Commit 69cdcfa6 authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
Browse files

KVM: selftests: Require GPA to be aligned when backed by hugepages 



Assert that the GPA for a memslot backed by a hugepage is aligned to
the hugepage size and fix perf_test_util accordingly.  Lack of GPA
alignment prevents KVM from backing the guest with hugepages, e.g. x86's
write-protection of hugepages when dirty logging is activated is
otherwise not exercised.

Add a comment explaining that guest_page_size is for non-huge pages to
try and avoid confusion about what it actually tracks.

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: default avatarSean Christopherson <seanjc@google.com>
[Used get_backing_src_pagesz() to determine alignment dynamically.]
Signed-off-by: default avatarDavid Matlack <dmatlack@google.com>
Message-Id: <20211111000310.1435032-5-dmatlack@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent f4870ef3

tools/testing/selftests/kvm/lib/kvm_util.c

+2 −0
Original line number Diff line number Diff line
@@ -875,6 +875,8 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm, 
	if (src_type == VM_MEM_SRC_ANONYMOUS_THP)

		alignment = max(backing_src_pagesz, alignment);



	ASSERT_EQ(guest_paddr, align_up(guest_paddr, backing_src_pagesz));



	/* Add enough memory to align up if necessary */

	if (alignment > 1)

		region->mmap_size += alignment;

tools/testing/selftests/kvm/lib/perf_test_util.c

+6 −1
Original line number Diff line number Diff line
@@ -55,11 +55,16 @@ struct kvm_vm *perf_test_create_vm(enum vm_guest_mode mode, int vcpus, 
{

	struct kvm_vm *vm;

	uint64_t guest_num_pages;

	uint64_t backing_src_pagesz = get_backing_src_pagesz(backing_src);

	int i;



	pr_info("Testing guest mode: %s\n", vm_guest_mode_string(mode));



	perf_test_args.host_page_size = getpagesize();

	/*

	 * Snapshot the non-huge page size.  This is used by the guest code to

	 * access/dirty pages at the logging granularity.

	 */

	perf_test_args.guest_page_size = vm_guest_mode_params[mode].page_size;



	guest_num_pages = vm_adjust_num_guest_pages(mode,
@@ -92,7 +97,7 @@ struct kvm_vm *perf_test_create_vm(enum vm_guest_mode mode, int vcpus, 


	guest_test_phys_mem = (vm_get_max_gfn(vm) - guest_num_pages) *

			      perf_test_args.guest_page_size;

	guest_test_phys_mem = align_down(guest_test_phys_mem, perf_test_args.host_page_size);

	guest_test_phys_mem = align_down(guest_test_phys_mem, backing_src_pagesz);

#ifdef __s390x__

	/* Align to 1M (segment size) */

	guest_test_phys_mem = align_down(guest_test_phys_mem, 1 << 20);