This allows us to have CET active much earlier in boot. Signed-off-by: Andrew Cooper <andrew.coop...@citrix.com> Reviewed-by: Jan Beulich <jbeul...@suse.com> --- xen/arch/x86/alternative.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/xen/arch/x86/alternative.c b/xen/arch/x86/alternative.c index 436047abe021..ec24692e9595 100644 --- a/xen/arch/x86/alternative.c +++ b/xen/arch/x86/alternative.c @@ -333,9 +333,13 @@ static int __init cf_check nmi_apply_alternatives( */ if ( !(alt_done & alt_todo) ) { - unsigned long cr0; + unsigned long cr0, cr4; cr0 = read_cr0(); + cr4 = read_cr4(); + + if ( cr4 & X86_CR4_CET ) + write_cr4(cr4 & ~X86_CR4_CET); /* Disable WP to allow patching read-only pages. */ write_cr0(cr0 & ~X86_CR0_WP); @@ -345,6 +349,9 @@ static int __init cf_check nmi_apply_alternatives( write_cr0(cr0); + if ( cr4 & X86_CR4_CET ) + write_cr4(cr4); + alt_done |= alt_todo; } -- 2.11.0