* [PATCH] x86/sgx: Migrate to mmu_notifier_put()
@ 2019-10-03 16:55 Jarkko Sakkinen
2019-10-03 22:07 ` Jarkko Sakkinen
0 siblings, 1 reply; 2+ messages in thread
From: Jarkko Sakkinen @ 2019-10-03 16:55 UTC (permalink / raw)
To: linux-sgx; +Cc: Jarkko Sakkinen, Sean Christopherson
Use mmu_notifier_put() to synchronize sgx_encl_mm usage, which means
that we can drop our own RCU.
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 | 30 ++++++++++--------------------
arch/x86/kernel/cpu/sgx/encl.h | 1 -
2 files changed, 10 insertions(+), 21 deletions(-)
diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c
index d145360380d5..25b210f57295 100644
--- a/arch/x86/kernel/cpu/sgx/encl.c
+++ b/arch/x86/kernel/cpu/sgx/encl.c
@@ -131,14 +131,6 @@ static struct sgx_encl_page *sgx_encl_load_page(struct sgx_encl *encl,
return entry;
}
-static void sgx_encl_mm_release_deferred(struct rcu_head *rcu)
-{
- struct sgx_encl_mm *encl_mm =
- container_of(rcu, struct sgx_encl_mm, rcu);
-
- kfree(encl_mm);
-}
-
static void sgx_mmu_notifier_release(struct mmu_notifier *mn,
struct mm_struct *mm)
{
@@ -159,21 +151,21 @@ static void sgx_mmu_notifier_release(struct mmu_notifier *mn,
}
spin_unlock(&encl_mm->encl->mm_lock);
- if (tmp == encl_mm) {
- synchronize_srcu(&encl_mm->encl->srcu);
+ if (tmp == encl_mm)
+ mmu_notifier_put(mn);
+}
+
+static void sgx_mmu_notifier_free(struct mmu_notifier *mn)
+{
+ struct sgx_encl_mm *encl_mm =
+ container_of(mn, struct sgx_encl_mm, mmu_notifier);
- /*
- * Delay freeing encl_mm until after mmu_notifier synchronizes
- * its SRCU to ensure encl_mm cannot be dereferenced.
- */
- mmu_notifier_unregister_no_release(mn, mm);
- mmu_notifier_call_srcu(&encl_mm->rcu,
- &sgx_encl_mm_release_deferred);
- }
+ kfree(encl_mm);
}
static const struct mmu_notifier_ops sgx_mmu_notifier_ops = {
.release = sgx_mmu_notifier_release,
+ .free_notifier = sgx_mmu_notifier_free,
};
static struct sgx_encl_mm *sgx_encl_find_mm(struct sgx_encl *encl,
@@ -231,8 +223,6 @@ int sgx_encl_mm_add(struct sgx_encl *encl, struct mm_struct *mm)
list_add_rcu(&encl_mm->list, &encl->mm_list);
spin_unlock(&encl->mm_lock);
- synchronize_srcu(&encl->srcu);
-
return 0;
}
diff --git a/arch/x86/kernel/cpu/sgx/encl.h b/arch/x86/kernel/cpu/sgx/encl.h
index 71454f059b99..b8ecffe27c93 100644
--- a/arch/x86/kernel/cpu/sgx/encl.h
+++ b/arch/x86/kernel/cpu/sgx/encl.h
@@ -63,7 +63,6 @@ struct sgx_encl_mm {
struct mm_struct *mm;
struct list_head list;
struct mmu_notifier mmu_notifier;
- struct rcu_head rcu;
};
struct sgx_encl {
--
2.20.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] x86/sgx: Migrate to mmu_notifier_put()
2019-10-03 16:55 [PATCH] x86/sgx: Migrate to mmu_notifier_put() Jarkko Sakkinen
@ 2019-10-03 22:07 ` Jarkko Sakkinen
0 siblings, 0 replies; 2+ messages in thread
From: Jarkko Sakkinen @ 2019-10-03 22:07 UTC (permalink / raw)
To: linux-sgx; +Cc: Sean Christopherson
On Thu, Oct 03, 2019 at 07:55:11PM +0300, Jarkko Sakkinen wrote:
> Use mmu_notifier_put() to synchronize sgx_encl_mm usage, which means
> that we can drop our own RCU.
>
> Cc: Sean Christopherson <sean.j.christopherson@intel.com>
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Ignore :/
/Jarkko
^ permalink raw reply [flat|nested] 2+ messages in thread
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