[PATCH v2 03/15] Drivers: hv: Move vmbus_handler to common code

Naman Jain
2026-04-23T12:43:05Z

Move the vmbus_handler global variable and hv_setup_vmbus_handler()/
hv_remove_vmbus_handler() from arch/x86 to drivers/hv/hv_common.c.

hv_setup_vmbus_handler() is called unconditionally in vmbus_bus_init()
and works for both x86 (sysvec handler) and arm64 (vmbus_percpu_isr).

This eliminates the need for separate percpu vmbus handler setup
functions and __weak stubs, that are needed for adding ARM64 support
in MSHV_VTL driver where we need to set a custom per-cpu vmbus handler.

Signed-off-by: Naman Jain <namjain@linux.microsoft.com>
---
arch/x86/kernel/cpu/mshyperv.c | 12 ------------
drivers/hv/hv_common.c | 9 +++++++--
drivers/hv/vmbus_drv.c | 17 +++++++++--------
include/asm-generic/mshyperv.h | 1 +
4 files changed, 17 insertions(+), 22 deletions(-)

diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 89a2eb8a0722..68706ff5880e 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -145,7 +145,6 @@ void hv_set_msr(unsigned int reg, u64 value)
EXPORT_SYMBOL_GPL(hv_set_msr);

static void (*mshv_handler)(void);
-static void (*vmbus_handler)(void);
static void (*hv_stimer0_handler)(void);
static void (*hv_kexec_handler)(void);
static void (*hv_crash_handler)(struct pt_regs *regs);
@@ -172,17 +171,6 @@ void hv_setup_mshv_handler(void (*handler)(void))
mshv_handler = handler;
}

-void hv_setup_vmbus_handler(void (*handler)(void))
-{
- vmbus_handler = handler;
-}
-
-void hv_remove_vmbus_handler(void)
-{
- /* We have no way to deallocate the interrupt gate */
- vmbus_handler = NULL;
-}
-
/*
* Routines to do per-architecture handling of stimer0
* interrupts when in Direct Mode
diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
index e8633bc51d56..eb7b0028b45d 100644
--- a/drivers/hv/hv_common.c
+++ b/drivers/hv/hv_common.c
@@ -758,13 +758,18 @@ bool __weak hv_isolation_type_tdx(void)
}
EXPORT_SYMBOL_GPL(hv_isolation_type_tdx);

-void __weak hv_setup_vmbus_handler(void (*handler)(void))
+void (*vmbus_handler)(void);
+EXPORT_SYMBOL_GPL(vmbus_handler);
+
+void hv_setup_vmbus_handler(void (*handler)(void))
{
+ vmbus_handler = handler;
}
EXPORT_SYMBOL_GPL(hv_setup_vmbus_handler);

-void __weak hv_remove_vmbus_handler(void)
+void hv_remove_vmbus_handler(void)
{
+ vmbus_handler = NULL;
}
EXPORT_SYMBOL_GPL(hv_remove_vmbus_handler);

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index bc4fc1951ae1..052ca8b11cee 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -1415,7 +1415,8 @@ EXPORT_SYMBOL_FOR_MODULES(vmbus_isr, "mshv_vtl");

static irqreturn_t vmbus_percpu_isr(int irq, void *dev_id)
{
- vmbus_isr();
+ if (vmbus_handler)
+ vmbus_handler();
return IRQ_HANDLED;
}

@@ -1517,8 +1518,10 @@ static int vmbus_bus_init(void)
vmbus_irq_initialized = true;
}

+ hv_setup_vmbus_handler(vmbus_isr);
+
if (vmbus_irq == -1) {
- hv_setup_vmbus_handler(vmbus_isr);
+ /* x86: sysvec handler uses vmbus_handler directly */
} else {
ret = request_percpu_irq(vmbus_irq, vmbus_percpu_isr,
"Hyper-V VMbus", &vmbus_evt);
@@ -1553,9 +1556,8 @@ static int vmbus_bus_init(void)
return 0;

err_connect:
- if (vmbus_irq == -1)
- hv_remove_vmbus_handler();
- else
+ hv_remove_vmbus_handler();
+ if (vmbus_irq != -1)
free_percpu_irq(vmbus_irq, &vmbus_evt);
err_setup:
if (IS_ENABLED(CONFIG_PREEMPT_RT) && vmbus_irq_initialized) {
@@ -3026,9 +3028,8 @@ static void __exit vmbus_exit(void)
vmbus_connection.conn_state = DISCONNECTED;
hv_stimer_global_cleanup();
vmbus_disconnect();
- if (vmbus_irq == -1)
- hv_remove_vmbus_handler();
- else
+ hv_remove_vmbus_handler();
+ if (vmbus_irq != -1)
free_percpu_irq(vmbus_irq, &vmbus_evt);
if (IS_ENABLED(CONFIG_PREEMPT_RT) && vmbus_irq_initialized) {
smpboot_unregister_percpu_thread(&vmbus_irq_threads);
diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
index 2810aa05dc73..db183c8cfb95 100644
--- a/include/asm-generic/mshyperv.h
+++ b/include/asm-generic/mshyperv.h
@@ -179,6 +179,7 @@ static inline u64 hv_generate_guest_id(u64 kernel_version)

int hv_get_hypervisor_version(union hv_hypervisor_version_info *info);

+extern void (*vmbus_handler)(void);
void hv_setup_vmbus_handler(void (*handler)(void));
void hv_remove_vmbus_handler(void);
void hv_setup_stimer0_handler(void (*handler)(void));