2021-09-10 18:59:16

by Wei Liu

Subject: [PATCH v2 1/2] asm-generic/hyperv: provide cpumask_to_vpset_noself

This is a new variant which removes `self' cpu from the vpset. It will
be used in Hyper-V enlightened IPI code.

Signed-off-by: Wei Liu <[email protected]>
---
Provide a new variant instead of adding a new parameter because it makes
it easier to backport -- we don't need to fix the users of
cpumask_to_vpset.

v2:
1. Rename function
2. Add preemptible check
---
include/asm-generic/mshyperv.h | 21 +++++++++++++++++++--
1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
index 9a000ba2bb75..9a134806f1d5 100644
--- a/include/asm-generic/mshyperv.h
+++ b/include/asm-generic/mshyperv.h
@@ -184,10 +184,12 @@ static inline int hv_cpu_number_to_vp_number(int cpu_number)
return hv_vp_index[cpu_number];
}

-static inline int cpumask_to_vpset(struct hv_vpset *vpset,
- const struct cpumask *cpus)
+static inline int __cpumask_to_vpset(struct hv_vpset *vpset,
+ const struct cpumask *cpus,
+ bool exclude_self)
{
int cpu, vcpu, vcpu_bank, vcpu_offset, nr_bank = 1;
+ int this_cpu = smp_processor_id();

/* valid_bank_mask can represent up to 64 banks */
if (hv_max_vp_index / 64 >= 64)
@@ -205,6 +207,8 @@ static inline int cpumask_to_vpset(struct hv_vpset *vpset,
* Some banks may end up being empty but this is acceptable.
*/
for_each_cpu(cpu, cpus) {
+ if (exclude_self && cpu == this_cpu)
+ continue;
vcpu = hv_cpu_number_to_vp_number(cpu);
if (vcpu == VP_INVAL)
return -1;
@@ -219,6 +223,19 @@ static inline int cpumask_to_vpset(struct hv_vpset *vpset,
return nr_bank;
}

+static inline int cpumask_to_vpset(struct hv_vpset *vpset,
+ const struct cpumask *cpus)
+{
+ return __cpumask_to_vpset(vpset, cpus, false);
+}
+
+static inline int cpumask_to_vpset_noself(struct hv_vpset *vpset,
+ const struct cpumask *cpus)
+{
+ WARN_ON_ONCE(preemptible());
+ return __cpumask_to_vpset(vpset, cpus, true);
+}
+
void hyperv_report_panic(struct pt_regs *regs, long err, bool in_die);
bool hv_is_hyperv_initialized(void);
bool hv_is_hibernation_supported(void);
--
2.30.2

2021-09-11 15:10:54

by Michael Kelley (LINUX)

Subject: RE: [PATCH v2 1/2] asm-generic/hyperv: provide cpumask_to_vpset_noself

From: Wei Liu <[email protected]> Sent: Friday, September 10, 2021 11:57 AM
>
> This is a new variant which removes `self' cpu from the vpset. It will
> be used in Hyper-V enlightened IPI code.
>
> Signed-off-by: Wei Liu <[email protected]>
> ---
> Provide a new variant instead of adding a new parameter because it makes
> it easier to backport -- we don't need to fix the users of
> cpumask_to_vpset.
>
> v2:
> 1. Rename function
> 2. Add preemptible check
> ---
> include/asm-generic/mshyperv.h | 21 +++++++++++++++++++--
> 1 file changed, 19 insertions(+), 2 deletions(-)
>
> diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
> index 9a000ba2bb75..9a134806f1d5 100644
> --- a/include/asm-generic/mshyperv.h
> +++ b/include/asm-generic/mshyperv.h
> @@ -184,10 +184,12 @@ static inline int hv_cpu_number_to_vp_number(int cpu_number)
> return hv_vp_index[cpu_number];
> }
>
> -static inline int cpumask_to_vpset(struct hv_vpset *vpset,
> - const struct cpumask *cpus)
> +static inline int __cpumask_to_vpset(struct hv_vpset *vpset,
> + const struct cpumask *cpus,
> + bool exclude_self)
> {
> int cpu, vcpu, vcpu_bank, vcpu_offset, nr_bank = 1;
> + int this_cpu = smp_processor_id();
>
> /* valid_bank_mask can represent up to 64 banks */
> if (hv_max_vp_index / 64 >= 64)
> @@ -205,6 +207,8 @@ static inline int cpumask_to_vpset(struct hv_vpset *vpset,
> * Some banks may end up being empty but this is acceptable.
> */
> for_each_cpu(cpu, cpus) {
> + if (exclude_self && cpu == this_cpu)
> + continue;
> vcpu = hv_cpu_number_to_vp_number(cpu);
> if (vcpu == VP_INVAL)
> return -1;
> @@ -219,6 +223,19 @@ static inline int cpumask_to_vpset(struct hv_vpset *vpset,
> return nr_bank;
> }
>
> +static inline int cpumask_to_vpset(struct hv_vpset *vpset,
> + const struct cpumask *cpus)
> +{
> + return __cpumask_to_vpset(vpset, cpus, false);
> +}
> +
> +static inline int cpumask_to_vpset_noself(struct hv_vpset *vpset,
> + const struct cpumask *cpus)
> +{
> + WARN_ON_ONCE(preemptible());
> + return __cpumask_to_vpset(vpset, cpus, true);
> +}
> +
> void hyperv_report_panic(struct pt_regs *regs, long err, bool in_die);
> bool hv_is_hyperv_initialized(void);
> bool hv_is_hibernation_supported(void);
> --
> 2.30.2

Reviewed-by: Michael Kelley <[email protected]>