Don't bother zeroing out MPX state in the guest's FPU on a reset event, the guest's FPU is always zero allocated and there is no path between kvm_arch_vcpu_create() and kvm_arch_vcpu_setup() that can lead to guest MPX state being modified. No functional change intended. Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx> --- arch/x86/kvm/x86.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 854ae27bb021..e6f4174f55cd 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -9194,15 +9194,14 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) kvm_async_pf_hash_reset(vcpu); vcpu->arch.apf.halted = false; - if (kvm_mpx_supported()) { + if (kvm_mpx_supported() && init_event) { void *mpx_state_buffer; /* - * To avoid have the INIT path from kvm_apic_has_events() that be - * called with loaded FPU and does not let userspace fix the state. + * Temporarily flush the guest's FPU to memory so that zeroing + * out the MPX areas is done using up-to-date state. */ - if (init_event) - kvm_put_guest_fpu(vcpu); + kvm_put_guest_fpu(vcpu); mpx_state_buffer = get_xsave_addr(&vcpu->arch.guest_fpu->state.xsave, XFEATURE_BNDREGS); if (mpx_state_buffer) @@ -9211,8 +9210,7 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) XFEATURE_BNDCSR); if (mpx_state_buffer) memset(mpx_state_buffer, 0, sizeof(struct mpx_bndcsr)); - if (init_event) - kvm_load_guest_fpu(vcpu); + kvm_load_guest_fpu(vcpu); } if (!init_event) { -- 2.24.0