nop_cli(void)
+{
+	asm volatile ("sti; nop; cli");
+}
+
+static inline void sti(void)
+{
+	asm volatile("sti");
+}
+
+static inline void cli(void)
+{
+	asm volatile ("cli");
+}
+
 void __vm_xsave_require_permission(uint64_t xfeature, const char *name);
 
 #define vm_xsave_require_permission(xfeature)	\

tools/testing/selftests/kvm/x86/hyperv_ipi.c

@@ -63,8 +63,10 @@ static void receiver_code(void *hcall_page, vm_vaddr_t pgs_gpa)
 	/* Signal sender vCPU we're ready */
 	ipis_rcvd[vcpu_id] = (u64)-1;
 
-	for (;;)
-		asm volatile("sti; hlt; cli");
+	for (;;) {
+		safe_halt();
+		cli();
+	}
 }
 
 static void guest_ipi_handler(struct ex_regs *regs)