| Message ID | 1345683830-10768-1-git-send-email-scottwood@freescale.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 23.08.2012, at 03:03, Scott Wood wrote: > Avoid a race as described in the code comment. > > Also remove a related smp_wmb() from booke's kvmppc_prepare_to_enter(). > I can't see any reason for it, and the book3s_pr version doesn't have it. > > Signed-off-by: Scott Wood <scottwood@freescale.com> Does this patch address your comments on the previous pull request? Applied to kvm-ppc-next. Alex > --- > arch/powerpc/kvm/booke.c | 1 - > arch/powerpc/kvm/powerpc.c | 14 +++++++++----- > 2 files changed, 9 insertions(+), 6 deletions(-) > > diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c > index 5f0476a..88711f8 100644 > --- a/arch/powerpc/kvm/booke.c > +++ b/arch/powerpc/kvm/booke.c > @@ -674,7 +674,6 @@ int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu) > > out: > vcpu->mode = OUTSIDE_GUEST_MODE; > - smp_wmb(); > return ret; > } > > diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c > index 32d217c..3d460a0 100644 > --- a/arch/powerpc/kvm/powerpc.c > +++ b/arch/powerpc/kvm/powerpc.c > @@ -78,7 +78,16 @@ int kvmppc_prepare_to_enter(struct kvm_vcpu *vcpu) > break; > } > > + vcpu->mode = IN_GUEST_MODE; > + > + /* > + * Reading vcpu->requests must happen after setting vcpu->mode, > + * so we don't miss a request because the requester sees > + * OUTSIDE_GUEST_MODE and assumes we'll be checking requests > + * before next entering the guest (and thus doesn't IPI). > + */ > smp_mb(); > + > if (vcpu->requests) { > /* Make sure we process requests preemptable */ > local_irq_enable(); > @@ -111,11 +120,6 @@ int kvmppc_prepare_to_enter(struct kvm_vcpu *vcpu) > #endif > > kvm_guest_enter(); > - > - /* Going into guest context! Yay! */ > - vcpu->mode = IN_GUEST_MODE; > - smp_wmb(); > - > break; > } > > -- > 1.7.9.5 > > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 09/25/2012 02:44:52 AM, Alexander Graf wrote: > > On 23.08.2012, at 03:03, Scott Wood wrote: > > > Avoid a race as described in the code comment. > > > > Also remove a related smp_wmb() from booke's > kvmppc_prepare_to_enter(). > > I can't see any reason for it, and the book3s_pr version doesn't > have it. > > > > Signed-off-by: Scott Wood <scottwood@freescale.com> > > Does this patch address your comments on the previous pull request? It addresses the comments on the vcpu->mode race... I don't remember if I had any other comments. :-) -Scott -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c index 5f0476a..88711f8 100644 --- a/arch/powerpc/kvm/booke.c +++ b/arch/powerpc/kvm/booke.c @@ -674,7 +674,6 @@ int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu) out: vcpu->mode = OUTSIDE_GUEST_MODE; - smp_wmb(); return ret; } diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c index 32d217c..3d460a0 100644 --- a/arch/powerpc/kvm/powerpc.c +++ b/arch/powerpc/kvm/powerpc.c @@ -78,7 +78,16 @@ int kvmppc_prepare_to_enter(struct kvm_vcpu *vcpu) break; } + vcpu->mode = IN_GUEST_MODE; + + /* + * Reading vcpu->requests must happen after setting vcpu->mode, + * so we don't miss a request because the requester sees + * OUTSIDE_GUEST_MODE and assumes we'll be checking requests + * before next entering the guest (and thus doesn't IPI). + */ smp_mb(); + if (vcpu->requests) { /* Make sure we process requests preemptable */ local_irq_enable(); @@ -111,11 +120,6 @@ int kvmppc_prepare_to_enter(struct kvm_vcpu *vcpu) #endif kvm_guest_enter(); - - /* Going into guest context! Yay! */ - vcpu->mode = IN_GUEST_MODE; - smp_wmb(); - break; }
Avoid a race as described in the code comment. Also remove a related smp_wmb() from booke's kvmppc_prepare_to_enter(). I can't see any reason for it, and the book3s_pr version doesn't have it. Signed-off-by: Scott Wood <scottwood@freescale.com> --- arch/powerpc/kvm/booke.c | 1 - arch/powerpc/kvm/powerpc.c | 14 +++++++++----- 2 files changed, 9 insertions(+), 6 deletions(-)