From: Fenghua Yu <fenghua...@intel.com>
Add kernel parameter noxsaves to disable xsaves/xrstors feature.
Add kernel parameter noxsaveopt in doc.
Signed-off-by: Fenghua Yu <fenghua...@intel.com>
---
Documentation/kernel-parameters.txt | 9 +++++++++
arch/x86/kernel/cpu/common.c | 8 ++++++++
2 files changed, 17 insertions(+)
diff --git a/Documentation/kernel-parameters.txt
b/Documentation/kernel-parameters.txt
index 4384217..8541752 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2124,6 +2124,15 @@ 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 x86 extended register state context
+ switch using xsaveopt. The kernel wil fallback to use
+ not optimized xsave to do context switch.
+
+ noxsaves [X86] Disables x86 extended register state context
+ switch and save/restore compacted formated xsave
+ area using xsaves. Then the kernel uses standard
+ xsave area for xstate.
+
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 a135239..409f47c 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;
--
1.8.1.2
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