Re: [kvm-unit-tests PATCH v3 08/14] arm/arm64: ITS: its_enable_defaults

[Andrew Jones]

On Tue, Jan 28, 2020 at 11:34:53AM +0100, Eric Auger wrote:
> its_enable_defaults() is the top init function that allocates the
> command queue and all the requested tables (device, collection,
> lpi config and pending tables), enable LPIs at distributor level
> and ITS level.
> 
> gicv3_enable_defaults must be called before.
> 
> Signed-off-by: Eric Auger <address@hidden>
> 
> ---
> 
> v2 -> v3:
> - introduce its_setup_baser in this patch
> - squash "arm/arm64: ITS: Init the command queue" in this patch.
> ---
>  lib/arm/asm/gic-v3-its.h |  8 ++++
>  lib/arm/gic-v3-its.c     | 89 ++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 97 insertions(+)
> 
> diff --git a/lib/arm/asm/gic-v3-its.h b/lib/arm/asm/gic-v3-its.h
> index 815c515..fe73c04 100644
> --- a/lib/arm/asm/gic-v3-its.h
> +++ b/lib/arm/asm/gic-v3-its.h
> @@ -36,6 +36,8 @@ struct its_data {
>       void *base;
>       struct its_typer typer;
>       struct its_baser baser[GITS_BASER_NR_REGS];
> +     struct its_cmd_block *cmd_base;
> +     struct its_cmd_block *cmd_write;
>  };
>  
>  extern struct its_data its_data;
> @@ -88,10 +90,16 @@ 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];
> +};
> +
>  extern void its_parse_typer(void);
>  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);
>  
>  #else /* __arm__ */
>  
> diff --git a/lib/arm/gic-v3-its.c b/lib/arm/gic-v3-its.c
> index 2c0ce13..d1e7e52 100644
> --- a/lib/arm/gic-v3-its.c
> +++ b/lib/arm/gic-v3-its.c
> @@ -86,3 +86,92 @@ void its_init(void)
>               its_parse_baser(i, &its_data.baser[i]);
>  }
>  
> +static void its_setup_baser(int i, struct its_baser *baser)
> +{
> +     unsigned long n = (baser->nr_pages * baser->psz) >> PAGE_SHIFT;
> +     unsigned long order = is_power_of_2(n) ? fls(n) : fls(n) + 1;
> +     u64 val;
> +
> +     baser->table_addr = (u64)virt_to_phys(alloc_pages(order));
> +
> +     val = ((u64)baser->table_addr                                   |
> +             ((u64)baser->type       << GITS_BASER_TYPE_SHIFT)       |
> +             ((u64)(baser->esz - 1)  << GITS_BASER_ENTRY_SIZE_SHIFT) |
> +             ((baser->nr_pages - 1)  << GITS_BASER_PAGES_SHIFT)      |
> +             (u64)baser->indirect    << 62                           |
> +             (u64)baser->valid       << 63);

 << GITS_BASER_INDIRECT
 << GITS_BASER_VALID

> +
> +     switch (baser->psz) {
> +     case SZ_4K:
> +             val |= GITS_BASER_PAGE_SIZE_4K;
> +             break;
> +     case SZ_16K:
> +             val |= GITS_BASER_PAGE_SIZE_16K;
> +             break;
> +     case SZ_64K:
> +             val |= GITS_BASER_PAGE_SIZE_64K;
> +             break;
> +     }
> +
> +     writeq(val, gicv3_its_base() + GITS_BASER + i * 8);
> +}
> +
> +/**
> + * init_cmd_queue: Allocate the command queue and initialize
> + * CBASER, CREADR, CWRITER
> + */
> +static void its_cmd_queue_init(void)
> +{
> +     unsigned long n = SZ_64K >> PAGE_SHIFT;
> +     unsigned long order = fls(n);
> +     u64 cbaser;
> +
> +     its_data.cmd_base = (void *)virt_to_phys(alloc_pages(order));
> +
> +     cbaser = ((u64)its_data.cmd_base | (SZ_64K / SZ_4K - 1) | 
> GITS_CBASER_VALID);
> +
> +     writeq(cbaser, its_data.base + GITS_CBASER);
> +
> +     its_data.cmd_write = its_data.cmd_base;
> +     writeq(0, its_data.base + GITS_CWRITER);
> +}
> +
> +void its_enable_defaults(void)
> +{
> +     unsigned int i;
> +
> +     its_parse_typer();
> +
> +     /* Allocate BASER tables (device and collection tables) */
> +     for (i = 0; i < GITS_BASER_NR_REGS; i++) {
> +             struct its_baser *baser = &its_data.baser[i];
> +             int ret;
> +
> +             ret = its_parse_baser(i, baser);
> +             if (ret)
> +                     continue;

Didn't we already parse typer and baser at its_init time? How/why would
its_parse_baser fail? Should we assert when it does?

> +
> +             switch (baser->type) {
> +             case GITS_BASER_TYPE_DEVICE:
> +                     baser->valid = true;
> +                     its_setup_baser(i, baser);
> +                     break;
> +             case GITS_BASER_TYPE_COLLECTION:
> +                     baser->valid = true;
> +                     its_setup_baser(i, baser);
> +                     break;
> +             default:
> +                     break;

assert() ?

> +             }
> +     }
> +
> +     /* Allocate LPI config and pending tables */
> +     gicv3_lpi_alloc_tables();
> +
> +     its_cmd_queue_init();
> +
> +     for (i = 0; i < nr_cpus; i++)
> +             gicv3_lpi_rdist_ctrl(i, true);
> +
> +     writel(GITS_CTLR_ENABLE, its_data.base + GITS_CTLR);
> +}
> -- 
> 2.20.1
> 
>

It's looking like we don't have a clean separation between its_init and
its_enable_defaults. I'd expect its_init to do all the allocating of
memory and its_enable_defaults to do all the write's to the device.
We should only do its_init once and its_enable should be something
we can do again (after a disable, on reset, etc.). Is that not possible
with the ITS device?

Thanks,
drew