[RFC PATCH] x86/sgx: Remove 'reclaim' boolean parameters

From: Haitao Huang
Date: Mon Feb 19 2024 - 10:40:08 EST

Remove all boolean parameters for 'reclaim' from the function
sgx_alloc_epc_page() and its callers by making two versions of each
function.

Also opportunistically remove non-static declaration of
__sgx_alloc_epc_page() and a typo

Signed-off-by: Haitao Huang <haitao.huang@xxxxxxxxxxxxxxx>
Suggested-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
---
arch/x86/kernel/cpu/sgx/encl.c | 56 +++++++++++++++++++++------
arch/x86/kernel/cpu/sgx/encl.h | 6 ++-
arch/x86/kernel/cpu/sgx/ioctl.c | 23 ++++++++---
arch/x86/kernel/cpu/sgx/main.c | 68 ++++++++++++++++++++++-----------
arch/x86/kernel/cpu/sgx/sgx.h | 4 +-
arch/x86/kernel/cpu/sgx/virt.c | 2 +-
6 files changed, 115 insertions(+), 44 deletions(-)

diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c
index 279148e72459..07f369ae855c 100644
--- a/arch/x86/kernel/cpu/sgx/encl.c
+++ b/arch/x86/kernel/cpu/sgx/encl.c
@@ -217,7 +217,7 @@ static struct sgx_epc_page *sgx_encl_eldu(struct sgx_encl_page *encl_page,
struct sgx_epc_page *epc_page;
int ret;

- epc_page = sgx_alloc_epc_page(encl_page, false);
+ epc_page = sgx_alloc_epc_page(encl_page);
if (IS_ERR(epc_page))
return epc_page;

@@ -359,14 +359,14 @@ static vm_fault_t sgx_encl_eaug_page(struct vm_area_struct *vma,
goto err_out_unlock;
}

- epc_page = sgx_alloc_epc_page(encl_page, false);
+ epc_page = sgx_alloc_epc_page(encl_page);
if (IS_ERR(epc_page)) {
if (PTR_ERR(epc_page) == -EBUSY)
vmret = VM_FAULT_NOPAGE;
goto err_out_unlock;
}

- va_page = sgx_encl_grow(encl, false);
+ va_page = sgx_encl_grow(encl);
if (IS_ERR(va_page)) {
if (PTR_ERR(va_page) == -EBUSY)
vmret = VM_FAULT_NOPAGE;
@@ -1230,23 +1230,23 @@ void sgx_zap_enclave_ptes(struct sgx_encl *encl, unsigned long addr)
} while (unlikely(encl->mm_list_version != mm_list_version));
}

-/**
- * sgx_alloc_va_page() - Allocate a Version Array (VA) page
- * @reclaim: Reclaim EPC pages directly if none available. Enclave
- * mutex should not be held if this is set.
- *
- * Allocate a free EPC page and convert it to a Version Array (VA) page.
+typedef struct sgx_epc_page *(*sgx_alloc_epc_page_fn_t)(void *owner);
+
+/*
+ * Allocate a Version Array (VA) page
+ * @alloc_fn: the EPC page allocation function.
*
* Return:
* a VA page,
* -errno otherwise
*/
-struct sgx_epc_page *sgx_alloc_va_page(bool reclaim)
+static struct sgx_epc_page *__sgx_alloc_va_page(sgx_alloc_epc_page_fn_t alloc_fn)
{
struct sgx_epc_page *epc_page;
int ret;

- epc_page = sgx_alloc_epc_page(NULL, reclaim);
+ epc_page = alloc_fn(NULL);
+
if (IS_ERR(epc_page))
return ERR_CAST(epc_page);

@@ -1260,6 +1260,40 @@ struct sgx_epc_page *sgx_alloc_va_page(bool reclaim)
return epc_page;
}

+/**
+ * sgx_alloc_va_page() - Allocate a Version Array (VA) page
+ *
+ * Allocate a free EPC page and convert it to a VA page.
+ *
+ * Do not reclaim EPC pages if none available.
+ *
+ * Return:
+ * a VA page,
+ * -errno otherwise
+ */
+struct sgx_epc_page *sgx_alloc_va_page(void)
+{
+ return __sgx_alloc_va_page(sgx_alloc_epc_page);
+}
+
+/**
+ * sgx_alloc_va_page_reclaim() - Allocate a Version Array (VA) page
+ *
+ * Allocate a free EPC page and convert it to a VA page.
+ *
+ * Reclaim EPC pages directly if none available. Enclave mutex should not be
+ * held.
+ *
+ * Return:
+ * a VA page,
+ * -errno otherwise
+ */
+
+struct sgx_epc_page *sgx_alloc_va_page_reclaim(void)
+{
+ return __sgx_alloc_va_page(sgx_alloc_epc_page_reclaim);
+}
+
/**
* sgx_alloc_va_slot - allocate a VA slot
* @va_page: a &struct sgx_va_page instance
diff --git a/arch/x86/kernel/cpu/sgx/encl.h b/arch/x86/kernel/cpu/sgx/encl.h
index f94ff14c9486..3248ff72e573 100644
--- a/arch/x86/kernel/cpu/sgx/encl.h
+++ b/arch/x86/kernel/cpu/sgx/encl.h
@@ -116,14 +116,16 @@ struct sgx_encl_page *sgx_encl_page_alloc(struct sgx_encl *encl,
unsigned long offset,
u64 secinfo_flags);
void sgx_zap_enclave_ptes(struct sgx_encl *encl, unsigned long addr);
-struct sgx_epc_page *sgx_alloc_va_page(bool reclaim);
+struct sgx_epc_page *sgx_alloc_va_page(void);
+struct sgx_epc_page *sgx_alloc_va_page_reclaim(void);
unsigned int sgx_alloc_va_slot(struct sgx_va_page *va_page);
void sgx_free_va_slot(struct sgx_va_page *va_page, unsigned int offset);
bool sgx_va_page_full(struct sgx_va_page *va_page);
void sgx_encl_free_epc_page(struct sgx_epc_page *page);
struct sgx_encl_page *sgx_encl_load_page(struct sgx_encl *encl,
unsigned long addr);
-struct sgx_va_page *sgx_encl_grow(struct sgx_encl *encl, bool reclaim);
+struct sgx_va_page *sgx_encl_grow(struct sgx_encl *encl);
+struct sgx_va_page *sgx_encl_grow_reclaim(struct sgx_encl *encl);
void sgx_encl_shrink(struct sgx_encl *encl, struct sgx_va_page *va_page);

#endif /* _X86_ENCL_H */
diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
index b65ab214bdf5..70f904f753aa 100644
--- a/arch/x86/kernel/cpu/sgx/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -17,7 +17,8 @@
#include "encl.h"
#include "encls.h"

-struct sgx_va_page *sgx_encl_grow(struct sgx_encl *encl, bool reclaim)
+typedef struct sgx_epc_page *(*sgx_alloc_va_page_fn_t)(void);
+static struct sgx_va_page *__sgx_encl_grow(struct sgx_encl *encl, sgx_alloc_va_page_fn_t alloc_fn)
{
struct sgx_va_page *va_page = NULL;
void *err;
@@ -30,7 +31,7 @@ struct sgx_va_page *sgx_encl_grow(struct sgx_encl *encl, bool reclaim)
if (!va_page)
return ERR_PTR(-ENOMEM);

- va_page->epc_page = sgx_alloc_va_page(reclaim);
+ va_page->epc_page = alloc_fn();
if (IS_ERR(va_page->epc_page)) {
err = ERR_CAST(va_page->epc_page);
kfree(va_page);
@@ -43,6 +44,16 @@ struct sgx_va_page *sgx_encl_grow(struct sgx_encl *encl, bool reclaim)
return va_page;
}

+struct sgx_va_page *sgx_encl_grow_reclaim(struct sgx_encl *encl)
+{
+ return __sgx_encl_grow(encl, sgx_alloc_va_page_reclaim);
+}
+
+struct sgx_va_page *sgx_encl_grow(struct sgx_encl *encl)
+{
+ return __sgx_encl_grow(encl, sgx_alloc_va_page);
+}
+
void sgx_encl_shrink(struct sgx_encl *encl, struct sgx_va_page *va_page)
{
encl->page_cnt--;
@@ -64,7 +75,7 @@ static int sgx_encl_create(struct sgx_encl *encl, struct sgx_secs *secs)
struct file *backing;
long ret;

- va_page = sgx_encl_grow(encl, true);
+ va_page = sgx_encl_grow_reclaim(encl);
if (IS_ERR(va_page))
return PTR_ERR(va_page);
else if (va_page)
@@ -83,7 +94,7 @@ static int sgx_encl_create(struct sgx_encl *encl, struct sgx_secs *secs)

encl->backing = backing;

- secs_epc = sgx_alloc_epc_page(&encl->secs, true);
+ secs_epc = sgx_alloc_epc_page_reclaim(&encl->secs);
if (IS_ERR(secs_epc)) {
ret = PTR_ERR(secs_epc);
goto err_out_backing;
@@ -269,13 +280,13 @@ static int sgx_encl_add_page(struct sgx_encl *encl, unsigned long src,
if (IS_ERR(encl_page))
return PTR_ERR(encl_page);

- epc_page = sgx_alloc_epc_page(encl_page, true);
+ epc_page = sgx_alloc_epc_page_reclaim(encl_page);
if (IS_ERR(epc_page)) {
kfree(encl_page);
return PTR_ERR(epc_page);
}

- va_page = sgx_encl_grow(encl, true);
+ va_page = sgx_encl_grow_reclaim(encl);
if (IS_ERR(va_page)) {
ret = PTR_ERR(va_page);
goto err_out_free;
diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
index 166692f2d501..ed9b711049c2 100644
--- a/arch/x86/kernel/cpu/sgx/main.c
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -463,14 +463,16 @@ static struct sgx_epc_page *__sgx_alloc_epc_page_from_node(int nid)
/**
* __sgx_alloc_epc_page() - Allocate an EPC page
*
- * Iterate through NUMA nodes and reserve ia free EPC page to the caller. Start
+ * Iterate through NUMA nodes and reserve a free EPC page to the caller. Start
* from the NUMA node, where the caller is executing.
*
+ * When a page is no longer needed it must be released with sgx_free_epc_page().
+ *
* Return:
* - an EPC page: A borrowed EPC pages were available.
- * - NULL: Out of EPC pages.
+ * - -errno: Out of EPC pages.
*/
-struct sgx_epc_page *__sgx_alloc_epc_page(void)
+static struct sgx_epc_page *__sgx_alloc_epc_page(void)
{
struct sgx_epc_page *page;
int nid_of_current = numa_node_id();
@@ -493,7 +495,24 @@ struct sgx_epc_page *__sgx_alloc_epc_page(void)
return page;
}

- return ERR_PTR(-ENOMEM);
+ if (list_empty(&sgx_active_page_list))
+ return ERR_PTR(-ENOMEM);
+
+ return ERR_PTR(-EBUSY);
+}
+
+/*
+ * Post-processing after allocating an EPC page.
+ *
+ * Set its owner, wake up ksgxd when the number of pages goes below the watermark.
+ */
+static void sgx_alloc_epc_page_post(struct sgx_epc_page *page, void* owner)
+{
+ if (!IS_ERR(page))
+ page->owner = owner;
+
+ if (sgx_should_reclaim(SGX_NR_LOW_PAGES))
+ wake_up(&ksgxd_waitq);
}

/**
@@ -542,38 +561,44 @@ int sgx_unmark_page_reclaimable(struct sgx_epc_page *page)
/**
* sgx_alloc_epc_page() - Allocate an EPC page
* @owner: the owner of the EPC page
- * @reclaim: reclaim pages if necessary
*
- * Iterate through EPC sections and borrow a free EPC page to the caller. When a
- * page is no longer needed it must be released with sgx_free_epc_page(). If
- * @reclaim is set to true, directly reclaim pages when we are out of pages. No
- * mm's can be locked when @reclaim is set to true.
+ * When a page is no longer needed it must be released with sgx_free_epc_page().
*
- * Finally, wake up ksgxd when the number of pages goes below the watermark
- * before returning back to the caller.
+ * Return:
+ * an EPC page,
+ * -errno on error
+ */
+struct sgx_epc_page *sgx_alloc_epc_page(void *owner)
+{
+ struct sgx_epc_page *page;
+
+ page = __sgx_alloc_epc_page();
+
+ sgx_alloc_epc_page_post(page, owner);
+
+ return page;
+}
+/**
+ * sgx_alloc_epc_page_reclaim() - Allocate an EPC page, reclaim pages if necessary
+ * @owner: the owner of the EPC page
+ *
+ * Reclaim pages when we are out of pages. No mm's can be locked.
*
* Return:
* an EPC page,
* -errno on error
*/
-struct sgx_epc_page *sgx_alloc_epc_page(void *owner, bool reclaim)
+struct sgx_epc_page *sgx_alloc_epc_page_reclaim(void *owner)
{
struct sgx_epc_page *page;

for ( ; ; ) {
page = __sgx_alloc_epc_page();
if (!IS_ERR(page)) {
- page->owner = owner;
break;
}
-
- if (list_empty(&sgx_active_page_list))
- return ERR_PTR(-ENOMEM);
-
- if (!reclaim) {
- page = ERR_PTR(-EBUSY);
+ if (PTR_ERR(page) != -EBUSY)
break;
- }

if (signal_pending(current)) {
page = ERR_PTR(-ERESTARTSYS);
@@ -584,8 +609,7 @@ struct sgx_epc_page *sgx_alloc_epc_page(void *owner, bool reclaim)
cond_resched();
}

- if (sgx_should_reclaim(SGX_NR_LOW_PAGES))
- wake_up(&ksgxd_waitq);
+ sgx_alloc_epc_page_post(page, owner);

return page;
}
diff --git a/arch/x86/kernel/cpu/sgx/sgx.h b/arch/x86/kernel/cpu/sgx/sgx.h
index d2dad21259a8..d6246a79f0b6 100644
--- a/arch/x86/kernel/cpu/sgx/sgx.h
+++ b/arch/x86/kernel/cpu/sgx/sgx.h
@@ -83,13 +83,13 @@ static inline void *sgx_get_epc_virt_addr(struct sgx_epc_page *page)
return section->virt_addr + index * PAGE_SIZE;
}

-struct sgx_epc_page *__sgx_alloc_epc_page(void);
void sgx_free_epc_page(struct sgx_epc_page *page);

void sgx_reclaim_direct(void);
void sgx_mark_page_reclaimable(struct sgx_epc_page *page);
int sgx_unmark_page_reclaimable(struct sgx_epc_page *page);
-struct sgx_epc_page *sgx_alloc_epc_page(void *owner, bool reclaim);
+struct sgx_epc_page *sgx_alloc_epc_page(void *owner);
+struct sgx_epc_page *sgx_alloc_epc_page_reclaim(void *owner);

void sgx_ipi_cb(void *info);

diff --git a/arch/x86/kernel/cpu/sgx/virt.c b/arch/x86/kernel/cpu/sgx/virt.c
index 7aaa3652e31d..6a81d8af84ab 100644
--- a/arch/x86/kernel/cpu/sgx/virt.c
+++ b/arch/x86/kernel/cpu/sgx/virt.c
@@ -46,7 +46,7 @@ static int __sgx_vepc_fault(struct sgx_vepc *vepc,
if (epc_page)
return 0;

- epc_page = sgx_alloc_epc_page(vepc, false);
+ epc_page = sgx_alloc_epc_page(vepc);
if (IS_ERR(epc_page))
return PTR_ERR(epc_page);

--
2.25.1