2020-11-26 15:57:20

by David Brazdil

Subject: [PATCH v3 02/23] psci: Accessor for configured PSCI function IDs

Function IDs used by PSCI are configurable for v0.1 via DT/APCI. If the
host is using PSCI v0.1, KVM's host PSCI proxy needs to use the same IDs.
Expose the array holding the information with a read-only accessor.

Signed-off-by: David Brazdil <[email protected]>
---
drivers/firmware/psci/psci.c | 16 ++++++++--------
include/linux/psci.h | 10 ++++++++++
2 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c
index 213c68418a65..40609564595e 100644
--- a/drivers/firmware/psci/psci.c
+++ b/drivers/firmware/psci/psci.c
@@ -58,16 +58,16 @@ typedef unsigned long (psci_fn)(unsigned long, unsigned long,
unsigned long, unsigned long);
static psci_fn *invoke_psci_fn;

-enum psci_function {
- PSCI_FN_CPU_SUSPEND,
- PSCI_FN_CPU_ON,
- PSCI_FN_CPU_OFF,
- PSCI_FN_MIGRATE,
- PSCI_FN_MAX,
-};
-
static u32 psci_function_id[PSCI_FN_MAX];

+u32 psci_get_function_id(enum psci_function fn)
+{
+ if (WARN_ON_ONCE(fn < 0 || fn >= PSCI_FN_MAX))
+ return 0;
+
+ return psci_function_id[fn];
+}
+
#define PSCI_0_2_POWER_STATE_MASK \
(PSCI_0_2_POWER_STATE_ID_MASK | \
PSCI_0_2_POWER_STATE_TYPE_MASK | \
diff --git a/include/linux/psci.h b/include/linux/psci.h
index 2a1bfb890e58..5b49a5c82d6f 100644
--- a/include/linux/psci.h
+++ b/include/linux/psci.h
@@ -21,6 +21,16 @@ bool psci_power_state_is_valid(u32 state);
int psci_set_osi_mode(bool enable);
bool psci_has_osi_support(void);

+enum psci_function {
+ PSCI_FN_CPU_SUSPEND,
+ PSCI_FN_CPU_ON,
+ PSCI_FN_CPU_OFF,
+ PSCI_FN_MIGRATE,
+ PSCI_FN_MAX,
+};
+
+u32 psci_get_function_id(enum psci_function fn);
+
struct psci_operations {
u32 (*get_version)(void);
int (*cpu_suspend)(u32 state, unsigned long entry_point);
--
2.29.2.454.gaff20da3a2-goog

2020-11-26 17:35:48

by David Brazdil

Subject: Re: [PATCH v3 02/23] psci: Accessor for configured PSCI function IDs

Hey Mark,

On Thu, Nov 26, 2020 at 05:24:50PM +0000, Mark Rutland wrote:
> On Thu, Nov 26, 2020 at 03:54:00PM +0000, David Brazdil wrote:
> > Function IDs used by PSCI are configurable for v0.1 via DT/APCI. If the
> > host is using PSCI v0.1, KVM's host PSCI proxy needs to use the same IDs.
> > Expose the array holding the information with a read-only accessor.
> >
> > Signed-off-by: David Brazdil <[email protected]>
> > ---
> > drivers/firmware/psci/psci.c | 16 ++++++++--------
> > include/linux/psci.h | 10 ++++++++++
> > 2 files changed, 18 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c
> > index 213c68418a65..40609564595e 100644
> > --- a/drivers/firmware/psci/psci.c
> > +++ b/drivers/firmware/psci/psci.c
> > @@ -58,16 +58,16 @@ typedef unsigned long (psci_fn)(unsigned long, unsigned long,
> > unsigned long, unsigned long);
> > static psci_fn *invoke_psci_fn;
> >
> > -enum psci_function {
> > - PSCI_FN_CPU_SUSPEND,
> > - PSCI_FN_CPU_ON,
> > - PSCI_FN_CPU_OFF,
> > - PSCI_FN_MIGRATE,
> > - PSCI_FN_MAX,
> > -};
> > -
> > static u32 psci_function_id[PSCI_FN_MAX];
> >
> > +u32 psci_get_function_id(enum psci_function fn)
> > +{
> > + if (WARN_ON_ONCE(fn < 0 || fn >= PSCI_FN_MAX))
> > + return 0;
> > +
> > + return psci_function_id[fn];
> > +}
>
> I'd really like if we could namespace this with a psci_0_1_* prefix
> before we expose it outside of the PSCI code. I appreciate that's a
> larger change, but I reckon we only need a couple of new patches:
>
> 1) Split the ops which consume the FN ids into separate psci_0_1_*() and
> psci_0_2_*() variants, with a common __psci_*() helper that takes the
> function ID as an argument. The 0_1 variants would read the function
> ID from a variable, and the 0_2 variants would hard-code the id.
>
> 2) Replace the psci_function_id array with:
>
> struct psci_0_1_function_ids {
> u32 suspend;
> u32 cpu_on;
> u32 cpu_off;
> u32 migrate;
> };
>
> ... and remove enum psci_function entirely.
>
> 3) Add a helper which returns the entire psci_0_1_function_ids struct in
> one go. No warnings necessary.
>
> Does that sound OK to you?

Sure, sounds easy enough and 2) is in line with how I structured the handlers
in KVM.

Thanks,
David

2020-11-27 08:38:35

by Mark Rutland

Subject: Re: [PATCH v3 02/23] psci: Accessor for configured PSCI function IDs

On Thu, Nov 26, 2020 at 03:54:00PM +0000, David Brazdil wrote:
> Function IDs used by PSCI are configurable for v0.1 via DT/APCI. If the
> host is using PSCI v0.1, KVM's host PSCI proxy needs to use the same IDs.
> Expose the array holding the information with a read-only accessor.
>
> Signed-off-by: David Brazdil <[email protected]>
> ---
> drivers/firmware/psci/psci.c | 16 ++++++++--------
> include/linux/psci.h | 10 ++++++++++
> 2 files changed, 18 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c
> index 213c68418a65..40609564595e 100644
> --- a/drivers/firmware/psci/psci.c
> +++ b/drivers/firmware/psci/psci.c
> @@ -58,16 +58,16 @@ typedef unsigned long (psci_fn)(unsigned long, unsigned long,
> unsigned long, unsigned long);
> static psci_fn *invoke_psci_fn;
>
> -enum psci_function {
> - PSCI_FN_CPU_SUSPEND,
> - PSCI_FN_CPU_ON,
> - PSCI_FN_CPU_OFF,
> - PSCI_FN_MIGRATE,
> - PSCI_FN_MAX,
> -};
> -
> static u32 psci_function_id[PSCI_FN_MAX];
>
> +u32 psci_get_function_id(enum psci_function fn)
> +{
> + if (WARN_ON_ONCE(fn < 0 || fn >= PSCI_FN_MAX))
> + return 0;
> +
> + return psci_function_id[fn];
> +}

I'd really like if we could namespace this with a psci_0_1_* prefix
before we expose it outside of the PSCI code. I appreciate that's a
larger change, but I reckon we only need a couple of new patches:

1) Split the ops which consume the FN ids into separate psci_0_1_*() and
psci_0_2_*() variants, with a common __psci_*() helper that takes the
function ID as an argument. The 0_1 variants would read the function
ID from a variable, and the 0_2 variants would hard-code the id.

2) Replace the psci_function_id array with:

struct psci_0_1_function_ids {
u32 suspend;
u32 cpu_on;
u32 cpu_off;
u32 migrate;
};

... and remove enum psci_function entirely.

3) Add a helper which returns the entire psci_0_1_function_ids struct in
one go. No warnings necessary.

Does that sound OK to you?

Thanks,
Mark.

> +
> #define PSCI_0_2_POWER_STATE_MASK \
> (PSCI_0_2_POWER_STATE_ID_MASK | \
> PSCI_0_2_POWER_STATE_TYPE_MASK | \
> diff --git a/include/linux/psci.h b/include/linux/psci.h
> index 2a1bfb890e58..5b49a5c82d6f 100644
> --- a/include/linux/psci.h
> +++ b/include/linux/psci.h
> @@ -21,6 +21,16 @@ bool psci_power_state_is_valid(u32 state);
> int psci_set_osi_mode(bool enable);
> bool psci_has_osi_support(void);
>
> +enum psci_function {
> + PSCI_FN_CPU_SUSPEND,
> + PSCI_FN_CPU_ON,
> + PSCI_FN_CPU_OFF,
> + PSCI_FN_MIGRATE,
> + PSCI_FN_MAX,
> +};
> +
> +u32 psci_get_function_id(enum psci_function fn);
> +
> struct psci_operations {
> u32 (*get_version)(void);
> int (*cpu_suspend)(u32 state, unsigned long entry_point);
> --
> 2.29.2.454.gaff20da3a2-goog
>

2020-11-27 08:38:46

by Lorenzo Pieralisi

Subject: Re: [PATCH v3 02/23] psci: Accessor for configured PSCI function IDs

On Thu, Nov 26, 2020 at 03:54:00PM +0000, David Brazdil wrote:
> Function IDs used by PSCI are configurable for v0.1 via DT/APCI. If the

Side note: in ACPI we don't support versions < 0.2, for commit log
accuracy.

Other than that I agree with Mark's change request.

Thanks,
Lorenzo

> host is using PSCI v0.1, KVM's host PSCI proxy needs to use the same IDs.
> Expose the array holding the information with a read-only accessor.
>
> Signed-off-by: David Brazdil <[email protected]>
> ---
> drivers/firmware/psci/psci.c | 16 ++++++++--------
> include/linux/psci.h | 10 ++++++++++
> 2 files changed, 18 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c
> index 213c68418a65..40609564595e 100644
> --- a/drivers/firmware/psci/psci.c
> +++ b/drivers/firmware/psci/psci.c
> @@ -58,16 +58,16 @@ typedef unsigned long (psci_fn)(unsigned long, unsigned long,
> unsigned long, unsigned long);
> static psci_fn *invoke_psci_fn;
>
> -enum psci_function {
> - PSCI_FN_CPU_SUSPEND,
> - PSCI_FN_CPU_ON,
> - PSCI_FN_CPU_OFF,
> - PSCI_FN_MIGRATE,
> - PSCI_FN_MAX,
> -};
> -
> static u32 psci_function_id[PSCI_FN_MAX];
>
> +u32 psci_get_function_id(enum psci_function fn)
> +{
> + if (WARN_ON_ONCE(fn < 0 || fn >= PSCI_FN_MAX))
> + return 0;
> +
> + return psci_function_id[fn];
> +}
> +
> #define PSCI_0_2_POWER_STATE_MASK \
> (PSCI_0_2_POWER_STATE_ID_MASK | \
> PSCI_0_2_POWER_STATE_TYPE_MASK | \
> diff --git a/include/linux/psci.h b/include/linux/psci.h
> index 2a1bfb890e58..5b49a5c82d6f 100644
> --- a/include/linux/psci.h
> +++ b/include/linux/psci.h
> @@ -21,6 +21,16 @@ bool psci_power_state_is_valid(u32 state);
> int psci_set_osi_mode(bool enable);
> bool psci_has_osi_support(void);
>
> +enum psci_function {
> + PSCI_FN_CPU_SUSPEND,
> + PSCI_FN_CPU_ON,
> + PSCI_FN_CPU_OFF,
> + PSCI_FN_MIGRATE,
> + PSCI_FN_MAX,
> +};
> +
> +u32 psci_get_function_id(enum psci_function fn);
> +
> struct psci_operations {
> u32 (*get_version)(void);
> int (*cpu_suspend)(u32 state, unsigned long entry_point);
> --
> 2.29.2.454.gaff20da3a2-goog
>