[PATCH RFC 2/3] x86/sgx: Export sgx_encl_page_alloc()

Jarkko Sakkinen
2022-03-06T05:33:15Z

Move sgx_encl_page_alloc() to encl.c and export it so that it can be
used in the implementation for MAP_POPULATE, which requires to allocate
new enclave pages.

Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
arch/x86/kernel/cpu/sgx/encl.c | 38 +++++++++++++++++++++++++++++++++
arch/x86/kernel/cpu/sgx/encl.h | 3 +++
arch/x86/kernel/cpu/sgx/ioctl.c | 38 ---------------------------------
3 files changed, 41 insertions(+), 38 deletions(-)

diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c
index 89aeed798ffb..79e39bd99c09 100644
--- a/arch/x86/kernel/cpu/sgx/encl.c
+++ b/arch/x86/kernel/cpu/sgx/encl.c
@@ -914,6 +914,44 @@ int sgx_encl_test_and_clear_young(struct mm_struct *mm,
return ret;
}

+struct sgx_encl_page *sgx_encl_page_alloc(struct sgx_encl *encl,
+ unsigned long offset,
+ u64 secinfo_flags)
+{
+ struct sgx_encl_page *encl_page;
+ unsigned long prot;
+
+ encl_page = kzalloc(sizeof(*encl_page), GFP_KERNEL);
+ if (!encl_page)
+ return ERR_PTR(-ENOMEM);
+
+ encl_page->desc = encl->base + offset;
+ encl_page->encl = encl;
+
+ prot = _calc_vm_trans(secinfo_flags, SGX_SECINFO_R, PROT_READ) |
+ _calc_vm_trans(secinfo_flags, SGX_SECINFO_W, PROT_WRITE) |
+ _calc_vm_trans(secinfo_flags, SGX_SECINFO_X, PROT_EXEC);
+
+ /*
+ * TCS pages must always RW set for CPU access while the SECINFO
+ * permissions are *always* zero - the CPU ignores the user provided
+ * values and silently overwrites them with zero permissions.
+ */
+ if ((secinfo_flags & SGX_SECINFO_PAGE_TYPE_MASK) == SGX_SECINFO_TCS)
+ prot |= PROT_READ | PROT_WRITE;
+
+ /* Calculate maximum of the VM flags for the page. */
+ encl_page->vm_max_prot_bits = calc_vm_prot_bits(prot, 0);
+
+ /*
+ * At time of allocation, the runtime protection bits are the same
+ * as the maximum protection bits.
+ */
+ encl_page->vm_run_prot_bits = encl_page->vm_max_prot_bits;
+
+ return encl_page;
+}
+
/**
* sgx_zap_enclave_ptes() - remove PTEs mapping the address from enclave
* @encl: the enclave
diff --git a/arch/x86/kernel/cpu/sgx/encl.h b/arch/x86/kernel/cpu/sgx/encl.h
index 1b6ce1da7c92..3df0d3faf3a1 100644
--- a/arch/x86/kernel/cpu/sgx/encl.h
+++ b/arch/x86/kernel/cpu/sgx/encl.h
@@ -113,6 +113,9 @@ int sgx_encl_get_backing(struct sgx_encl *encl, unsigned long page_index,
void sgx_encl_put_backing(struct sgx_backing *backing, bool do_write);
int sgx_encl_test_and_clear_young(struct mm_struct *mm,
struct sgx_encl_page *page);
+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(void);
unsigned int sgx_alloc_va_slot(struct sgx_va_page *va_page);
diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
index d8c3c07badb3..3e3ca27a6f72 100644
--- a/arch/x86/kernel/cpu/sgx/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -169,44 +169,6 @@ static long sgx_ioc_enclave_create(struct sgx_encl *encl, void __user *arg)
return ret;
}

-static struct sgx_encl_page *sgx_encl_page_alloc(struct sgx_encl *encl,
- unsigned long offset,
- u64 secinfo_flags)
-{
- struct sgx_encl_page *encl_page;
- unsigned long prot;
-
- encl_page = kzalloc(sizeof(*encl_page), GFP_KERNEL);
- if (!encl_page)
- return ERR_PTR(-ENOMEM);
-
- encl_page->desc = encl->base + offset;
- encl_page->encl = encl;
-
- prot = _calc_vm_trans(secinfo_flags, SGX_SECINFO_R, PROT_READ) |
- _calc_vm_trans(secinfo_flags, SGX_SECINFO_W, PROT_WRITE) |
- _calc_vm_trans(secinfo_flags, SGX_SECINFO_X, PROT_EXEC);
-
- /*
- * TCS pages must always RW set for CPU access while the SECINFO
- * permissions are *always* zero - the CPU ignores the user provided
- * values and silently overwrites them with zero permissions.
- */
- if ((secinfo_flags & SGX_SECINFO_PAGE_TYPE_MASK) == SGX_SECINFO_TCS)
- prot |= PROT_READ | PROT_WRITE;
-
- /* Calculate maximum of the VM flags for the page. */
- encl_page->vm_max_prot_bits = calc_vm_prot_bits(prot, 0);
-
- /*
- * At time of allocation, the runtime protection bits are the same
- * as the maximum protection bits.
- */
- encl_page->vm_run_prot_bits = encl_page->vm_max_prot_bits;
-
- return encl_page;
-}
-
static int sgx_validate_secinfo(struct sgx_secinfo *secinfo)
{
u64 perm = secinfo->flags & SGX_SECINFO_PERMISSION_MASK;
--
2.35.1