diff options
Diffstat (limited to 'arch/x86/kernel/fpu/xstate.c')
| -rw-r--r-- | arch/x86/kernel/fpu/xstate.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 603edeb7b913..77739b0a56d5 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -137,6 +137,15 @@ void fpu__init_cpu_xstate(void) cr4_set_bits(X86_CR4_OSXSAVE); /* + * Must happen after CR4 setup and before xsetbv() to allow KVM + * lazy passthrough. Write independent of the dynamic state static + * key as that does not work on the boot CPU. This also ensures + * that any stale state is wiped out from XFD. + */ + if (cpu_feature_enabled(X86_FEATURE_XFD)) + wrmsrl(MSR_IA32_XFD, init_fpstate.xfd); + + /* * XCR_XFEATURE_ENABLED_MASK (aka. XCR0) sets user features * managed by XSAVE{C, OPT, S} and XRSTOR{S}. Only XSAVE user * states can be set here. @@ -875,6 +884,9 @@ void fpu__resume_cpu(void) wrmsrl(MSR_IA32_XSS, xfeatures_mask_supervisor() | xfeatures_mask_independent()); } + + if (fpu_state_size_dynamic()) + wrmsrl(MSR_IA32_XFD, current->thread.fpu.fpstate->xfd); } /* |