diff options
| author | Joerg Roedel <jroedel@suse.de> | 2020-09-07 15:16:09 +0200 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2020-09-09 11:33:20 +0200 |
| commit | 3ecacdbd23956a549d93023f86adc87b4a9d6520 (patch) | |
| tree | b8b381ffd9cadf91cd0d4875cb53ec81c94a61ea | |
| parent | 520d030852b4c9babfce9a79d8b5320b6b5545e6 (diff) | |
x86/head/64: Don't call verify_cpu() on starting APs
The APs are not ready to handle exceptions when verify_cpu() is called
in secondary_startup_64().
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/20200907131613.12703-69-joro@8bytes.org
| -rw-r--r-- | arch/x86/include/asm/realmode.h | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/head_64.S | 12 | ||||
| -rw-r--r-- | arch/x86/realmode/init.c | 6 |
3 files changed, 19 insertions, 0 deletions
diff --git a/arch/x86/include/asm/realmode.h b/arch/x86/include/asm/realmode.h index 4d4d853f6841..5db5d083c873 100644 --- a/arch/x86/include/asm/realmode.h +++ b/arch/x86/include/asm/realmode.h @@ -72,6 +72,7 @@ extern unsigned char startup_32_smp[]; extern unsigned char boot_gdt[]; #else extern unsigned char secondary_startup_64[]; +extern unsigned char secondary_startup_64_no_verify[]; #endif static inline size_t real_mode_size_needed(void) diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index 1a71d0d4d575..7eb2a1c87969 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -126,6 +126,18 @@ SYM_CODE_START(secondary_startup_64) call verify_cpu /* + * The secondary_startup_64_no_verify entry point is only used by + * SEV-ES guests. In those guests the call to verify_cpu() would cause + * #VC exceptions which can not be handled at this stage of secondary + * CPU bringup. + * + * All non SEV-ES systems, especially Intel systems, need to execute + * verify_cpu() above to make sure NX is enabled. + */ +SYM_INNER_LABEL(secondary_startup_64_no_verify, SYM_L_GLOBAL) + UNWIND_HINT_EMPTY + + /* * Retrieve the modifier (SME encryption mask if SME is active) to be * added to the initial pgdir entry that will be programmed into CR3. */ diff --git a/arch/x86/realmode/init.c b/arch/x86/realmode/init.c index 3fb9b60be07a..22fda7d99159 100644 --- a/arch/x86/realmode/init.c +++ b/arch/x86/realmode/init.c @@ -46,6 +46,12 @@ static void sme_sev_setup_real_mode(struct trampoline_header *th) th->flags |= TH_FLAGS_SME_ACTIVE; if (sev_es_active()) { + /* + * Skip the call to verify_cpu() in secondary_startup_64 as it + * will cause #VC exceptions when the AP can't handle them yet. + */ + th->start = (u64) secondary_startup_64_no_verify; + if (sev_es_setup_ap_jump_table(real_mode_header)) panic("Failed to get/update SEV-ES AP Jump Table"); } |