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

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Date:   Tue, 30 Aug 2022 15:56:29 -0700
From:   Reinette Chatre <reinette.chatre@...el.com>
To:     Jarkko Sakkinen <jarkko@...nel.org>, <linux-sgx@...r.kernel.org>
CC:     Haitao Huang <haitao.huang@...ux.intel.com>,
        Vijay Dhanraj <vijay.dhanraj@...el.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        "Shuah Khan" <shuah@...nel.org>,
        "open list:KERNEL SELFTEST FRAMEWORK" 
        <linux-kselftest@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 5/6] selftests/sgx: retry the ioctls returned with EAGAIN

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@...ux.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@...ux.intel.com>
> Tested-by: Jarkko Sakkinen <jarkko@...nel.org>
> Signed-off-by: Jarkko Sakkinen <jarkko@...nel.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