[PATCHv5 10/19] x86/mm: Implement page_keyid() using page_ext
From: Kirill A. Shutemov <hidden>
Date: 2018-07-17 11:22:37
Also in:
lkml
Subsystem:
memory management, memory management - page allocator, the rest, x86 architecture (32-bit and 64-bit), x86 mm · Maintainers:
Andrew Morton, Vlastimil Babka, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, Andy Lutomirski, Peter Zijlstra
Store KeyID in bits 31:16 of extended page flags. These bits are unused. page_keyid() returns zero until page_ext is ready. page_ext initializer enables static branch to indicate that page_keyid() can use page_ext. The same static branch will gate MKTME readiness in general. We don't yet set KeyID for the page. It will come in the following patch that implements prep_encrypted_page(). All pages have KeyID-0 for now. Signed-off-by: Kirill A. Shutemov <redacted> --- arch/x86/include/asm/mktme.h | 7 +++++++ arch/x86/include/asm/page.h | 1 + arch/x86/mm/mktme.c | 34 ++++++++++++++++++++++++++++++++++ include/linux/page_ext.h | 11 ++++++++++- mm/page_ext.c | 3 +++ 5 files changed, 55 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/mktme.h b/arch/x86/include/asm/mktme.h
index df31876ec48c..7266494b4f0a 100644
--- a/arch/x86/include/asm/mktme.h
+++ b/arch/x86/include/asm/mktme.h@@ -2,11 +2,18 @@ #define _ASM_X86_MKTME_H #include <linux/types.h> +#include <linux/page_ext.h> #ifdef CONFIG_X86_INTEL_MKTME extern phys_addr_t mktme_keyid_mask; extern int mktme_nr_keyids; extern int mktme_keyid_shift; + +extern struct page_ext_operations page_mktme_ops; + +#define page_keyid page_keyid +int page_keyid(const struct page *page); + #else #define mktme_keyid_mask ((phys_addr_t)0) #define mktme_nr_keyids 0
diff --git a/arch/x86/include/asm/page.h b/arch/x86/include/asm/page.h
index 7555b48803a8..39af59487d5f 100644
--- a/arch/x86/include/asm/page.h
+++ b/arch/x86/include/asm/page.h@@ -19,6 +19,7 @@ struct page; #include <linux/range.h> +#include <asm/mktme.h> extern struct range pfn_mapped[]; extern int nr_pfn_mapped;
diff --git a/arch/x86/mm/mktme.c b/arch/x86/mm/mktme.c
index 467f1b26c737..09cbff678b9f 100644
--- a/arch/x86/mm/mktme.c
+++ b/arch/x86/mm/mktme.c@@ -3,3 +3,37 @@ phys_addr_t mktme_keyid_mask; int mktme_nr_keyids; int mktme_keyid_shift; + +static DEFINE_STATIC_KEY_FALSE(mktme_enabled_key); + +static inline bool mktme_enabled(void) +{ + return static_branch_unlikely(&mktme_enabled_key); +} + +int page_keyid(const struct page *page) +{ + if (!mktme_enabled()) + return 0; + + return lookup_page_ext(page)->keyid; +} +EXPORT_SYMBOL(page_keyid); + +static bool need_page_mktme(void) +{ + /* Make sure keyid doesn't collide with extended page flags */ + BUILD_BUG_ON(__NR_PAGE_EXT_FLAGS > 16); + + return !!mktme_nr_keyids; +} + +static void init_page_mktme(void) +{ + static_branch_enable(&mktme_enabled_key); +} + +struct page_ext_operations page_mktme_ops = { + .need = need_page_mktme, + .init = init_page_mktme, +};
diff --git a/include/linux/page_ext.h b/include/linux/page_ext.h
index f84f167ec04c..d9c5aae9523f 100644
--- a/include/linux/page_ext.h
+++ b/include/linux/page_ext.h@@ -23,6 +23,7 @@ enum page_ext_flags { PAGE_EXT_YOUNG, PAGE_EXT_IDLE, #endif + __NR_PAGE_EXT_FLAGS }; /*
@@ -33,7 +34,15 @@ enum page_ext_flags { * then the page_ext for pfn always exists. */ struct page_ext { - unsigned long flags; + union { + unsigned long flags; +#ifdef CONFIG_X86_INTEL_MKTME + struct { + unsigned short __pad; + unsigned short keyid; + }; +#endif + }; }; extern void pgdat_page_ext_init(struct pglist_data *pgdat);
diff --git a/mm/page_ext.c b/mm/page_ext.c
index a9826da84ccb..036658229842 100644
--- a/mm/page_ext.c
+++ b/mm/page_ext.c@@ -68,6 +68,9 @@ static struct page_ext_operations *page_ext_ops[] = { #if defined(CONFIG_IDLE_PAGE_TRACKING) && !defined(CONFIG_64BIT) &page_idle_ops, #endif +#ifdef CONFIG_X86_INTEL_MKTME + &page_mktme_ops, +#endif }; static unsigned long total_usage;
--
2.18.0