2 files changed, 23 insertions, 0 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 30a8ad0dae53..0ebd95252c3f 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2124,6 +2124,21 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                         and restore using xsave. The kernel will fallback to
                         enabling legacy floating-point and sse state.
 
+        noxsaveopt      [X86] Disables xsaveopt used in saving x86 extended
+                        register states. The kernel will fall back to use
+                        xsave to save the states. By using this parameter,
+                        performance of saving the states is degraded because
+                        xsave doesn't support modified optimization while
+                        xsaveopt supports it on xsaveopt enabled systems.
+
+        noxsaves        [X86] Disables xsaves and xrstors used in saving and
+                        restoring x86 extended register state in compacted
+                        form of xsave area. The kernel will fall back to use
+                        xsaveopt and xrstor to save and restore the states
+                        in standard form of xsave area. By using this
+                        parameter, xsave area per process might occupy more
+                        memory on xsaves enabled systems.
+
         eagerfpu=       [X86]
                         on      enable eager fpu restore
                         off     disable eager fpu restore
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index e7c4b979d504..cdc95852532d 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -146,6 +146,7 @@ static int __init x86_xsave_setup(char *s)
 {
         setup_clear_cpu_cap(X86_FEATURE_XSAVE);
         setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT);
+        setup_clear_cpu_cap(X86_FEATURE_XSAVES);
         setup_clear_cpu_cap(X86_FEATURE_AVX);
         setup_clear_cpu_cap(X86_FEATURE_AVX2);
         return 1;
@@ -159,6 +160,13 @@ static int __init x86_xsaveopt_setup(char *s)
 }
 __setup("noxsaveopt", x86_xsaveopt_setup);
 
+static int __init x86_xsaves_setup(char *s)
+{
+        setup_clear_cpu_cap(X86_FEATURE_XSAVES);
+        return 1;
+}
+__setup("noxsaves", x86_xsaves_setup);
+
 #ifdef CONFIG_X86_32
 static int cachesize_override = -1;
 static int disable_x86_serial_nr = 1;