x86/sgx: Mark PCMD page as dirty when modifying contents

rchatre · hansendc · commit 2154e1c11b70 · 2022-05-16T15:17:14.000-07:00
Recent commit 08999b2 ("x86/sgx: Free backing memory after faulting the enclave page") expanded __sgx_encl_eldu() to clear an enclave page's PCMD (Paging Crypto MetaData) from the PCMD page in the backing store after the enclave page is restored to the enclave. Since the PCMD page in the backing store is modified the page should be marked as dirty to ensure the modified data is retained. Cc: stable@vger.kernel.org Fixes: 08999b2 ("x86/sgx: Free backing memory after faulting the enclave page") Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> Tested-by: Haitao Huang <haitao.huang@intel.com> Link: https://lkml.kernel.org/r/00cd2ac480db01058d112e347b32599c1a806bc4.1652389823.git.reinette.chatre@intel.com
diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c
@@ -84,6 +84,7 @@ static int __sgx_encl_eldu(struct sgx_encl_page *encl_page,
 	}
 
 	memset(pcmd_page + b.pcmd_offset, 0, sizeof(struct sgx_pcmd));
+	set_page_dirty(b.pcmd);
 
 	/*
 	 * The area for the PCMD in the page was zeroed above.  Check if the

Original file line number	Diff line number	Diff line change
`@@ -84,6 +84,7 @@ static int __sgx_encl_eldu(struct sgx_encl_page *encl_page,`
`84`	`84`	`}`
`85`	`85`
`86`	`86`	`memset(pcmd_page + b.pcmd_offset, 0, sizeof(struct sgx_pcmd));`
	`87`	`+ set_page_dirty(b.pcmd);`
`87`	`88`
`88`	`89`	`/*`
`89`	`90`	`* The area for the PCMD in the page was zeroed above. Check if the`