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KVM: selftests: Assert mmap HVA is aligned when using HugeTLB

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Manually padding and aligning the mmap region is only needed when using
THP. When using HugeTLB, mmap will always return an address aligned to
the HugeTLB page size. Add a comment to clarify this and assert the mmap
behavior for HugeTLB.

[Removed requirement that HugeTLB mmaps must be padded per Yanan's
 feedback and added assertion that mmap returns aligned addresses
 when using HugeTLB.]

Cc: Ben Gardon <bgardon@google.com>
Cc: Yanan Wang <wangyanan55@huawei.com>
Cc: Andrew Jones <drjones@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Aaron Lewis <aaronlewis@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20211111000310.1435032-4-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Sean Christopherson 2021-11-11 00:03:01 +00:00 committed by Paolo Bonzini
parent c071ff41e1
commit f4870ef3e1
3 changed files with 17 additions and 0 deletions
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1
tools/testing/selftests/kvm/include/test_util.h
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@ -104,6 +104,7 @@ size_t get_trans_hugepagesz(void);
size_t get_def_hugetlb_pagesz(void);
const struct vm_mem_backing_src_alias *vm_mem_backing_src_alias(uint32_t i);
size_t get_backing_src_pagesz(uint32_t i);
bool is_backing_src_hugetlb(uint32_t i);
void backing_src_help(const char *flag);
enum vm_mem_backing_src_type parse_backing_src_type(const char *type_name);
long get_run_delay(void);

11
tools/testing/selftests/kvm/lib/kvm_util.c
View File

@ -866,6 +866,12 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm,
alignment = 1;
#endif
/*
* When using THP mmap is not guaranteed to returned a hugepage aligned
* address so we have to pad the mmap. Padding is not needed for HugeTLB
* because mmap will always return an address aligned to the HugeTLB
* page size.
*/
if (src_type == VM_MEM_SRC_ANONYMOUS_THP)
alignment = max(backing_src_pagesz, alignment);
@ -901,6 +907,11 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm,
"test_malloc failed, mmap_start: %p errno: %i",
region->mmap_start, errno);
TEST_ASSERT(!is_backing_src_hugetlb(src_type) ||
region->mmap_start == align_ptr_up(region->mmap_start, backing_src_pagesz),
"mmap_start %p is not aligned to HugeTLB page size 0x%lx",
region->mmap_start, backing_src_pagesz);
/* Align host address */
region->host_mem = align_ptr_up(region->mmap_start, alignment);

5
tools/testing/selftests/kvm/lib/test_util.c
View File

@ -283,6 +283,11 @@ size_t get_backing_src_pagesz(uint32_t i)
}
}
bool is_backing_src_hugetlb(uint32_t i)
{
return !!(vm_mem_backing_src_alias(i)->flag & MAP_HUGETLB);
}
static void print_available_backing_src_types(const char *prefix)
{
int i;