diff options
| author | Jiri Kosina <jkosina@suse.cz> | 2018-01-02 14:19:49 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-01-05 15:44:26 +0100 |
| commit | e4ba212ec64109b17fb8653ccfa2ed2c6e3e8217 (patch) | |
| tree | e55c525d53c118912bab67e116c8cfa6859dc9db | |
| parent | 750fb627d764eb66430c36961b94ab0002694c02 (diff) | |
kaiser: disabled on Xen PV
Kaiser cannot be used on paravirtualized MMUs (namely reading and writing CR3).
This does not work with KAISER as the CR3 switch from and to user space PGD
would require to map the whole XEN_PV machinery into both.
More importantly, enabling KAISER on Xen PV doesn't make too much sense, as PV
guests use distinct %cr3 values for kernel and user already.
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/x86/mm/kaiser.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/x86/mm/kaiser.c b/arch/x86/mm/kaiser.c index 9d6b7517fca5..6a2e00a80105 100644 --- a/arch/x86/mm/kaiser.c +++ b/arch/x86/mm/kaiser.c @@ -264,6 +264,9 @@ void __init kaiser_check_boottime_disable(void) char arg[5]; int ret; + if (boot_cpu_has(X86_FEATURE_XENPV)) + goto silent_disable; + ret = cmdline_find_option(boot_command_line, "pti", arg, sizeof(arg)); if (ret > 0) { if (!strncmp(arg, "on", 2)) @@ -291,6 +294,8 @@ enable: disable: pr_info("Kernel/User page tables isolation: disabled\n"); + +silent_disable: kaiser_enabled = 0; setup_clear_cpu_cap(X86_FEATURE_KAISER); } |