diff options
Diffstat (limited to 'arch/x86/kernel/fpu/xstate.c')
| -rw-r--r-- | arch/x86/kernel/fpu/xstate.c | 28 |
1 files changed, 19 insertions, 9 deletions
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index fa71af643025..a68213ed5be6 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -228,13 +228,14 @@ void fpu__init_cpu_xstate(void) * states can be set here. */ xsetbv(XCR_XFEATURE_ENABLED_MASK, xfeatures_mask_user()); + + /* + * MSR_IA32_XSS sets supervisor states managed by XSAVES. + */ + if (boot_cpu_has(X86_FEATURE_XSAVES)) + wrmsrl(MSR_IA32_XSS, xfeatures_mask_supervisor()); } -/* - * Note that in the future we will likely need a pair of - * functions here: one for user xstates and the other for - * system xstates. For now, they are the same. - */ static bool xfeature_enabled(enum xfeature xfeature) { return xfeatures_mask_all & BIT_ULL(xfeature); @@ -625,9 +626,6 @@ static void do_extra_xstate_size_checks(void) * the size of the *user* states. If we use it to size a buffer * that we use 'XSAVES' on, we could potentially overflow the * buffer because 'XSAVES' saves system states too. - * - * Note that we do not currently set any bits on IA32_XSS so - * 'XCR0 | IA32_XSS == XCR0' for now. */ static unsigned int __init get_xsaves_size(void) { @@ -750,7 +748,12 @@ void __init fpu__init_system_xstate(void) cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx); xfeatures_mask_all = eax + ((u64)edx << 32); - /* Place supervisor features in xfeatures_mask_all here */ + /* + * Find supervisor xstates supported by the processor. + */ + cpuid_count(XSTATE_CPUID, 1, &eax, &ebx, &ecx, &edx); + xfeatures_mask_all |= ecx + ((u64)edx << 32); + if ((xfeatures_mask_user() & XFEATURE_MASK_FPSSE) != XFEATURE_MASK_FPSSE) { /* * This indicates that something really unexpected happened @@ -810,6 +813,13 @@ void fpu__resume_cpu(void) */ if (boot_cpu_has(X86_FEATURE_XSAVE)) xsetbv(XCR_XFEATURE_ENABLED_MASK, xfeatures_mask_user()); + + /* + * Restore IA32_XSS. The same CPUID bit enumerates support + * of XSAVES and MSR_IA32_XSS. + */ + if (boot_cpu_has(X86_FEATURE_XSAVES)) + wrmsrl(MSR_IA32_XSS, xfeatures_mask_supervisor()); } /* |