[PATCH 3/3] migration dirtybitmap support ARMv7

[PATCH 3/3] migration dirtybitmap support ARMv7

[Mario Smarduch]

- 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);
 }
 
 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;
 }
 
 static int kvm_vm_ioctl_set_device_addr(struct kvm *kvm,
-- 
1.7.9.5

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

[Marc Zyngier]

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...

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

[Mario Smarduch]

Hi Eric, Mark -
   what repository should I use to pick up Eric patches?

For kvm_vm_ioctl_get_dirty_log() not sure what to make generic
it appears generic enough and it does what it needs to do?

Thanks,
  Mario

On 04/15/2014 02:06 AM, Marc Zyngier wrote:
> 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.
> 

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

[Marc Zyngier]

Hi Mario,

On 16/04/14 02:24, Mario Smarduch wrote:
> Hi Eric, Mark -
>    what repository should I use to pick up Eric patches?

The initial posting was there:

https://lists.cs.columbia.edu/pipermail/kvmarm/2014-April/008791.html

Reading Eric's patch again, it is not doing exactly the same thing, but
actually dealing with a slightly different (but connected) case.

I suggest you both work together on a common patch (or patch series)
that deals with the various memory region change thingy.

> For kvm_vm_ioctl_get_dirty_log() not sure what to make generic
> it appears generic enough and it does what it needs to do?

What I'm saying is that it should be put in a common location
(virt/kvm/kvm_main.c?), possibly as a weak symbol so it can be
overridden by other architectures.

As much as possible, try to share code with other arches rather than
duplicating it.

Thanks,

	M.

> Thanks,
>   Mario
> 
> On 04/15/2014 02:06 AM, Marc Zyngier wrote:
>> 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...

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

[Christian Borntraeger]

On 16/04/14 10:13, Marc Zyngier wrote:
> Hi Mario,
> 
> On 16/04/14 02:24, Mario Smarduch wrote:
>> Hi Eric, Mark -
>>    what repository should I use to pick up Eric patches?
> 
> The initial posting was there:
> 
> https://lists.cs.columbia.edu/pipermail/kvmarm/2014-April/008791.html
> 
> Reading Eric's patch again, it is not doing exactly the same thing, but
> actually dealing with a slightly different (but connected) case.
> 
> I suggest you both work together on a common patch (or patch series)
> that deals with the various memory region change thingy.
> 
>> For kvm_vm_ioctl_get_dirty_log() not sure what to make generic
>> it appears generic enough and it does what it needs to do?
> 
> What I'm saying is that it should be put in a common location
> (virt/kvm/kvm_main.c?), possibly as a weak symbol so it can be
> overridden by other architectures.

Yes, make it weak. The s390 implementation looks different.