On Wed, Jan 02, 2019 at 11:19:34AM -0800, Jim Mattson wrote: Thanks Sean and Jim for your valuable comments, I'll consolidate them in next release! > On Wed, Jan 2, 2019 at 10:24 AM Sean Christopherson > <sean.j.christopherson@xxxxxxxxx> wrote: > > > > On Wed, Dec 26, 2018 at 04:15:29PM +0800, Yang Weijiang wrote: > > > For kvm Guest OS, right now, only bit 11(user mode CET) and bit 12 > > > (supervisor CET) are supported in XSS MSR, if other bits are being set, > > > the write to XSS will be skipped. > > > > > > Signed-off-by: Zhang Yi Z <yi.z.zhang@xxxxxxxxxxxxxxx> > > > Signed-off-by: Yang Weijiang <weijiang.yang@xxxxxxxxx> > > > --- > > > arch/x86/kvm/vmx.c | 11 ++++++++--- > > > 1 file changed, 8 insertions(+), 3 deletions(-) > > > > > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > > > index fa2db6248404..5739ab393b90 100644 > > > --- a/arch/x86/kvm/vmx.c > > > +++ b/arch/x86/kvm/vmx.c > > > @@ -47,6 +47,7 @@ > > > #include <asm/virtext.h> > > > #include <asm/mce.h> > > > #include <asm/fpu/internal.h> > > > +#include <asm/fpu/types.h> > > > #include <asm/perf_event.h> > > > #include <asm/debugreg.h> > > > #include <asm/kexec.h> > > > @@ -4323,12 +4324,16 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) > > > case MSR_IA32_XSS: > > > if (!vmx_xsaves_supported()) > > > return 1; > > > + > > > /* > > > - * The only supported bit as of Skylake is bit 8, but > > > - * it is not supported on KVM. > > > + * Right now, only support XSS_CET_U[bit 11] and > > > + * XSS_CET_S[bit 12] in MSR_IA32_XSS. > > > */ > > > - if (data != 0) > > > + > > > + if (data & ~(XFEATURE_MASK_SHSTK_USER > > > + | XFEATURE_MASK_SHSTK_KERNEL)) > > > > New lines are usually after the operator, e.g.: > > > > if (data & ~(XFEATURE_MASK_SHSTK_USER | > > XFEATURE_MASK_SHSTK_KERNEL)) > > > > And doesn't this flow need to check that the bits are actually supported? > Supported on the host and in the guest.
