On Thu, Aug 02, 2012 at 05:14:02PM -0300, Marcelo Tosatti wrote: > On Tue, Jul 31, 2012 at 04:19:02PM +0530, Nikunj A. Dadhania wrote: > > From: Nikunj A. Dadhania <[email protected]> > > > > PV-Flush guest would indicate to flush on enter, flush the TLB before > > entering and exiting the guest. > > > > Signed-off-by: Nikunj A. Dadhania <[email protected]> > > --- > > arch/x86/kvm/x86.c | 23 +++++++---------------- > > 1 files changed, 7 insertions(+), 16 deletions(-) > > > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > > index 580abcf..a67e971 100644 > > --- a/arch/x86/kvm/x86.c > > +++ b/arch/x86/kvm/x86.c > > @@ -1557,20 +1557,9 @@ static void record_steal_time(struct kvm_vcpu *vcpu) > > &vcpu->arch.st.steal, sizeof(struct kvm_steal_time)); > > } > > > > -static void kvm_set_atomic(u64 *addr, u64 old, u64 new) > > -{ > > - int loop = 1000000; > > - while (1) { > > - if (cmpxchg(addr, old, new) == old) > > - break; > > - loop--; > > - if (!loop) { > > - pr_info("atomic cur: %lx old: %lx new: %lx\n", > > - *addr, old, new); > > - break; > > - } > > - } > > -} > > +#define VS_NOT_IN_GUEST (0) > > +#define VS_IN_GUEST (1 << KVM_VCPU_STATE_IN_GUEST_MODE) > > +#define VS_SHOULD_FLUSH (1 << KVM_VCPU_STATE_SHOULD_FLUSH) > > > > static void kvm_set_vcpu_state(struct kvm_vcpu *vcpu) > > { > > @@ -1584,7 +1573,8 @@ static void kvm_set_vcpu_state(struct kvm_vcpu *vcpu) > > kaddr = kmap_atomic(vcpu->arch.v_state.vs_page); > > kaddr += vcpu->arch.v_state.vs_offset; > > vs = kaddr; > > - kvm_set_atomic(&vs->state, 0, 1 << KVM_VCPU_STATE_IN_GUEST_MODE); > > + if (xchg(&vs->state, VS_IN_GUEST) == VS_SHOULD_FLUSH) > > + kvm_x86_ops->tlb_flush(vcpu); > > kunmap_atomic(kaddr); > > } > > > > @@ -1600,7 +1590,8 @@ static void kvm_clear_vcpu_state(struct kvm_vcpu > > *vcpu) > > kaddr = kmap_atomic(vcpu->arch.v_state.vs_page); > > kaddr += vcpu->arch.v_state.vs_offset; > > vs = kaddr; > > - kvm_set_atomic(&vs->state, 1 << KVM_VCPU_STATE_IN_GUEST_MODE, 0); > > + if (xchg(&vs->state, VS_NOT_IN_GUEST) == VS_SHOULD_FLUSH) > > + kvm_x86_ops->tlb_flush(vcpu); > > kunmap_atomic(kaddr); > > } > > Nevermind the early comment (the other comments on that message are > valid).
Ah, so the pseucode mentions flush-on-exit because we can be clearing the flag on xchg. Setting KVM_REQ_TLB_FLUSH instead should be enough (please verify). -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
