linux-kernel - [PATCH v4 5/7] mshv: Update hv_stats

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Message-ID: <20260121214623.76374-6-nunodasneves@linux.microsoft.com>
Date: Wed, 21 Jan 2026 13:46:21 -0800
From: Nuno Das Neves <nunodasneves@...ux.microsoft.com>
To: linux-hyperv@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	mhklinux@...look.com,
	skinsburskii@...ux.microsoft.com
Cc: kys@...rosoft.com,
	haiyangz@...rosoft.com,
	wei.liu@...nel.org,
	decui@...rosoft.com,
	longli@...rosoft.com,
	prapal@...ux.microsoft.com,
	mrathor@...ux.microsoft.com,
	paekkaladevi@...ux.microsoft.com,
	Nuno Das Neves <nunodasneves@...ux.microsoft.com>
Subject: [PATCH v4 5/7] mshv: Update hv_stats_page definitions

hv_stats_page belongs in hvhdk.h, move it there.

It does not require a union to access the data for different counters,
just use a single u64 array for simplicity and to match the Windows
definitions.

While at it, correct the ARM64 value for VpRootDispatchThreadBlocked.

Signed-off-by: Nuno Das Neves <nunodasneves@...ux.microsoft.com>
---
 drivers/hv/mshv_root_main.c | 22 ++++++----------------
 include/hyperv/hvhdk.h      |  8 ++++++++
 2 files changed, 14 insertions(+), 16 deletions(-)

diff --git a/drivers/hv/mshv_root_main.c b/drivers/hv/mshv_root_main.c
index fbfc9e7d9fa4..12825666e21b 100644
--- a/drivers/hv/mshv_root_main.c
+++ b/drivers/hv/mshv_root_main.c
@@ -39,23 +39,14 @@ MODULE_AUTHOR("Microsoft");
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("Microsoft Hyper-V root partition VMM interface /dev/mshv");
 
-/* TODO move this to another file when debugfs code is added */
 enum hv_stats_vp_counters {			/* HV_THREAD_COUNTER */
 #if defined(CONFIG_X86)
-	VpRootDispatchThreadBlocked			= 202,
+	VpRootDispatchThreadBlocked = 202,
 #elif defined(CONFIG_ARM64)
-	VpRootDispatchThreadBlocked			= 94,
+	VpRootDispatchThreadBlocked = 95,
 #endif
-	VpStatsMaxCounter
 };
 
-struct hv_stats_page {
-	union {
-		u64 vp_cntrs[VpStatsMaxCounter];		/* VP counters */
-		u8 data[HV_HYP_PAGE_SIZE];
-	};
-} __packed;
-
 struct mshv_root mshv_root;
 
 enum hv_scheduler_type hv_scheduler_type;
@@ -485,12 +476,11 @@ static u64 mshv_vp_interrupt_pending(struct mshv_vp *vp)
 static bool mshv_vp_dispatch_thread_blocked(struct mshv_vp *vp)
 {
 	struct hv_stats_page **stats = vp->vp_stats_pages;
-	u64 *self_vp_cntrs = stats[HV_STATS_AREA_SELF]->vp_cntrs;
-	u64 *parent_vp_cntrs = stats[HV_STATS_AREA_PARENT]->vp_cntrs;
+	u64 *self_vp_cntrs = stats[HV_STATS_AREA_SELF]->data;
+	u64 *parent_vp_cntrs = stats[HV_STATS_AREA_PARENT]->data;
 
-	if (self_vp_cntrs[VpRootDispatchThreadBlocked])
-		return self_vp_cntrs[VpRootDispatchThreadBlocked];
-	return parent_vp_cntrs[VpRootDispatchThreadBlocked];
+	return parent_vp_cntrs[VpRootDispatchThreadBlocked] ||
+	       self_vp_cntrs[VpRootDispatchThreadBlocked];
 }
 
 static int
diff --git a/include/hyperv/hvhdk.h b/include/hyperv/hvhdk.h
index 469186df7826..ac501969105c 100644
--- a/include/hyperv/hvhdk.h
+++ b/include/hyperv/hvhdk.h
@@ -10,6 +10,14 @@
 #include "hvhdk_mini.h"
 #include "hvgdk.h"
 
+/*
+ * Hypervisor statistics page format
+ */
+struct hv_stats_page {
+	u64 data[HV_HYP_PAGE_SIZE / sizeof(u64)];
+} __packed;
+
+
 /* Bits for dirty mask of hv_vp_register_page */
 #define HV_X64_REGISTER_CLASS_GENERAL	0
 #define HV_X64_REGISTER_CLASS_IP	1
-- 
2.34.1