From b9d05200bc12444c7778a49c9694d8382ed06aa8 Mon Sep 17 00:00:00 2001 From: Tom Lendacky Date: Mon, 17 Jul 2017 16:10:11 -0500 Subject: [PATCH] x86/mm: Insure that boot memory areas are mapped properly MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit The boot data and command line data are present in memory in a decrypted state and are copied early in the boot process. The early page fault support will map these areas as encrypted, so before attempting to copy them, add decrypted mappings so the data is accessed properly when copied. For the initrd, encrypt this data in place. Since the future mapping of the initrd area will be mapped as encrypted the data will be accessed properly. Signed-off-by: Tom Lendacky Reviewed-by: Thomas Gleixner Cc: Alexander Potapenko Cc: Andrey Ryabinin Cc: Andy Lutomirski Cc: Arnd Bergmann Cc: Borislav Petkov Cc: Brijesh Singh Cc: Dave Young Cc: Dmitry Vyukov Cc: Jonathan Corbet Cc: Konrad Rzeszutek Wilk Cc: Larry Woodman Cc: Linus Torvalds Cc: Matt Fleming Cc: Michael S. Tsirkin Cc: Paolo Bonzini Cc: Peter Zijlstra Cc: Radim Krčmář Cc: Rik van Riel Cc: Toshimitsu Kani Cc: kasan-dev@googlegroups.com Cc: kvm@vger.kernel.org Cc: linux-arch@vger.kernel.org Cc: linux-doc@vger.kernel.org Cc: linux-efi@vger.kernel.org Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/bb0d430b41efefd45ee515aaf0979dcfda8b6a44.1500319216.git.thomas.lendacky@amd.com Signed-off-by: Ingo Molnar --- arch/x86/include/asm/mem_encrypt.h | 6 +++ arch/x86/include/asm/pgtable.h | 3 ++ arch/x86/kernel/head64.c | 30 ++++++++++++-- arch/x86/kernel/setup.c | 9 +++++ arch/x86/mm/kasan_init_64.c | 2 +- arch/x86/mm/mem_encrypt.c | 63 ++++++++++++++++++++++++++++++ 6 files changed, 108 insertions(+), 5 deletions(-) diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h index 8baa35ba2316..ab1fe77c2f73 100644 --- a/arch/x86/include/asm/mem_encrypt.h +++ b/arch/x86/include/asm/mem_encrypt.h @@ -26,6 +26,9 @@ void __init sme_early_encrypt(resource_size_t paddr, void __init sme_early_decrypt(resource_size_t paddr, unsigned long size); +void __init sme_map_bootdata(char *real_mode_data); +void __init sme_unmap_bootdata(char *real_mode_data); + void __init sme_early_init(void); void __init sme_encrypt_kernel(void); @@ -40,6 +43,9 @@ static inline void __init sme_early_encrypt(resource_size_t paddr, static inline void __init sme_early_decrypt(resource_size_t paddr, unsigned long size) { } +static inline void __init sme_map_bootdata(char *real_mode_data) { } +static inline void __init sme_unmap_bootdata(char *real_mode_data) { } + static inline void __init sme_early_init(void) { } static inline void __init sme_encrypt_kernel(void) { } diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index c6452cb12c0b..bbeae4a2bd01 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -23,6 +23,9 @@ #ifndef __ASSEMBLY__ #include +extern pgd_t early_top_pgt[PTRS_PER_PGD]; +int __init __early_make_pgtable(unsigned long address, pmdval_t pmd); + void ptdump_walk_pgd_level(struct seq_file *m, pgd_t *pgd); void ptdump_walk_pgd_level_checkwx(void); diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c index 5cd0b72a0283..0cdb53bf4c4b 100644 --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -34,7 +34,6 @@ /* * Manage page tables very early on. */ -extern pgd_t early_top_pgt[PTRS_PER_PGD]; extern pmd_t early_dynamic_pgts[EARLY_DYNAMIC_PAGE_TABLES][PTRS_PER_PMD]; static unsigned int __initdata next_early_pgt; pmdval_t early_pmd_flags = __PAGE_KERNEL_LARGE & ~(_PAGE_GLOBAL | _PAGE_NX); @@ -181,13 +180,13 @@ static void __init reset_early_page_tables(void) } /* Create a new PMD entry */ -int __init early_make_pgtable(unsigned long address) +int __init __early_make_pgtable(unsigned long address, pmdval_t pmd) { unsigned long physaddr = address - __PAGE_OFFSET; pgdval_t pgd, *pgd_p; p4dval_t p4d, *p4d_p; pudval_t pud, *pud_p; - pmdval_t pmd, *pmd_p; + pmdval_t *pmd_p; /* Invalid address or early pgt is done ? */ if (physaddr >= MAXMEM || read_cr3_pa() != __pa_nodebug(early_top_pgt)) @@ -246,12 +245,21 @@ again: memset(pmd_p, 0, sizeof(*pmd_p) * PTRS_PER_PMD); *pud_p = (pudval_t)pmd_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE; } - pmd = (physaddr & PMD_MASK) + early_pmd_flags; pmd_p[pmd_index(address)] = pmd; return 0; } +int __init early_make_pgtable(unsigned long address) +{ + unsigned long physaddr = address - __PAGE_OFFSET; + pmdval_t pmd; + + pmd = (physaddr & PMD_MASK) + early_pmd_flags; + + return __early_make_pgtable(address, pmd); +} + /* Don't add a printk in there. printk relies on the PDA which is not initialized yet. */ static void __init clear_bss(void) @@ -274,6 +282,12 @@ static void __init copy_bootdata(char *real_mode_data) char * command_line; unsigned long cmd_line_ptr; + /* + * If SME is active, this will create decrypted mappings of the + * boot data in advance of the copy operations. + */ + sme_map_bootdata(real_mode_data); + memcpy(&boot_params, real_mode_data, sizeof boot_params); sanitize_boot_params(&boot_params); cmd_line_ptr = get_cmd_line_ptr(); @@ -281,6 +295,14 @@ static void __init copy_bootdata(char *real_mode_data) command_line = __va(cmd_line_ptr); memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE); } + + /* + * The old boot data is no longer needed and won't be reserved, + * freeing up that memory for use by the system. If SME is active, + * we need to remove the mappings that were created so that the + * memory doesn't remain mapped as decrypted. + */ + sme_unmap_bootdata(real_mode_data); } asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data) diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index 3486d0498800..0bfe0c1628f6 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -69,6 +69,7 @@ #include #include #include +#include #include #include