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linux-next/arch/x86/boot/compressed/misc.h
Tom Lendacky 1958b5fc40 x86/boot: Add early boot support when running with SEV active
Early in the boot process, add checks to determine if the kernel is
running with Secure Encrypted Virtualization (SEV) active.

Checking for SEV requires checking that the kernel is running under a
hypervisor (CPUID 0x00000001, bit 31), that the SEV feature is available
(CPUID 0x8000001f, bit 1) and then checking a non-interceptable SEV MSR
(0xc0010131, bit 0).

This check is required so that during early compressed kernel booting the
pagetables (both the boot pagetables and KASLR pagetables (if enabled) are
updated to include the encryption mask so that when the kernel is
decompressed into encrypted memory, it can boot properly.

After the kernel is decompressed and continues booting the same logic is
used to check if SEV is active and set a flag indicating so.  This allows
to distinguish between SME and SEV, each of which have unique differences
in how certain things are handled: e.g. DMA (always bounce buffered with
SEV) or EFI tables (always access decrypted with SME).

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Tested-by: Borislav Petkov <bp@suse.de>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: kvm@vger.kernel.org
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Link: https://lkml.kernel.org/r/20171020143059.3291-13-brijesh.singh@amd.com
2017-11-07 15:35:58 +01:00

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2.7 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef BOOT_COMPRESSED_MISC_H
#define BOOT_COMPRESSED_MISC_H
/*
* Special hack: we have to be careful, because no indirections are allowed here,
* and paravirt_ops is a kind of one. As it will only run in baremetal anyway,
* we just keep it from happening. (This list needs to be extended when new
* paravirt and debugging variants are added.)
*/
#undef CONFIG_PARAVIRT
#undef CONFIG_PARAVIRT_SPINLOCKS
#undef CONFIG_KASAN
#include <linux/linkage.h>
#include <linux/screen_info.h>
#include <linux/elf.h>
#include <linux/io.h>
#include <asm/page.h>
#include <asm/boot.h>
#include <asm/bootparam.h>
#include <asm/bootparam_utils.h>
#define BOOT_BOOT_H
#include "../ctype.h"
#ifdef CONFIG_X86_64
#define memptr long
#else
#define memptr unsigned
#endif
/* misc.c */
extern memptr free_mem_ptr;
extern memptr free_mem_end_ptr;
extern struct boot_params *boot_params;
void __putstr(const char *s);
void __puthex(unsigned long value);
#define error_putstr(__x) __putstr(__x)
#define error_puthex(__x) __puthex(__x)
#ifdef CONFIG_X86_VERBOSE_BOOTUP
#define debug_putstr(__x) __putstr(__x)
#define debug_puthex(__x) __puthex(__x)
#define debug_putaddr(__x) { \
debug_putstr(#__x ": 0x"); \
debug_puthex((unsigned long)(__x)); \
debug_putstr("\n"); \
}
#else
static inline void debug_putstr(const char *s)
{ }
static inline void debug_puthex(const char *s)
{ }
#define debug_putaddr(x) /* */
#endif
#if CONFIG_EARLY_PRINTK || CONFIG_RANDOMIZE_BASE
/* cmdline.c */
int cmdline_find_option(const char *option, char *buffer, int bufsize);
int cmdline_find_option_bool(const char *option);
#endif
#if CONFIG_RANDOMIZE_BASE
/* kaslr.c */
void choose_random_location(unsigned long input,
unsigned long input_size,
unsigned long *output,
unsigned long output_size,
unsigned long *virt_addr);
/* cpuflags.c */
bool has_cpuflag(int flag);
#else
static inline void choose_random_location(unsigned long input,
unsigned long input_size,
unsigned long *output,
unsigned long output_size,
unsigned long *virt_addr)
{
}
#endif
#ifdef CONFIG_X86_64
void initialize_identity_maps(void);
void add_identity_map(unsigned long start, unsigned long size);
void finalize_identity_maps(void);
extern unsigned char _pgtable[];
#else
static inline void initialize_identity_maps(void)
{ }
static inline void add_identity_map(unsigned long start, unsigned long size)
{ }
static inline void finalize_identity_maps(void)
{ }
#endif
#ifdef CONFIG_EARLY_PRINTK
/* early_serial_console.c */
extern int early_serial_base;
void console_init(void);
#else
static const int early_serial_base;
static inline void console_init(void)
{ }
#endif
unsigned long get_sev_encryption_mask(void);
#endif