| Message ID | 20201109113233.9012-2-dbrazdil@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Opt-in always-on nVHE hypervisor | expand |
On 2020-11-09 11:32, David Brazdil wrote: > The version of PSCI that the kernel should use to communicate with > firmware is typically obtained from probing PSCI_VERSION. However, that > doesn't work for PSCI v0.1 where the host gets the information from > DT/ACPI, or if PSCI is not supported / was disabled. > > KVM's host PSCI proxy needs to be configured with the same version > used by the host driver. Expose the PSCI version used by the host > with a read-only accessor. > > Signed-off-by: David Brazdil <dbrazdil@google.com> > --- > drivers/firmware/psci/psci.c | 11 +++++++++++ > include/linux/psci.h | 8 ++++++++ > 2 files changed, 19 insertions(+) > > diff --git a/drivers/firmware/psci/psci.c > b/drivers/firmware/psci/psci.c > index 00af99b6f97c..bc1b2d60fdbf 100644 > --- a/drivers/firmware/psci/psci.c > +++ b/drivers/firmware/psci/psci.c > @@ -49,6 +49,13 @@ static int resident_cpu = -1; > struct psci_operations psci_ops; > static enum arm_smccc_conduit psci_conduit = SMCCC_CONDUIT_NONE; > > +static int driver_version = PSCI_VERSION(0, 0); > + > +int psci_driver_version(void) > +{ > + return driver_version; > +} > + > bool psci_tos_resident_on(int cpu) > { > return cpu == resident_cpu; > @@ -461,6 +468,8 @@ static int __init psci_probe(void) > return -EINVAL; > } > > + driver_version = ver; > + > psci_0_2_set_functions(); > > psci_init_migrate(); > @@ -514,6 +523,8 @@ static int __init psci_0_1_init(struct device_node > *np) > > pr_info("Using PSCI v0.1 Function IDs from DT\n"); > > + driver_version = PSCI_VERSION(0, 1); > + > if (!of_property_read_u32(np, "cpu_suspend", &id)) { > psci_function_id[PSCI_FN_CPU_SUSPEND] = id; > psci_ops.cpu_suspend = psci_cpu_suspend; > diff --git a/include/linux/psci.h b/include/linux/psci.h > index 2a1bfb890e58..5b5dcf176aa6 100644 > --- a/include/linux/psci.h > +++ b/include/linux/psci.h > @@ -21,6 +21,14 @@ bool psci_power_state_is_valid(u32 state); > int psci_set_osi_mode(bool enable); > bool psci_has_osi_support(void); > > +/** > + * The version of the PSCI specification followed by the driver. > + * This is equivalent to calling PSCI_VERSION except: > + * (a) it also works for PSCI v0.1, which does not support > PSCI_VERSION, and > + * (b) it is set to v0.0 if the PSCI driver was not initialized. > + */ > +int psci_driver_version(void); > + > struct psci_operations { > u32 (*get_version)(void); > int (*cpu_suspend)(u32 state, unsigned long entry_point); I still maintain that populating .get_version in all cases instead of duplicating an existing functionality is a better outcome. PSCI not supported would be implied by .get_version being NULL. What breaks? M.
> > + > > struct psci_operations { > > u32 (*get_version)(void); > > int (*cpu_suspend)(u32 state, unsigned long entry_point); > > I still maintain that populating .get_version in all cases instead of > duplicating an existing functionality is a better outcome. PSCI not > supported would be implied by .get_version being NULL. > > What breaks? Must have missed that suggestion before. Good idea, I'll do that.
diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c index 00af99b6f97c..bc1b2d60fdbf 100644 --- a/drivers/firmware/psci/psci.c +++ b/drivers/firmware/psci/psci.c @@ -49,6 +49,13 @@ static int resident_cpu = -1; struct psci_operations psci_ops; static enum arm_smccc_conduit psci_conduit = SMCCC_CONDUIT_NONE; +static int driver_version = PSCI_VERSION(0, 0); + +int psci_driver_version(void) +{ + return driver_version; +} + bool psci_tos_resident_on(int cpu) { return cpu == resident_cpu; @@ -461,6 +468,8 @@ static int __init psci_probe(void) return -EINVAL; } + driver_version = ver; + psci_0_2_set_functions(); psci_init_migrate(); @@ -514,6 +523,8 @@ static int __init psci_0_1_init(struct device_node *np) pr_info("Using PSCI v0.1 Function IDs from DT\n"); + driver_version = PSCI_VERSION(0, 1); + if (!of_property_read_u32(np, "cpu_suspend", &id)) { psci_function_id[PSCI_FN_CPU_SUSPEND] = id; psci_ops.cpu_suspend = psci_cpu_suspend; diff --git a/include/linux/psci.h b/include/linux/psci.h index 2a1bfb890e58..5b5dcf176aa6 100644 --- a/include/linux/psci.h +++ b/include/linux/psci.h @@ -21,6 +21,14 @@ bool psci_power_state_is_valid(u32 state); int psci_set_osi_mode(bool enable); bool psci_has_osi_support(void); +/** + * The version of the PSCI specification followed by the driver. + * This is equivalent to calling PSCI_VERSION except: + * (a) it also works for PSCI v0.1, which does not support PSCI_VERSION, and + * (b) it is set to v0.0 if the PSCI driver was not initialized. + */ +int psci_driver_version(void); + struct psci_operations { u32 (*get_version)(void); int (*cpu_suspend)(u32 state, unsigned long entry_point);
The version of PSCI that the kernel should use to communicate with firmware is typically obtained from probing PSCI_VERSION. However, that doesn't work for PSCI v0.1 where the host gets the information from DT/ACPI, or if PSCI is not supported / was disabled. KVM's host PSCI proxy needs to be configured with the same version used by the host driver. Expose the PSCI version used by the host with a read-only accessor. Signed-off-by: David Brazdil <dbrazdil@google.com> --- drivers/firmware/psci/psci.c | 11 +++++++++++ include/linux/psci.h | 8 ++++++++ 2 files changed, 19 insertions(+)