Re: [PATCH 5/6] selftests/sgx: retry the ioctls returned with EAGAIN

Reinette Chatre
2022-08-30T22:56:40Z

Hi Haitao and Jarkko,

selftests/sgx: Retry the ioctl()s returned with EAGAIN

On 8/29/2022 8:12 PM, Jarkko Sakkinen wrote:
> From: Haitao Huang <haitao.huang@linux.intel.com>
>
> For EMODT and EREMOVE ioctls with a large range, kernel

ioctl()s?

> may not finish in one shot and return EAGAIN error code
> and count of bytes of EPC pages on that operations are
> finished successfully.
>
> Change the unclobbered_vdso_oversubscribed_remove test
> to rerun the ioctls in a loop, updating offset and length

ioctl()s?

> using the byte count returned in each iteration.
>

This is a valuable addition, thank you very much.

> Signed-off-by: Haitao Huang <haitao.huang@linux.intel.com>
> Tested-by: Jarkko Sakkinen <jarkko@kernel.org>
> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
> ---
> tools/testing/selftests/sgx/main.c | 39 +++++++++++++++++++++++-------
> 1 file changed, 30 insertions(+), 9 deletions(-)
>
> diff --git a/tools/testing/selftests/sgx/main.c b/tools/testing/selftests/sgx/main.c
> index 867e98502120..3268d8b01b0b 100644
> --- a/tools/testing/selftests/sgx/main.c
> +++ b/tools/testing/selftests/sgx/main.c
> @@ -399,7 +399,7 @@ TEST_F_TIMEOUT(enclave, unclobbered_vdso_oversubscribed_remove, 900)
> unsigned long total_mem;
> int ret, errno_save;
> unsigned long addr;
> - unsigned long i;
> + unsigned long i, count;

Reverse fir tree?

>
> /*
> * Create enclave with additional heap that is as big as all
> @@ -461,16 +461,27 @@ TEST_F_TIMEOUT(enclave, unclobbered_vdso_oversubscribed_remove, 900)
> modt_ioc.offset = heap->offset;
> modt_ioc.length = heap->size;
> modt_ioc.page_type = SGX_PAGE_TYPE_TRIM;
> -
> + count = 0;
> TH_LOG("Changing type of %zd bytes to trimmed may take a while ...",
> heap->size);
> - ret = ioctl(self->encl.fd, SGX_IOC_ENCLAVE_MODIFY_TYPES, &modt_ioc);
> - errno_save = ret == -1 ? errno : 0;
> + do {
> + ret = ioctl(self->encl.fd, SGX_IOC_ENCLAVE_MODIFY_TYPES, &modt_ioc);
> + errno_save = ret == -1 ? errno : 0;
> + if (errno_save == EAGAIN) {
> + count += modt_ioc.count;
> + modt_ioc.offset += modt_ioc.count;
> + modt_ioc.length -= modt_ioc.count;
> + modt_ioc.result = 0;

As part of the test I think it would be helpful to know if there was a result code
in here. What do you think of failing the test if it is not zero?

> + modt_ioc.count = 0;
> + } else
> + break;

Watch out for unbalanced braces (also later in patch). This causes
checkpatch.pl noise.

> + } while (modt_ioc.length != 0);
>
> EXPECT_EQ(ret, 0);
> EXPECT_EQ(errno_save, 0);
> EXPECT_EQ(modt_ioc.result, 0);
> - EXPECT_EQ(modt_ioc.count, heap->size);
> + count += modt_ioc.count;
> + EXPECT_EQ(count, heap->size);
>
> /* EACCEPT all removed pages. */
> addr = self->encl.encl_base + heap->offset;
> @@ -498,15 +509,25 @@ TEST_F_TIMEOUT(enclave, unclobbered_vdso_oversubscribed_remove, 900)
>
> remove_ioc.offset = heap->offset;
> remove_ioc.length = heap->size;
> -
> + count = 0;
> TH_LOG("Removing %zd bytes from enclave may take a while ...",
> heap->size);
> - ret = ioctl(self->encl.fd, SGX_IOC_ENCLAVE_REMOVE_PAGES, &remove_ioc);
> - errno_save = ret == -1 ? errno : 0;
> + do {
> + ret = ioctl(self->encl.fd, SGX_IOC_ENCLAVE_REMOVE_PAGES, &remove_ioc);
> + errno_save = ret == -1 ? errno : 0;
> + if (errno_save == EAGAIN) {
> + count += remove_ioc.count;
> + remove_ioc.offset += remove_ioc.count;
> + remove_ioc.length -= remove_ioc.count;
> + remove_ioc.count = 0;
> + } else
> + break;
> + } while (remove_ioc.length != 0);
>
> EXPECT_EQ(ret, 0);
> EXPECT_EQ(errno_save, 0);
> - EXPECT_EQ(remove_ioc.count, heap->size);
> + count += remove_ioc.count;
> + EXPECT_EQ(count, heap->size);
> }
>
> TEST_F(enclave, clobbered_vdso)

Reinette