Anshuman Khandual <khand...@linux.vnet.ibm.com> writes:
> For partition running on PHYP, there can be a adjunct partition
> which shares the virtual address range with the operating system.
> Virtual address ranges which can be used by the adjunct partition
> are communicated with virtual device node of the device tree with
> a property known as "ibm,reserved-virtual-addresses". This patch
> introduces a new function named 'validate_reserved_va_range' which
> is called during initialization to validate that these reserved
> virtual address ranges do not overlap with the address ranges used
> by the kernel for all supported memory contexts. This helps prevent
> the possibility of getting return codes similar to H_RESOURCE for
> H_PROTECT hcalls for conflicting HPTE entries.
Have you tested this? The endian conversions look wrong to me.
> diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
> index ba59d59..b47f667 100644
> --- a/arch/powerpc/mm/hash_utils_64.c
> +++ b/arch/powerpc/mm/hash_utils_64.c
> @@ -1564,3 +1564,80 @@ void setup_initial_memory_limit(phys_addr_t
> first_memblock_base,
> /* Finally limit subsequent allocations */
> memblock_set_current_limit(ppc64_rma_size);
> }
> +
> +/*
> + * PAPR says that each reserved virtual address range record
> + * contains three be32 elements which is of toal 12 bytes.
> + * First two be32 elements contain the abbreviated virtual
> + * address (high order 32 bits and low order 32 bits that
> + * generate the abbreviated virtual address of 64 bits which
> + * need to be concatenated with 24 bits of 0 at the end) and
> + * the third be32 element contains the size of the reserved
> + * virtual address range as number of consecutive 4K pages.
> + */
> +struct reserved_va_record {
> + __be32 high_addr;
> + __be32 low_addr;
> + __be32 nr_pages_4K;
> +};
Here you define those fields as __be32.
> +/*
> + * Linux uses 65 bits (CONTEXT_BITS + ESID_BITS + SID_SHIFT)
> + * of virtual address. As reserved virtual address comes in
> + * as an abbreviated form (64 bits) from the device tree, we
> + * will use a partial address bit mask (65 >> 24) to match it
> + * for simplicity.
> + */
> +#define RVA_LESS_BITS 24
> +#define LINUX_VA_BITS (CONTEXT_BITS + ESID_BITS + SID_SHIFT)
> +#define PARTIAL_LINUX_VA_MASK ((1ULL << (LINUX_VA_BITS -
> RVA_LESS_BITS)) - 1)
> +
> +static int __init validate_reserved_va_range(void)
> +{
> + struct reserved_va_record rva;
> + struct device_node *np;
> + int records, ret, i;
> + __be64 vaddr;
> +
> + np = of_find_node_by_name(NULL, "vdevice");
> + if (!np)
> + return -ENODEV;
> +
> + records = of_property_count_elems_of_size(np,
> + "ibm,reserved-virtual-addresses",
> + sizeof(struct reserved_va_record));
> + if (records < 0)
> + return records;
> +
> + for (i = 0; i < records; i++) {
> + ret = of_property_read_u32_index(np,
> + "ibm,reserved-virtual-addresses",
> + 3 * i, &rva.high_addr);
But then here you use of_property_read_u32_index(), which does the
endian conversion (to CPU endian) for you.
> + ret = of_property_read_u32_index(np,
> + "ibm,reserved-virtual-addresses",
> + 3 * i + 1, &rva.low_addr);
> + ret = of_property_read_u32_index(np,
> + "ibm,reserved-virtual-addresses",
> + 3 * i + 2, &rva.nr_pages_4K);
So now all the values in rva are CPU endian.
> + vaddr = rva.high_addr;
> + vaddr = (vaddr << 32) | rva.low_addr;
> + if (vaddr & cpu_to_be64(~PARTIAL_LINUX_VA_MASK))
> + continue;
But then here you do the comparison against a __be64 value.
I know I told you to use "properly endian-annotated struct", but you
stil need to use the right conversions in the right places.
I think the best option is to use of_property_read_u32_array() and just
read the three 32 values into a CPU endian struct.
cheers
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