[PATCHv4 10/18] x86/mm: Implement vma_keyid()

[Kirill A. Shutemov]

We store KeyID in upper bits for vm_page_prot that match position of
KeyID in PTE. vma_keyid() extracts KeyID from vm_page_prot.

With KeyID in vm_page_prot we don't need to modify any page table helper
to propagate the KeyID to page table entires.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
 arch/x86/include/asm/mktme.h |  5 +++++
 arch/x86/mm/mktme.c          | 12 ++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/arch/x86/include/asm/mktme.h b/arch/x86/include/asm/mktme.h
index 7266494b4f0a..f0b7844e36a4 100644
--- a/arch/x86/include/asm/mktme.h
+++ b/arch/x86/include/asm/mktme.h
@@ -4,6 +4,8 @@
 #include <linux/types.h>
 #include <linux/page_ext.h>
 
+struct vm_area_struct;
+
 #ifdef CONFIG_X86_INTEL_MKTME
 extern phys_addr_t mktme_keyid_mask;
 extern int mktme_nr_keyids;
@@ -14,6 +16,9 @@ extern struct page_ext_operations page_mktme_ops;
 #define page_keyid page_keyid
 int page_keyid(const struct page *page);
 
+#define vma_keyid vma_keyid
+int vma_keyid(struct vm_area_struct *vma);
+
 #else
 #define mktme_keyid_mask	((phys_addr_t)0)
 #define mktme_nr_keyids		0
diff --git a/arch/x86/mm/mktme.c b/arch/x86/mm/mktme.c
index 09cbff678b9f..a1f40ee61b25 100644
--- a/arch/x86/mm/mktme.c
+++ b/arch/x86/mm/mktme.c
@@ -1,3 +1,4 @@
+#include <linux/mm.h>
 #include <asm/mktme.h>
 
 phys_addr_t mktme_keyid_mask;
@@ -37,3 +38,14 @@ struct page_ext_operations page_mktme_ops = {
 	.need = need_page_mktme,
 	.init = init_page_mktme,
 };
+
+int vma_keyid(struct vm_area_struct *vma)
+{
+	pgprotval_t prot;
+
+	if (!mktme_enabled())
+		return 0;
+
+	prot = pgprot_val(vma->vm_page_prot);
+	return (prot & mktme_keyid_mask) >> mktme_keyid_shift;
+}
-- 
2.18.0