On 8/9/2021 9:06 AM, Borislav Petkov wrote:
On Thu, Jul 22, 2021 at 01:51:51PM -0700, Yu-cheng Yu wrote:
/*
* Some CPU features depend on higher CPUID levels, which may not always
* be available due to CPUID level capping or broken virtualization
@@ -1249,6 +1257,11 @@ static void __init cpu_parse_early_param(void)
if (cmdline_find_option_bool(boot_command_line, "noxsaves"))
setup_clear_cpu_cap(X86_FEATURE_XSAVES);
+ if (cmdline_find_option_bool(boot_command_line, "no_user_shstk"))
+ setup_clear_cpu_cap(X86_FEATURE_SHSTK);
+ if (cmdline_find_option_bool(boot_command_line, "no_user_ibt"))
+ setup_clear_cpu_cap(X86_FEATURE_IBT);
Patch 1 says:
"Disabling shadow stack also disables IBT."
I don't see that here.
We have X86_FEATURE_IBT dependent on X86_FEATURE_SHSTK (patch #3).
