On 25/04/14 18:01, Mark Salter wrote:
> Ping. Can we get this into 3.15rc as a bug fix? Anything I can help
> with?
It sure has to go in. I'll queue it.
Thanks for the reminder.
M.
> On Sat, 2014-03-29 at 14:01 +0000, Marc Zyngier wrote:
>> On 2014-03-28 19:37, Christoffer Dall wrote:
>>> On Fri, Mar 28, 2014 at 10:25:19AM -0400, Mark Salter wrote:
>>>> The kvm/mmu code shared by arm and arm64 uses kalloc() to allocate
>>>> a bounce page (if hypervisor init code crosses page boundary) and
>>>> hypervisor PGDs. The problem is that kalloc() does not guarantee
>>>> the proper alignment. In the case of the bounce page, the page sized
>>>> buffer allocated may also cross a page boundary negating the purpose
>>>> and leading to a hang during kvm initialization. Likewise the PGDs
>>>> allocated may not meet the minimum alignment requirements of the
>>>> underlying MMU. This patch uses __get_free_page() to guarantee the
>>>> worst case alignment needs of the bounce page and PGDs on both arm
>>>> and arm64.
>>>>
>>>> Signed-off-by: Mark Salter <msal...@redhat.com>
>>>> ---
>>>> arch/arm/kvm/mmu.c | 15 +++++++++------
>>>> 1 file changed, 9 insertions(+), 6 deletions(-)
>>>>
>>>> diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
>>>> index 7789857..575d790 100644
>>>> --- a/arch/arm/kvm/mmu.c
>>>> +++ b/arch/arm/kvm/mmu.c
>>>> @@ -42,6 +42,8 @@ static unsigned long hyp_idmap_start;
>>>> static unsigned long hyp_idmap_end;
>>>> static phys_addr_t hyp_idmap_vector;
>>>>
>>>> +#define pgd_order get_order(PTRS_PER_PGD * sizeof(pgd_t))
>>>> +
>>>> #define kvm_pmd_huge(_x) (pmd_huge(_x) || pmd_trans_huge(_x))
>>>>
>>>> static void kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t
>>>> ipa)
>>>> @@ -199,14 +201,14 @@ void free_boot_hyp_pgd(void)
>>>> if (boot_hyp_pgd) {
>>>> unmap_range(NULL, boot_hyp_pgd, hyp_idmap_start, PAGE_SIZE);
>>>> unmap_range(NULL, boot_hyp_pgd, TRAMPOLINE_VA, PAGE_SIZE);
>>>> - kfree(boot_hyp_pgd);
>>>> + free_pages((unsigned long)boot_hyp_pgd, pgd_order);
>>>> boot_hyp_pgd = NULL;
>>>> }
>>>>
>>>> if (hyp_pgd)
>>>> unmap_range(NULL, hyp_pgd, TRAMPOLINE_VA, PAGE_SIZE);
>>>>
>>>> - kfree(init_bounce_page);
>>>> + free_page((unsigned long)init_bounce_page);
>>>> init_bounce_page = NULL;
>>>>
>>>> mutex_unlock(&kvm_hyp_pgd_mutex);
>>>> @@ -236,7 +238,7 @@ void free_hyp_pgds(void)
>>>> for (addr = VMALLOC_START; is_vmalloc_addr((void*)addr); addr
>>>> +=
>>>> PGDIR_SIZE)
>>>> unmap_range(NULL, hyp_pgd, KERN_TO_HYP(addr),
>>>> PGDIR_SIZE);
>>>>
>>>> - kfree(hyp_pgd);
>>>> + free_pages((unsigned long)hyp_pgd, pgd_order);
>>>> hyp_pgd = NULL;
>>>> }
>>>>
>>>> @@ -930,7 +932,7 @@ int kvm_mmu_init(void)
>>>> size_t len = __hyp_idmap_text_end - __hyp_idmap_text_start;
>>>> phys_addr_t phys_base;
>>>>
>>>> - init_bounce_page = kmalloc(PAGE_SIZE, GFP_KERNEL);
>>>> + init_bounce_page = (void *)__get_free_page(GFP_KERNEL);
>>>> if (!init_bounce_page) {
>>>> kvm_err("Couldn't allocate HYP init bounce page\n");
>>>> err = -ENOMEM;
>>>> @@ -956,8 +958,9 @@ int kvm_mmu_init(void)
>>>> (unsigned long)phys_base);
>>>> }
>>>>
>>>> - hyp_pgd = kzalloc(PTRS_PER_PGD * sizeof(pgd_t), GFP_KERNEL);
>>>> - boot_hyp_pgd = kzalloc(PTRS_PER_PGD * sizeof(pgd_t), GFP_KERNEL);
>>>> + hyp_pgd = (pgd_t *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
>>>> pgd_order);
>>>> + boot_hyp_pgd = (pgd_t *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
>>>> pgd_order);
>>>> +
>>>> if (!hyp_pgd || !boot_hyp_pgd) {
>>>> kvm_err("Hyp mode PGD not allocated\n");
>>>> err = -ENOMEM;
>>>> --
>>>> 1.8.5.3
>>>>
>>> This looks right to me. Funnily enough I seem to remember a
>>> discussion
>>> from when we originally merged this code where someone (maybe me)
>>> argued
>>> that kmalloc() would align to the size of the allocation, but I don't
>>> see anything backing this up at this point.
>>>
>>> So:
>>>
>>> Acked-by: Christoffer Dall <christoffer.d...@linaro.org>
>>>
>>> If Marc agrees I can queue this for -rc1.
>>
>> Looks good to me indeed.
>>
>> Acked-by: Marc Zyngier <marc.zyng...@arm.com>
>>
>> M.
>
>
>
--
Jazz is not dead. It just smells funny...
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