From 6229ad278ca74acdbc8bd3a3d469322a3de91039 Mon Sep 17 00:00:00 2001 From: Fenghua Yu Date: Thu, 29 May 2014 11:12:30 -0700 Subject: x86/xsaves: Detect xsaves/xrstors feature Detect the xsaveopt, xsavec, xgetbv, and xsaves features in processor extended state enumberation sub-leaf (eax=0x0d, ecx=1): Bit 00: XSAVEOPT is available Bit 01: Supports XSAVEC and the compacted form of XRSTOR if set Bit 02: Supports XGETBV with ECX = 1 if set Bit 03: Supports XSAVES/XRSTORS and IA32_XSS if set The above features are defined in the new word 10 in cpu features. The IA32_XSS MSR (index DA0H) contains a state-component bitmap that specifies the state components that software has enabled xsaves and xrstors to manage. If the bit corresponding to a state component is clear in XCR0 | IA32_XSS, xsaves and xrstors will not operate on that state component, regardless of the value of the instruction mask. Signed-off-by: Fenghua Yu Link: http://lkml.kernel.org/r/1401387164-43416-3-git-send-email-fenghua.yu@intel.com Signed-off-by: H. Peter Anvin --- arch/x86/kernel/cpu/common.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'arch/x86/kernel/cpu/common.c') diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index a135239badb7..e7c4b979d504 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -632,6 +632,15 @@ void get_cpu_cap(struct cpuinfo_x86 *c) c->x86_capability[9] = ebx; } + /* Extended state features: level 0x0000000d */ + if (c->cpuid_level >= 0x0000000d) { + u32 eax, ebx, ecx, edx; + + cpuid_count(0x0000000d, 1, &eax, &ebx, &ecx, &edx); + + c->x86_capability[10] = eax; + } + /* AMD-defined flags: level 0x80000001 */ xlvl = cpuid_eax(0x80000000); c->extended_cpuid_level = xlvl; -- cgit v1.2.3