| Message ID | 20210519200339.829146-5-axelrasmussen@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: selftests: exercise userfaultfd minor faults | expand |
On Wed, May 19, 2021 at 1:03 PM Axel Rasmussen <axelrasmussen@google.com> wrote: > > This is a preparatory commit needed before we can use different kinds of > backing pages for guest memory. > > Previously, we used perf_test_args.host_page_size, which is the host's > native page size (commonly 4K). For VM_MEM_SRC_ANONYMOUS this turns out > to be okay, but in a follow-up commit we want to allow using different > kinds of backing memory. > > Take VM_MEM_SRC_ANONYMOUS_HUGETLB for example. Without this change, if > we used that backing page type, when we issued a UFFDIO_COPY ioctl we'd > only do so with 4K, rather than the full 2M of a backing hugepage. In > this case, UFFDIO_COPY returns -EINVAL (__mcopy_atomic_hugetlb checks > the size). > > Signed-off-by: Axel Rasmussen <axelrasmussen@google.com> Reviewed-by: Ben Gardon <bgardon@google.com> > --- > tools/testing/selftests/kvm/demand_paging_test.c | 11 +++++++---- > 1 file changed, 7 insertions(+), 4 deletions(-) > > diff --git a/tools/testing/selftests/kvm/demand_paging_test.c b/tools/testing/selftests/kvm/demand_paging_test.c > index 601a1df24dd2..94cf047358d5 100644 > --- a/tools/testing/selftests/kvm/demand_paging_test.c > +++ b/tools/testing/selftests/kvm/demand_paging_test.c > @@ -40,6 +40,7 @@ > > static int nr_vcpus = 1; > static uint64_t guest_percpu_mem_size = DEFAULT_PER_VCPU_MEM_SIZE; > +static size_t demand_paging_size; > static char *guest_data_prototype; > > static void *vcpu_worker(void *data) > @@ -85,7 +86,7 @@ static int handle_uffd_page_request(int uffd, uint64_t addr) > > copy.src = (uint64_t)guest_data_prototype; > copy.dst = addr; > - copy.len = perf_test_args.host_page_size; > + copy.len = demand_paging_size; > copy.mode = 0; > > clock_gettime(CLOCK_MONOTONIC, &start); > @@ -102,7 +103,7 @@ static int handle_uffd_page_request(int uffd, uint64_t addr) > PER_PAGE_DEBUG("UFFDIO_COPY %d \t%ld ns\n", tid, > timespec_to_ns(ts_diff)); > PER_PAGE_DEBUG("Paged in %ld bytes at 0x%lx from thread %d\n", > - perf_test_args.host_page_size, addr, tid); > + demand_paging_size, addr, tid); > > return 0; > } > @@ -261,10 +262,12 @@ static void run_test(enum vm_guest_mode mode, void *arg) > > perf_test_args.wr_fract = 1; > > - guest_data_prototype = malloc(perf_test_args.host_page_size); > + demand_paging_size = get_backing_src_pagesz(VM_MEM_SRC_ANONYMOUS); > + > + guest_data_prototype = malloc(demand_paging_size); > TEST_ASSERT(guest_data_prototype, > "Failed to allocate buffer for guest data pattern"); > - memset(guest_data_prototype, 0xAB, perf_test_args.host_page_size); > + memset(guest_data_prototype, 0xAB, demand_paging_size); > > vcpu_threads = malloc(nr_vcpus * sizeof(*vcpu_threads)); > TEST_ASSERT(vcpu_threads, "Memory allocation failed"); > -- > 2.31.1.751.gd2f1c929bd-goog >
diff --git a/tools/testing/selftests/kvm/demand_paging_test.c b/tools/testing/selftests/kvm/demand_paging_test.c index 601a1df24dd2..94cf047358d5 100644 --- a/tools/testing/selftests/kvm/demand_paging_test.c +++ b/tools/testing/selftests/kvm/demand_paging_test.c @@ -40,6 +40,7 @@ static int nr_vcpus = 1; static uint64_t guest_percpu_mem_size = DEFAULT_PER_VCPU_MEM_SIZE; +static size_t demand_paging_size; static char *guest_data_prototype; static void *vcpu_worker(void *data) @@ -85,7 +86,7 @@ static int handle_uffd_page_request(int uffd, uint64_t addr) copy.src = (uint64_t)guest_data_prototype; copy.dst = addr; - copy.len = perf_test_args.host_page_size; + copy.len = demand_paging_size; copy.mode = 0; clock_gettime(CLOCK_MONOTONIC, &start); @@ -102,7 +103,7 @@ static int handle_uffd_page_request(int uffd, uint64_t addr) PER_PAGE_DEBUG("UFFDIO_COPY %d \t%ld ns\n", tid, timespec_to_ns(ts_diff)); PER_PAGE_DEBUG("Paged in %ld bytes at 0x%lx from thread %d\n", - perf_test_args.host_page_size, addr, tid); + demand_paging_size, addr, tid); return 0; } @@ -261,10 +262,12 @@ static void run_test(enum vm_guest_mode mode, void *arg) perf_test_args.wr_fract = 1; - guest_data_prototype = malloc(perf_test_args.host_page_size); + demand_paging_size = get_backing_src_pagesz(VM_MEM_SRC_ANONYMOUS); + + guest_data_prototype = malloc(demand_paging_size); TEST_ASSERT(guest_data_prototype, "Failed to allocate buffer for guest data pattern"); - memset(guest_data_prototype, 0xAB, perf_test_args.host_page_size); + memset(guest_data_prototype, 0xAB, demand_paging_size); vcpu_threads = malloc(nr_vcpus * sizeof(*vcpu_threads)); TEST_ASSERT(vcpu_threads, "Memory allocation failed");
This is a preparatory commit needed before we can use different kinds of backing pages for guest memory. Previously, we used perf_test_args.host_page_size, which is the host's native page size (commonly 4K). For VM_MEM_SRC_ANONYMOUS this turns out to be okay, but in a follow-up commit we want to allow using different kinds of backing memory. Take VM_MEM_SRC_ANONYMOUS_HUGETLB for example. Without this change, if we used that backing page type, when we issued a UFFDIO_COPY ioctl we'd only do so with 4K, rather than the full 2M of a backing hugepage. In this case, UFFDIO_COPY returns -EINVAL (__mcopy_atomic_hugetlb checks the size). Signed-off-by: Axel Rasmussen <axelrasmussen@google.com> --- tools/testing/selftests/kvm/demand_paging_test.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-)