Il 10/10/2013 10:32, Bhushan Bharat-R65777 ha scritto: > > >> -----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, patch on its way to Linus. Paolo > 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
