x86/mm/cpa: Add large page preservation statistics (5c280cf6) · Commits · 戴 / test

arch/x86/Kconfig

+8 −0

Original line number	Original line	Diff line number	Diff line
	@@ -1491,6 +1491,14 @@ config X86_DIRECT_GBPAGES
	supports them), so don't confuse the user by printing		supports them), so don't confuse the user by printing
	that we have them enabled.		that we have them enabled.

			config X86_CPA_STATISTICS
			bool "Enable statistic for Change Page Attribute"
			depends on DEBUG_FS
			---help---
			Expose statistics about the Change Page Attribute mechanims, which
			helps to determine the effectivness of preserving large and huge
			page mappings when mapping protections are changed.

	config ARCH_HAS_MEM_ENCRYPT		config ARCH_HAS_MEM_ENCRYPT
	def_bool y		def_bool y

arch/x86/mm/pageattr.c

+97 −2

Original line number	Original line	Diff line number	Diff line
	@@ -101,6 +101,95 @@ void arch_report_meminfo(struct seq_file *m)
	static inline void split_page_count(int level) { }		static inline void split_page_count(int level) { }
	#endif		#endif

			#ifdef CONFIG_X86_CPA_STATISTICS

			static unsigned long cpa_1g_checked;
			static unsigned long cpa_1g_sameprot;
			static unsigned long cpa_1g_preserved;
			static unsigned long cpa_2m_checked;
			static unsigned long cpa_2m_sameprot;
			static unsigned long cpa_2m_preserved;
			static unsigned long cpa_4k_checked;
			static unsigned long cpa_4k_install;

			static inline void cpa_inc_1g_checked(void)
			{
			cpa_1g_checked++;
			}

			static inline void cpa_inc_2m_checked(void)
			{
			cpa_2m_checked++;
			}

			static inline void cpa_inc_4k_checked(void)
			{
			cpa_4k_checked++;
			}

			static inline void cpa_inc_4k_install(void)
			{
			cpa_4k_install++;
			}

			static inline void cpa_inc_lp_sameprot(int level)
			{
			if (level == PG_LEVEL_1G)
			cpa_1g_sameprot++;
			else
			cpa_2m_sameprot++;
			}

			static inline void cpa_inc_lp_preserved(int level)
			{
			if (level == PG_LEVEL_1G)
			cpa_1g_preserved++;
			else
			cpa_2m_preserved++;
			}

			static int cpastats_show(struct seq_file m, void p)
			{
			seq_printf(m, "1G pages checked: %16lu\n", cpa_1g_checked);
			seq_printf(m, "1G pages sameprot: %16lu\n", cpa_1g_sameprot);
			seq_printf(m, "1G pages preserved: %16lu\n", cpa_1g_preserved);
			seq_printf(m, "2M pages checked: %16lu\n", cpa_2m_checked);
			seq_printf(m, "2M pages sameprot: %16lu\n", cpa_2m_sameprot);
			seq_printf(m, "2M pages preserved: %16lu\n", cpa_2m_preserved);
			seq_printf(m, "4K pages checked: %16lu\n", cpa_4k_checked);
			seq_printf(m, "4K pages set-checked: %16lu\n", cpa_4k_install);
			return 0;
			}

			static int cpastats_open(struct inode inode, struct file file)
			{
			return single_open(file, cpastats_show, NULL);
			}

			static const struct file_operations cpastats_fops = {
			.open = cpastats_open,
			.read = seq_read,
			.llseek = seq_lseek,
			.release = single_release,
			};

			static int __init cpa_stats_init(void)
			{
			debugfs_create_file("cpa_stats", S_IRUSR, arch_debugfs_dir, NULL,
			&cpastats_fops);
			return 0;
			}
			late_initcall(cpa_stats_init);
			#else
			static inline void cpa_inc_1g_checked(void) { }
			static inline void cpa_inc_2m_checked(void) { }
			static inline void cpa_inc_4k_checked(void) { }
			static inline void cpa_inc_4k_install(void) { }
			static inline void cpa_inc_lp_sameprot(int level) { }
			static inline void cpa_inc_lp_preserved(int level) { }
			#endif


	static inline int		static inline int
	within(unsigned long addr, unsigned long start, unsigned long end)		within(unsigned long addr, unsigned long start, unsigned long end)
	{		{
	@@ -664,10 +753,12 @@ static int __should_split_large_page(pte_t *kpte, unsigned long address,
	case PG_LEVEL_2M:		case PG_LEVEL_2M:
	old_prot = pmd_pgprot((pmd_t )kpte);		old_prot = pmd_pgprot((pmd_t )kpte);
	old_pfn = pmd_pfn((pmd_t )kpte);		old_pfn = pmd_pfn((pmd_t )kpte);
			cpa_inc_2m_checked();
	break;		break;
	case PG_LEVEL_1G:		case PG_LEVEL_1G:
	old_prot = pud_pgprot((pud_t )kpte);		old_prot = pud_pgprot((pud_t )kpte);
	old_pfn = pud_pfn((pud_t )kpte);		old_pfn = pud_pfn((pud_t )kpte);
			cpa_inc_1g_checked();
	break;		break;
	default:		default:
	return -EINVAL;		return -EINVAL;
	@@ -732,14 +823,16 @@ static int __should_split_large_page(pte_t *kpte, unsigned long address,
	for (i = 0, addr = lpaddr; i < numpages; i++, addr += PAGE_SIZE, pfn++) {		for (i = 0, addr = lpaddr; i < numpages; i++, addr += PAGE_SIZE, pfn++) {
	pgprot_t chk_prot = static_protections(req_prot, addr, pfn, 1,		pgprot_t chk_prot = static_protections(req_prot, addr, pfn, 1,
	CPA_DETECT);		CPA_DETECT);
			cpa_inc_4k_checked();
	if (pgprot_val(chk_prot) != pgprot_val(new_prot))		if (pgprot_val(chk_prot) != pgprot_val(new_prot))
	return 1;		return 1;
	}		}

	/* If there are no changes, return. */		/* If there are no changes, return. */
	if (pgprot_val(new_prot) == pgprot_val(old_prot))		if (pgprot_val(new_prot) == pgprot_val(old_prot)) {
			cpa_inc_lp_sameprot(level);
	return 0;		return 0;
			}

	/*		/*
	* Verify that the address is aligned and the number of pages		* Verify that the address is aligned and the number of pages
	@@ -752,6 +845,7 @@ static int __should_split_large_page(pte_t *kpte, unsigned long address,
	new_pte = pfn_pte(old_pfn, new_prot);		new_pte = pfn_pte(old_pfn, new_prot);
	__set_pmd_pte(kpte, address, new_pte);		__set_pmd_pte(kpte, address, new_pte);
	cpa->flags \|= CPA_FLUSHTLB;		cpa->flags \|= CPA_FLUSHTLB;
			cpa_inc_lp_preserved(level);
	return 0;		return 0;
	}		}

	@@ -1341,6 +1435,7 @@ repeat:
	pgprot_val(new_prot) &= ~pgprot_val(cpa->mask_clr);		pgprot_val(new_prot) &= ~pgprot_val(cpa->mask_clr);
	pgprot_val(new_prot) \|= pgprot_val(cpa->mask_set);		pgprot_val(new_prot) \|= pgprot_val(cpa->mask_set);

			cpa_inc_4k_install();
	new_prot = static_protections(new_prot, address, pfn, 1,		new_prot = static_protections(new_prot, address, pfn, 1,
	CPA_PROTECT);		CPA_PROTECT);

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