diff options
| author | Joerg Roedel <jroedel@suse.de> | 2020-09-08 14:38:16 +0200 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2020-09-09 11:32:27 +0200 |
| commit | 1aa9aa8ee517e0443b06e816a4fd2d15f2113615 (patch) | |
| tree | ad1f72353003e2342bc9be7a265fe6b9d64fe36f /arch/x86/kernel/head_64.S | |
| parent | 74d8d9d531b4cc945a9f75aa2fc21d99ca5a9fe3 (diff) | |
x86/sev-es: Setup GHCB-based boot #VC handler
Add the infrastructure to handle #VC exceptions when the kernel runs on
virtual addresses and has mapped a GHCB. This handler will be used until
the runtime #VC handler takes over.
Since the handler runs very early, disable instrumentation for sev-es.c.
[ bp: Make vc_ghcb_invalidate() __always_inline so that it can be
inlined in noinstr functions like __sev_es_nmi_complete(). ]
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200908123816.GB3764@8bytes.org
Diffstat (limited to 'arch/x86/kernel/head_64.S')
| -rw-r--r-- | arch/x86/kernel/head_64.S | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index 6e68bca64ae4..1a71d0d4d575 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -281,11 +281,47 @@ SYM_CODE_START(start_cpu0) SYM_CODE_END(start_cpu0) #endif +#ifdef CONFIG_AMD_MEM_ENCRYPT +/* + * VC Exception handler used during early boot when running on kernel + * addresses, but before the switch to the idt_table can be made. + * The early_idt_handler_array can't be used here because it calls into a lot + * of __init code and this handler is also used during CPU offlining/onlining. + * Therefore this handler ends up in the .text section so that it stays around + * when .init.text is freed. + */ +SYM_CODE_START_NOALIGN(vc_boot_ghcb) + UNWIND_HINT_IRET_REGS offset=8 + + /* Build pt_regs */ + PUSH_AND_CLEAR_REGS + + /* Call C handler */ + movq %rsp, %rdi + movq ORIG_RAX(%rsp), %rsi + movq initial_vc_handler(%rip), %rax + ANNOTATE_RETPOLINE_SAFE + call *%rax + + /* Unwind pt_regs */ + POP_REGS + + /* Remove Error Code */ + addq $8, %rsp + + /* Pure iret required here - don't use INTERRUPT_RETURN */ + iretq +SYM_CODE_END(vc_boot_ghcb) +#endif + /* Both SMP bootup and ACPI suspend change these variables */ __REFDATA .balign 8 SYM_DATA(initial_code, .quad x86_64_start_kernel) SYM_DATA(initial_gs, .quad INIT_PER_CPU_VAR(fixed_percpu_data)) +#ifdef CONFIG_AMD_MEM_ENCRYPT +SYM_DATA(initial_vc_handler, .quad handle_vc_boot_ghcb) +#endif /* * The SIZEOF_PTREGS gap is a convention which helps the in-kernel unwinder |