Re: [PATCH v2 02/15] xen/arm: vpsci: Add support for PSCI 1.1

[Mirela Simonovic <mirela.simonovic@aggios.com>]

Hi Julien,

I've done pretty much the same work in parallel, but there are few 
additional minor changes I've made. Briefly, the difference is in return 
values that some already implemented functions should return starting 
from v1.0 (and even v0.2 errata). Please let me know whether you omitted 
that intentionally.
I can submit these patches if you want. Currently I have few - one for 
each fix, easier to review. I guess all of them should be squashed with 
the patch you submitted.

One more note - starting from v1.0, PSCI_NOT_SUPPORTED error should be 
returned for all optional functions that are not implemented. Is that 
the case? I.e. when there is no case for a particular function ID in 
do_vpsci_0_2_call the PSCI_NOT_SUPPORTED error will be returned?


On 02/08/2018 08:21 PM, Julien Grall wrote:
> At the moment, Xen provides virtual PSCI interface compliant with 0.1
> and 0.2. Since them, the specification has been updated and the latest
> version is 1.1 (see ARM DEN 0022D).
>
>  From an implementation point of view, only PSCI_FEATURES is mandatory.
> The rest is optional and can be left unimplemented for now.
>
> At the same time, the compatible for PSCI node have been updated to
> expose "arm,psci-1.0".
>
> Signed-off-by: Julien Grall <julien.grall@arm.com>
> Cc: Wei Liu <wei.liu2@citrix.com>
> Cc: Ian Jackson <ian.jackson@eu.citrix.com>
> Cc: mirela.simonovic@aggios.com
>
> ---
>      We may want to provide a way for the toolstack to specify a PSCI
>      version. This could be useful if a guest is expecting a given
>      version.
>
>      Changes in v2:
>          - Return v1.1 on GET_VERSION call as claimed by this patch
>          - Order by function ID the calls in FEATURES call
> ---
>   tools/libxl/libxl_arm.c          |  3 ++-
>   xen/arch/arm/domain_build.c      |  1 +
>   xen/arch/arm/vpsci.c             | 39 ++++++++++++++++++++++++++++++++++++++-
>   xen/include/asm-arm/perfc_defn.h |  1 +
>   xen/include/asm-arm/psci.h       |  1 +
>   xen/include/asm-arm/vpsci.h      |  2 +-
>   6 files changed, 44 insertions(+), 3 deletions(-)
>
> diff --git a/tools/libxl/libxl_arm.c b/tools/libxl/libxl_arm.c
> index 3e46554301..86f59c0d80 100644
> --- a/tools/libxl/libxl_arm.c
> +++ b/tools/libxl/libxl_arm.c
> @@ -410,7 +410,8 @@ static int make_psci_node(libxl__gc *gc, void *fdt)
>       res = fdt_begin_node(fdt, "psci");
>       if (res) return res;
>   
> -    res = fdt_property_compat(gc, fdt, 2, "arm,psci-0.2","arm,psci");
> +    res = fdt_property_compat(gc, fdt, 3, "arm,psci-1.0",
> +                              "arm,psci-0.2", "arm,psci");
>       if (res) return res;
>   
>       res = fdt_property_string(fdt, "method", "hvc");
> diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
> index 155c952349..941688a2ce 100644
> --- a/xen/arch/arm/domain_build.c
> +++ b/xen/arch/arm/domain_build.c
> @@ -637,6 +637,7 @@ static int make_psci_node(void *fdt, const struct dt_device_node *parent)
>   {
>       int res;
>       const char compat[] =
> +        "arm,psci-1.0""\0"
>           "arm,psci-0.2""\0"
>           "arm,psci";
>   
> diff --git a/xen/arch/arm/vpsci.c b/xen/arch/arm/vpsci.c
> index 6ab8ab64d0..e82b62db1a 100644
> --- a/xen/arch/arm/vpsci.c
> +++ b/xen/arch/arm/vpsci.c
> @@ -106,7 +106,11 @@ static int32_t do_psci_cpu_off(uint32_t power_state)
>   
>   static uint32_t do_psci_0_2_version(void)
>   {
> -    return PSCI_VERSION(0, 2);
> +    /*
> +     * PSCI is backward compatible from 0.2. So we can bump the version
> +     * without any issue.
> +     */
> +    return PSCI_VERSION(1, 1);
>   }
>   
>   static register_t do_psci_0_2_cpu_suspend(uint32_t power_state,
> @@ -191,6 +195,29 @@ static void do_psci_0_2_system_reset(void)
>       domain_shutdown(d,SHUTDOWN_reboot);
>   }
>   
> +static int32_t do_psci_1_0_features(uint32_t psci_func_id)
> +{
> +    /* /!\ Ordered by function ID and not name */
> +    switch ( psci_func_id )
> +    {
> +    case PSCI_0_2_FN32_PSCI_VERSION:
> +    case PSCI_0_2_FN32_CPU_SUSPEND:
> +    case PSCI_0_2_FN64_CPU_SUSPEND:

Just a note here - PSCI_FEATURES should return additional information 
just for CPU_SUSPEND (supported power state and mode). AFAIU, that value 
is also 0, so the return code should be fine.

> +    case PSCI_0_2_FN32_CPU_OFF:
> +    case PSCI_0_2_FN32_CPU_ON:
> +    case PSCI_0_2_FN64_CPU_ON:
> +    case PSCI_0_2_FN32_AFFINITY_INFO:
> +    case PSCI_0_2_FN64_AFFINITY_INFO:
> +    case PSCI_0_2_FN32_MIGRATE_INFO_TYPE:
> +    case PSCI_0_2_FN32_SYSTEM_OFF:
> +    case PSCI_0_2_FN32_SYSTEM_RESET:
> +    case PSCI_1_0_FN32_PSCI_FEATURES:
> +        return 0;
> +    default:
> +        return PSCI_NOT_SUPPORTED;
> +    }
> +}
> +
>   #define PSCI_SET_RESULT(reg, val) set_user_reg(reg, 0, val)
>   #define PSCI_ARG(reg, n) get_user_reg(reg, n)
>   
> @@ -304,6 +331,16 @@ bool do_vpsci_0_2_call(struct cpu_user_regs *regs, uint32_t fid)
>           PSCI_SET_RESULT(regs, do_psci_0_2_affinity_info(taff, laff));
>           return true;
>       }
> +
> +    case PSCI_1_0_FN32_PSCI_FEATURES:
> +    {
> +        uint32_t psci_func_id = PSCI_ARG32(regs, 1);
> +
> +        perfc_incr(vpsci_features);
> +        PSCI_SET_RESULT(regs, do_psci_1_0_features(psci_func_id));
> +        return true;
> +    }
> +
>       default:
>           return false;
>       }
> diff --git a/xen/include/asm-arm/perfc_defn.h b/xen/include/asm-arm/perfc_defn.h
> index a7acb7d21c..87866264ca 100644
> --- a/xen/include/asm-arm/perfc_defn.h
> +++ b/xen/include/asm-arm/perfc_defn.h
> @@ -31,6 +31,7 @@ PERFCOUNTER(vpsci_system_off,          "vpsci: system_off")
>   PERFCOUNTER(vpsci_system_reset,        "vpsci: system_reset")
>   PERFCOUNTER(vpsci_cpu_suspend,         "vpsci: cpu_suspend")
>   PERFCOUNTER(vpsci_cpu_affinity_info,   "vpsci: cpu_affinity_info")
> +PERFCOUNTER(vpsci_features,            "vpsci: features")
>   
>   PERFCOUNTER(vgicd_reads,                "vgicd: read")
>   PERFCOUNTER(vgicd_writes,               "vgicd: write")
> diff --git a/xen/include/asm-arm/psci.h b/xen/include/asm-arm/psci.h
> index becc9f9ded..e2629eed01 100644
> --- a/xen/include/asm-arm/psci.h
> +++ b/xen/include/asm-arm/psci.h
> @@ -40,6 +40,7 @@ void call_psci_system_reset(void);
>   #define PSCI_0_2_FN32_MIGRATE_INFO_TYPE   PSCI_0_2_FN32(6)
>   #define PSCI_0_2_FN32_SYSTEM_OFF          PSCI_0_2_FN32(8)
>   #define PSCI_0_2_FN32_SYSTEM_RESET        PSCI_0_2_FN32(9)
> +#define PSCI_1_0_FN32_PSCI_FEATURES       PSCI_0_2_FN32(10)
>   
>   #define PSCI_0_2_FN64_CPU_SUSPEND         PSCI_0_2_FN64(1)
>   #define PSCI_0_2_FN64_CPU_ON              PSCI_0_2_FN64(3)
> diff --git a/xen/include/asm-arm/vpsci.h b/xen/include/asm-arm/vpsci.h
> index 035a41e812..0cca5e6830 100644
> --- a/xen/include/asm-arm/vpsci.h
> +++ b/xen/include/asm-arm/vpsci.h
> @@ -23,7 +23,7 @@
>   #include <asm/psci.h>
>   
>   /* Number of function implemented by virtual PSCI (only 0.2 or later) */
> -#define VPSCI_NR_FUNCS  11
> +#define VPSCI_NR_FUNCS  12
>   
>   /* Functions handle PSCI calls from the guests */
>   bool do_vpsci_0_1_call(struct cpu_user_regs *regs, uint32_t fid);


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