[PATCH v3 4/5] KVM: selftests: Add an interface to read the data of named vcpu stat

[Manali Shukla <manali.shukla@amd.com>]

From: Manali Shukla <Manali.Shukla@amd.com>

The interface is used to read the data values of a specified vcpu stat
from the currenly available binary stats interface.

Signed-off-by: Manali Shukla <Manali.Shukla@amd.com>
---
 .../kvm/include/kvm_arch_vcpu_states.h        | 49 +++++++++++++++++++
 .../testing/selftests/kvm/include/kvm_util.h  | 34 +++++++++++++
 tools/testing/selftests/kvm/lib/kvm_util.c    | 32 ++++++++++++
 3 files changed, 115 insertions(+)
 create mode 100644 tools/testing/selftests/kvm/include/kvm_arch_vcpu_states.h

diff --git a/tools/testing/selftests/kvm/include/kvm_arch_vcpu_states.h b/tools/testing/selftests/kvm/include/kvm_arch_vcpu_states.h
new file mode 100644
index 000000000000..755ff7de53d9
--- /dev/null
+++ b/tools/testing/selftests/kvm/include/kvm_arch_vcpu_states.h
@@ -0,0 +1,49 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/*
+ * Arch-specific stats are added to the kvm_arch_vcpu_states.h. Sequence
+ * of arch-specific vcpu_stat_type should be same as they are declared in
+ * arch-specific kvm_vcpu_stat.
+ */
+#ifdef __x86_64__
+#define KVM_X86_VCPU_STATE(x) KVM_VCPU_STATE(x)
+
+KVM_X86_VCPU_STATE(PF_TAKEN)
+KVM_X86_VCPU_STATE(PF_FIXED)
+KVM_X86_VCPU_STATE(PF_EMULATE)
+KVM_X86_VCPU_STATE(PF_SPURIOUS)
+KVM_X86_VCPU_STATE(PF_FAST)
+KVM_X86_VCPU_STATE(PF_MMIO_SPTE_CREATED)
+KVM_X86_VCPU_STATE(PF_GUEST)
+KVM_X86_VCPU_STATE(TLB_FLUSH)
+KVM_X86_VCPU_STATE(INVLPG)
+KVM_X86_VCPU_STATE(EXITS)
+KVM_X86_VCPU_STATE(IO_EXITS)
+KVM_X86_VCPU_STATE(MMIO_EXITS)
+KVM_X86_VCPU_STATE(SIGNAL_EXITS)
+KVM_X86_VCPU_STATE(IRQ_WINDOW_EXITS)
+KVM_X86_VCPU_STATE(NMI_WINDOW_EXITS)
+KVM_X86_VCPU_STATE(LD_FLUSH)
+KVM_X86_VCPU_STATE(HALT_EXITS)
+KVM_X86_VCPU_STATE(REQUEST_IRQ_EXITS)
+KVM_X86_VCPU_STATE(IRQ_EXITS)
+KVM_X86_VCPU_STATE(HOST_STATE_RELOAD)
+KVM_X86_VCPU_STATE(FPU_RELOAD)
+KVM_X86_VCPU_STATE(INSN_EMULATION)
+KVM_X86_VCPU_STATE(INSN_EMULATION_FAIL)
+KVM_X86_VCPU_STATE(HYPERCALLS)
+KVM_X86_VCPU_STATE(IRQ_INJECTIONS)
+KVM_X86_VCPU_STATE(NMI_INJECTIONS)
+KVM_X86_VCPU_STATE(REQ_EVENT)
+KVM_X86_VCPU_STATE(NESTED_RUN)
+KVM_X86_VCPU_STATE(DIRECTED_YIELD_ATTEMPTED)
+KVM_X86_VCPU_STATE(DIRECTED_YIELD_SUCCESSFUL)
+KVM_X86_VCPU_STATE(PREEMPTION_REPORTED)
+KVM_X86_VCPU_STATE(PREEMPTION_OTHER)
+KVM_X86_VCPU_STATE(GUEST_MODE)
+KVM_X86_VCPU_STATE(NOTIFY_WINDOW_EXITS)
+
+#undef KVM_X86_VCPU_STATE
+#undef KVM_VCPU_STATE
+#endif
+
diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index 63c2aaae51f3..fe66b1736060 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -518,6 +518,40 @@ static inline uint64_t vm_get_stat(struct kvm_vm *vm, const char *stat_name)
 	return data;
 }
 
+/*
+ * Ensure that the sequence of the enum vcpu_stat_types matches the order of
+ * kvm_vcpu_stats_desc[].  Otherwise, vcpu_get_stat() may return incorrect data
+ * because __vcpu_get_stat() uses the enum type as an index to get the
+ * descriptor for a given stat and then uses read_stat_data() to get the stats
+ * from the descriptor.
+ */
+enum vcpu_stat_types {
+	HALT_SUCCESSFUL_POLL,
+	HALT_ATTEMPTED_POLL,
+	HALT_POLL_INVALID,
+	HALT_WAKEUP,
+	HALT_POLL_SUCCESS_NS,
+	HALT_POLL_FAIL_NS,
+	HALT_WAIT_NS,
+	HALT_POLL_SUCCESS_HIST,
+	HALT_POLL_FAIL_HIST,
+	HALT_WAIT_HIST,
+	BLOCKING,
+#define KVM_VCPU_STATE(x)  x,
+#include "kvm_arch_vcpu_states.h"
+};
+
+void __vcpu_get_stat(struct kvm_vcpu *vcpu, enum vcpu_stat_types type, uint64_t *data,
+		   size_t max_elements);
+
+static inline uint64_t vcpu_get_stat(struct kvm_vcpu *vcpu, enum vcpu_stat_types type)
+{
+	uint64_t data;
+
+	__vcpu_get_stat(vcpu, type, &data, 1);
+	return data;
+}
+
 void vm_create_irqchip(struct kvm_vm *vm);
 
 static inline int __vm_create_guest_memfd(struct kvm_vm *vm, uint64_t size,
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index ad00e4761886..d4b6a352c1ae 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -2264,6 +2264,38 @@ void read_stat_data(int stats_fd, struct kvm_stats_header *header,
 		    desc->name, size, ret);
 }
 
+/*
+ * Read the data of the named vcpu stat
+ *
+ * Input Args:
+ *   vcpu - the vcpu for which the stat should be read
+ *   stat_name - the name of the stat to read
+ *   max_elements - the maximum number of 8-byte values to read into data
+ *
+ * Output Args:
+ *   data - the buffer into which stat data should be read
+ *
+ * Read the data values of a specified stat from the binary stats interface.
+ */
+void __vcpu_get_stat(struct kvm_vcpu *vcpu, enum vcpu_stat_types type, uint64_t *data,
+		   size_t max_elements)
+{
+	int vcpu_stats_fd;
+	struct kvm_stats_header header;
+	struct kvm_stats_desc *desc, *t_desc;
+	size_t size_desc;
+
+	vcpu_stats_fd = vcpu_get_stats_fd(vcpu);
+	read_stats_header(vcpu_stats_fd, &header);
+
+	desc = read_stats_descriptors(vcpu_stats_fd, &header);
+	size_desc = get_stats_descriptor_size(&header);
+
+	t_desc = (void *)desc + (type * size_desc);
+	read_stat_data(vcpu_stats_fd, &header, t_desc,
+			data, max_elements);
+}
+
 /*
  * Read the data of the named stat
  *
-- 
2.34.1