Re: [Xen-devel] [PATCH v5 11/25] xen/arm: introduce allocate_memory

[Julien Grall <julien.grall@xxxxxxx>]

Hi Stefano,

More comments on it :).

On 10/23/18 3:02 AM, Stefano Stabellini wrote:
> Introduce an allocate_memory function able to allocate memory for DomUs
> and map it at the right guest addresses, according to the guest memory
> map: GUEST_RAM0_BASE and GUEST_RAM1_BASE.
>
> This is under #if 0 as not used for now.
>
> Signed-off-by: Stefano Stabellini <stefanos@xxxxxxxxxx>
> ---
> Changes in v5:
> - improve commit message
> - code style
> - remove unneeded local var
> - while loop in allocate_bank_memory to allocate memory so that it
>    doesn't have to be contiguos
> - combile while loops in allocate_memory
>
> Changes in v4:
> - move earlier, add #if 0
> - introduce allocate_bank_memory, remove insert_bank
> - allocate_bank_memory allocate memory and inserts the bank, while
>    allocate_memory specifies where to do that
>
> Changes in v3:
> - new patch
> ---
>   xen/arch/arm/domain_build.c | 99 +++++++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 99 insertions(+)
>
> diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
> index c61a27f..146d81e 100644
> --- a/xen/arch/arm/domain_build.c
> +++ b/xen/arch/arm/domain_build.c
> @@ -368,6 +368,105 @@ static void __init allocate_memory_11(struct domain *d,
>       }
>   }
>   
> +#if 0
> +static bool __init allocate_bank_memory(struct domain *d,
> +                                        struct kernel_info *kinfo,
> +                                        gfn_t sgfn,
> +                                        unsigned int order)
> +{
> +    int res;
> +    struct page_info *pg;
> +    struct membank *bank;
> +    paddr_t size = pfn_to_paddr(1UL << order);
> +    gfn_t _sgfn = sgfn;
> +    gfn_t _egfn = gfn_add(sgfn, 1UL << order);
> +
> +    while ( gfn_x(_sgfn) < gfn_x(_egfn) )
> +    {
> +        pg = alloc_domheap_pages(d, order, 0);
> +        if ( pg != NULL )
> +        {
> +            res = guest_physmap_add_page(d, _sgfn, page_to_mfn(pg), order);
> +            if ( res )
> +            {
> +                dprintk(XENLOG_ERR, "Failed map pages to DOMU: %d", res);
> +                goto fail;
> +            }
> +            _sgfn = gfn_add(_sgfn, 1UL << order);
> +        }
> +        else
> +        {
> +            order--;
> +            if ( order == 0 )
> +            {
> +                dprintk(XENLOG_ERR, "Failed to allocated DOMU memory");
> +                goto fail;
> +            }
> +        }
> +    }
> +
> +    bank = &kinfo->mem.bank[kinfo->mem.nr_banks];
> +    bank->start = gfn_to_gaddr(sgfn);
> +    bank->size = size;
> +    kinfo->mem.nr_banks++;
> +    kinfo->unassigned_mem -= size;
> +
> +    return true;
> +
> +fail:
> +    /*
> +     * Fatal failure, don't attempt to free memory.
> +     */
> +    return false;
> +}
> +
> +static void __init allocate_memory(struct domain *d, struct kernel_info *kinfo)
> +{
> +    unsigned int order = get_allocation_size(kinfo->unassigned_mem);
> +    unsigned int order_req;
> +    unsigned int i;
> +
> +    dprintk(XENLOG_INFO, "Allocating mappings totalling %ldMB for dom%d:\n",
> +            /* Don't want format this as PRIpaddr (16 digit hex) */
> +            (unsigned long)(kinfo->unassigned_mem >> 20), d->domain_id);
While you are re-spinning this series. I would turn all the dprintk to 
printk as those messages are useful in non-debug build.
> +
> +    kinfo->mem.nr_banks = 0;
> +
> +    order = get_allocation_size(kinfo->unassigned_mem);
> +    if ( order > get_order_from_bytes(GUEST_RAM0_SIZE) )
> +        order_req = get_order_from_bytes(GUEST_RAM0_SIZE);
> +    else
> +        order_req = order;
> +    if ( !allocate_bank_memory(d, kinfo, gaddr_to_gfn(GUEST_RAM0_BASE), 
> order_req) )
> +        goto fail;
> +
> +    order -= order_req;
> +    if ( order > 0 &&
> +         !allocate_bank_memory(d, kinfo, gaddr_to_gfn(GUEST_RAM1_BASE), order) 
> )
> +        goto fail;
> +
> +    for( i = 0; i < kinfo->mem.nr_banks; i++ )
> +    {
> +        dprintk(XENLOG_INFO, "Dom%d BANK[%d] %#"PRIpaddr"-%#"PRIpaddr" 
> (%ldMB)\n",
> +                d->domain_id,
> +                i,
> +                kinfo->mem.bank[i].start,
> +                kinfo->mem.bank[i].start + kinfo->mem.bank[i].size,
> +                /* Don't want format this as PRIpaddr (16 digit hex) */
> +                (unsigned long)(kinfo->mem.bank[i].size >> 20));
> +    }
> +
> +    return;
> +
> +fail:
> +    dprintk(XENLOG_ERR, "Failed to allocate requested domain memory."
> +            /* Don't want format this as PRIpaddr (16 digit hex) */
> +            " %ldKB unallocated. Fix the VMs configurations.\n",
> +            (unsigned long)kinfo->unassigned_mem >> 10);
For this one, I would turned to a panic, avoid the BUG() below.

> +    BUG();
> +}
> +#endif
> +
>   static int __init write_properties(struct domain *d, struct kernel_info 
> *kinfo,
>                                      const struct dt_device_node *node)
>   {
Cheers,

--
Julien Grall

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