Re: [kvm-unit-tests PATCH v3 09/14] arm/arm64: ITS: Device and collection Initialization

[Andrew Jones]

On Tue, Jan 28, 2020 at 11:34:54AM +0100, Eric Auger wrote:
> Introduce an helper functions to register
> - a new device, characterized by its device id and the
>   max number of event IDs that dimension its ITT (Interrupt
>   Translation Table).  The function allocates the ITT.
> 
> - a new collection, characterized by its ID and the
>   target processing engine (PE).
> 
> Signed-off-by: Eric Auger <address@hidden>
> 
> ---
> 
> v2 -> v3:
> - s/report_abort/assert
> 
> v1 -> v2:
> - s/nb_/nr_
> ---
>  lib/arm/asm/gic-v3-its.h | 20 +++++++++++++++++-
>  lib/arm/gic-v3-its.c     | 44 ++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 63 insertions(+), 1 deletion(-)
> 
> diff --git a/lib/arm/asm/gic-v3-its.h b/lib/arm/asm/gic-v3-its.h
> index fe73c04..acd97a9 100644
> --- a/lib/arm/asm/gic-v3-its.h
> +++ b/lib/arm/asm/gic-v3-its.h
> @@ -31,6 +31,19 @@ struct its_baser {
>  };
>  
>  #define GITS_BASER_NR_REGS              8
> +#define GITS_MAX_DEVICES             8
> +#define GITS_MAX_COLLECTIONS         8
> +
> +struct its_device {
> +     u32 device_id;  /* device ID */
> +     u32 nr_ites;    /* Max Interrupt Translation Entries */
> +     void *itt;      /* Interrupt Translation Table GPA */
> +};
> +
> +struct its_collection {
> +     u64 target_address;
> +     u16 col_id;
> +};
>  
>  struct its_data {
>       void *base;
> @@ -38,6 +51,10 @@ struct its_data {
>       struct its_baser baser[GITS_BASER_NR_REGS];
>       struct its_cmd_block *cmd_base;
>       struct its_cmd_block *cmd_write;
> +     struct its_device devices[GITS_MAX_DEVICES];
> +     u32 nr_devices;         /* Allocated Devices */
> +     struct its_collection collections[GITS_MAX_COLLECTIONS];
> +     u32 nr_collections;     /* Allocated Collections */
>  };
>  
>  extern struct its_data its_data;
> @@ -90,7 +107,6 @@ extern struct its_data its_data;
>  #define GITS_BASER_TYPE_DEVICE               1
>  #define GITS_BASER_TYPE_COLLECTION   4
>  
> -
>  struct its_cmd_block {
>       u64 raw_cmd[4];
>  };
> @@ -100,6 +116,8 @@ extern void its_init(void);
>  extern int its_parse_baser(int i, struct its_baser *baser);
>  extern struct its_baser *its_lookup_baser(int type);
>  extern void its_enable_defaults(void);
> +extern struct its_device *its_create_device(u32 dev_id, int nr_ites);
> +extern struct its_collection *its_create_collection(u32 col_id, u32 
> target_pe);
>  
>  #else /* __arm__ */
>  
> diff --git a/lib/arm/gic-v3-its.c b/lib/arm/gic-v3-its.c
> index d1e7e52..c2dcd01 100644
> --- a/lib/arm/gic-v3-its.c
> +++ b/lib/arm/gic-v3-its.c
> @@ -175,3 +175,47 @@ void its_enable_defaults(void)
>  
>       writel(GITS_CTLR_ENABLE, its_data.base + GITS_CTLR);
>  }
> +
> +struct its_device *its_create_device(u32 device_id, int nr_ites)
> +{
> +     struct its_baser *baser;
> +     struct its_device *new;
> +     unsigned long n, order;
> +
> +     assert(its_data.nr_devices < GITS_MAX_DEVICES);
> +
> +     baser = its_lookup_baser(GITS_BASER_TYPE_DEVICE);
> +     if (!baser)
> +             return NULL;

Should we assert here if we can't find a GITS_BASER_TYPE_DEVICE ?
It seems none of the callers of its_create_device are checking
for null.

> +
> +     new = &its_data.devices[its_data.nr_devices];
> +
> +     new->device_id = device_id;
> +     new->nr_ites = nr_ites;
> +
> +     n = (its_data.typer.ite_size * nr_ites) >> PAGE_SHIFT;
> +     order = is_power_of_2(n) ? fls(n) : fls(n) + 1;

I've seen this calculation several times now, so I think an
arch-neutral order calculator is in order:

 int get_order(size_t size);

> +     new->itt = (void *)virt_to_phys(alloc_pages(order));

If this is a physical address then shouldn't itt be phys_addr_t ?

> +
> +     its_data.nr_devices++;
> +     return new;
> +}
> +
> +struct its_collection *its_create_collection(u32 col_id, u32 pe)
> +{
> +     struct its_collection *new;
> +
> +     assert(its_data.nr_collections < GITS_MAX_COLLECTIONS);
> +
> +     new = &its_data.collections[its_data.nr_collections];
> +
> +     new->col_id = col_id;
> +
> +     if (its_data.typer.pta)
> +             new->target_address = (u64)gicv3_data.redist_base[pe];
> +     else
> +             new->target_address = pe << 16;
> +
> +     its_data.nr_collections++;
> +     return new;
> +}
> -- 
> 2.20.1
>

Thanks,
drew