Re: [PATCH 3/3] migration dirtybitmap support ARMv7

[Marc Zyngier <marc.zyngier@arm.com>]

On 15/04/14 02:24, Mario Smarduch wrote:
> 
> - support QEMU interface for initial VM Write Protect
> - QEMU Dirty bit map log retrieval
> 
> 
> Signed-off-by: Mario Smarduch <m.smarduch@samsung.com>
> ---
>  arch/arm/kvm/arm.c |   62 +++++++++++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 61 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
> index bd18bb8..9076e3d 100644
> --- a/arch/arm/kvm/arm.c
> +++ b/arch/arm/kvm/arm.c
> @@ -241,6 +241,8 @@ void kvm_arch_commit_memory_region(struct kvm *kvm,
>  				   const struct kvm_memory_slot *old,
>  				   enum kvm_mr_change change)
>  {
> +	if ((change != KVM_MR_DELETE) && (mem->flags & KVM_MEM_LOG_DIRTY_PAGES))
> +		kvm_mmu_slot_remove_write_access(kvm, mem->slot);
>  }

There is a patch by Eric Auger doing the same thing. Please use it as a
dependency.

>  void kvm_arch_flush_shadow_all(struct kvm *kvm)
> @@ -773,9 +775,67 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
>  	}
>  }
>  
> +/*
> + * Walks the memslot dirty bitmap, write protects dirty pages for next rount,
> + * and stores the dirty bitmap fo QEMU retrieval.
> + *
> + */
>  int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log)
>  {
> -	return -EINVAL;
> +	int r;
> +	struct kvm_memory_slot *memslot;
> +	unsigned long n, i;
> +	unsigned long *dirty_bitmap;
> +	unsigned long *dirty_bitmap_buffer;
> +	bool is_dirty = false;
> +	gfn_t offset;
> +
> +	mutex_lock(&kvm->slots_lock);
> +	r = -EINVAL;
> +
> +	if (log->slot >= KVM_USER_MEM_SLOTS)
> +		goto out;
> +
> +	memslot = id_to_memslot(kvm->memslots, log->slot);
> +	dirty_bitmap = memslot->dirty_bitmap;
> +
> +	r = -ENOENT;
> +	if (!dirty_bitmap)
> +		goto out;
> +
> +	n = kvm_dirty_bitmap_bytes(memslot);
> +	dirty_bitmap_buffer = dirty_bitmap + n / sizeof(long);
> +	memset(dirty_bitmap_buffer, 0, n);
> +
> +	spin_lock(&kvm->mmu_lock);
> +	for (i = 0; i < n / sizeof(long); i++) {
> +		unsigned long mask;
> +
> +		if (!dirty_bitmap[i])
> +			continue;
> +
> +		is_dirty = true;
> +		offset = i * BITS_PER_LONG;
> +		kvm_mmu_write_protect_pt_masked(kvm, memslot, offset,
> +							dirty_bitmap[i]);
> +		mask = dirty_bitmap[i];
> +		dirty_bitmap_buffer[i] = mask;
> +		dirty_bitmap[i] = 0;
> +	}
> +
> +	if (is_dirty)
> +		kvm_tlb_flush_vmid(kvm);
> +
> +	spin_unlock(&kvm->mmu_lock);
> +	r = -EFAULT;
> +
> +	if (copy_to_user(log->dirty_bitmap, dirty_bitmap_buffer, n))
> +		goto out;
> +
> +	r = 0;
> +out:
> +	mutex_unlock(&kvm->slots_lock);
> +	return r;
>  }

This is a direct copy of the x86 code. Please make it generic.

>  static int kvm_vm_ioctl_set_device_addr(struct kvm *kvm,
> 

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...