[PATCHv2 08/59] x86/mm: Introduce helpers to read number, shift and mask of KeyIDs

Kirill A. Shutemov
2019-07-31T15:10:09Z

mktme_nr_keyids() returns the number of KeyIDs available for MKTME,
excluding KeyID zero which used by TME. MKTME KeyIDs start from 1.

mktme_keyid_shift() returns the shift of KeyID within physical address.

mktme_keyid_mask() returns the mask to extract KeyID from physical address.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
arch/x86/include/asm/mktme.h | 19 +++++++++++++++++++
arch/x86/kernel/cpu/intel.c | 15 ++++++++++++---
arch/x86/mm/Makefile | 2 ++
arch/x86/mm/mktme.c | 27 +++++++++++++++++++++++++++
4 files changed, 60 insertions(+), 3 deletions(-)
create mode 100644 arch/x86/include/asm/mktme.h
create mode 100644 arch/x86/mm/mktme.c

diff --git a/arch/x86/include/asm/mktme.h b/arch/x86/include/asm/mktme.h
new file mode 100644
index 000000000000..b9ba2ea5b600
--- /dev/null
+++ b/arch/x86/include/asm/mktme.h
@@ -0,0 +1,19 @@
+#ifndef _ASM_X86_MKTME_H
+#define _ASM_X86_MKTME_H
+
+#include <linux/types.h>
+
+#ifdef CONFIG_X86_INTEL_MKTME
+extern phys_addr_t __mktme_keyid_mask;
+extern phys_addr_t mktme_keyid_mask(void);
+extern int __mktme_keyid_shift;
+extern int mktme_keyid_shift(void);
+extern int __mktme_nr_keyids;
+extern int mktme_nr_keyids(void);
+#else
+#define mktme_keyid_mask() ((phys_addr_t)0)
+#define mktme_nr_keyids() 0
+#define mktme_keyid_shift() 0
+#endif
+
+#endif
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index f03eee666761..7ba44825be42 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -618,6 +618,9 @@ static void detect_tme(struct cpuinfo_x86 *c)

#ifdef CONFIG_X86_INTEL_MKTME
if (mktme_status == MKTME_ENABLED && nr_keyids) {
+ __mktme_nr_keyids = nr_keyids;
+ __mktme_keyid_shift = c->x86_phys_bits - keyid_bits;
+
/*
* Mask out bits claimed from KeyID from physical address mask.
*
@@ -625,17 +628,23 @@ static void detect_tme(struct cpuinfo_x86 *c)
* and number of bits claimed for KeyID is 6, bits 51:46 of
* physical address is unusable.
*/
- phys_addr_t keyid_mask;
+ __mktme_keyid_mask = GENMASK_ULL(c->x86_phys_bits - 1, mktme_keyid_shift());
+ physical_mask &= ~mktme_keyid_mask();

- keyid_mask = GENMASK_ULL(c->x86_phys_bits - 1, c->x86_phys_bits - keyid_bits);
- physical_mask &= ~keyid_mask;
} else {
/*
* Reset __PHYSICAL_MASK.
* Maybe needed if there's inconsistent configuation
* between CPUs.
+ *
+ * FIXME: broken for hotplug.
+ * We must not allow onlining secondary CPUs with non-matching
+ * configuration.
*/
physical_mask = (1ULL << __PHYSICAL_MASK_SHIFT) - 1;
+ __mktme_keyid_mask = 0;
+ __mktme_keyid_shift = 0;
+ __mktme_nr_keyids = 0;
}
#endif

diff --git a/arch/x86/mm/Makefile b/arch/x86/mm/Makefile
index 84373dc9b341..600d18691876 100644
--- a/arch/x86/mm/Makefile
+++ b/arch/x86/mm/Makefile
@@ -53,3 +53,5 @@ obj-$(CONFIG_PAGE_TABLE_ISOLATION) += pti.o
obj-$(CONFIG_AMD_MEM_ENCRYPT) += mem_encrypt.o
obj-$(CONFIG_AMD_MEM_ENCRYPT) += mem_encrypt_identity.o
obj-$(CONFIG_AMD_MEM_ENCRYPT) += mem_encrypt_boot.o
+
+obj-$(CONFIG_X86_INTEL_MKTME) += mktme.o
diff --git a/arch/x86/mm/mktme.c b/arch/x86/mm/mktme.c
new file mode 100644
index 000000000000..0f48ef2720cc
--- /dev/null
+++ b/arch/x86/mm/mktme.c
@@ -0,0 +1,27 @@
+#include <asm/mktme.h>
+
+/* Mask to extract KeyID from physical address. */
+phys_addr_t __mktme_keyid_mask;
+phys_addr_t mktme_keyid_mask(void)
+{
+ return __mktme_keyid_mask;
+}
+EXPORT_SYMBOL_GPL(mktme_keyid_mask);
+
+/* Shift of KeyID within physical address. */
+int __mktme_keyid_shift;
+int mktme_keyid_shift(void)
+{
+ return __mktme_keyid_shift;
+}
+EXPORT_SYMBOL_GPL(mktme_keyid_shift);
+
+/*
+ * Number of KeyIDs available for MKTME.
+ * Excludes KeyID-0 which used by TME. MKTME KeyIDs start from 1.
+ */
+int __mktme_nr_keyids;
+int mktme_nr_keyids(void)
+{
+ return __mktme_nr_keyids;
+}
--
2.21.0