[PATCH v4 70/75] x86/head/64: Don't call verify_cpu() on starting APs
From: Joerg Roedel <joro@8bytes.org>
Date: 2020-07-14 12:12:07
Also in:
kvm, lkml
Subsystem:
the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
From: Joerg Roedel <redacted> The APs are not ready to handle exceptions when verify_cpu() is called in secondary_startup_64. Signed-off-by: Joerg Roedel <redacted> --- arch/x86/include/asm/realmode.h | 1 + arch/x86/kernel/head_64.S | 1 + arch/x86/realmode/init.c | 6 ++++++ 3 files changed, 8 insertions(+)
diff --git a/arch/x86/include/asm/realmode.h b/arch/x86/include/asm/realmode.h
index 6590394af309..5c97807c38a4 100644
--- a/arch/x86/include/asm/realmode.h
+++ b/arch/x86/include/asm/realmode.h@@ -69,6 +69,7 @@ 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 5b577d6bce7a..8b43ed0592e8 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S@@ -165,6 +165,7 @@ SYM_CODE_START(secondary_startup_64) /* Sanitize CPU configuration */ call verify_cpu +SYM_INNER_LABEL(secondary_startup_64_no_verify, SYM_L_GLOBAL) /* * 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 61a52b925d15..df701f87ddef 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 update SEV-ES AP Jump Table"); }
--
2.27.0