[PATCH v2 1/5] selftests/sgx: Retry the ioctl()'s returned with EAGAIN

[Jarkko Sakkinen <jarkko@xxxxxxxxxx>]

From: Haitao Huang <haitao.huang@xxxxxxxxxxxxxxx>

For EMODT and EREMOVE ioctl()'s with a large range, kernel
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 ioctl()'s in a loop, updating offset and length
using the byte count returned in each iteration.

Fixes: 6507cce561b4 ("selftests/sgx: Page removal stress test")
Signed-off-by: Haitao Huang <haitao.huang@xxxxxxxxxxxxxxx>
Tested-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
Signed-off-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
---
v3:
* Added a fixes tag. The bug is in v6.0 patches.
* Added my tested-by (the bug reproduced in my NUC often).
v2:
* Changed branching in EAGAIN condition so that else branch
  is not required.
* Addressed Reinette's feedback:
---
 tools/testing/selftests/sgx/main.c | 42 ++++++++++++++++++++++++------
 1 file changed, 34 insertions(+), 8 deletions(-)

diff --git a/tools/testing/selftests/sgx/main.c b/tools/testing/selftests/sgx/main.c
index 9820b3809c69..59cca806eda1 100644
--- a/tools/testing/selftests/sgx/main.c
+++ b/tools/testing/selftests/sgx/main.c
@@ -390,6 +390,7 @@ TEST_F_TIMEOUT(enclave, unclobbered_vdso_oversubscribed_remove, 900)
 	struct encl_segment *heap;
 	unsigned long total_mem;
 	int ret, errno_save;
+	unsigned long count;
 	unsigned long addr;
 	unsigned long i;
 
@@ -453,16 +454,30 @@ 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)
+			break;
+
+		EXPECT_EQ(modt_ioc.result, 0);
+
+		count += modt_ioc.count;
+		modt_ioc.offset += modt_ioc.count;
+		modt_ioc.length -= modt_ioc.count;
+		modt_ioc.result = 0;
+		modt_ioc.count = 0;
+	} 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;
@@ -490,15 +505,26 @@ 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)
+			break;
+
+		count += remove_ioc.count;
+		remove_ioc.offset += remove_ioc.count;
+		remove_ioc.length -= remove_ioc.count;
+		remove_ioc.count = 0;
+	} 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)
-- 
2.37.2