From: Tom Lendacky <thomas.lendacky@amd.com>
To: <linux-arch@vger.kernel.org>, <linux-efi@vger.kernel.org>,
<kvm@vger.kernel.org>, <linux-doc@vger.kernel.org>,
<x86@kernel.org>, <linux-kernel@vger.kernel.org>,
<kasan-dev@googlegroups.com>, <linux-mm@kvack.org>,
<iommu@lists.linux-foundation.org>
Cc: "Rik van Riel" <riel@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Arnd Bergmann" <arnd@arndb.de>,
"Jonathan Corbet" <corbet@lwn.net>,
"Matt Fleming" <matt@codeblueprint.co.uk>,
"Joerg Roedel" <joro@8bytes.org>,
"Konrad Rzeszutek Wilk" <konrad.wilk@oracle.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Larry Woodman" <lwoodman@redhat.com>,
"Ingo Molnar" <mingo@redhat.com>,
"Borislav Petkov" <bp@alien8.de>,
"Andy Lutomirski" <luto@kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
"Andrey Ryabinin" <aryabinin@virtuozzo.com>,
"Alexander Potapenko" <glider@google.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Dmitry Vyukov" <dvyukov@google.com>
Subject: [RFC PATCH v3 19/20] x86: Add support to make use of Secure Memory Encryption
Date: Wed, 9 Nov 2016 18:38:26 -0600 [thread overview]
Message-ID: <20161110003826.3280.5546.stgit@tlendack-t1.amdoffice.net> (raw)
In-Reply-To: <20161110003426.3280.2999.stgit@tlendack-t1.amdoffice.net>
This patch adds the support to check if SME has been enabled and if the
mem_encrypt=on command line option is set. If both of these conditions
are true, then the encryption mask is set and the kernel is encrypted
"in place."
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
---
arch/x86/kernel/Makefile | 1
arch/x86/kernel/mem_encrypt_boot.S | 156 +++++++++++++++++++++++++++++
arch/x86/kernel/mem_encrypt_init.c | 196 ++++++++++++++++++++++++++++++++++++
3 files changed, 353 insertions(+)
create mode 100644 arch/x86/kernel/mem_encrypt_boot.S
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 27e22f4..020759f 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -143,4 +143,5 @@ ifeq ($(CONFIG_X86_64),y)
obj-y += vsmp_64.o
obj-y += mem_encrypt_init.o
+ obj-y += mem_encrypt_boot.o
endif
diff --git a/arch/x86/kernel/mem_encrypt_boot.S b/arch/x86/kernel/mem_encrypt_boot.S
new file mode 100644
index 0000000..d4917ba
--- /dev/null
+++ b/arch/x86/kernel/mem_encrypt_boot.S
@@ -0,0 +1,156 @@
+/*
+ * AMD Memory Encryption Support
+ *
+ * Copyright (C) 2016 Advanced Micro Devices, Inc.
+ *
+ * Author: Tom Lendacky <thomas.lendacky@amd.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/linkage.h>
+#include <asm/pgtable.h>
+#include <asm/page.h>
+#include <asm/processor-flags.h>
+#include <asm/msr-index.h>
+
+ .text
+ .code64
+ENTRY(sme_encrypt_execute)
+
+#ifdef CONFIG_AMD_MEM_ENCRYPT
+ /*
+ * Entry parameters:
+ * RDI - virtual address for the encrypted kernel mapping
+ * RSI - virtual address for the un-encrypted kernel mapping
+ * RDX - length of kernel
+ * RCX - address of the encryption workarea
+ * - stack page (PAGE_SIZE)
+ * - encryption routine page (PAGE_SIZE)
+ * - intermediate copy buffer (PMD_PAGE_SIZE)
+ * R8 - address of the pagetables to use for encryption
+ */
+
+ /* Set up a one page stack in the non-encrypted memory area */
+ movq %rcx, %rax
+ addq $PAGE_SIZE, %rax
+ movq %rsp, %rbp
+ movq %rax, %rsp
+ push %rbp
+
+ push %r12
+ push %r13
+
+ movq %rdi, %r10
+ movq %rsi, %r11
+ movq %rdx, %r12
+ movq %rcx, %r13
+
+ /* Copy encryption routine into the workarea */
+ movq %rax, %rdi
+ leaq .Lencrypt_start(%rip), %rsi
+ movq $(.Lencrypt_stop - .Lencrypt_start), %rcx
+ rep movsb
+
+ /* Setup registers for call */
+ movq %r10, %rdi
+ movq %r11, %rsi
+ movq %r8, %rdx
+ movq %r12, %rcx
+ movq %rax, %r8
+ addq $PAGE_SIZE, %r8
+
+ /* Call the encryption routine */
+ call *%rax
+
+ pop %r13
+ pop %r12
+
+ pop %rsp /* Restore original stack pointer */
+.Lencrypt_exit:
+#endif /* CONFIG_AMD_MEM_ENCRYPT */
+
+ ret
+ENDPROC(sme_encrypt_execute)
+
+#ifdef CONFIG_AMD_MEM_ENCRYPT
+/*
+ * Routine used to encrypt kernel.
+ * This routine must be run outside of the kernel proper since
+ * the kernel will be encrypted during the process. So this
+ * routine is defined here and then copied to an area outside
+ * of the kernel where it will remain and run un-encrypted
+ * during execution.
+ *
+ * On entry the registers must be:
+ * RDI - virtual address for the encrypted kernel mapping
+ * RSI - virtual address for the un-encrypted kernel mapping
+ * RDX - address of the pagetables to use for encryption
+ * RCX - length of kernel
+ * R8 - intermediate copy buffer
+ *
+ * RAX - points to this routine
+ *
+ * The kernel will be encrypted by copying from the non-encrypted
+ * kernel space to an intermediate buffer and then copying from the
+ * intermediate buffer back to the encrypted kernel space. The physical
+ * addresses of the two kernel space mappings are the same which
+ * results in the kernel being encrypted "in place".
+ */
+.Lencrypt_start:
+ /* Enable the new page tables */
+ mov %rdx, %cr3
+
+ /* Flush any global TLBs */
+ mov %cr4, %rdx
+ andq $~X86_CR4_PGE, %rdx
+ mov %rdx, %cr4
+ orq $X86_CR4_PGE, %rdx
+ mov %rdx, %cr4
+
+ /* Set the PAT register PA5 entry to write-protect */
+ push %rcx
+ movl $MSR_IA32_CR_PAT, %ecx
+ rdmsr
+ push %rdx /* Save original PAT value */
+ andl $0xffff00ff, %edx /* Clear PA5 */
+ orl $0x00000500, %edx /* Set PA5 to WP */
+ wrmsr
+ pop %rdx /* RDX contains original PAT value */
+ pop %rcx
+
+ movq %rcx, %r9 /* Save length */
+ movq %rdi, %r10 /* Save destination address */
+ movq %rsi, %r11 /* Save source address */
+
+ wbinvd /* Invalidate any cache entries */
+
+ /* Copy/encrypt 2MB at a time */
+1:
+ movq %r11, %rsi
+ movq %r8, %rdi
+ movq $PMD_PAGE_SIZE, %rcx
+ rep movsb
+
+ movq %r8, %rsi
+ movq %r10, %rdi
+ movq $PMD_PAGE_SIZE, %rcx
+ rep movsb
+
+ addq $PMD_PAGE_SIZE, %r11
+ addq $PMD_PAGE_SIZE, %r10
+ subq $PMD_PAGE_SIZE, %r9
+ jnz 1b
+
+ /* Restore PAT register */
+ push %rdx
+ movl $MSR_IA32_CR_PAT, %ecx
+ rdmsr
+ pop %rdx
+ wrmsr
+
+ ret
+.Lencrypt_stop:
+#endif /* CONFIG_AMD_MEM_ENCRYPT */
diff --git a/arch/x86/kernel/mem_encrypt_init.c b/arch/x86/kernel/mem_encrypt_init.c
index 388d6fb..7bdd159 100644
--- a/arch/x86/kernel/mem_encrypt_init.c
+++ b/arch/x86/kernel/mem_encrypt_init.c
@@ -13,9 +13,205 @@
#include <linux/linkage.h>
#include <linux/init.h>
#include <linux/mem_encrypt.h>
+#include <linux/mm.h>
+
+#include <asm/sections.h>
+
+#ifdef CONFIG_AMD_MEM_ENCRYPT
+
+extern void sme_encrypt_execute(unsigned long, unsigned long, unsigned long,
+ void *, pgd_t *);
+
+#define PGD_FLAGS _KERNPG_TABLE_NO_ENC
+#define PUD_FLAGS _KERNPG_TABLE_NO_ENC
+#define PMD_FLAGS __PAGE_KERNEL_LARGE_EXEC
+
+static void __init *sme_pgtable_entry(pgd_t *pgd, void *next_page,
+ void *vaddr, pmdval_t pmd_val)
+{
+ pud_t *pud;
+ pmd_t *pmd;
+
+ pgd += pgd_index((unsigned long)vaddr);
+ if (pgd_none(*pgd)) {
+ pud = next_page;
+ memset(pud, 0, sizeof(*pud) * PTRS_PER_PUD);
+ native_set_pgd(pgd,
+ native_make_pgd((unsigned long)pud + PGD_FLAGS));
+ next_page += sizeof(*pud) * PTRS_PER_PUD;
+ } else {
+ pud = (pud_t *)(native_pgd_val(*pgd) & ~PTE_FLAGS_MASK);
+ }
+
+ pud += pud_index((unsigned long)vaddr);
+ if (pud_none(*pud)) {
+ pmd = next_page;
+ memset(pmd, 0, sizeof(*pmd) * PTRS_PER_PMD);
+ native_set_pud(pud,
+ native_make_pud((unsigned long)pmd + PUD_FLAGS));
+ next_page += sizeof(*pmd) * PTRS_PER_PMD;
+ } else {
+ pmd = (pmd_t *)(native_pud_val(*pud) & ~PTE_FLAGS_MASK);
+ }
+
+ pmd += pmd_index((unsigned long)vaddr);
+ if (pmd_none(*pmd) || !pmd_large(*pmd))
+ native_set_pmd(pmd, native_make_pmd(pmd_val));
+
+ return next_page;
+}
+
+static unsigned long __init sme_pgtable_calc(unsigned long start,
+ unsigned long end)
+{
+ unsigned long addr, total;
+
+ total = 0;
+ addr = start;
+ while (addr < end) {
+ unsigned long pgd_end;
+
+ pgd_end = (addr & PGDIR_MASK) + PGDIR_SIZE;
+ if (pgd_end > end)
+ pgd_end = end;
+
+ total += sizeof(pud_t) * PTRS_PER_PUD * 2;
+
+ while (addr < pgd_end) {
+ unsigned long pud_end;
+
+ pud_end = (addr & PUD_MASK) + PUD_SIZE;
+ if (pud_end > end)
+ pud_end = end;
+
+ total += sizeof(pmd_t) * PTRS_PER_PMD * 2;
+
+ addr = pud_end;
+ }
+
+ addr = pgd_end;
+ }
+ total += sizeof(pgd_t) * PTRS_PER_PGD;
+
+ return total;
+}
+#endif /* CONFIG_AMD_MEM_ENCRYPT */
void __init sme_encrypt_kernel(void)
{
+#ifdef CONFIG_AMD_MEM_ENCRYPT
+ pgd_t *pgd;
+ void *workarea, *next_page, *vaddr;
+ unsigned long kern_start, kern_end, kern_len;
+ unsigned long index, paddr, pmd_flags;
+ unsigned long exec_size, full_size;
+
+ /* If SME is not active then no need to prepare */
+ if (!sme_me_mask)
+ return;
+
+ /* Set the workarea to be after the kernel */
+ workarea = (void *)ALIGN(__pa_symbol(_end), PMD_PAGE_SIZE);
+
+ /*
+ * Prepare for encrypting the kernel by building new pagetables with
+ * the necessary attributes needed to encrypt the kernel in place.
+ *
+ * One range of virtual addresses will map the memory occupied
+ * by the kernel as encrypted.
+ *
+ * Another range of virtual addresses will map the memory occupied
+ * by the kernel as un-encrypted and write-protected.
+ *
+ * The use of write-protect attribute will prevent any of the
+ * memory from being cached.
+ */
+
+ /* Physical address gives us the identity mapped virtual address */
+ kern_start = __pa_symbol(_text);
+ kern_end = ALIGN(__pa_symbol(_end), PMD_PAGE_SIZE) - 1;
+ kern_len = kern_end - kern_start + 1;
+
+ /*
+ * Calculate required number of workarea bytes needed:
+ * executable encryption area size:
+ * stack page (PAGE_SIZE)
+ * encryption routine page (PAGE_SIZE)
+ * intermediate copy buffer (PMD_PAGE_SIZE)
+ * pagetable structures for workarea (in case not currently mapped)
+ * pagetable structures for the encryption of the kernel
+ */
+ exec_size = (PAGE_SIZE * 2) + PMD_PAGE_SIZE;
+
+ full_size = exec_size;
+ full_size += ALIGN(exec_size, PMD_PAGE_SIZE) / PMD_PAGE_SIZE *
+ sizeof(pmd_t) * PTRS_PER_PMD;
+ full_size += sme_pgtable_calc(kern_start, kern_end + exec_size);
+
+ next_page = workarea + exec_size;
+
+ /* Make sure the current pagetables have entries for the workarea */
+ pgd = (pgd_t *)native_read_cr3();
+ paddr = (unsigned long)workarea;
+ while (paddr < (unsigned long)workarea + full_size) {
+ vaddr = (void *)paddr;
+ next_page = sme_pgtable_entry(pgd, next_page, vaddr,
+ paddr + PMD_FLAGS);
+
+ paddr += PMD_PAGE_SIZE;
+ }
+ native_write_cr3(native_read_cr3());
+
+ /* Calculate a PGD index to be used for the un-encrypted mapping */
+ index = (pgd_index(kern_end + full_size) + 1) & (PTRS_PER_PGD - 1);
+ index <<= PGDIR_SHIFT;
+
+ /* Set and clear the PGD */
+ pgd = next_page;
+ memset(pgd, 0, sizeof(*pgd) * PTRS_PER_PGD);
+ next_page += sizeof(*pgd) * PTRS_PER_PGD;
+
+ /* Add encrypted (identity) mappings for the kernel */
+ pmd_flags = PMD_FLAGS | _PAGE_ENC;
+ paddr = kern_start;
+ while (paddr < kern_end) {
+ vaddr = (void *)paddr;
+ next_page = sme_pgtable_entry(pgd, next_page, vaddr,
+ paddr + pmd_flags);
+
+ paddr += PMD_PAGE_SIZE;
+ }
+
+ /* Add un-encrypted (non-identity) mappings for the kernel */
+ pmd_flags = (PMD_FLAGS & ~_PAGE_CACHE_MASK) | (_PAGE_PAT | _PAGE_PWT);
+ paddr = kern_start;
+ while (paddr < kern_end) {
+ vaddr = (void *)(paddr + index);
+ next_page = sme_pgtable_entry(pgd, next_page, vaddr,
+ paddr + pmd_flags);
+
+ paddr += PMD_PAGE_SIZE;
+ }
+
+ /* Add the workarea to both mappings */
+ paddr = kern_end + 1;
+ while (paddr < (kern_end + exec_size)) {
+ vaddr = (void *)paddr;
+ next_page = sme_pgtable_entry(pgd, next_page, vaddr,
+ paddr + PMD_FLAGS);
+
+ vaddr = (void *)(paddr + index);
+ next_page = sme_pgtable_entry(pgd, next_page, vaddr,
+ paddr + PMD_FLAGS);
+
+ paddr += PMD_PAGE_SIZE;
+ }
+
+ /* Perform the encryption */
+ sme_encrypt_execute(kern_start, kern_start + index, kern_len,
+ workarea, pgd);
+
+#endif /* CONFIG_AMD_MEM_ENCRYPT */
}
unsigned long __init sme_get_me_mask(void)
next prev parent reply other threads:[~2016-11-10 0:53 UTC|newest]
Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-10 0:34 [RFC PATCH v3 00/20] x86: Secure Memory Encryption (AMD) Tom Lendacky
2016-11-10 0:34 ` [RFC PATCH v3 01/20] x86: Documentation for AMD Secure Memory Encryption (SME) Tom Lendacky
2016-11-10 10:51 ` Borislav Petkov
2016-11-14 17:15 ` Tom Lendacky
2016-11-10 0:34 ` [RFC PATCH v3 02/20] x86: Set the write-protect cache mode for full PAT support Tom Lendacky
2016-11-10 13:14 ` Borislav Petkov
2016-11-11 1:26 ` Kani, Toshimitsu
2016-11-14 16:51 ` Tom Lendacky
2016-11-10 0:34 ` [RFC PATCH v3 03/20] x86: Add the Secure Memory Encryption cpu feature Tom Lendacky
2016-11-11 11:53 ` Borislav Petkov
2016-11-10 0:35 ` [RFC PATCH v3 04/20] x86: Handle reduction in physical address size with SME Tom Lendacky
2016-11-15 12:10 ` Joerg Roedel
2016-11-15 12:14 ` Borislav Petkov
2016-11-15 14:40 ` Tom Lendacky
2016-11-15 15:33 ` Borislav Petkov
2016-11-15 16:06 ` Tom Lendacky
2016-11-15 16:33 ` Borislav Petkov
2016-11-15 17:08 ` Tom Lendacky
2016-11-15 21:22 ` Tom Lendacky
2016-11-15 21:33 ` Borislav Petkov
2016-11-15 22:01 ` Tom Lendacky
2016-11-15 14:32 ` Tom Lendacky
2016-11-10 0:35 ` [RFC PATCH v3 05/20] x86: Add Secure Memory Encryption (SME) support Tom Lendacky
2016-11-10 0:35 ` [RFC PATCH v3 06/20] x86: Add support to enable SME during early boot processing Tom Lendacky
2016-11-14 17:29 ` Borislav Petkov
2016-11-14 18:18 ` Tom Lendacky
2016-11-14 20:01 ` Borislav Petkov
2016-11-10 0:35 ` [RFC PATCH v3 07/20] x86: Provide general kernel support for memory encryption Tom Lendacky
2016-11-10 0:36 ` [RFC PATCH v3 08/20] x86: Add support for early encryption/decryption of memory Tom Lendacky
2016-11-16 10:46 ` Borislav Petkov
2016-11-16 19:22 ` Tom Lendacky
2016-11-10 0:36 ` [RFC PATCH v3 09/20] x86: Insure that boot memory areas are mapped properly Tom Lendacky
2016-11-17 12:20 ` Borislav Petkov
2016-11-19 18:12 ` Tom Lendacky
2016-11-10 0:36 ` [RFC PATCH v3 10/20] Add support to access boot related data in the clear Tom Lendacky
2016-11-11 16:17 ` Kani, Toshimitsu
2016-11-14 16:24 ` Tom Lendacky
2016-11-17 15:55 ` Borislav Petkov
2016-11-19 18:33 ` Tom Lendacky
2016-11-20 23:04 ` Borislav Petkov
2016-12-07 13:19 ` Matt Fleming
2016-12-09 14:26 ` Tom Lendacky
2016-11-10 0:36 ` [RFC PATCH v3 11/20] x86: Add support for changing memory encryption attribute Tom Lendacky
2016-11-17 17:39 ` Borislav Petkov
2016-11-19 18:48 ` Tom Lendacky
2016-11-21 8:27 ` Borislav Petkov
2016-11-10 0:37 ` [RFC PATCH v3 12/20] x86: Decrypt trampoline area if memory encryption is active Tom Lendacky
2016-11-17 18:09 ` Borislav Petkov
2016-11-19 18:50 ` Tom Lendacky
2016-11-10 0:37 ` [RFC PATCH v3 13/20] x86: DMA support for memory encryption Tom Lendacky
2016-11-15 14:39 ` Radim Krčmář
2016-11-15 17:02 ` Tom Lendacky
2016-11-15 18:17 ` Radim Krčmář
2016-11-15 20:33 ` Tom Lendacky
2016-11-15 15:16 ` Michael S. Tsirkin
2016-11-15 18:29 ` Tom Lendacky
2016-11-15 19:16 ` Michael S. Tsirkin
2016-11-22 11:38 ` Borislav Petkov
2016-11-22 15:22 ` Michael S. Tsirkin
2016-11-22 15:41 ` Borislav Petkov
2016-11-22 20:41 ` Michael S. Tsirkin
2016-11-10 0:37 ` [RFC PATCH v3 14/20] iommu/amd: Disable AMD IOMMU if memory encryption is active Tom Lendacky
2016-11-14 16:32 ` Joerg Roedel
2016-11-14 16:48 ` Tom Lendacky
2016-11-10 0:37 ` [RFC PATCH v3 15/20] x86: Check for memory encryption on the APs Tom Lendacky
2016-11-22 19:25 ` Borislav Petkov
2016-11-29 18:00 ` Tom Lendacky
2016-11-10 0:37 ` [RFC PATCH v3 16/20] x86: Do not specify encrypted memory for video mappings Tom Lendacky
2016-11-10 0:38 ` [RFC PATCH v3 17/20] x86/kvm: Enable Secure Memory Encryption of nested page tables Tom Lendacky
2016-11-10 0:38 ` [RFC PATCH v3 18/20] x86: Access the setup data through debugfs un-encrypted Tom Lendacky
2016-11-10 0:38 ` Tom Lendacky [this message]
2016-11-24 12:50 ` [RFC PATCH v3 19/20] x86: Add support to make use of Secure Memory Encryption Borislav Petkov
2016-11-29 18:40 ` Tom Lendacky
2016-11-10 0:38 ` [RFC PATCH v3 20/20] " Tom Lendacky
2016-11-22 18:58 ` Borislav Petkov
2016-11-26 20:47 ` Borislav Petkov
2016-11-29 18:48 ` Tom Lendacky
2016-11-29 19:56 ` Borislav Petkov
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20161110003826.3280.5546.stgit@tlendack-t1.amdoffice.net \
--to=thomas.lendacky@amd.com \
--cc=arnd@arndb.de \
--cc=aryabinin@virtuozzo.com \
--cc=bp@alien8.de \
--cc=corbet@lwn.net \
--cc=dvyukov@google.com \
--cc=glider@google.com \
--cc=hpa@zytor.com \
--cc=iommu@lists.linux-foundation.org \
--cc=joro@8bytes.org \
--cc=kasan-dev@googlegroups.com \
--cc=konrad.wilk@oracle.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-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=luto@kernel.org \
--cc=lwoodman@redhat.com \
--cc=matt@codeblueprint.co.uk \
--cc=mingo@redhat.com \
--cc=pbonzini@redhat.com \
--cc=riel@redhat.com \
--cc=rkrcmar@redhat.com \
--cc=tglx@linutronix.de \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).