Hi Jarkko,
On Mon, 31 Oct 2022 20:21:16 -0500, Jarkko Sakkinen <jarkko@xxxxxxxxxx>
wrote:
On Thu, Oct 27, 2022 at 12:45:30PM -0700, Haitao Huang wrote:
Support madvise(..., MADV_WILLNEED) by adding EPC pages with EAUG in
the newly added fops->fadvise() callback implementation, sgx_fadvise().
Change the return type and values of the sgx_encl_eaug_page function
so that more specific error codes are returned for different treatment
by the page fault handler and the fadvise callback.
On any error, sgx_fadvise() will discontinue further operations
and return as normal. The page fault handler allows a PF retried
by returning VM_FAULT_NOPAGE in handling -EBUSY returned from
sgx_encl_eaug_page.
Signed-off-by: Haitao Huang <haitao.huang@xxxxxxxxxxxxxxx>
---
arch/x86/kernel/cpu/sgx/driver.c | 81 ++++++++++++++++++++++++++++++++
arch/x86/kernel/cpu/sgx/encl.c | 46 +++++++++++-------
arch/x86/kernel/cpu/sgx/encl.h | 4 +-
3 files changed, 113 insertions(+), 18 deletions(-)
diff --git a/arch/x86/kernel/cpu/sgx/driver.c
b/arch/x86/kernel/cpu/sgx/driver.c
index aa9b8b868867..54b24897605b 100644
--- a/arch/x86/kernel/cpu/sgx/driver.c
+++ b/arch/x86/kernel/cpu/sgx/driver.c
@@ -2,6 +2,7 @@
/* Copyright(c) 2016-20 Intel Corporation. */
#include <linux/acpi.h>
+#include <linux/fadvise.h>
#include <linux/miscdevice.h>
#include <linux/mman.h>
#include <linux/security.h>
@@ -9,6 +10,7 @@
#include <asm/traps.h>
#include "driver.h"
#include "encl.h"
+#include "encls.h"
u64 sgx_attributes_reserved_mask;
u64 sgx_xfrm_reserved_mask = ~0x3;
@@ -97,10 +99,88 @@ static int sgx_mmap(struct file *file, struct
vm_area_struct *vma)
vma->vm_ops = &sgx_vm_ops;
vma->vm_flags |= VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP | VM_IO;
vma->vm_private_data = encl;
+ /* Anchor vm_pgoff to the enclave base.
+ * So offset passed back to sgx_fadvise hook
+ * is relative to the enclave base
+ */
This comment only convolutes code because it does not tell anything
that is non-intuitive to understand from the code.
+ vma->vm_pgoff = (vma->vm_start - encl->base) >> PAGE_SHIFT;
vma->vm_pgoff = PFN_DOWN(vma->vm_start - encl->base);
return 0;
}
+/*
+ * Add new pages to the enclave sequentially with ENCLS[EAUG] for the
WILLNEED advice.
+ * Only do this to existing VMAs in the same enclave and reject the
request.
Keep this.
+ * Returns: 0 if EAUG done with best effort, -EINVAL if any sub-range
given
+ * is not in the enclave, or enclave is not initialized..
+ */
Please remove this.
It is useless and also incorrect, given that the function can also return
other return values.
+static int sgx_fadvise(struct file *file, loff_t offset, loff_t len,
int advice)
+{
+ struct sgx_encl *encl = file->private_data;
+ unsigned long start, end, pos;
+ int ret = -EINVAL;
+ struct vm_area_struct *vma = NULL;
Reverse christmas tree order.
+
+ /* Only support WILLNEED */
+ if (advice != POSIX_FADV_WILLNEED)
+ return -EINVAL;
+ if (!encl)
+ return -EINVAL;
...
+
+ /* EAUG works only for initialized enclaves. */
Please, remove this comment.
+ if (!test_bit(SGX_ENCL_INITIALIZED, &encl->flags))
+ return -EINVAL;
...
+ /* Don't allow any gaps */
+ goto unlock;
+ }
Empty line.
+ /* Here: vm_start <= pos < end <= vm_end */
...
+ if (ret)
+ break;
+ pos = pos + PAGE_SIZE;
+ cond_resched();
+ }
+ ret = 0;
Empty line.
Thanks for the review. Will fix all above in next version.
BR
Haitao
