On Mon, 12 Feb 2024 13:46:06 -0600, Jarkko Sakkinen <jarkko@xxxxxxxxxx>
wrote:
On Mon Feb 5, 2024 at 11:06 PM EET, Haitao Huang wrote:
Enclave Page Cache(EPC) memory can be swapped out to regular system
"Enclave Page Cache (EPC)"
~
Will fix.
[...]
int sgx_encl_alloc_backing(struct sgx_encl *encl, unsigned long
page_index,
- struct sgx_backing *backing)
+ struct sgx_backing *backing, bool indirect)
Boolean parameters should be avoided when possible because they confuse
in the call sites.
{
- struct mem_cgroup *encl_memcg = sgx_encl_get_mem_cgroup(encl);
- struct mem_cgroup *memcg = set_active_memcg(encl_memcg);
+ struct mem_cgroup *encl_memcg;
+ struct mem_cgroup *memcg;
int ret;
- ret = __sgx_encl_get_backing(encl, page_index, backing);
+ if (!indirect)
+ return __sgx_encl_get_backing(encl, page_index, backing);
If a call is either in heead or tail of the code block, then
obviously better option is to make __sgx_encl_get_backing()
as non-static sgx_encl_get_backing() and call it in those
call sites that would call this with "false".
I.e. you need a new patch where this preparation is done.
This would actually require more intrusive changes to the call stack for
global and cgroup reclaim:
{sgx_epc_cgroup_reclaim_pages(),sgx_reclaim_pages_global()}->sgx_reclaim_pages()[->sgx_reclaimer_write()]->sgx_encl_alloc_backing()
We need make two versions of each of those functions.
It'd be especially complicated in refactoring sgx_reclaim_pages() for two
versions.
I now double checked the history of current_is_ksgxd()[1], it seemed the
intent was to replace "current->mm == NULL" criteria so it is more obvious
we are running in ksgxd.
@Dave, @Kristen,
Can we restore the original criteria like below so it works for the cgroup
work-queues?
bool current_is_ksgxd(void)
{
return current == ksgxd_tsk;
}
--->
bool current_is_kthread(void)
{
return current->mm == NULL;
}
I'm not experienced in this area and not sure how reliable it is to use
current->mm == NULL for kthread and work-queues. But it would eliminate
the need for the boolean parameter.
Would appreciate the input.
Haitao
[1]https://lore.kernel.org/linux-sgx/9c269c70-35fe-a1a4-34c9-b1e62ab3bb3b@xxxxxxxxx/
