[PATCH v5 4/8] lib: sbi: Add sbi_domain_check_addr_range() function

[Andrew Jones <ajones@ventanamicro.com>]

On Fri, Jan 13, 2023 at 05:11:06PM +0530, Anup Patel wrote:
> We add sbi_domain_check_addr_range() helper function to check
> whether a given address range is accessible under a particular
> domain.
> 
> Signed-off-by: Anup Patel <apatel@ventanamicro.com>
> Reviewed-by: Atish Patra <atishp@rivosinc.com>
> Reviewed-by: Xiang W <wxjstz@126.com>
> Reviewed-by: Bin Meng <bmeng@tinylab.org>
> ---
>  include/sbi/sbi_domain.h | 15 +++++++++
>  lib/sbi/sbi_domain.c     | 69 ++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 84 insertions(+)
> 
> diff --git a/include/sbi/sbi_domain.h b/include/sbi/sbi_domain.h
> index bbb3eff..ab1a944 100644
> --- a/include/sbi/sbi_domain.h
> +++ b/include/sbi/sbi_domain.h
> @@ -196,6 +196,21 @@ bool sbi_domain_check_addr(const struct sbi_domain *dom,
>  			   unsigned long addr, unsigned long mode,
>  			   unsigned long access_flags);
>  
> +/**
> + * Check whether we can access specified address range for given mode and
> + * memory region flags under a domain
> + * @param dom pointer to domain
> + * @param addr the start of the address range to be checked
> + * @param size the size of the address range to be checked
> + * @param mode the privilege mode of access
> + * @param access_flags bitmask of domain access types (enum sbi_domain_access)
> + * @return TRUE if access allowed otherwise FALSE
> + */
> +bool sbi_domain_check_addr_range(const struct sbi_domain *dom,
> +				 unsigned long addr, unsigned long size,
> +				 unsigned long mode,
> +				 unsigned long access_flags);
> +
>  /** Dump domain details on the console */
>  void sbi_domain_dump(const struct sbi_domain *dom, const char *suffix);
>  
> diff --git a/lib/sbi/sbi_domain.c b/lib/sbi/sbi_domain.c
> index 60fda01..683b6cf 100644
> --- a/lib/sbi/sbi_domain.c
> +++ b/lib/sbi/sbi_domain.c
> @@ -208,6 +208,44 @@ static bool is_region_before(const struct sbi_domain_memregion *regA,
>  	return false;
>  }
>  
> +static const struct sbi_domain_memregion *find_region(
> +						const struct sbi_domain *dom,
> +						unsigned long addr)
> +{
> +	unsigned long rstart, rend;
> +	struct sbi_domain_memregion *reg;
> +
> +	sbi_domain_for_each_memregion(dom, reg) {
> +		rstart = reg->base;
> +		rend = (reg->order < __riscv_xlen) ?
> +			rstart + ((1UL << reg->order) - 1) : -1UL;
> +		if (rstart <= addr && addr <= rend)
> +			return reg;
> +	}
> +
> +	return NULL;
> +}
> +
> +static const struct sbi_domain_memregion *find_next_subset_region(
> +				const struct sbi_domain *dom,
> +				const struct sbi_domain_memregion *reg,
> +				unsigned long addr)
> +{
> +	struct sbi_domain_memregion *sreg, *ret = NULL;
> +
> +	sbi_domain_for_each_memregion(dom, sreg) {
> +		if (sreg == reg || (sreg->base <= addr) ||
> +		    !is_region_subset(sreg, reg))
> +			continue;
> +
> +		if (!ret || (sreg->base < ret->base) ||
> +		    ((sreg->base == ret->base) && (sreg->order < ret->order)))
> +			ret = sreg;
> +	}
> +
> +	return ret;
> +}
> +
>  static int sanitize_domain(const struct sbi_platform *plat,
>  			   struct sbi_domain *dom)
>  {
> @@ -316,6 +354,37 @@ static int sanitize_domain(const struct sbi_platform *plat,
>  	return 0;
>  }
>  
> +bool sbi_domain_check_addr_range(const struct sbi_domain *dom,
> +				 unsigned long addr, unsigned long size,
> +				 unsigned long mode,
> +				 unsigned long access_flags)
> +{
> +	unsigned long max = addr + size;
> +	const struct sbi_domain_memregion *reg, *sreg;
> +
> +	if (!dom)
> +		return false;
> +
> +	while (addr < max) {
> +		reg = find_region(dom, addr);
> +		if (!reg)
> +			return false;
> +
> +		if (!sbi_domain_check_addr(dom, addr, mode, access_flags))
> +			return false;
> +
> +		sreg = find_next_subset_region(dom, reg, addr);
> +		if (sreg)
> +			addr = sreg->base;
> +		else if (reg->order < __riscv_xlen)
> +			addr = reg->base + (1UL << reg->order);
> +		else
> +			break;
> +	}
> +
> +	return true;
> +}
> +

It seems like there should be a way to optimize this check / these
searches, but I suppose we can do that later.

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>

Thanks,
drew