Re: [PATCH OLK-5.10 V2 08/44] x86/sgx: Add SGX page allocator functions

Reviewed-by: Bamvor Zhang bamvor.zhang@suse.com

在 2/15/22 11:05 AM, Laibin Qiu 写道:

From: Jarkko Sakkinen jarkko@kernel.org

mainline inclusion from mainline-v5.11-rc1 commit d2285493bef310b66b56dfe4eb75c1e2f431ea5c category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I4SIGI CVE: NA

---

Add functions for runtime allocation and free.

This allocator and its algorithms are as simple as it gets. They do a linear search across all EPC sections and find the first free page. They are not NUMA-aware and only hand out individual pages. The SGX hardware does not support large pages, so something more complicated like a buddy allocator is unwarranted.

The free function (sgx_free_epc_page()) implicitly calls ENCLS[EREMOVE], which returns the page to the uninitialized state. This ensures that the page is ready for use at the next allocation.

Intel-SIG: commit d2285493bef3 x86/sgx: Add SGX page allocator functions Backport for SGX Foundations support

Co-developed-by: Sean Christopherson sean.j.christopherson@intel.com Signed-off-by: Sean Christopherson sean.j.christopherson@intel.com Signed-off-by: Jarkko Sakkinen jarkko@kernel.org Signed-off-by: Borislav Petkov bp@suse.de Acked-by: Jethro Beekman jethro@fortanix.com Link: https://lkml.kernel.org/r/20201112220135.165028-10-jarkko@kernel.org Signed-off-by: Fan Du fan.du@intel.com #openEuler_contributor Signed-off-by: Laibin Qiu qiulaibin@huawei.com

---

arch/x86/kernel/cpu/sgx/main.c | 65 ++++++++++++++++++++++++++++++++++ arch/x86/kernel/cpu/sgx/sgx.h | 3 ++ 2 files changed, 68 insertions(+)

diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c index 187a237eec38..2e53afc288a4 100644 --- a/arch/x86/kernel/cpu/sgx/main.c +++ b/arch/x86/kernel/cpu/sgx/main.c @@ -85,6 +85,71 @@ static bool __init sgx_page_reclaimer_init(void) return true; }

+static struct sgx_epc_page *__sgx_alloc_epc_page_from_section(struct sgx_epc_section *section) +{

• struct sgx_epc_page *page;
• spin_lock(&section->lock);
• if (list_empty(&section->page_list)) {

• spin_unlock(&section->lock);
  

• return NULL;
  

• }
• page = list_first_entry(&section->page_list, struct sgx_epc_page, list);
• list_del_init(&page->list);
• spin_unlock(&section->lock);
• return page;

+}

+/**

• • __sgx_alloc_epc_page() - Allocate an EPC page
• • 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().
• • Return:
• • an EPC page,
• • -errno on error
• */

+struct sgx_epc_page *__sgx_alloc_epc_page(void) +{

• struct sgx_epc_section *section;
• struct sgx_epc_page *page;
• int i;
• for (i = 0; i < sgx_nr_epc_sections; i++) {

• section = &sgx_epc_sections[i];
  

• page = __sgx_alloc_epc_page_from_section(section);
  

• if (page)
  

• 	return page;
  

• }
• return ERR_PTR(-ENOMEM);

+}

+/**

• • sgx_free_epc_page() - Free an EPC page
• • @page: an EPC page
• • Call EREMOVE for an EPC page and insert it back to the list of free pages.
• */

+void sgx_free_epc_page(struct sgx_epc_page *page) +{

• struct sgx_epc_section *section = &sgx_epc_sections[page->section];
• int ret;
• ret = __eremove(sgx_get_epc_virt_addr(page));
• if (WARN_ONCE(ret, "EREMOVE returned %d (0x%x)", ret, ret))

• return;
  

• spin_lock(&section->lock);
• list_add_tail(&page->list, &section->page_list);
• spin_unlock(&section->lock);

+}

• static bool __init sgx_setup_epc_section(u64 phys_addr, u64 size, unsigned long index, struct sgx_epc_section *section)

diff --git a/arch/x86/kernel/cpu/sgx/sgx.h b/arch/x86/kernel/cpu/sgx/sgx.h index 02afa84dd8fd..bd9dcb1ffcfa 100644 --- a/arch/x86/kernel/cpu/sgx/sgx.h +++ b/arch/x86/kernel/cpu/sgx/sgx.h @@ -57,4 +57,7 @@ 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);

• #endif /* _X86_SGX_H */