[RFC PATCH 02/12] x86/kexec/64: Forbid kexec when running as an SEV-ES guest

[Joerg Roedel]

From: Joerg Roedel <jroedel@xxxxxxx>

For now, kexec is not supported when running as an SEV-ES guest. Doing
so requires additional hypervisor support and special code to hand
over the CPUs to the new kernel in a safe way.

Until this is implemented, do not support kexec in SEV-ES guests.

Cc: stable@xxxxxxxxxxxxxxx # v5.10+
Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
---
 arch/x86/kernel/machine_kexec_64.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
index c078b0d3ab0e..f902cc9cc634 100644
--- a/arch/x86/kernel/machine_kexec_64.c
+++ b/arch/x86/kernel/machine_kexec_64.c
@@ -620,3 +620,11 @@ void arch_kexec_pre_free_pages(void *vaddr, unsigned int pages)
 	 */
 	set_memory_encrypted((unsigned long)vaddr, pages);
 }
+
+/*
+ * Kexec is not supported in SEV-ES guests yet
+ */
+bool arch_kexec_supported(void)
+{
+	return !sev_es_active();
+}
-- 
2.31.1