On Tue, Apr 02, 2013 at 02:25:09PM +0100, Marc Zyngier wrote:
> The way we populate HYP mappings is a bit convoluted, to say the least.
> Passing a pointer around to keep track of the current PFN is quite
> odd, and we end-up having two different PTE accessors for no good
> reason.
>
> Simplify the whole thing by unifying the two PTE accessors, passing
> a pgprot_t around, and moving the various validity checks to the
> upper layers.
>
> Signed-off-by: Marc Zyngier <[email protected]>
> ---
> arch/arm/kvm/mmu.c | 100
> ++++++++++++++++++++++-------------------------------
> 1 file changed, 41 insertions(+), 59 deletions(-)
>
> diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
> index 2f12e40..24811d1 100644
> --- a/arch/arm/kvm/mmu.c
> +++ b/arch/arm/kvm/mmu.c
> @@ -125,54 +125,34 @@ void free_hyp_pmds(void)
> }
>
> static void create_hyp_pte_mappings(pmd_t *pmd, unsigned long start,
> - unsigned long end)
> + unsigned long end, unsigned long pfn,
> + pgprot_t prot)
> {
> pte_t *pte;
> unsigned long addr;
> - struct page *page;
>
> - for (addr = start & PAGE_MASK; addr < end; addr += PAGE_SIZE) {
> - unsigned long hyp_addr = KERN_TO_HYP(addr);
> -
> - pte = pte_offset_kernel(pmd, hyp_addr);
> - BUG_ON(!virt_addr_valid(addr));
> - page = virt_to_page(addr);
> - kvm_set_pte(pte, mk_pte(page, PAGE_HYP));
> - }
> -}
> -
> -static void create_hyp_io_pte_mappings(pmd_t *pmd, unsigned long start,
> - unsigned long end,
> - unsigned long *pfn_base)
> -{
> - pte_t *pte;
> - unsigned long addr;
> -
> - for (addr = start & PAGE_MASK; addr < end; addr += PAGE_SIZE) {
> - unsigned long hyp_addr = KERN_TO_HYP(addr);
> -
> - pte = pte_offset_kernel(pmd, hyp_addr);
> - BUG_ON(pfn_valid(*pfn_base));
> - kvm_set_pte(pte, pfn_pte(*pfn_base, PAGE_HYP_DEVICE));
> - (*pfn_base)++;
> + for (addr = start; addr < end; addr += PAGE_SIZE) {
> + pte = pte_offset_kernel(pmd, addr);
> + kvm_set_pte(pte, pfn_pte(pfn, prot));
> + pfn++;
> }
> }
>
> static int create_hyp_pmd_mappings(pud_t *pud, unsigned long start,
> - unsigned long end, unsigned long *pfn_base)
> + unsigned long end, unsigned long pfn,
> + pgprot_t prot)
> {
> pmd_t *pmd;
> pte_t *pte;
> unsigned long addr, next;
>
> for (addr = start; addr < end; addr = next) {
> - unsigned long hyp_addr = KERN_TO_HYP(addr);
> - pmd = pmd_offset(pud, hyp_addr);
> + pmd = pmd_offset(pud, addr);
>
> BUG_ON(pmd_sect(*pmd));
>
> if (pmd_none(*pmd)) {
> - pte = pte_alloc_one_kernel(NULL, hyp_addr);
> + pte = pte_alloc_one_kernel(NULL, addr);
> if (!pte) {
> kvm_err("Cannot allocate Hyp pte\n");
> return -ENOMEM;
> @@ -182,25 +162,17 @@ static int create_hyp_pmd_mappings(pud_t *pud, unsigned
> long start,
>
> next = pmd_addr_end(addr, end);
>
> - /*
> - * If pfn_base is NULL, we map kernel pages into HYP with the
> - * virtual address. Otherwise, this is considered an I/O
> - * mapping and we map the physical region starting at
> - * *pfn_base to [start, end[.
> - */
> - if (!pfn_base)
> - create_hyp_pte_mappings(pmd, addr, next);
> - else
> - create_hyp_io_pte_mappings(pmd, addr, next, pfn_base);
> + create_hyp_pte_mappings(pmd, addr, next, pfn, prot);
> + pfn += (next - addr) >> PAGE_SHIFT;
so this scheme always assumes a physically contiguous memory reason,
and I wasn't sure if we ever wanted to support mapping vmalloc'ed
regions into Hyp mode, which is why I wrote the code the way it was
(which goes to your "for no good reason" comment above).
I'm fine with assuming that this only works for contiguous regions, but
I think it deserves a line in the comments on the exported functions
(the non-IO one anyway).
> }
>
> return 0;
> }
>
> -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);
> if (err)
> goto out;
> + pfn += (next - addr) >> PAGE_SHIFT;
nit: consider passing a pointer to pfn instead? Not sure if it's nicer.
> }
> out:
> mutex_unlock(&kvm_hyp_pgd_mutex);
> @@ -255,7 +221,16 @@ out:
> */
> int create_hyp_mappings(void *from, void *to)
> {
> - return __create_hyp_mappings(from, to, NULL);
> + unsigned long phys_addr = virt_to_phys(from);
> + unsigned long start = KERN_TO_HYP((unsigned long)from);
> + unsigned long end = KERN_TO_HYP((unsigned long)to);
> +
> + /* Check for a valid kernel memory mapping */
> + if (!virt_addr_valid(from) || !virt_addr_valid(to - 1))
> + return -EINVAL;
> +
> + return __create_hyp_mappings(hyp_pgd, start, end,
> + __phys_to_pfn(phys_addr), PAGE_HYP);
> }
>
> /**
> @@ -267,10 +242,17 @@ int create_hyp_mappings(void *from, void *to)
> * The resulting HYP VA is the same as the kernel VA, modulo
> * HYP_PAGE_OFFSET.
> */
> -int create_hyp_io_mappings(void *from, void *to, phys_addr_t addr)
> +int create_hyp_io_mappings(void *from, void *to, phys_addr_t phys_addr)
nit: change the parameter documentation name as well.
> {
> - unsigned long pfn = __phys_to_pfn(addr);
> - return __create_hyp_mappings(from, to, &pfn);
> + unsigned long start = KERN_TO_HYP((unsigned long)from);
> + unsigned long end = KERN_TO_HYP((unsigned long)to);
> +
> + /* Check for a valid kernel IO mapping */
> + if (!is_vmalloc_addr(from) || !is_vmalloc_addr(to - 1))
> + return -EINVAL;
> +
> + return __create_hyp_mappings(hyp_pgd, start, end,
> + __phys_to_pfn(phys_addr), PAGE_HYP_DEVICE);
> }
>
> /**
> --
> 1.8.1.4
>
If the contigous thing is not a concern, then I'm happy about the
simplification.
-Christoffer
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