From 7fa0da5373685e7ed249af3fa317ab1e1ba8b0a6 Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Thu, 17 Oct 2024 15:27:31 +0200 Subject: x86/xen: remove hypercall page The hypercall page is no longer needed. It can be removed, as from the Xen perspective it is optional. But, from Linux's perspective, it removes naked RET instructions that escape the speculative protections that Call Depth Tracking and/or Untrain Ret are trying to achieve. This is part of XSA-466 / CVE-2024-53241. Reported-by: Andrew Cooper Signed-off-by: Juergen Gross Reviewed-by: Andrew Cooper Reviewed-by: Jan Beulich --- arch/x86/kernel/callthunks.c | 5 ----- 1 file changed, 5 deletions(-) (limited to 'arch/x86/kernel/callthunks.c') diff --git a/arch/x86/kernel/callthunks.c b/arch/x86/kernel/callthunks.c index 465647456753..f17d16607882 100644 --- a/arch/x86/kernel/callthunks.c +++ b/arch/x86/kernel/callthunks.c @@ -142,11 +142,6 @@ static bool skip_addr(void *dest) if (dest >= (void *)relocate_kernel && dest < (void*)relocate_kernel + KEXEC_CONTROL_CODE_MAX_SIZE) return true; -#endif -#ifdef CONFIG_XEN - if (dest >= (void *)hypercall_page && - dest < (void*)hypercall_page + PAGE_SIZE) - return true; #endif return false; } -- cgit v1.2.3