diff mbox

[v4,18/22] KVM: arm64: ITS: Collection table save/restore

Message ID 1490607072-21610-19-git-send-email-eric.auger@redhat.com (mailing list archive)
State New, archived
Headers show

Commit Message

Eric Auger March 27, 2017, 9:31 a.m. UTC
The flush path copies the collection entries into guest RAM
at the GPA specified in the BASER register. This obviously
requires the BASER to be set. The last written element
is a dummy collection table entry.

We do not index by collection ID as the collection entry
can fit into 8 bytes while containing the collection ID.

On restore path we re-allocate the collection objects.

Signed-off-by: Eric Auger <eric.auger@redhat.com>

---

v3 -> v4:
- replaced u64 *ptr by gpa_t gpa
- check the collection does not exist before allocating it

v1 -> v2:
- reword commit message and directly use 8 as entry size
- no kvm parameter anymore
- add helper for flush/restore cte
- table size computed here
- add le64/cpu conversions
---
 virt/kvm/arm/vgic/vgic-its.c | 99 +++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 97 insertions(+), 2 deletions(-)

Comments

Marc Zyngier April 10, 2017, 9:55 a.m. UTC | #1
On 27/03/17 10:31, Eric Auger wrote:
> The flush path copies the collection entries into guest RAM
> at the GPA specified in the BASER register. This obviously
> requires the BASER to be set. The last written element
> is a dummy collection table entry.
> 
> We do not index by collection ID as the collection entry
> can fit into 8 bytes while containing the collection ID.
> 
> On restore path we re-allocate the collection objects.
> 
> Signed-off-by: Eric Auger <eric.auger@redhat.com>
> 
> ---
> 
> v3 -> v4:
> - replaced u64 *ptr by gpa_t gpa
> - check the collection does not exist before allocating it
> 
> v1 -> v2:
> - reword commit message and directly use 8 as entry size
> - no kvm parameter anymore
> - add helper for flush/restore cte
> - table size computed here
> - add le64/cpu conversions
> ---
>  virt/kvm/arm/vgic/vgic-its.c | 99 +++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 97 insertions(+), 2 deletions(-)
> 
> diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
> index 8eaeba4..df984b6 100644
> --- a/virt/kvm/arm/vgic/vgic-its.c
> +++ b/virt/kvm/arm/vgic/vgic-its.c
> @@ -1828,13 +1828,89 @@ static int vgic_its_restore_device_tables(struct vgic_its *its)
>  	return -ENXIO;
>  }
>  
> +static int vgic_its_flush_cte(struct vgic_its *its,
> +			      struct its_collection *collection, gpa_t gpa)

Given that the pendent of this function is name ..._restore_..., should
this be called ..._save_... ?

> +{
> +	u64 val;
> +	int ret;
> +
> +	val = ((u64)1 << 63 | ((u64)collection->target_addr << 16) |
> +	       collection->collection_id);

Please provide some #defines that describe the encoding. This will be
specially useful if we need to export this to userspace (KVM/TCG
interoperability?).

> +	val = cpu_to_le64(val);
> +	ret = kvm_write_guest(its->dev->kvm, gpa, &val, 8);
> +	return ret;
> +}
> +
> +static int vgic_its_restore_cte(struct vgic_its *its, gpa_t gpa, bool *valid)
> +{
> +	struct its_collection *collection;
> +	u32 target_addr;
> +	u32 coll_id;
> +	u64 val;
> +	int ret;
> +
> +	*valid = false;
> +
> +	ret = kvm_read_guest(its->dev->kvm, gpa, &val, 8);
> +	if (ret)
> +		return ret;
> +	val = le64_to_cpu(val);
> +	*valid = val & BIT_ULL(63);
> +
> +	if (!*valid)
> +		return 0;
> +
> +	target_addr = (u32)(val >> 16);

u32?

> +	coll_id = val & 0xFFFF;

Same comment about the various shifts/masks.

> +
> +	collection = find_collection(its, coll_id);
> +	if (collection)
> +		return -EEXIST;
> +	ret = vgic_its_alloc_collection(its, &collection, coll_id);
> +	if (ret)
> +		return ret;
> +	collection->target_addr = target_addr;
> +	return 0;
> +}
> +
>  /**
>   * vgic_its_flush_collection_table - flush the collection table into
>   * guest RAM
>   */
>  static int vgic_its_flush_collection_table(struct vgic_its *its)
>  {
> -	return -ENXIO;
> +	struct its_collection *collection;
> +	u64 val;
> +	gpa_t gpa;
> +	size_t max_size, filled = 0;
> +	int ret;
> +
> +	gpa = BASER_ADDRESS(its->baser_coll_table);
> +	if (!gpa)
> +		return 0;
> +
> +	max_size = GITS_BASER_NR_PAGES(its->baser_coll_table) * SZ_64K;
> +
> +	list_for_each_entry(collection, &its->collection_list, coll_list) {
> +		if (filled == max_size)
> +			return -ENOSPC;
> +		ret = vgic_its_flush_cte(its, collection, gpa);
> +		if (ret)
> +			return ret;
> +		gpa += 8;
> +		filled += 8;

This "8" should be extracted from the BASER register itself (Entry_Size).

> +	}
> +
> +	if (filled == max_size)
> +		return 0;
> +
> +	/*
> +	 * table is not fully filled, add a last dummy element
> +	 * with valid bit unset
> +	 */
> +	val = 0;
> +	ret = kvm_write_guest(its->dev->kvm, gpa, &val, 8);
> +	return ret;
>  }
>  
>  /**
> @@ -1844,7 +1920,26 @@ static int vgic_its_flush_collection_table(struct vgic_its *its)
>   */
>  static int vgic_its_restore_collection_table(struct vgic_its *its)
>  {
> -	return -ENXIO;
> +	size_t max_size, read = 0;
> +	gpa_t gpa;
> +	int ret;
> +
> +	gpa = BASER_ADDRESS(its->baser_coll_table);
> +	if (!gpa)
> +		return 0;
> +
> +	max_size = GITS_BASER_NR_PAGES(its->baser_coll_table) * SZ_64K;
> +
> +	while (read < max_size) {
> +		bool valid;
> +
> +		ret = vgic_its_restore_cte(its, gpa, &valid);
> +		if (!valid || ret)
> +			break;
> +		gpa += 8;
> +		read += 8;
> +	}
> +	return ret;
>  }
>  
>  /**
> 

Thanks,

	M.
Eric Auger April 11, 2017, 9:57 a.m. UTC | #2
Hi Marc,

On 10/04/2017 11:55, Marc Zyngier wrote:
> On 27/03/17 10:31, Eric Auger wrote:
>> The flush path copies the collection entries into guest RAM
>> at the GPA specified in the BASER register. This obviously
>> requires the BASER to be set. The last written element
>> is a dummy collection table entry.
>>
>> We do not index by collection ID as the collection entry
>> can fit into 8 bytes while containing the collection ID.
>>
>> On restore path we re-allocate the collection objects.
>>
>> Signed-off-by: Eric Auger <eric.auger@redhat.com>
>>
>> ---
>>
>> v3 -> v4:
>> - replaced u64 *ptr by gpa_t gpa
>> - check the collection does not exist before allocating it
>>
>> v1 -> v2:
>> - reword commit message and directly use 8 as entry size
>> - no kvm parameter anymore
>> - add helper for flush/restore cte
>> - table size computed here
>> - add le64/cpu conversions
>> ---
>>  virt/kvm/arm/vgic/vgic-its.c | 99 +++++++++++++++++++++++++++++++++++++++++++-
>>  1 file changed, 97 insertions(+), 2 deletions(-)
>>
>> diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
>> index 8eaeba4..df984b6 100644
>> --- a/virt/kvm/arm/vgic/vgic-its.c
>> +++ b/virt/kvm/arm/vgic/vgic-its.c
>> @@ -1828,13 +1828,89 @@ static int vgic_its_restore_device_tables(struct vgic_its *its)
>>  	return -ENXIO;
>>  }
>>  
>> +static int vgic_its_flush_cte(struct vgic_its *its,
>> +			      struct its_collection *collection, gpa_t gpa)
> 
> Given that the pendent of this function is name ..._restore_..., should
> this be called ..._save_... ?
> 
>> +{
>> +	u64 val;
>> +	int ret;
>> +
>> +	val = ((u64)1 << 63 | ((u64)collection->target_addr << 16) |
>> +	       collection->collection_id);
> 
> Please provide some #defines that describe the encoding. This will be
> specially useful if we need to export this to userspace (KVM/TCG
> interoperability?).
> 
>> +	val = cpu_to_le64(val);
>> +	ret = kvm_write_guest(its->dev->kvm, gpa, &val, 8);
>> +	return ret;
>> +}
>> +
>> +static int vgic_its_restore_cte(struct vgic_its *its, gpa_t gpa, bool *valid)
>> +{
>> +	struct its_collection *collection;
>> +	u32 target_addr;
>> +	u32 coll_id;
>> +	u64 val;
>> +	int ret;
>> +
>> +	*valid = false;
>> +
>> +	ret = kvm_read_guest(its->dev->kvm, gpa, &val, 8);
>> +	if (ret)
>> +		return ret;
>> +	val = le64_to_cpu(val);
>> +	*valid = val & BIT_ULL(63);
>> +
>> +	if (!*valid)
>> +		return 0;
>> +
>> +	target_addr = (u32)(val >> 16);
> 
> u32?
At the moment its_collection.target_addr is u32 and corresponds to the
PE number. Only GITS_TYPER.PTA = 0 is supported.

Or do I miss something?

Thanks

Eric
> 
>> +	coll_id = val & 0xFFFF;
> 
> Same comment about the various shifts/masks.
> 
>> +
>> +	collection = find_collection(its, coll_id);
>> +	if (collection)
>> +		return -EEXIST;
>> +	ret = vgic_its_alloc_collection(its, &collection, coll_id);
>> +	if (ret)
>> +		return ret;
>> +	collection->target_addr = target_addr;
>> +	return 0;
>> +}
>> +
>>  /**
>>   * vgic_its_flush_collection_table - flush the collection table into
>>   * guest RAM
>>   */
>>  static int vgic_its_flush_collection_table(struct vgic_its *its)
>>  {
>> -	return -ENXIO;
>> +	struct its_collection *collection;
>> +	u64 val;
>> +	gpa_t gpa;
>> +	size_t max_size, filled = 0;
>> +	int ret;
>> +
>> +	gpa = BASER_ADDRESS(its->baser_coll_table);
>> +	if (!gpa)
>> +		return 0;
>> +
>> +	max_size = GITS_BASER_NR_PAGES(its->baser_coll_table) * SZ_64K;
>> +
>> +	list_for_each_entry(collection, &its->collection_list, coll_list) {
>> +		if (filled == max_size)
>> +			return -ENOSPC;
>> +		ret = vgic_its_flush_cte(its, collection, gpa);
>> +		if (ret)
>> +			return ret;
>> +		gpa += 8;
>> +		filled += 8;
> 
> This "8" should be extracted from the BASER register itself (Entry_Size).
> 
>> +	}
>> +
>> +	if (filled == max_size)
>> +		return 0;
>> +
>> +	/*
>> +	 * table is not fully filled, add a last dummy element
>> +	 * with valid bit unset
>> +	 */
>> +	val = 0;
>> +	ret = kvm_write_guest(its->dev->kvm, gpa, &val, 8);
>> +	return ret;
>>  }
>>  
>>  /**
>> @@ -1844,7 +1920,26 @@ static int vgic_its_flush_collection_table(struct vgic_its *its)
>>   */
>>  static int vgic_its_restore_collection_table(struct vgic_its *its)
>>  {
>> -	return -ENXIO;
>> +	size_t max_size, read = 0;
>> +	gpa_t gpa;
>> +	int ret;
>> +
>> +	gpa = BASER_ADDRESS(its->baser_coll_table);
>> +	if (!gpa)
>> +		return 0;
>> +
>> +	max_size = GITS_BASER_NR_PAGES(its->baser_coll_table) * SZ_64K;
>> +
>> +	while (read < max_size) {
>> +		bool valid;
>> +
>> +		ret = vgic_its_restore_cte(its, gpa, &valid);
>> +		if (!valid || ret)
>> +			break;
>> +		gpa += 8;
>> +		read += 8;
>> +	}
>> +	return ret;
>>  }
>>  
>>  /**
>>
> 
> Thanks,
> 
> 	M.
>
Marc Zyngier April 11, 2017, 10:03 a.m. UTC | #3
On 11/04/17 10:57, Auger Eric wrote:
> Hi Marc,
> 
> On 10/04/2017 11:55, Marc Zyngier wrote:
>> On 27/03/17 10:31, Eric Auger wrote:
>>> The flush path copies the collection entries into guest RAM
>>> at the GPA specified in the BASER register. This obviously
>>> requires the BASER to be set. The last written element
>>> is a dummy collection table entry.
>>>
>>> We do not index by collection ID as the collection entry
>>> can fit into 8 bytes while containing the collection ID.
>>>
>>> On restore path we re-allocate the collection objects.
>>>
>>> Signed-off-by: Eric Auger <eric.auger@redhat.com>
>>>
>>> ---
>>>
>>> v3 -> v4:
>>> - replaced u64 *ptr by gpa_t gpa
>>> - check the collection does not exist before allocating it
>>>
>>> v1 -> v2:
>>> - reword commit message and directly use 8 as entry size
>>> - no kvm parameter anymore
>>> - add helper for flush/restore cte
>>> - table size computed here
>>> - add le64/cpu conversions
>>> ---
>>>  virt/kvm/arm/vgic/vgic-its.c | 99 +++++++++++++++++++++++++++++++++++++++++++-
>>>  1 file changed, 97 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
>>> index 8eaeba4..df984b6 100644
>>> --- a/virt/kvm/arm/vgic/vgic-its.c
>>> +++ b/virt/kvm/arm/vgic/vgic-its.c
>>> @@ -1828,13 +1828,89 @@ static int vgic_its_restore_device_tables(struct vgic_its *its)
>>>  	return -ENXIO;
>>>  }
>>>  
>>> +static int vgic_its_flush_cte(struct vgic_its *its,
>>> +			      struct its_collection *collection, gpa_t gpa)
>>
>> Given that the pendent of this function is name ..._restore_..., should
>> this be called ..._save_... ?
>>
>>> +{
>>> +	u64 val;
>>> +	int ret;
>>> +
>>> +	val = ((u64)1 << 63 | ((u64)collection->target_addr << 16) |
>>> +	       collection->collection_id);
>>
>> Please provide some #defines that describe the encoding. This will be
>> specially useful if we need to export this to userspace (KVM/TCG
>> interoperability?).
>>
>>> +	val = cpu_to_le64(val);
>>> +	ret = kvm_write_guest(its->dev->kvm, gpa, &val, 8);
>>> +	return ret;
>>> +}
>>> +
>>> +static int vgic_its_restore_cte(struct vgic_its *its, gpa_t gpa, bool *valid)
>>> +{
>>> +	struct its_collection *collection;
>>> +	u32 target_addr;
>>> +	u32 coll_id;
>>> +	u64 val;
>>> +	int ret;
>>> +
>>> +	*valid = false;
>>> +
>>> +	ret = kvm_read_guest(its->dev->kvm, gpa, &val, 8);
>>> +	if (ret)
>>> +		return ret;
>>> +	val = le64_to_cpu(val);
>>> +	*valid = val & BIT_ULL(63);
>>> +
>>> +	if (!*valid)
>>> +		return 0;
>>> +
>>> +	target_addr = (u32)(val >> 16);
>>
>> u32?
> At the moment its_collection.target_addr is u32 and corresponds to the
> PE number. Only GITS_TYPER.PTA = 0 is supported.
> 
> Or do I miss something?

No, you're right. I'm getting confused between the model I'm working
with and the ITS emulation... Ignore me.

Thanks,

	M.
diff mbox

Patch

diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index 8eaeba4..df984b6 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -1828,13 +1828,89 @@  static int vgic_its_restore_device_tables(struct vgic_its *its)
 	return -ENXIO;
 }
 
+static int vgic_its_flush_cte(struct vgic_its *its,
+			      struct its_collection *collection, gpa_t gpa)
+{
+	u64 val;
+	int ret;
+
+	val = ((u64)1 << 63 | ((u64)collection->target_addr << 16) |
+	       collection->collection_id);
+	val = cpu_to_le64(val);
+	ret = kvm_write_guest(its->dev->kvm, gpa, &val, 8);
+	return ret;
+}
+
+static int vgic_its_restore_cte(struct vgic_its *its, gpa_t gpa, bool *valid)
+{
+	struct its_collection *collection;
+	u32 target_addr;
+	u32 coll_id;
+	u64 val;
+	int ret;
+
+	*valid = false;
+
+	ret = kvm_read_guest(its->dev->kvm, gpa, &val, 8);
+	if (ret)
+		return ret;
+	val = le64_to_cpu(val);
+	*valid = val & BIT_ULL(63);
+
+	if (!*valid)
+		return 0;
+
+	target_addr = (u32)(val >> 16);
+	coll_id = val & 0xFFFF;
+
+	collection = find_collection(its, coll_id);
+	if (collection)
+		return -EEXIST;
+	ret = vgic_its_alloc_collection(its, &collection, coll_id);
+	if (ret)
+		return ret;
+	collection->target_addr = target_addr;
+	return 0;
+}
+
 /**
  * vgic_its_flush_collection_table - flush the collection table into
  * guest RAM
  */
 static int vgic_its_flush_collection_table(struct vgic_its *its)
 {
-	return -ENXIO;
+	struct its_collection *collection;
+	u64 val;
+	gpa_t gpa;
+	size_t max_size, filled = 0;
+	int ret;
+
+	gpa = BASER_ADDRESS(its->baser_coll_table);
+	if (!gpa)
+		return 0;
+
+	max_size = GITS_BASER_NR_PAGES(its->baser_coll_table) * SZ_64K;
+
+	list_for_each_entry(collection, &its->collection_list, coll_list) {
+		if (filled == max_size)
+			return -ENOSPC;
+		ret = vgic_its_flush_cte(its, collection, gpa);
+		if (ret)
+			return ret;
+		gpa += 8;
+		filled += 8;
+	}
+
+	if (filled == max_size)
+		return 0;
+
+	/*
+	 * table is not fully filled, add a last dummy element
+	 * with valid bit unset
+	 */
+	val = 0;
+	ret = kvm_write_guest(its->dev->kvm, gpa, &val, 8);
+	return ret;
 }
 
 /**
@@ -1844,7 +1920,26 @@  static int vgic_its_flush_collection_table(struct vgic_its *its)
  */
 static int vgic_its_restore_collection_table(struct vgic_its *its)
 {
-	return -ENXIO;
+	size_t max_size, read = 0;
+	gpa_t gpa;
+	int ret;
+
+	gpa = BASER_ADDRESS(its->baser_coll_table);
+	if (!gpa)
+		return 0;
+
+	max_size = GITS_BASER_NR_PAGES(its->baser_coll_table) * SZ_64K;
+
+	while (read < max_size) {
+		bool valid;
+
+		ret = vgic_its_restore_cte(its, gpa, &valid);
+		if (!valid || ret)
+			break;
+		gpa += 8;
+		read += 8;
+	}
+	return ret;
 }
 
 /**