RE: [PATCH 3/7] Drivers: hv: vmbus: Split hv_synic_init/cleanup into regs and timer settings

Michael Kelley
2019-07-30T22:35:38Z

From: Dexuan Cui <decui@microsoft.com> Sent: Monday, July 8, 2019 10:29 PM
>
> There is only one functional change: the unnecessary check
> "if (sctrl.enable != 1) return -EFAULT;" is removed, because when we're in
> hv_synic_cleanup(), we're absolutely sure sctrl.enable must be 1.
>
> The new functions hv_synic_disable/enable_regs() will be used by a later patch
> to support hibernation.

Seems like this commit message doesn't really describe the main change.
How about:

Break out synic enable and disable operations into separate
hv_synic_disable_regs() and hv_synic_enable_regs() functions for use by a
later patch to support hibernation.

There is no functional change except the unnecessary check
"if (sctrl.enable != 1) return -EFAULT;" is removed, because when we're in
hv_synic_cleanup(), we're absolutely sure sctrl.enable must be 1.

Otherwise,

Reviewed-by: Michael Kelley <mikelley@microsoft.com>

>
> Signed-off-by: Dexuan Cui <decui@microsoft.com>
> ---
> drivers/hv/hv.c | 66 ++++++++++++++++++++++++++---------------------
> drivers/hv/hyperv_vmbus.h | 2 ++
> 2 files changed, 39 insertions(+), 29 deletions(-)
>
> diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
> index 6188fb7..fcc5279 100644
> --- a/drivers/hv/hv.c
> +++ b/drivers/hv/hv.c
> @@ -154,7 +154,7 @@ void hv_synic_free(void)
> * retrieve the initialized message and event pages. Otherwise, we create and
> * initialize the message and event pages.
> */
> -int hv_synic_init(unsigned int cpu)
> +void hv_synic_enable_regs(unsigned int cpu)
> {
> struct hv_per_cpu_context *hv_cpu
> = per_cpu_ptr(hv_context.cpu_context, cpu);
> @@ -196,6 +196,11 @@ int hv_synic_init(unsigned int cpu)
> sctrl.enable = 1;
>
> hv_set_synic_state(sctrl.as_uint64);
> +}
> +
> +int hv_synic_init(unsigned int cpu)
> +{
> + hv_synic_enable_regs(cpu);
>
> hv_stimer_init(cpu);
>
> @@ -205,20 +210,45 @@ int hv_synic_init(unsigned int cpu)
> /*
> * hv_synic_cleanup - Cleanup routine for hv_synic_init().
> */
> -int hv_synic_cleanup(unsigned int cpu)
> +void hv_synic_disable_regs(unsigned int cpu)
> {
> union hv_synic_sint shared_sint;
> union hv_synic_simp simp;
> union hv_synic_siefp siefp;
> union hv_synic_scontrol sctrl;
> +
> + hv_get_synint_state(VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
> +
> + shared_sint.masked = 1;
> +
> + /* Need to correctly cleanup in the case of SMP!!! */
> + /* Disable the interrupt */
> + hv_set_synint_state(VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
> +
> + hv_get_simp(simp.as_uint64);
> + simp.simp_enabled = 0;
> + simp.base_simp_gpa = 0;
> +
> + hv_set_simp(simp.as_uint64);
> +
> + hv_get_siefp(siefp.as_uint64);
> + siefp.siefp_enabled = 0;
> + siefp.base_siefp_gpa = 0;
> +
> + hv_set_siefp(siefp.as_uint64);
> +
> + /* Disable the global synic bit */
> + hv_get_synic_state(sctrl.as_uint64);
> + sctrl.enable = 0;
> + hv_set_synic_state(sctrl.as_uint64);
> +}
> +
> +int hv_synic_cleanup(unsigned int cpu)
> +{
> struct vmbus_channel *channel, *sc;
> bool channel_found = false;
> unsigned long flags;
>
> - hv_get_synic_state(sctrl.as_uint64);
> - if (sctrl.enable != 1)
> - return -EFAULT;
> -
> /*
> * Search for channels which are bound to the CPU we're about to
> * cleanup. In case we find one and vmbus is still connected we need to
> @@ -249,29 +279,7 @@ int hv_synic_cleanup(unsigned int cpu)
>
> hv_stimer_cleanup(cpu);
>
> - hv_get_synint_state(VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
> -
> - shared_sint.masked = 1;
> -
> - /* Need to correctly cleanup in the case of SMP!!! */
> - /* Disable the interrupt */
> - hv_set_synint_state(VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
> -
> - hv_get_simp(simp.as_uint64);
> - simp.simp_enabled = 0;
> - simp.base_simp_gpa = 0;
> -
> - hv_set_simp(simp.as_uint64);
> -
> - hv_get_siefp(siefp.as_uint64);
> - siefp.siefp_enabled = 0;
> - siefp.base_siefp_gpa = 0;
> -
> - hv_set_siefp(siefp.as_uint64);
> -
> - /* Disable the global synic bit */
> - sctrl.enable = 0;
> - hv_set_synic_state(sctrl.as_uint64);
> + hv_synic_disable_regs(cpu);
>
> return 0;
> }
> diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
> index 362e70e..26ea161 100644
> --- a/drivers/hv/hyperv_vmbus.h
> +++ b/drivers/hv/hyperv_vmbus.h
> @@ -171,8 +171,10 @@ extern int hv_post_message(union hv_connection_id
> connection_id,
>
> extern void hv_synic_free(void);
>
> +extern void hv_synic_enable_regs(unsigned int cpu);
> extern int hv_synic_init(unsigned int cpu);
>
> +extern void hv_synic_disable_regs(unsigned int cpu);
> extern int hv_synic_cleanup(unsigned int cpu);
>
> /* Interface */
> --
> 1.8.3.1