From: Alison Schofield <alison.schofield@intel.com>
To: dhowells@redhat.com, tglx@linutronix.de
Cc: jmorris@namei.org, mingo@redhat.com, hpa@zytor.com, bp@alien8.de,
luto@kernel.org, peterz@infradead.org,
kirill.shutemov@linux.intel.com, dave.hansen@intel.com,
kai.huang@intel.com, jun.nakajima@intel.com,
dan.j.williams@intel.com, jarkko.sakkinen@intel.com,
keyrings@vger.kernel.org, linux-security-module@vger.kernel.org,
linux-mm@kvack.org, x86@kernel.org
Subject: [RFC v2 07/13] x86/mm: Add helpers for reference counting encrypted VMAs
Date: Mon, 3 Dec 2018 23:39:54 -0800 [thread overview]
Message-ID: <e4407d95c74300c4a6b4c5f9321660e9097fff8f.1543903910.git.alison.schofield@intel.com> (raw)
In-Reply-To: <cover.1543903910.git.alison.schofield@intel.com>
In-Reply-To: <cover.1543903910.git.alison.schofield@intel.com>
In order to safely manage the usage of memory encryption keys, VMAs
using each KeyID need to be counted. This count allows the MKTME
(Multi-Key Total Memory Encryption) Key Service to know when the KeyID
resource is actually in use, or when it is idle and may be considered
for reuse.
Define a global refcount_t array and provide helper functions to
manipulate the counts.
Signed-off-by: Alison Schofield <alison.schofield@intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
arch/x86/include/asm/mktme.h | 9 +++++++
arch/x86/mm/mktme.c | 58 ++++++++++++++++++++++++++++++++++++++++++++
include/linux/mm.h | 2 ++
3 files changed, 69 insertions(+)
diff --git a/arch/x86/include/asm/mktme.h b/arch/x86/include/asm/mktme.h
index de3e529f3ab0..22d52635562c 100644
--- a/arch/x86/include/asm/mktme.h
+++ b/arch/x86/include/asm/mktme.h
@@ -28,6 +28,15 @@ extern int mktme_map_get_free_keyid(void);
extern void mprotect_set_encrypt(struct vm_area_struct *vma, int newkeyid,
unsigned long start, unsigned long end);
+/* Manage the MTKME encrypt_count references */
+extern int mktme_alloc_encrypt_array(void);
+extern void mktme_free_encrypt_array(void);
+extern int mktme_read_encrypt_ref(int keyid);
+extern void vma_get_encrypt_ref(struct vm_area_struct *vma);
+extern void vma_put_encrypt_ref(struct vm_area_struct *vma);
+extern void key_get_encrypt_ref(int keyid);
+extern void key_put_encrypt_ref(int keyid);
+
DECLARE_STATIC_KEY_FALSE(mktme_enabled_key);
static inline bool mktme_enabled(void)
{
diff --git a/arch/x86/mm/mktme.c b/arch/x86/mm/mktme.c
index e3fdf7b48173..facf08f9cb74 100644
--- a/arch/x86/mm/mktme.c
+++ b/arch/x86/mm/mktme.c
@@ -157,6 +157,64 @@ void mprotect_set_encrypt(struct vm_area_struct *vma, int newkeyid,
unlink_anon_vmas(vma);
}
+/*
+ * Helper functions manage the encrypt_count[] array that counts
+ * references on each MKTME hardware keyid. The gets & puts are
+ * used in core mm code that allocates and free's VMA's. The alloc,
+ * free, and read functions are used by the MKTME key service to
+ * manage key allocation and programming.
+ */
+refcount_t *encrypt_count;
+
+int mktme_alloc_encrypt_array(void)
+{
+ encrypt_count = kvcalloc(mktme_nr_keyids, sizeof(refcount_t),
+ GFP_KERNEL);
+ if (!encrypt_count)
+ return -ENOMEM;
+ return 0;
+}
+
+void mktme_free_encrypt_array(void)
+{
+ kvfree(encrypt_count);
+}
+
+int mktme_read_encrypt_ref(int keyid)
+{
+ return refcount_read(&encrypt_count[keyid]);
+}
+
+void vma_get_encrypt_ref(struct vm_area_struct *vma)
+{
+ if (vma_keyid(vma))
+ refcount_inc(&encrypt_count[vma_keyid(vma)]);
+}
+
+void vma_put_encrypt_ref(struct vm_area_struct *vma)
+{
+ if (vma_keyid(vma))
+ if (refcount_dec_and_test(&encrypt_count[vma_keyid(vma)])) {
+ mktme_map_lock();
+ mktme_map_free_keyid(vma_keyid(vma));
+ mktme_map_unlock();
+ }
+}
+
+void key_get_encrypt_ref(int keyid)
+{
+ refcount_inc(&encrypt_count[keyid]);
+}
+
+void key_put_encrypt_ref(int keyid)
+{
+ if (refcount_dec_and_test(&encrypt_count[keyid])) {
+ mktme_map_lock();
+ mktme_map_free_keyid(keyid);
+ mktme_map_unlock();
+ }
+}
+
/* Prepare page to be used for encryption. Called from page allocator. */
void __prep_encrypted_page(struct page *page, int order, int keyid, bool zero)
{
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 09182d78e7b7..453d675dd116 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2812,6 +2812,8 @@ static inline void mprotect_set_encrypt(struct vm_area_struct *vma,
int newkeyid,
unsigned long start,
unsigned long end) {}
+static inline void vma_get_encrypt_ref(struct vm_area_struct *vma) {}
+static inline void vma_put_encrypt_ref(struct vm_area_struct *vma) {}
#endif /* CONFIG_X86_INTEL_MKTME */
#endif /* __KERNEL__ */
#endif /* _LINUX_MM_H */
--
2.14.1
next prev parent reply other threads:[~2018-12-04 7:37 UTC|newest]
Thread overview: 91+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-04 7:39 [RFC v2 00/13] Multi-Key Total Memory Encryption API (MKTME) Alison Schofield
2018-12-04 7:39 ` [RFC v2 01/13] x86/mktme: Document the MKTME APIs Alison Schofield
2018-12-05 18:11 ` Andy Lutomirski
2018-12-05 19:22 ` Alison Schofield
2018-12-05 23:35 ` Andy Lutomirski
2018-12-06 8:04 ` Sakkinen, Jarkko
2018-12-04 7:39 ` [RFC v2 02/13] mm: Generalize the mprotect implementation to support extensions Alison Schofield
2018-12-06 8:08 ` Sakkinen, Jarkko
2018-12-04 7:39 ` [RFC v2 03/13] syscall/x86: Wire up a new system call for memory encryption keys Alison Schofield
2018-12-04 7:39 ` [RFC v2 04/13] x86/mm: Add helper functions for MKTME " Alison Schofield
2018-12-04 9:14 ` Peter Zijlstra
2018-12-05 5:49 ` Alison Schofield
2018-12-04 15:35 ` Andy Lutomirski
2018-12-05 5:52 ` Alison Schofield
2018-12-06 8:31 ` Sakkinen, Jarkko
2018-12-04 7:39 ` [RFC v2 05/13] x86/mm: Set KeyIDs in encrypted VMAs Alison Schofield
2018-12-06 8:37 ` Sakkinen, Jarkko
2018-12-04 7:39 ` [RFC v2 06/13] mm: Add the encrypt_mprotect() system call Alison Schofield
2018-12-06 8:38 ` Sakkinen, Jarkko
2018-12-04 7:39 ` Alison Schofield [this message]
2018-12-04 8:58 ` [RFC v2 07/13] x86/mm: Add helpers for reference counting encrypted VMAs Peter Zijlstra
2018-12-05 5:28 ` Alison Schofield
2018-12-04 7:39 ` [RFC v2 08/13] mm: Use reference counting for " Alison Schofield
2018-12-04 7:39 ` [RFC v2 09/13] mm: Restrict memory encryption to anonymous VMA's Alison Schofield
2018-12-04 9:10 ` Peter Zijlstra
2018-12-05 5:30 ` Alison Schofield
2018-12-05 9:07 ` Peter Zijlstra
2018-12-04 7:39 ` [RFC v2 10/13] keys/mktme: Add the MKTME Key Service type for memory encryption Alison Schofield
2018-12-06 8:51 ` Sakkinen, Jarkko
2018-12-06 8:54 ` Sakkinen, Jarkko
2018-12-06 15:11 ` Dave Hansen
2018-12-06 22:56 ` Sakkinen, Jarkko
2018-12-04 7:39 ` [RFC v2 11/13] keys/mktme: Program memory encryption keys on a system wide basis Alison Schofield
2018-12-04 9:21 ` Peter Zijlstra
2018-12-04 9:50 ` Kirill A. Shutemov
2018-12-05 5:44 ` Alison Schofield
2018-12-05 5:43 ` Alison Schofield
2018-12-05 9:10 ` Peter Zijlstra
2018-12-05 17:26 ` Alison Schofield
2018-12-04 7:39 ` [RFC v2 12/13] keys/mktme: Save MKTME data if kernel cmdline parameter allows Alison Schofield
2018-12-04 9:22 ` Peter Zijlstra
2018-12-07 2:14 ` Huang, Kai
2018-12-07 3:42 ` Alison Schofield
2018-12-07 6:39 ` Jarkko Sakkinen
2018-12-07 6:45 ` Jarkko Sakkinen
2018-12-07 11:47 ` Kirill A. Shutemov
2018-12-04 7:40 ` [RFC v2 13/13] keys/mktme: Support CPU Hotplug for MKTME keys Alison Schofield
2018-12-04 9:28 ` Peter Zijlstra
2018-12-05 5:32 ` Alison Schofield
2018-12-04 9:31 ` Peter Zijlstra
2018-12-05 5:36 ` Alison Schofield
2018-12-04 9:25 ` [RFC v2 00/13] Multi-Key Total Memory Encryption API (MKTME) Peter Zijlstra
2018-12-04 9:46 ` Kirill A. Shutemov
2018-12-05 20:32 ` Sakkinen, Jarkko
2018-12-06 11:22 ` Kirill A. Shutemov
2018-12-06 14:59 ` Dave Hansen
2018-12-07 10:12 ` Huang, Kai
2018-12-06 21:23 ` Sakkinen, Jarkko
2018-12-07 11:54 ` Kirill A. Shutemov
2018-12-04 19:19 ` Andy Lutomirski
2018-12-04 20:00 ` Andy Lutomirski
2018-12-04 20:32 ` Dave Hansen
2018-12-05 22:19 ` Sakkinen, Jarkko
2018-12-07 2:05 ` Huang, Kai
2018-12-07 6:48 ` Jarkko Sakkinen
2018-12-07 11:57 ` Kirill A. Shutemov
2018-12-07 21:59 ` Sakkinen, Jarkko
2018-12-07 23:45 ` Sakkinen, Jarkko
2018-12-07 23:48 ` Andy Lutomirski
2018-12-08 1:33 ` Huang, Kai
2018-12-08 3:53 ` Sakkinen, Jarkko
2018-12-12 15:31 ` Sakkinen, Jarkko
2018-12-12 16:29 ` Andy Lutomirski
2018-12-12 16:43 ` Sakkinen, Jarkko
2018-12-12 23:27 ` Huang, Kai
2018-12-13 5:49 ` Sakkinen, Jarkko
2018-12-13 5:52 ` Sakkinen, Jarkko
2018-12-12 23:24 ` Huang, Kai
2018-12-07 23:35 ` Eric Rannaud
2018-12-05 23:49 ` Dave Hansen
2018-12-06 1:09 ` Andy Lutomirski
2018-12-06 1:25 ` Dan Williams
2018-12-06 15:39 ` Dave Hansen
2018-12-06 19:10 ` Andy Lutomirski
2018-12-06 19:31 ` Dave Hansen
2018-12-07 1:55 ` Huang, Kai
2018-12-07 4:23 ` Dave Hansen
2018-12-07 23:53 ` Andy Lutomirski
2018-12-08 1:11 ` Dave Hansen
2018-12-08 2:07 ` Huang, Kai
2018-12-05 20:30 ` Sakkinen, Jarkko
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