[5/9] KVM: selftests: Align memory region addresses to 1M on s390x
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Message ID 20190523164309.13345-6-thuth@redhat.com
State New
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Series
  • KVM selftests for s390x
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Commit Message

Thomas Huth May 23, 2019, 4:43 p.m. UTC
On s390x, there is a constraint that memory regions have to be aligned
to 1M (or running the VM will fail). Introduce a new "alignment" variable
in the vm_userspace_mem_region_add() function which now can be used for
both, huge page and s390x alignment requirements.

Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 tools/testing/selftests/kvm/lib/kvm_util.c | 21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

Comments

Andrew Jones May 23, 2019, 5:40 p.m. UTC | #1
On Thu, May 23, 2019 at 06:43:05PM +0200, Thomas Huth wrote:
> On s390x, there is a constraint that memory regions have to be aligned
> to 1M (or running the VM will fail). Introduce a new "alignment" variable
> in the vm_userspace_mem_region_add() function which now can be used for
> both, huge page and s390x alignment requirements.
> 
> Signed-off-by: Thomas Huth <thuth@redhat.com>
> ---
>  tools/testing/selftests/kvm/lib/kvm_util.c | 21 ++++++++++++++++-----
>  1 file changed, 16 insertions(+), 5 deletions(-)
> 
> diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
> index 08edb8436c47..656df9d5cd4d 100644
> --- a/tools/testing/selftests/kvm/lib/kvm_util.c
> +++ b/tools/testing/selftests/kvm/lib/kvm_util.c
> @@ -559,6 +559,7 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm,
>  	unsigned long pmem_size = 0;
>  	struct userspace_mem_region *region;
>  	size_t huge_page_size = KVM_UTIL_PGS_PER_HUGEPG * vm->page_size;
> +	size_t alignment;
>  
>  	TEST_ASSERT((guest_paddr % vm->page_size) == 0, "Guest physical "
>  		"address not on a page boundary.\n"
> @@ -608,9 +609,20 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm,
>  	TEST_ASSERT(region != NULL, "Insufficient Memory");
>  	region->mmap_size = npages * vm->page_size;
>  
> -	/* Enough memory to align up to a huge page. */
> +#ifdef __s390x__
> +	/* On s390x, the host address must be aligned to 1M (due to PGSTEs) */
> +	alignment = 0x100000;
> +#else
> +	alignment = 1;
> +#endif
> +
>  	if (src_type == VM_MEM_SRC_ANONYMOUS_THP)
> -		region->mmap_size += huge_page_size;
> +		alignment = huge_page_size;

I guess s390x won't ever support VM_MEM_SRC_ANONYMOUS_THP? If it does,
then we need 'alignment = max(huge_page_size, alignment)'. Actually
that might be a nice way to write this anyway for future-proofing.

> +
> +	/* Add enough memory to align up if necessary */
> +	if (alignment > 1)
> +		region->mmap_size += alignment;
> +
>  	region->mmap_start = mmap(NULL, region->mmap_size,
>  				  PROT_READ | PROT_WRITE,
>  				  MAP_PRIVATE | MAP_ANONYMOUS
> @@ -620,9 +632,8 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm,
>  		    "test_malloc failed, mmap_start: %p errno: %i",
>  		    region->mmap_start, errno);
>  
> -	/* Align THP allocation up to start of a huge page. */
> -	region->host_mem = align(region->mmap_start,
> -				 src_type == VM_MEM_SRC_ANONYMOUS_THP ?  huge_page_size : 1);
> +	/* Align host address */
> +	region->host_mem = align(region->mmap_start, alignment);
>  
>  	/* As needed perform madvise */
>  	if (src_type == VM_MEM_SRC_ANONYMOUS || src_type == VM_MEM_SRC_ANONYMOUS_THP) {
> -- 
> 2.21.0
>
Christian Borntraeger May 24, 2019, 8:29 a.m. UTC | #2
On 23.05.19 19:40, Andrew Jones wrote:
> On Thu, May 23, 2019 at 06:43:05PM +0200, Thomas Huth wrote:
>> On s390x, there is a constraint that memory regions have to be aligned
>> to 1M (or running the VM will fail). Introduce a new "alignment" variable
>> in the vm_userspace_mem_region_add() function which now can be used for
>> both, huge page and s390x alignment requirements.
>>
>> Signed-off-by: Thomas Huth <thuth@redhat.com>
>> ---
>>  tools/testing/selftests/kvm/lib/kvm_util.c | 21 ++++++++++++++++-----
>>  1 file changed, 16 insertions(+), 5 deletions(-)
>>
>> diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
>> index 08edb8436c47..656df9d5cd4d 100644
>> --- a/tools/testing/selftests/kvm/lib/kvm_util.c
>> +++ b/tools/testing/selftests/kvm/lib/kvm_util.c
>> @@ -559,6 +559,7 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm,
>>  	unsigned long pmem_size = 0;
>>  	struct userspace_mem_region *region;
>>  	size_t huge_page_size = KVM_UTIL_PGS_PER_HUGEPG * vm->page_size;
>> +	size_t alignment;
>>  
>>  	TEST_ASSERT((guest_paddr % vm->page_size) == 0, "Guest physical "
>>  		"address not on a page boundary.\n"
>> @@ -608,9 +609,20 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm,
>>  	TEST_ASSERT(region != NULL, "Insufficient Memory");
>>  	region->mmap_size = npages * vm->page_size;
>>  
>> -	/* Enough memory to align up to a huge page. */
>> +#ifdef __s390x__
>> +	/* On s390x, the host address must be aligned to 1M (due to PGSTEs) */
>> +	alignment = 0x100000;
>> +#else
>> +	alignment = 1;
>> +#endif
>> +
>>  	if (src_type == VM_MEM_SRC_ANONYMOUS_THP)
>> -		region->mmap_size += huge_page_size;
>> +		alignment = huge_page_size;
> 
> I guess s390x won't ever support VM_MEM_SRC_ANONYMOUS_THP? If it does,
> then we need 'alignment = max(huge_page_size, alignment)'. Actually
> that might be a nice way to write this anyway for future-proofing.

I can do 
-		alignment = huge_page_size;
+		alignment = max(huge_page_size, alignment);

when applying.


> 
>> +
>> +	/* Add enough memory to align up if necessary */
>> +	if (alignment > 1)
>> +		region->mmap_size += alignment;
>> +
>>  	region->mmap_start = mmap(NULL, region->mmap_size,
>>  				  PROT_READ | PROT_WRITE,
>>  				  MAP_PRIVATE | MAP_ANONYMOUS
>> @@ -620,9 +632,8 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm,
>>  		    "test_malloc failed, mmap_start: %p errno: %i",
>>  		    region->mmap_start, errno);
>>  
>> -	/* Align THP allocation up to start of a huge page. */
>> -	region->host_mem = align(region->mmap_start,
>> -				 src_type == VM_MEM_SRC_ANONYMOUS_THP ?  huge_page_size : 1);
>> +	/* Align host address */
>> +	region->host_mem = align(region->mmap_start, alignment);
>>  
>>  	/* As needed perform madvise */
>>  	if (src_type == VM_MEM_SRC_ANONYMOUS || src_type == VM_MEM_SRC_ANONYMOUS_THP) {
>> -- 
>> 2.21.0
>>
>
Thomas Huth May 24, 2019, 6:17 p.m. UTC | #3
On 24/05/2019 10.29, Christian Borntraeger wrote:
> 
> 
> On 23.05.19 19:40, Andrew Jones wrote:
>> On Thu, May 23, 2019 at 06:43:05PM +0200, Thomas Huth wrote:
>>> On s390x, there is a constraint that memory regions have to be aligned
>>> to 1M (or running the VM will fail). Introduce a new "alignment" variable
>>> in the vm_userspace_mem_region_add() function which now can be used for
>>> both, huge page and s390x alignment requirements.
>>>
>>> Signed-off-by: Thomas Huth <thuth@redhat.com>
>>> ---
>>>  tools/testing/selftests/kvm/lib/kvm_util.c | 21 ++++++++++++++++-----
>>>  1 file changed, 16 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
>>> index 08edb8436c47..656df9d5cd4d 100644
>>> --- a/tools/testing/selftests/kvm/lib/kvm_util.c
>>> +++ b/tools/testing/selftests/kvm/lib/kvm_util.c
>>> @@ -559,6 +559,7 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm,
>>>  	unsigned long pmem_size = 0;
>>>  	struct userspace_mem_region *region;
>>>  	size_t huge_page_size = KVM_UTIL_PGS_PER_HUGEPG * vm->page_size;
>>> +	size_t alignment;
>>>  
>>>  	TEST_ASSERT((guest_paddr % vm->page_size) == 0, "Guest physical "
>>>  		"address not on a page boundary.\n"
>>> @@ -608,9 +609,20 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm,
>>>  	TEST_ASSERT(region != NULL, "Insufficient Memory");
>>>  	region->mmap_size = npages * vm->page_size;
>>>  
>>> -	/* Enough memory to align up to a huge page. */
>>> +#ifdef __s390x__
>>> +	/* On s390x, the host address must be aligned to 1M (due to PGSTEs) */
>>> +	alignment = 0x100000;
>>> +#else
>>> +	alignment = 1;
>>> +#endif
>>> +
>>>  	if (src_type == VM_MEM_SRC_ANONYMOUS_THP)
>>> -		region->mmap_size += huge_page_size;
>>> +		alignment = huge_page_size;
>>
>> I guess s390x won't ever support VM_MEM_SRC_ANONYMOUS_THP? If it does,
>> then we need 'alignment = max(huge_page_size, alignment)'. Actually
>> that might be a nice way to write this anyway for future-proofing.
> 
> I can do 
> -		alignment = huge_page_size;
> +		alignment = max(huge_page_size, alignment);
> 
> when applying.

Yes, please, that's certainly cleaner this way.

 Thanks,
  Thomas

Patch
diff mbox series

diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index 08edb8436c47..656df9d5cd4d 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -559,6 +559,7 @@  void vm_userspace_mem_region_add(struct kvm_vm *vm,
 	unsigned long pmem_size = 0;
 	struct userspace_mem_region *region;
 	size_t huge_page_size = KVM_UTIL_PGS_PER_HUGEPG * vm->page_size;
+	size_t alignment;
 
 	TEST_ASSERT((guest_paddr % vm->page_size) == 0, "Guest physical "
 		"address not on a page boundary.\n"
@@ -608,9 +609,20 @@  void vm_userspace_mem_region_add(struct kvm_vm *vm,
 	TEST_ASSERT(region != NULL, "Insufficient Memory");
 	region->mmap_size = npages * vm->page_size;
 
-	/* Enough memory to align up to a huge page. */
+#ifdef __s390x__
+	/* On s390x, the host address must be aligned to 1M (due to PGSTEs) */
+	alignment = 0x100000;
+#else
+	alignment = 1;
+#endif
+
 	if (src_type == VM_MEM_SRC_ANONYMOUS_THP)
-		region->mmap_size += huge_page_size;
+		alignment = huge_page_size;
+
+	/* Add enough memory to align up if necessary */
+	if (alignment > 1)
+		region->mmap_size += alignment;
+
 	region->mmap_start = mmap(NULL, region->mmap_size,
 				  PROT_READ | PROT_WRITE,
 				  MAP_PRIVATE | MAP_ANONYMOUS
@@ -620,9 +632,8 @@  void vm_userspace_mem_region_add(struct kvm_vm *vm,
 		    "test_malloc failed, mmap_start: %p errno: %i",
 		    region->mmap_start, errno);
 
-	/* Align THP allocation up to start of a huge page. */
-	region->host_mem = align(region->mmap_start,
-				 src_type == VM_MEM_SRC_ANONYMOUS_THP ?  huge_page_size : 1);
+	/* Align host address */
+	region->host_mem = align(region->mmap_start, alignment);
 
 	/* As needed perform madvise */
 	if (src_type == VM_MEM_SRC_ANONYMOUS || src_type == VM_MEM_SRC_ANONYMOUS_THP) {