[PATCH v4 1/7] ARM: KVM: simplify HYP mapping population

[catalin.marinas@arm.com (Catalin Marinas)]

On Fri, Apr 12, 2013 at 07:12:01PM +0100, Marc Zyngier wrote:
> diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
> index 2f12e40..3003321 100644
> --- a/arch/arm/kvm/mmu.c
> +++ b/arch/arm/kvm/mmu.c
...
> -static int __create_hyp_mappings(void *from, void *to, unsigned long *pfn_base)
> +static int __create_hyp_mappings(pgd_t *pgdp,
> +				 unsigned long start, unsigned long end,
> +				 unsigned long pfn, pgprot_t prot)
>  {
> -	unsigned long start = (unsigned long)from;
> -	unsigned long end = (unsigned long)to;
>  	pgd_t *pgd;
>  	pud_t *pud;
>  	pmd_t *pmd;
> @@ -209,21 +181,14 @@ static int __create_hyp_mappings(void *from, void *to, unsigned long *pfn_base)
>  
>  	if (start >= end)
>  		return -EINVAL;
> -	/* Check for a valid kernel memory mapping */
> -	if (!pfn_base && (!virt_addr_valid(from) || !virt_addr_valid(to - 1)))
> -		return -EINVAL;
> -	/* Check for a valid kernel IO mapping */
> -	if (pfn_base && (!is_vmalloc_addr(from) || !is_vmalloc_addr(to - 1)))
> -		return -EINVAL;
>  
>  	mutex_lock(&kvm_hyp_pgd_mutex);
> -	for (addr = start; addr < end; addr = next) {
> -		unsigned long hyp_addr = KERN_TO_HYP(addr);
> -		pgd = hyp_pgd + pgd_index(hyp_addr);
> -		pud = pud_offset(pgd, hyp_addr);
> +	for (addr = start & PAGE_MASK; addr < end; addr = next) {
> +		pgd = pgdp + pgd_index(addr);
> +		pud = pud_offset(pgd, addr);
>  
>  		if (pud_none_or_clear_bad(pud)) {
> -			pmd = pmd_alloc_one(NULL, hyp_addr);
> +			pmd = pmd_alloc_one(NULL, addr);
>  			if (!pmd) {
>  				kvm_err("Cannot allocate Hyp pmd\n");
>  				err = -ENOMEM;
> @@ -233,9 +198,10 @@ static int __create_hyp_mappings(void *from, void *to, unsigned long *pfn_base)
>  		}
>  
>  		next = pgd_addr_end(addr, end);
> -		err = create_hyp_pmd_mappings(pud, addr, next, pfn_base);
> +		err = create_hyp_pmd_mappings(pud, addr, next, pfn, prot);

I would add another indirection function here like
create_hyp_pud_mappings() if we are to share this code with arm64. If
written correctly, the compiler should turn it into no-op. But here you
just make the assumption that pgd/pud are the same.

(it can be additional patch at some point if you already prepared these
patches for upstream)

-- 
Catalin