On 08/10/2017 04:35, Wanpeng Li wrote: > From: Wanpeng Li <wanpeng.li@xxxxxxxxxxx> > > SDM section 2.6 mentioned: > > After reset, all bits (except bit 0) in XCR0 are cleared to zero; XCR0[0] is set to 1. > > This patch sets XCRO to the 0x1 after vCPU reset. > > Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx> > Cc: Radim Krčmář <rkrcmar@xxxxxxxxxx> > Signed-off-by: Wanpeng Li <wanpeng.li@xxxxxxxxxxx> > --- > arch/x86/kvm/x86.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index b0d2915..c784cd6 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -7816,6 +7816,8 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) > vcpu->arch.regs_avail = ~0; > vcpu->arch.regs_dirty = ~0; > > + vcpu->arch.xcr0 = XFEATURE_MASK_FP; XCR0 is unchanged by INIT. There are many other registers that are zeroed by RESET by not INIT; KVM pretty much relies on userspace doing that. On the other hand, it's useful to zero here those registers that are zeroed by INIT as well: - XSS - BNDCFGU, BND0-BND3, BNDCFGS (BNDCFGS probably would go in vmx_vcpu_reset, the others are in vcpu->arch.guest_fpu.state.xsave). > kvm_x86_ops->vcpu_reset(vcpu, init_event); > } > >
