From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751327AbcGMOaL (ORCPT ); Wed, 13 Jul 2016 10:30:11 -0400 Received: from mx1.redhat.com ([209.132.183.28]:52119 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751117AbcGMOaE (ORCPT ); Wed, 13 Jul 2016 10:30:04 -0400 Date: Wed, 13 Jul 2016 16:29:54 +0200 From: Radim =?utf-8?B?S3LEjW3DocWZ?= To: Suravee Suthikulpanit Cc: joro@8bytes.org, pbonzini@redhat.com, alex.williamson@redhat.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, sherry.hurwitz@amd.com Subject: Re: [PART2 PATCH v4 10/11] svm: Introduce AMD IOMMU avic_ga_log_notifier Message-ID: <20160713142953.GA13201@potion> References: <1468416032-7692-1-git-send-email-suravee.suthikulpanit@amd.com> <1468416032-7692-11-git-send-email-suravee.suthikulpanit@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1468416032-7692-11-git-send-email-suravee.suthikulpanit@amd.com> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Wed, 13 Jul 2016 14:29:57 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2016-07-13 08:20-0500, Suravee Suthikulpanit: > From: Suravee Suthikulpanit > > This patch introduces avic_ga_log_notifier, which will be called > by IOMMU driver whenever it handles the Guest vAPIC (GA) log entry. > > Signed-off-by: Suravee Suthikulpanit > --- > arch/x86/include/asm/kvm_host.h | 2 ++ > arch/x86/kvm/svm.c | 68 +++++++++++++++++++++++++++++++++++++++-- > 2 files changed, 68 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > index 69e62862..a9466ad 100644 > --- a/arch/x86/include/asm/kvm_host.h > +++ b/arch/x86/include/asm/kvm_host.h > @@ -776,9 +776,11 @@ struct kvm_arch { > bool disabled_lapic_found; > > /* Struct members for AVIC */ > + u32 avic_vm_id; > u32 ldr_mode; > struct page *avic_logical_id_table_page; > struct page *avic_physical_id_table_page; > + struct hlist_node hnode; > }; > > struct kvm_vm_stat { > diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c > index 16ef31b..1d9f2f6 100644 > --- a/arch/x86/kvm/svm.c > +++ b/arch/x86/kvm/svm.c > @@ -34,6 +34,8 @@ > #include > #include > #include > +#include > +#include > > #include > #include > @@ -928,6 +930,53 @@ static void svm_disable_lbrv(struct vcpu_svm *svm) > set_msr_interception(msrpm, MSR_IA32_LASTINTTOIP, 0, 0); > } > > +/* Note: > + * This hash table is used to map VM_ID to a struct kvm_arch, > + * when handling AMD IOMMU GALOG notification to schedule in > + * a particular vCPU. > + */ > +#define SVM_VM_DATA_HASH_BITS 8 > +DECLARE_HASHTABLE(svm_vm_data_hash, SVM_VM_DATA_HASH_BITS); > +static spinlock_t svm_vm_data_hash_lock; > + > +/* Note: > + * This function is called from IOMMU driver to notify > + * SVM to schedule in a particular vCPU of a particular VM. > + */ > +static int avic_ga_log_notifier(int vm_id, int vcpu_id) > +{ > + unsigned long flags; > + struct kvm_arch *ka = NULL; > + struct kvm_vcpu *vcpu = NULL; > + struct vcpu_svm *svm = NULL; > + > + pr_debug("SVM: %s: vm_id=%#x, vcpu_id=%#x\n", __func__, vm_id, vcpu_id); > + > + spin_lock_irqsave(&svm_vm_data_hash_lock, flags); > + hash_for_each_possible(svm_vm_data_hash, ka, hnode, vm_id) { > + struct kvm *kvm = container_of(ka, struct kvm, arch); > + > + vcpu = kvm_get_vcpu_by_id(kvm, vcpu_id); The first result is not neccessarily the correct one. With more than active 256 VMs, there is a guaranteed collision that cannot be disambiguated, so VCPUs in both VMs need to be woken up. Having a 24 bit vm_id and checking that kvm->*.avic_id & 0xfffff == vm_id would help a bit to avoid useless wakeups, but the collision cannot be avoided. > + break; > + } > + spin_unlock_irqrestore(&svm_vm_data_hash_lock, flags); > + > + if (!vcpu) > + return 0; > + > + svm = to_svm(vcpu); > + > + /* Note: > + * At this point, the IOMMU should have already set the pending > + * bit in the vAPIC backing page. So, we just need to schedule > + * in the vcpu. > + */ > + if (vcpu->mode == OUTSIDE_GUEST_MODE) > + kvm_vcpu_wake_up(vcpu); > + > + return 0; > +}