From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: linux-sgx@vger.kernel.org
Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
Sean Christopherson <sean.j.christopherson@intel.com>
Subject: [PATCH 1/2] x86/sgx: Remove duplicate check for entry->epc_page in sgx_encl_load_page()
Date: Thu, 22 Aug 2019 02:29:01 +0300 [thread overview]
Message-ID: <20190821232902.29476-2-jarkko.sakkinen@linux.intel.com> (raw)
In-Reply-To: <20190821232902.29476-1-jarkko.sakkinen@linux.intel.com>
The existence of the page is checked first hand for legit race
conditions (either two or more concurrent threads running the #PF
handler or the reclaimer has taken over the page):
/* Page is already resident in the EPC. */
if (entry->epc_page) {
if (entry->desc & SGX_ENCL_PAGE_RECLAIMED)
return ERR_PTR(-EBUSY);
return entry;
}
After that the existence is a checked as a condition for ELDU.
This commit removes the redundant check.
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
arch/x86/kernel/cpu/sgx/encl.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c
index a20d498e9dcd..d6397f7ef3b8 100644
--- a/arch/x86/kernel/cpu/sgx/encl.c
+++ b/arch/x86/kernel/cpu/sgx/encl.c
@@ -123,7 +123,7 @@ static struct sgx_encl_page *sgx_encl_load_page(struct sgx_encl *encl,
return ERR_CAST(epc_page);
}
- epc_page = entry->epc_page ? entry->epc_page : sgx_encl_eldu(entry);
+ epc_page = sgx_encl_eldu(entry);
if (IS_ERR(epc_page))
return ERR_CAST(epc_page);
--
2.20.1
next prev parent reply other threads:[~2019-08-21 23:29 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-21 23:29 [PATCH 0/2] v22 fixes Jarkko Sakkinen
2019-08-21 23:29 ` Jarkko Sakkinen [this message]
2019-08-22 0:33 ` [PATCH 1/2] x86/sgx: Remove duplicate check for entry->epc_page in sgx_encl_load_page() Sean Christopherson
2019-08-22 14:45 ` Jarkko Sakkinen
2019-08-21 23:29 ` [PATCH 2/2] x86/sgx: Determine SECS at compile time in sgx_encl_eldu() Jarkko Sakkinen
2019-08-22 0:55 ` Sean Christopherson
2019-08-22 14:55 ` Jarkko Sakkinen
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