> -----Original Message----- > From: Paolo Bonzini [mailto:paolo.bonzini@xxxxxxxxx] On Behalf Of Paolo Bonzini > Sent: Monday, October 07, 2013 5:35 PM > To: Alexander Graf > Cc: Bhushan Bharat-R65777; Paul Mackerras; Wood Scott-B07421; kvm- > ppc@xxxxxxxxxxxxxxx; kvm@xxxxxxxxxxxxxxx mailing list; Bhushan Bharat-R65777; > Gleb Natapov > Subject: Re: [PATCH 2/2] kvm: ppc: booke: check range page invalidation progress > on page setup > > Il 04/10/2013 15:38, Alexander Graf ha scritto: > > > > On 07.08.2013, at 12:03, Bharat Bhushan wrote: > > > >> When the MM code is invalidating a range of pages, it calls the KVM > >> kvm_mmu_notifier_invalidate_range_start() notifier function, which calls > >> kvm_unmap_hva_range(), which arranges to flush all the TLBs for guest pages. > >> However, the Linux PTEs for the range being flushed are still valid at > >> that point. We are not supposed to establish any new references to pages > >> in the range until the ...range_end() notifier gets called. > >> The PPC-specific KVM code doesn't get any explicit notification of that; > >> instead, we are supposed to use mmu_notifier_retry() to test whether we > >> are or have been inside a range flush notifier pair while we have been > >> referencing a page. > >> > >> This patch calls the mmu_notifier_retry() while mapping the guest > >> page to ensure we are not referencing a page when in range invalidation. > >> > >> This call is inside a region locked with kvm->mmu_lock, which is the > >> same lock that is called by the KVM MMU notifier functions, thus > >> ensuring that no new notification can proceed while we are in the > >> locked region. > >> > >> Signed-off-by: Bharat Bhushan <bharat.bhushan@xxxxxxxxxxxxx> > > > > Acked-by: Alexander Graf <agraf@xxxxxxx> > > > > Gleb, Paolo, please queue for 3.12 directly. > > Here is the backport. The second hunk has a nontrivial conflict, so > someone please give their {Tested,Reviewed,Compiled}-by. {Compiled,Reviewed}-by: Bharat Bhushan <bharat.bhushan@xxxxxxxxxxxxx> Thanks -Bharat > > Paolo > > diff --git a/arch/powerpc/kvm/e500_mmu_host.c b/arch/powerpc/kvm/e500_mmu_host.c > index 1c6a9d7..c65593a 100644 > --- a/arch/powerpc/kvm/e500_mmu_host.c > +++ b/arch/powerpc/kvm/e500_mmu_host.c > @@ -332,6 +332,13 @@ static inline int kvmppc_e500_shadow_map(struct > kvmppc_vcpu_e500 *vcpu_e500, > unsigned long hva; > int pfnmap = 0; > int tsize = BOOK3E_PAGESZ_4K; > + int ret = 0; > + unsigned long mmu_seq; > + struct kvm *kvm = vcpu_e500->vcpu.kvm; > + > + /* used to check for invalidations in progress */ > + mmu_seq = kvm->mmu_notifier_seq; > + smp_rmb(); > > /* > * Translate guest physical to true physical, acquiring > @@ -449,6 +456,12 @@ static inline int kvmppc_e500_shadow_map(struct > kvmppc_vcpu_e500 *vcpu_e500, > gvaddr &= ~((tsize_pages << PAGE_SHIFT) - 1); > } > > + spin_lock(&kvm->mmu_lock); > + if (mmu_notifier_retry(kvm, mmu_seq)) { > + ret = -EAGAIN; > + goto out; > + } > + > kvmppc_e500_ref_setup(ref, gtlbe, pfn); > > kvmppc_e500_setup_stlbe(&vcpu_e500->vcpu, gtlbe, tsize, > @@ -457,10 +470,13 @@ static inline int kvmppc_e500_shadow_map(struct > kvmppc_vcpu_e500 *vcpu_e500, > /* Clear i-cache for new pages */ > kvmppc_mmu_flush_icache(pfn); > > +out: > + spin_unlock(&kvm->mmu_lock); > + > /* Drop refcount on page, so that mmu notifiers can clear it */ > kvm_release_pfn_clean(pfn); > > - return 0; > + return ret; > } > > /* XXX only map the one-one case, for now use TLB0 */ > > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
