x86/sgx: Do not fail on incomplete sanitization on premature stop of ksgxd

mainline inclusion
from mainline-v6.1-rc1
commit 133e049a
category: bugfix
bugzilla: https://gitee.com/openeuler/intel-kernel/issues/I6X1FF
CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=133e049a3f8c91b175029fb6a59b6039d5e79cba



Intel-SIG: commit 133e049a x86/sgx: Do not fail on incomplete
sanitization on premature stop of ksgxd
Incremental backporting patches for SGX on Intel Xeon platform.

--------------------------------

Unsanitized pages trigger WARN_ON() unconditionally, which can panic the
whole computer, if /proc/sys/kernel/panic_on_warn is set.

In sgx_init(), if misc_register() fails or misc_register() succeeds but
neither sgx_drv_init() nor sgx_vepc_init() succeeds, then ksgxd will be
prematurely stopped. This may leave unsanitized pages, which will result a
false warning.

Refine __sgx_sanitize_pages() to return:

1. Zero when the sanitization process is complete or ksgxd has been
   requested to stop.
2. The number of unsanitized pages otherwise.

Fixes: 51ab30eb ("x86/sgx: Replace section->init_laundry_list with sgx_dirty_page_list")
Reported-by: Paul Menzel <pmenzel@molgen.mpg.de>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/linux-sgx/20220825051827.246698-1-jarkko@kernel.org/T/#u
Link: https://lkml.kernel.org/r/20220906000221.34286-2-jarkko@kernel.org


[ Zhiquan: amend commit log. ]
Signed-off-by: Zhiquan Li <zhiquan1.li@intel.com>