[PATCHv2 13/59] x86/mm: Add a helper to retrieve KeyID for a VMA

Kirill A. Shutemov
2019-07-31T15:09:58Z

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@linux.intel.com>
---
arch/x86/include/asm/mktme.h | 12 ++++++++++++
arch/x86/mm/mktme.c | 7 +++++++
2 files changed, 19 insertions(+)

diff --git a/arch/x86/include/asm/mktme.h b/arch/x86/include/asm/mktme.h
index 46041075f617..52b115b30a42 100644
--- a/arch/x86/include/asm/mktme.h
+++ b/arch/x86/include/asm/mktme.h
@@ -5,6 +5,8 @@
#include <linux/page_ext.h>
#include <linux/jump_label.h>

+struct vm_area_struct;
+
#ifdef CONFIG_X86_INTEL_MKTME
extern phys_addr_t __mktme_keyid_mask;
extern phys_addr_t mktme_keyid_mask(void);
@@ -31,6 +33,16 @@ static inline int page_keyid(const struct page *page)
return lookup_page_ext(page)->keyid;
}

+#define vma_keyid vma_keyid
+int __vma_keyid(struct vm_area_struct *vma);
+static inline int vma_keyid(struct vm_area_struct *vma)
+{
+ if (!mktme_enabled())
+ return 0;
+
+ return __vma_keyid(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 48c2d4c97356..d02867212e33 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>

/* Mask to extract KeyID from physical address. */
@@ -48,3 +49,9 @@ 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 = pgprot_val(vma->vm_page_prot);
+ return (prot & mktme_keyid_mask()) >> mktme_keyid_shift();
+}
--
2.21.0