From: Joerg Roedel <jroedel@xxxxxxx>
Disable the exception handling before booting the kernel to make sure
any exceptions that happen during early kernel boot are not directed to
the pre-decompression code.
Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
---
arch/x86/boot/compressed/idt_64.c | 14 ++++++++++++++
arch/x86/boot/compressed/misc.c | 7 ++-----
arch/x86/boot/compressed/misc.h | 6 ++++++
3 files changed, 22 insertions(+), 5 deletions(-)
diff --git a/arch/x86/boot/compressed/idt_64.c b/arch/x86/boot/compressed/idt_64.c
index 804a502ee0d2..9b93567d663a 100644
--- a/arch/x86/boot/compressed/idt_64.c
+++ b/arch/x86/boot/compressed/idt_64.c
@@ -52,3 +52,17 @@ void load_stage2_idt(void)
load_boot_idt(&boot_idt_desc);
}
+
+void cleanup_exception_handling(void)
+{
+ /*
+ * Flush GHCB from cache and map it encrypted again when running as
+ * SEV-ES guest.
+ */
+ sev_es_shutdown_ghcb();
+
+ /* Set a null-idt, disabling #PF and #VC handling */
+ boot_idt_desc.size = 0;
+ boot_idt_desc.address = 0;
+ load_boot_idt(&boot_idt_desc);
+}
diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
index 267e7f93050e..cc9fd0e8766a 100644
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -443,11 +443,8 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
handle_relocations(output, output_len, virt_addr);
debug_putstr("done.\nBooting the kernel.\n");
- /*
- * Flush GHCB from cache and map it encrypted again when running as
- * SEV-ES guest.
- */
- sev_es_shutdown_ghcb();
+ /* Disable exception handling before booting the kernel */
+ cleanup_exception_handling();
return output;
}
diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index 901ea5ebec22..e5612f035498 100644
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -155,6 +155,12 @@ extern pteval_t __default_kernel_pte_mask;
extern gate_desc boot_idt[BOOT_IDT_ENTRIES];
extern struct desc_ptr boot_idt_desc;
+#ifdef CONFIG_X86_64
+void cleanup_exception_handling(void);
+#else
+static inline void cleanup_exception_handling(void) { }
+#endif
+
/* IDT Entry Points */
void boot_page_fault(void);
void boot_stage1_vc(void);
--
2.30.1
