[PATCH 2/6] x86/sgx: Handle VA page allocation failure for EAUG on PF.

Jarkko Sakkinen
2022-08-30T03:12:31Z

From: Haitao Huang <haitao.huang@linux.intel.com>

VM_FAULT_NOPAGE is expected behaviour for -EBUSY failure path, when
augmenting a page, as this means that the reclaimer thread has been
triggered, and the intention is just to round-trip in ring-3, and
retry with a new page fault.

Fixes: 5a90d2c3f5ef ("x86/sgx: Support adding of pages to an initialized enclave")
Signed-off-by: Haitao Huang <haitao.huang@linux.intel.com>
Tested-by: Vijay Dhanraj <vijay.dhanraj@intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
v2:
* Removed reviewed-by, no other changes.
---
arch/x86/kernel/cpu/sgx/encl.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c
index 24c1bb8eb196..de92c1c8b79d 100644
--- a/arch/x86/kernel/cpu/sgx/encl.c
+++ b/arch/x86/kernel/cpu/sgx/encl.c
@@ -344,8 +344,11 @@ static vm_fault_t sgx_encl_eaug_page(struct vm_area_struct *vma,
}

va_page = sgx_encl_grow(encl, false);
- if (IS_ERR(va_page))
+ if (IS_ERR(va_page)) {
+ if (PTR_ERR(va_page) == -EBUSY)
+ vmret = VM_FAULT_NOPAGE;
goto err_out_epc;
+ }

if (va_page)
list_add(&va_page->list, &encl->va_pages);
--
2.37.2