On Mon, Feb 02, 2026 at 06:27:05PM +0000, Anirudh Rayabharam wrote:
> From: Anirudh Rayabharam (Microsoft) <[email protected]>
>
> Rename mshv_synic_init() to mshv_synic_cpu_init() and
> mshv_synic_cleanup() to mshv_synic_cpu_exit() to better reflect that
> these functions handle per-cpu synic setup and teardown.
>
> Use mshv_synic_init/cleanup() to perform init/cleanup that is not per-cpu.
> Move all the synic related setup from mshv_parent_partition_init.
>
> Move the reboot notifier to mshv_synic.c because it currently only
> operates on the synic cpuhp state.
>
> Move out synic_pages from the global mshv_root since it's use is now
> completely local to mshv_synic.c.
>
> This is in preparation for the next patch which will add more stuff to
> mshv_synic_init().
>
> No functional change.
>
> Signed-off-by: Anirudh Rayabharam (Microsoft) <[email protected]>
> ---
> drivers/hv/mshv_root.h | 5 ++-
> drivers/hv/mshv_root_main.c | 59 +++++-------------------------
> drivers/hv/mshv_synic.c | 71 +++++++++++++++++++++++++++++++++----
> 3 files changed, 75 insertions(+), 60 deletions(-)
>
> diff --git a/drivers/hv/mshv_root.h b/drivers/hv/mshv_root.h
> index 3c1d88b36741..26e0320c8097 100644
> --- a/drivers/hv/mshv_root.h
> +++ b/drivers/hv/mshv_root.h
> @@ -183,7 +183,6 @@ struct hv_synic_pages {
> };
>
> struct mshv_root {
> - struct hv_synic_pages __percpu *synic_pages;
> spinlock_t pt_ht_lock;
> DECLARE_HASHTABLE(pt_htable, MSHV_PARTITIONS_HASH_BITS);
> struct hv_partition_property_vmm_capabilities vmm_caps;
> @@ -242,8 +241,8 @@ int mshv_register_doorbell(u64 partition_id,
> doorbell_cb_t doorbell_cb,
> void mshv_unregister_doorbell(u64 partition_id, int doorbell_portid);
>
> void mshv_isr(void);
> -int mshv_synic_init(unsigned int cpu);
> -int mshv_synic_cleanup(unsigned int cpu);
> +int mshv_synic_init(struct device *dev);
> +void mshv_synic_cleanup(void);
>
> static inline bool mshv_partition_encrypted(struct mshv_partition *partition)
> {
> diff --git a/drivers/hv/mshv_root_main.c b/drivers/hv/mshv_root_main.c
> index 681b58154d5e..7c1666456e78 100644
> --- a/drivers/hv/mshv_root_main.c
> +++ b/drivers/hv/mshv_root_main.c
> @@ -2035,7 +2035,6 @@ mshv_dev_release(struct inode *inode, struct file *filp)
> return 0;
> }
>
> -static int mshv_cpuhp_online;
> static int mshv_root_sched_online;
>
> static const char *scheduler_type_to_string(enum hv_scheduler_type type)
> @@ -2198,40 +2197,14 @@ root_scheduler_deinit(void)
> free_percpu(root_scheduler_output);
> }
>
> -static int mshv_reboot_notify(struct notifier_block *nb,
> - unsigned long code, void *unused)
> -{
> - cpuhp_remove_state(mshv_cpuhp_online);
> - return 0;
> -}
> -
Unrelated to the change, but it would be great to get rid of this
notifier altogether and just do the cleanup in the device shutdown hook.
This is a cleaner approach as this is a device driver and we do have the
device in hands.
Do you think you could make this change a part of this series?
> -struct notifier_block mshv_reboot_nb = {
> - .notifier_call = mshv_reboot_notify,
> -};
> -
> static void mshv_root_partition_exit(void)
> {
> - unregister_reboot_notifier(&mshv_reboot_nb);
> root_scheduler_deinit();
> }
>
> static int __init mshv_root_partition_init(struct device *dev)
> {
> - int err;
> -
> - err = root_scheduler_init(dev);
> - if (err)
> - return err;
> -
> - err = register_reboot_notifier(&mshv_reboot_nb);
> - if (err)
> - goto root_sched_deinit;
> -
> - return 0;
> -
> -root_sched_deinit:
> - root_scheduler_deinit();
> - return err;
> + return root_scheduler_init(dev);
> }
>
This conflicts with the "mshv: Add support for integrated scheduler"
patch out there.
Perhaps we should ask Wei to merge that change first.
> static void mshv_init_vmm_caps(struct device *dev)
> @@ -2276,31 +2249,18 @@ static int __init mshv_parent_partition_init(void)
> MSHV_HV_MAX_VERSION);
> }
>
> - mshv_root.synic_pages = alloc_percpu(struct hv_synic_pages);
> - if (!mshv_root.synic_pages) {
> - dev_err(dev, "Failed to allocate percpu synic page\n");
> - ret = -ENOMEM;
> + ret = mshv_synic_init(dev);
> + if (ret)
> goto device_deregister;
> - }
> -
> - ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "mshv_synic",
> - mshv_synic_init,
> - mshv_synic_cleanup);
> - if (ret < 0) {
> - dev_err(dev, "Failed to setup cpu hotplug state: %i\n", ret);
> - goto free_synic_pages;
> - }
> -
> - mshv_cpuhp_online = ret;
>
> ret = mshv_retrieve_scheduler_type(dev);
> if (ret)
> - goto remove_cpu_state;
> + goto synic_cleanup;
>
> if (hv_root_partition())
> ret = mshv_root_partition_init(dev);
> if (ret)
> - goto remove_cpu_state;
> + goto synic_cleanup;
>
> mshv_init_vmm_caps(dev);
>
> @@ -2318,10 +2278,8 @@ static int __init mshv_parent_partition_init(void)
> exit_partition:
> if (hv_root_partition())
> mshv_root_partition_exit();
> -remove_cpu_state:
> - cpuhp_remove_state(mshv_cpuhp_online);
> -free_synic_pages:
> - free_percpu(mshv_root.synic_pages);
> +synic_cleanup:
> + mshv_synic_cleanup();
> device_deregister:
> misc_deregister(&mshv_dev);
> return ret;
> @@ -2335,8 +2293,7 @@ static void __exit mshv_parent_partition_exit(void)
> mshv_irqfd_wq_cleanup();
> if (hv_root_partition())
> mshv_root_partition_exit();
> - cpuhp_remove_state(mshv_cpuhp_online);
> - free_percpu(mshv_root.synic_pages);
> + mshv_synic_cleanup();
> }
>
> module_init(mshv_parent_partition_init);
> diff --git a/drivers/hv/mshv_synic.c b/drivers/hv/mshv_synic.c
> index f8b0337cdc82..98c58755846d 100644
> --- a/drivers/hv/mshv_synic.c
> +++ b/drivers/hv/mshv_synic.c
> @@ -12,11 +12,16 @@
> #include <linux/mm.h>
> #include <linux/io.h>
> #include <linux/random.h>
> +#include <linux/cpuhotplug.h>
> +#include <linux/reboot.h>
> #include <asm/mshyperv.h>
>
> #include "mshv_eventfd.h"
> #include "mshv.h"
>
> +static int synic_cpuhp_online;
> +static struct hv_synic_pages __percpu *synic_pages;
> +
> static u32 synic_event_ring_get_queued_port(u32 sint_index)
> {
> struct hv_synic_event_ring_page **event_ring_page;
> @@ -26,7 +31,7 @@ static u32 synic_event_ring_get_queued_port(u32 sint_index)
> u32 message;
> u8 tail;
>
> - spages = this_cpu_ptr(mshv_root.synic_pages);
> + spages = this_cpu_ptr(synic_pages);
> event_ring_page = &spages->synic_event_ring_page;
> synic_eventring_tail = (u8 **)this_cpu_ptr(hv_synic_eventring_tail);
>
> @@ -393,7 +398,7 @@ mshv_intercept_isr(struct hv_message *msg)
>
> void mshv_isr(void)
> {
> - struct hv_synic_pages *spages = this_cpu_ptr(mshv_root.synic_pages);
> + struct hv_synic_pages *spages = this_cpu_ptr(synic_pages);
> struct hv_message_page **msg_page = &spages->hyp_synic_message_page;
> struct hv_message *msg;
> bool handled;
> @@ -446,7 +451,7 @@ void mshv_isr(void)
> }
> }
>
> -int mshv_synic_init(unsigned int cpu)
> +static int mshv_synic_cpu_init(unsigned int cpu)
> {
> union hv_synic_simp simp;
> union hv_synic_siefp siefp;
> @@ -455,7 +460,7 @@ int mshv_synic_init(unsigned int cpu)
> union hv_synic_sint sint;
> #endif
> union hv_synic_scontrol sctrl;
> - struct hv_synic_pages *spages = this_cpu_ptr(mshv_root.synic_pages);
> + struct hv_synic_pages *spages = this_cpu_ptr(synic_pages);
> struct hv_message_page **msg_page = &spages->hyp_synic_message_page;
> struct hv_synic_event_flags_page **event_flags_page =
> &spages->synic_event_flags_page;
> @@ -542,14 +547,14 @@ int mshv_synic_init(unsigned int cpu)
> return -EFAULT;
> }
>
> -int mshv_synic_cleanup(unsigned int cpu)
> +static int mshv_synic_cpu_exit(unsigned int cpu)
> {
> union hv_synic_sint sint;
> union hv_synic_simp simp;
> union hv_synic_siefp siefp;
> union hv_synic_sirbp sirbp;
> union hv_synic_scontrol sctrl;
> - struct hv_synic_pages *spages = this_cpu_ptr(mshv_root.synic_pages);
> + struct hv_synic_pages *spages = this_cpu_ptr(synic_pages);
> struct hv_message_page **msg_page = &spages->hyp_synic_message_page;
> struct hv_synic_event_flags_page **event_flags_page =
> &spages->synic_event_flags_page;
> @@ -663,3 +668,57 @@ mshv_unregister_doorbell(u64 partition_id, int
> doorbell_portid)
>
> mshv_portid_free(doorbell_portid);
> }
> +
> +static int mshv_synic_reboot_notify(struct notifier_block *nb,
> + unsigned long code, void *unused)
> +{
> + cpuhp_remove_state(synic_cpuhp_online);
> + return 0;
> +}
> +
> +static struct notifier_block mshv_synic_reboot_nb = {
> + .notifier_call = mshv_synic_reboot_notify,
> +};
> +
> +int __init mshv_synic_init(struct device *dev)
> +{
> + int ret = 0;
> +
> + synic_pages = alloc_percpu(struct hv_synic_pages);
> + if (!synic_pages) {
> + dev_err(dev, "Failed to allocate percpu synic page\n");
> + return -ENOMEM;
> + }
> +
> + ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "mshv_synic",
> + mshv_synic_cpu_init,
> + mshv_synic_cpu_exit);
> + if (ret < 0) {
> + dev_err(dev, "Failed to setup cpu hotplug state: %i\n", ret);
> + goto free_synic_pages;
> + }
> +
> + synic_cpuhp_online = ret;
> +
> + if (hv_root_partition()) {
Nit: it's probably better to branch in the notifier itself.
It will introduce an additional object, but the branching will be in one
palce instead of two and it will also make to code simpler and easier to
read.
Thanks
Stanislav.
> + ret = register_reboot_notifier(&mshv_synic_reboot_nb);
> + if (ret)
> + goto remove_cpuhp_state;
> + }
> +
> + return 0;
> +
> +remove_cpuhp_state:
> + cpuhp_remove_state(synic_cpuhp_online);
> +free_synic_pages:
> + free_percpu(synic_pages);
> + return ret;
> +}
> +
> +void mshv_synic_cleanup(void)
> +{
> + if (hv_root_partition())
> + unregister_reboot_notifier(&mshv_synic_reboot_nb);
> + cpuhp_remove_state(synic_cpuhp_online);
> + free_percpu(synic_pages);
> +}
> --
> 2.34.1
>
