From 16469e2094edab39279b9f6aaa97c84722baa812 Mon Sep 17 00:00:00 2001
From: Louis Burda <quent.burda@gmail.com>
Date: Thu, 27 Oct 2022 21:34:43 +0200
Subject: Add baseline measurement mode

---
 cachepc/cachepc.c | 13 +++++++++++++
 cachepc/cachepc.h |  4 ++++
 cachepc/kvm.c     | 31 +++++++++++++++++++++++++++++++
 cachepc/uapi.h    |  1 +
 4 files changed, 49 insertions(+)

diff --git a/cachepc/cachepc.c b/cachepc/cachepc.c
index fc948bb..11ddf95 100644
--- a/cachepc/cachepc.c
+++ b/cachepc/cachepc.c
@@ -10,6 +10,8 @@
 
 #define REMOVE_PAGE_OFFSET(ptr) ((void *) (((uintptr_t) ptr) & PAGE_MASK))
 
+#define MIN(a, b) ((a) < (b) ? (a) : (b))
+
 static void cl_insert(cacheline *last_cl, cacheline *new_cl);
 static void *remove_cache_set(cache_ctx *ctx, void *ptr);
 static void *remove_cache_group_set(void *ptr);
@@ -270,6 +272,17 @@ cachepc_print_msrmts(cacheline *head)
 	} while (curr_cl != head);
 }
 
+void
+cachepc_update_baseline(void)
+{
+	size_t i;
+
+	for (i = 0; i < cachepc_msrmts_count; i++) {
+		cachepc_baseline[i] = MIN(cachepc_baseline[i],
+			cachepc_msrmts[i]);
+	}
+}
+
 void __attribute__((optimize(1))) // prevent instruction reordering
 cachepc_prime_vcall(uintptr_t ret, cacheline *cl)
 {
diff --git a/cachepc/cachepc.h b/cachepc/cachepc.h
index 629b9ca..af38db3 100644
--- a/cachepc/cachepc.h
+++ b/cachepc/cachepc.h
@@ -99,6 +99,7 @@ void *cachepc_aligned_alloc(size_t alignment, size_t size);
 
 void cachepc_save_msrmts(cacheline *head);
 void cachepc_print_msrmts(cacheline *head);
+void cachepc_update_baseline(void);
 
 void cachepc_prime_vcall(uintptr_t ret, cacheline *cl);
 void cachepc_probe_vcall(uintptr_t ret, cacheline *cl);
@@ -121,6 +122,9 @@ static inline uint64_t cachepc_read_pmc(uint64_t event);
 extern uint16_t *cachepc_msrmts;
 extern size_t cachepc_msrmts_count;
 
+extern uint16_t *cachepc_baseline;
+extern bool cachepc_baseline_measure;
+
 extern cache_ctx *cachepc_ctx;
 extern cacheline *cachepc_ds;
 
diff --git a/cachepc/kvm.c b/cachepc/kvm.c
index 0cc41e0..a72f512 100644
--- a/cachepc/kvm.c
+++ b/cachepc/kvm.c
@@ -15,6 +15,11 @@ size_t cachepc_msrmts_count = 0;
 EXPORT_SYMBOL(cachepc_msrmts);
 EXPORT_SYMBOL(cachepc_msrmts_count);
 
+uint16_t *cachepc_baseline = NULL;
+bool cachepc_baseline_measure = false;
+EXPORT_SYMBOL(cachepc_baseline);
+EXPORT_SYMBOL(cachepc_baseline_measure);
+
 cache_ctx *cachepc_ctx = NULL;
 cacheline *cachepc_ds = NULL;
 EXPORT_SYMBOL(cachepc_ctx);
@@ -362,6 +367,26 @@ cachepc_kvm_setup_pmc_ioctl(void __user *arg_user)
 	return 0;
 }
 
+int
+cachepc_kvm_measure_baseline_ioctl(void __user *arg_user)
+{
+	bool state;
+
+	if (!arg_user) return -EINVAL;
+
+	if (copy_from_user(&state, arg_user, sizeof(state)))
+		return -EFAULT;
+
+	cachepc_baseline_measure = state;
+
+	if (!state) {
+		memset(cachepc_baseline, 0,
+			sizeof(uint16_t) * cachepc_msrmts_count);
+	}
+
+	return 0;
+}
+
 int
 cachepc_kvm_track_page_ioctl(void __user *arg_user)
 {
@@ -495,6 +520,8 @@ cachepc_kvm_ioctl(struct file *file, unsigned int ioctl, unsigned long arg)
 		return cachepc_kvm_read_counts_ioctl(arg_user);
 	case KVM_CPC_SETUP_PMC:
 		return cachepc_kvm_setup_pmc_ioctl(arg_user);
+	case KVM_CPC_MEASURE_BASELINE:
+		return cachepc_kvm_measure_baseline_ioctl(arg_user);
 	case KVM_CPC_TRACK_PAGE:
 		return cachepc_kvm_track_page_ioctl(arg_user);
 	case KVM_CPC_TRACK_ALL:
@@ -550,6 +577,10 @@ cachepc_kvm_init(void)
 	cachepc_msrmts = kzalloc(cachepc_msrmts_count * sizeof(uint16_t), GFP_KERNEL);
 	BUG_ON(cachepc_msrmts == NULL);
 
+	cachepc_baseline_measure = false;
+	cachepc_baseline = kzalloc(cachepc_msrmts_count * sizeof(uint16_t), GFP_KERNEL);
+	BUG_ON(cachepc_baseline == NULL);
+
 	ret = smp_call_function_single(2, cachepc_kvm_setup_test, NULL, true);
 	WARN_ON(ret != 0);
 }
diff --git a/cachepc/uapi.h b/cachepc/uapi.h
index b5ed18b..2519975 100644
--- a/cachepc/uapi.h
+++ b/cachepc/uapi.h
@@ -15,6 +15,7 @@
 #define KVM_CPC_READ_PMC _IOWR(KVMIO, 0x23, __u32)
 #define KVM_CPC_READ_COUNTS _IOR(KVMIO, 0x24, __u64)
 #define KVM_CPC_SETUP_PMC _IO(KVMIO, 0x25)
+#define KVM_CPC_MEASURE_BASELINE _IO(KVMIO, 0x26)
 
 #define KVM_CPC_TRACK_PAGE _IOWR(KVMIO, 0x30, struct cpc_track_config)
 #define KVM_CPC_TRACK_ALL _IOWR(KVMIO, 0x31, __u64)
-- 
cgit v1.2.3-71-gd317