From patchwork Tue Nov 8 04:10:33 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gavin Shan X-Patchwork-Id: 13035830 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 94C51C4332F for ; Tue, 8 Nov 2022 04:13:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232939AbiKHENZ (ORCPT ); Mon, 7 Nov 2022 23:13:25 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43484 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232381AbiKHENX (ORCPT ); Mon, 7 Nov 2022 23:13:23 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9670A15FD2 for ; Mon, 7 Nov 2022 20:12:27 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1667880746; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=zHFWHrDPitAZ2CFICQlKxokmuu7CotBRVEubYjCqj1c=; b=bm8YDfw2WCDbvACt7g9g35RMamY5yRa9csCiHIMR9v+jB6O6kZjwJRsckz+RcBoqWZ8+iu hdN58FGh2zu1XeCdXOI8vopBcdYVUnF80Zmkw+qfIJS9K/Jj3JLHhBrc+GDyeriVVIIxOa rL7fOKbQDXlu+XdqvdrMKwzNzQovTG4= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-664-d6ytsOAcOeeDwCl1-gHcXA-1; Mon, 07 Nov 2022 23:12:23 -0500 X-MC-Unique: d6ytsOAcOeeDwCl1-gHcXA-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 8FC30811E7A; Tue, 8 Nov 2022 04:12:22 +0000 (UTC) Received: from gshan.redhat.com (vpn2-54-78.bne.redhat.com [10.64.54.78]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 3682535429; Tue, 8 Nov 2022 04:12:15 +0000 (UTC) From: Gavin Shan To: kvmarm@lists.linux.dev Cc: kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, shuah@kernel.org, catalin.marinas@arm.com, andrew.jones@linux.dev, ajones@ventanamicro.com, bgardon@google.com, dmatlack@google.com, will@kernel.org, suzuki.poulose@arm.com, alexandru.elisei@arm.com, pbonzini@redhat.com, maz@kernel.org, peterx@redhat.com, oliver.upton@linux.dev, seanjc@google.com, zhenyzha@redhat.com, shan.gavin@gmail.com Subject: [PATCH v9 1/7] KVM: x86: Introduce KVM_REQ_DIRTY_RING_SOFT_FULL Date: Tue, 8 Nov 2022 12:10:33 +0800 Message-Id: <20221108041039.111145-2-gshan@redhat.com> In-Reply-To: <20221108041039.111145-1-gshan@redhat.com> References: <20221108041039.111145-1-gshan@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org The VCPU isn't expected to be runnable when the dirty ring becomes soft full, until the dirty pages are harvested and the dirty ring is reset from userspace. So there is a check in each guest's entrace to see if the dirty ring is soft full or not. The VCPU is stopped from running if its dirty ring has been soft full. The similar check will be needed when the feature is going to be supported on ARM64. As Marc Zyngier suggested, a new event will avoid pointless overhead to check the size of the dirty ring ('vcpu->kvm->dirty_ring_size') in each guest's entrance. Add KVM_REQ_DIRTY_RING_SOFT_FULL. The event is raised when the dirty ring becomes soft full in kvm_dirty_ring_push(). The event is only cleared in the check, done in the newly added helper kvm_dirty_ring_check_request(). Since the VCPU is not runnable when the dirty ring becomes soft full, the KVM_REQ_DIRTY_RING_SOFT_FULL event is always set to prevent the VCPU from running until the dirty pages are harvested and the dirty ring is reset by userspace. kvm_dirty_ring_soft_full() becomes a private function with the newly added helper kvm_dirty_ring_check_request(). The alignment for the various event definitions in kvm_host.h is changed to tab character by the way. In order to avoid using 'container_of()', the argument @ring is replaced by @vcpu in kvm_dirty_ring_push(). Link: https://lore.kernel.org/kvmarm/87lerkwtm5.wl-maz@kernel.org Suggested-by: Marc Zyngier Signed-off-by: Gavin Shan Reviewed-by: Peter Xu Reviewed-by: Sean Christopherson --- arch/x86/kvm/x86.c | 15 ++++++--------- include/linux/kvm_dirty_ring.h | 12 ++++-------- include/linux/kvm_host.h | 9 +++++---- virt/kvm/dirty_ring.c | 32 ++++++++++++++++++++++++++++++-- virt/kvm/kvm_main.c | 3 +-- 5 files changed, 46 insertions(+), 25 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 5f5eb577d583..a228a1b872bb 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -10515,20 +10515,17 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) bool req_immediate_exit = false; - /* Forbid vmenter if vcpu dirty ring is soft-full */ - if (unlikely(vcpu->kvm->dirty_ring_size && - kvm_dirty_ring_soft_full(&vcpu->dirty_ring))) { - vcpu->run->exit_reason = KVM_EXIT_DIRTY_RING_FULL; - trace_kvm_dirty_ring_exit(vcpu); - r = 0; - goto out; - } - if (kvm_request_pending(vcpu)) { if (kvm_check_request(KVM_REQ_VM_DEAD, vcpu)) { r = -EIO; goto out; } + + if (kvm_dirty_ring_check_request(vcpu)) { + r = 0; + goto out; + } + if (kvm_check_request(KVM_REQ_GET_NESTED_STATE_PAGES, vcpu)) { if (unlikely(!kvm_x86_ops.nested_ops->get_nested_state_pages(vcpu))) { r = 0; diff --git a/include/linux/kvm_dirty_ring.h b/include/linux/kvm_dirty_ring.h index 906f899813dc..9c13c4c3d30c 100644 --- a/include/linux/kvm_dirty_ring.h +++ b/include/linux/kvm_dirty_ring.h @@ -49,7 +49,7 @@ static inline int kvm_dirty_ring_reset(struct kvm *kvm, return 0; } -static inline void kvm_dirty_ring_push(struct kvm_dirty_ring *ring, +static inline void kvm_dirty_ring_push(struct kvm_vcpu *vcpu, u32 slot, u64 offset) { } @@ -64,11 +64,6 @@ static inline void kvm_dirty_ring_free(struct kvm_dirty_ring *ring) { } -static inline bool kvm_dirty_ring_soft_full(struct kvm_dirty_ring *ring) -{ - return true; -} - #else /* CONFIG_HAVE_KVM_DIRTY_RING */ u32 kvm_dirty_ring_get_rsvd_entries(void); @@ -84,13 +79,14 @@ int kvm_dirty_ring_reset(struct kvm *kvm, struct kvm_dirty_ring *ring); * returns =0: successfully pushed * <0: unable to push, need to wait */ -void kvm_dirty_ring_push(struct kvm_dirty_ring *ring, u32 slot, u64 offset); +void kvm_dirty_ring_push(struct kvm_vcpu *vcpu, u32 slot, u64 offset); + +bool kvm_dirty_ring_check_request(struct kvm_vcpu *vcpu); /* for use in vm_operations_struct */ struct page *kvm_dirty_ring_get_page(struct kvm_dirty_ring *ring, u32 offset); void kvm_dirty_ring_free(struct kvm_dirty_ring *ring); -bool kvm_dirty_ring_soft_full(struct kvm_dirty_ring *ring); #endif /* CONFIG_HAVE_KVM_DIRTY_RING */ diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 18592bdf4c1b..6fab55e58111 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -153,10 +153,11 @@ static inline bool is_error_page(struct page *page) * Architecture-independent vcpu->requests bit members * Bits 3-7 are reserved for more arch-independent bits. */ -#define KVM_REQ_TLB_FLUSH (0 | KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP) -#define KVM_REQ_VM_DEAD (1 | KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP) -#define KVM_REQ_UNBLOCK 2 -#define KVM_REQUEST_ARCH_BASE 8 +#define KVM_REQ_TLB_FLUSH (0 | KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP) +#define KVM_REQ_VM_DEAD (1 | KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP) +#define KVM_REQ_UNBLOCK 2 +#define KVM_REQ_DIRTY_RING_SOFT_FULL 3 +#define KVM_REQUEST_ARCH_BASE 8 /* * KVM_REQ_OUTSIDE_GUEST_MODE exists is purely as way to force the vCPU to diff --git a/virt/kvm/dirty_ring.c b/virt/kvm/dirty_ring.c index d6fabf238032..fecbb7d75ad2 100644 --- a/virt/kvm/dirty_ring.c +++ b/virt/kvm/dirty_ring.c @@ -26,7 +26,7 @@ static u32 kvm_dirty_ring_used(struct kvm_dirty_ring *ring) return READ_ONCE(ring->dirty_index) - READ_ONCE(ring->reset_index); } -bool kvm_dirty_ring_soft_full(struct kvm_dirty_ring *ring) +static bool kvm_dirty_ring_soft_full(struct kvm_dirty_ring *ring) { return kvm_dirty_ring_used(ring) >= ring->soft_limit; } @@ -142,13 +142,19 @@ int kvm_dirty_ring_reset(struct kvm *kvm, struct kvm_dirty_ring *ring) kvm_reset_dirty_gfn(kvm, cur_slot, cur_offset, mask); + /* + * The request KVM_REQ_DIRTY_RING_SOFT_FULL will be cleared + * by the VCPU thread next time when it enters the guest. + */ + trace_kvm_dirty_ring_reset(ring); return count; } -void kvm_dirty_ring_push(struct kvm_dirty_ring *ring, u32 slot, u64 offset) +void kvm_dirty_ring_push(struct kvm_vcpu *vcpu, u32 slot, u64 offset) { + struct kvm_dirty_ring *ring = &vcpu->dirty_ring; struct kvm_dirty_gfn *entry; /* It should never get full */ @@ -166,6 +172,28 @@ void kvm_dirty_ring_push(struct kvm_dirty_ring *ring, u32 slot, u64 offset) kvm_dirty_gfn_set_dirtied(entry); ring->dirty_index++; trace_kvm_dirty_ring_push(ring, slot, offset); + + if (kvm_dirty_ring_soft_full(ring)) + kvm_make_request(KVM_REQ_DIRTY_RING_SOFT_FULL, vcpu); +} + +bool kvm_dirty_ring_check_request(struct kvm_vcpu *vcpu) +{ + /* + * The VCPU isn't runnable when the dirty ring becomes soft full. + * The KVM_REQ_DIRTY_RING_SOFT_FULL event is always set to prevent + * the VCPU from running until the dirty pages are harvested and + * the dirty ring is reset by userspace. + */ + if (kvm_check_request(KVM_REQ_DIRTY_RING_SOFT_FULL, vcpu) && + kvm_dirty_ring_soft_full(&vcpu->dirty_ring)) { + kvm_make_request(KVM_REQ_DIRTY_RING_SOFT_FULL, vcpu); + vcpu->run->exit_reason = KVM_EXIT_DIRTY_RING_FULL; + trace_kvm_dirty_ring_exit(vcpu); + return true; + } + + return false; } struct page *kvm_dirty_ring_get_page(struct kvm_dirty_ring *ring, u32 offset) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 25d7872b29c1..c865d7d82685 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -3314,8 +3314,7 @@ void mark_page_dirty_in_slot(struct kvm *kvm, u32 slot = (memslot->as_id << 16) | memslot->id; if (kvm->dirty_ring_size) - kvm_dirty_ring_push(&vcpu->dirty_ring, - slot, rel_gfn); + kvm_dirty_ring_push(vcpu, slot, rel_gfn); else set_bit_le(rel_gfn, memslot->dirty_bitmap); } From patchwork Tue Nov 8 04:10:34 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gavin Shan X-Patchwork-Id: 13035831 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 75865C4332F for ; Tue, 8 Nov 2022 04:13:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233333AbiKHENl (ORCPT ); Mon, 7 Nov 2022 23:13:41 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43558 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233240AbiKHENc (ORCPT ); Mon, 7 Nov 2022 23:13:32 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7FFDD1B9C6 for ; 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Tue, 8 Nov 2022 04:12:29 +0000 (UTC) Received: from gshan.redhat.com (vpn2-54-78.bne.redhat.com [10.64.54.78]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 20E1435429; Tue, 8 Nov 2022 04:12:22 +0000 (UTC) From: Gavin Shan To: kvmarm@lists.linux.dev Cc: kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, shuah@kernel.org, catalin.marinas@arm.com, andrew.jones@linux.dev, ajones@ventanamicro.com, bgardon@google.com, dmatlack@google.com, will@kernel.org, suzuki.poulose@arm.com, alexandru.elisei@arm.com, pbonzini@redhat.com, maz@kernel.org, peterx@redhat.com, oliver.upton@linux.dev, seanjc@google.com, zhenyzha@redhat.com, shan.gavin@gmail.com Subject: [PATCH v9 2/7] KVM: Move declaration of kvm_cpu_dirty_log_size() to kvm_dirty_ring.h Date: Tue, 8 Nov 2022 12:10:34 +0800 Message-Id: <20221108041039.111145-3-gshan@redhat.com> In-Reply-To: <20221108041039.111145-1-gshan@redhat.com> References: <20221108041039.111145-1-gshan@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Not all architectures like ARM64 need to override the function. Move its declaration to kvm_dirty_ring.h to avoid the following compiling warning on ARM64 when the feature is enabled. arch/arm64/kvm/../../../virt/kvm/dirty_ring.c:14:12: \ warning: no previous prototype for 'kvm_cpu_dirty_log_size' \ [-Wmissing-prototypes] \ int __weak kvm_cpu_dirty_log_size(void) Reported-by: kernel test robot Signed-off-by: Gavin Shan Reviewed-by: Peter Xu --- arch/x86/include/asm/kvm_host.h | 2 -- include/linux/kvm_dirty_ring.h | 1 + 2 files changed, 1 insertion(+), 2 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 7551b6f9c31c..b4dbde7d9eb1 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -2090,8 +2090,6 @@ static inline int kvm_cpu_get_apicid(int mps_cpu) #define GET_SMSTATE(type, buf, offset) \ (*(type *)((buf) + (offset) - 0x7e00)) -int kvm_cpu_dirty_log_size(void); - int memslot_rmap_alloc(struct kvm_memory_slot *slot, unsigned long npages); #define KVM_CLOCK_VALID_FLAGS \ diff --git a/include/linux/kvm_dirty_ring.h b/include/linux/kvm_dirty_ring.h index 9c13c4c3d30c..199ead37b104 100644 --- a/include/linux/kvm_dirty_ring.h +++ b/include/linux/kvm_dirty_ring.h @@ -66,6 +66,7 @@ static inline void kvm_dirty_ring_free(struct kvm_dirty_ring *ring) #else /* CONFIG_HAVE_KVM_DIRTY_RING */ +int kvm_cpu_dirty_log_size(void); u32 kvm_dirty_ring_get_rsvd_entries(void); int kvm_dirty_ring_alloc(struct kvm_dirty_ring *ring, int index, u32 size); From patchwork Tue Nov 8 04:10:35 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gavin Shan X-Patchwork-Id: 13035832 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 76AD1C4332F for ; Tue, 8 Nov 2022 04:14:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233326AbiKHENz (ORCPT ); Mon, 7 Nov 2022 23:13:55 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43596 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232381AbiKHENn (ORCPT ); Mon, 7 Nov 2022 23:13:43 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6064117ABB for ; Mon, 7 Nov 2022 20:12:42 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1667880761; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=jAsjsbiKcbDZvxXijzOHyzkfcvKHa9BKl0bX7I+2rzU=; b=XA3MHdK3UyoGDAmVJFYKPDsn6fPcINFEzGGDynT6h+AOBv/cuKMqfObSoRazty2Pua4+Gb qgHe2+eAr6RBroKqiyubf5Vg+/wlwBpWmT/P85cb9p0zAaJIXVGlkC/NxuRMT2PxhXrBxp COWwp7jZfZc/NMkPkLzJEys+HagdA0g= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-300-N4zbFR_ENkqHY8B_fD2cFA-1; Mon, 07 Nov 2022 23:12:37 -0500 X-MC-Unique: N4zbFR_ENkqHY8B_fD2cFA-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 6F948800B30; Tue, 8 Nov 2022 04:12:36 +0000 (UTC) Received: from gshan.redhat.com (vpn2-54-78.bne.redhat.com [10.64.54.78]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2412B35429; Tue, 8 Nov 2022 04:12:29 +0000 (UTC) From: Gavin Shan To: kvmarm@lists.linux.dev Cc: kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, shuah@kernel.org, catalin.marinas@arm.com, andrew.jones@linux.dev, ajones@ventanamicro.com, bgardon@google.com, dmatlack@google.com, will@kernel.org, suzuki.poulose@arm.com, alexandru.elisei@arm.com, pbonzini@redhat.com, maz@kernel.org, peterx@redhat.com, oliver.upton@linux.dev, seanjc@google.com, zhenyzha@redhat.com, shan.gavin@gmail.com Subject: [PATCH v9 3/7] KVM: Support dirty ring in conjunction with bitmap Date: Tue, 8 Nov 2022 12:10:35 +0800 Message-Id: <20221108041039.111145-4-gshan@redhat.com> In-Reply-To: <20221108041039.111145-1-gshan@redhat.com> References: <20221108041039.111145-1-gshan@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org ARM64 needs to dirty memory outside of a VCPU context when VGIC/ITS is enabled. It's conflicting with that ring-based dirty page tracking always requires a running VCPU context. Introduce a new flavor of dirty ring that requires the use of both VCPU dirty rings and a dirty bitmap. The expectation is that for non-VCPU sources of dirty memory (such as the VGIC/ITS on arm64), KVM writes to the dirty bitmap. Userspace should scan the dirty bitmap before migrating the VM to the target. Use an additional capability to advertise this behavior. The newly added capability (KVM_CAP_DIRTY_LOG_RING_WITH_BITMAP) can't be enabled before KVM_CAP_DIRTY_LOG_RING_ACQ_REL on ARM64. In this way, the newly added capability is treated as an extension of KVM_CAP_DIRTY_LOG_RING_ACQ_REL. Suggested-by: Marc Zyngier Suggested-by: Peter Xu Co-developed-by: Oliver Upton Signed-off-by: Oliver Upton Signed-off-by: Gavin Shan Acked-by: Peter Xu --- Documentation/virt/kvm/api.rst | 34 ++++++++--- .../virt/kvm/devices/arm-vgic-its.rst | 5 +- include/linux/kvm_dirty_ring.h | 7 +++ include/linux/kvm_host.h | 1 + include/uapi/linux/kvm.h | 1 + virt/kvm/Kconfig | 8 +++ virt/kvm/dirty_ring.c | 12 ++++ virt/kvm/kvm_main.c | 61 ++++++++++++++++--- 8 files changed, 112 insertions(+), 17 deletions(-) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index eee9f857a986..1f1b09aa6db4 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -8003,13 +8003,6 @@ flushing is done by the KVM_GET_DIRTY_LOG ioctl). To achieve that, one needs to kick the vcpu out of KVM_RUN using a signal. The resulting vmexit ensures that all dirty GFNs are flushed to the dirty rings. -NOTE: the capability KVM_CAP_DIRTY_LOG_RING and the corresponding -ioctl KVM_RESET_DIRTY_RINGS are mutual exclusive to the existing ioctls -KVM_GET_DIRTY_LOG and KVM_CLEAR_DIRTY_LOG. After enabling -KVM_CAP_DIRTY_LOG_RING with an acceptable dirty ring size, the virtual -machine will switch to ring-buffer dirty page tracking and further -KVM_GET_DIRTY_LOG or KVM_CLEAR_DIRTY_LOG ioctls will fail. - NOTE: KVM_CAP_DIRTY_LOG_RING_ACQ_REL is the only capability that should be exposed by weakly ordered architecture, in order to indicate the additional memory ordering requirements imposed on userspace when @@ -8018,6 +8011,33 @@ Architecture with TSO-like ordering (such as x86) are allowed to expose both KVM_CAP_DIRTY_LOG_RING and KVM_CAP_DIRTY_LOG_RING_ACQ_REL to userspace. +After enabling the dirty rings, the userspace needs to detect the +capability of KVM_CAP_DIRTY_LOG_RING_WITH_BITMAP to see whether the +ring structures can be backed by per-slot bitmaps. With this capability +advertised, it means the architecture can dirty guest pages without +vcpu/ring context, so that some of the dirty information will still be +maintained in the bitmap structure. KVM_CAP_DIRTY_LOG_RING_WITH_BITMAP +can't be enabled if the capability of KVM_CAP_DIRTY_LOG_RING_ACQ_REL +hasn't been enabled, or any memslot has been existing. + +Note that the bitmap here is only a backup of the ring structure. The +use of the ring and bitmap combination is only beneficial if there is +only a very small amount of memory that is dirtied out of vcpu/ring +context. Otherwise, the stand-alone per-slot bitmap mechanism needs to +be considered. + +To collect dirty bits in the backup bitmap, userspace can use the same +KVM_GET_DIRTY_LOG ioctl. KVM_CLEAR_DIRTY_LOG isn't needed as long as all +the generation of the dirty bits is done in a single pass. Collecting +the dirty bitmap should be the very last thing that the VMM does before +considering the state as complete. VMM needs to ensure that the dirty +state is final and avoid missing dirty pages from another ioctl ordered +after the bitmap collection. + +NOTE: One example of using the backup bitmap is saving arm64 vgic/its +tables through KVM_DEV_ARM_{VGIC_GRP_CTRL, ITS_SAVE_TABLES} command on +KVM device "kvm-arm-vgic-its" when dirty ring is enabled. + 8.30 KVM_CAP_XEN_HVM -------------------- diff --git a/Documentation/virt/kvm/devices/arm-vgic-its.rst b/Documentation/virt/kvm/devices/arm-vgic-its.rst index d257eddbae29..e053124f77c4 100644 --- a/Documentation/virt/kvm/devices/arm-vgic-its.rst +++ b/Documentation/virt/kvm/devices/arm-vgic-its.rst @@ -52,7 +52,10 @@ KVM_DEV_ARM_VGIC_GRP_CTRL KVM_DEV_ARM_ITS_SAVE_TABLES save the ITS table data into guest RAM, at the location provisioned - by the guest in corresponding registers/table entries. + by the guest in corresponding registers/table entries. Should userspace + require a form of dirty tracking to identify which pages are modified + by the saving process, it should use a bitmap even if using another + mechanism to track the memory dirtied by the vCPUs. The layout of the tables in guest memory defines an ABI. The entries are laid out in little endian format as described in the last paragraph. diff --git a/include/linux/kvm_dirty_ring.h b/include/linux/kvm_dirty_ring.h index 199ead37b104..4862c98d80d3 100644 --- a/include/linux/kvm_dirty_ring.h +++ b/include/linux/kvm_dirty_ring.h @@ -37,6 +37,11 @@ static inline u32 kvm_dirty_ring_get_rsvd_entries(void) return 0; } +static inline bool kvm_use_dirty_bitmap(struct kvm *kvm) +{ + return true; +} + static inline int kvm_dirty_ring_alloc(struct kvm_dirty_ring *ring, int index, u32 size) { @@ -67,6 +72,8 @@ static inline void kvm_dirty_ring_free(struct kvm_dirty_ring *ring) #else /* CONFIG_HAVE_KVM_DIRTY_RING */ int kvm_cpu_dirty_log_size(void); +bool kvm_use_dirty_bitmap(struct kvm *kvm); +bool kvm_arch_allow_write_without_running_vcpu(struct kvm *kvm); u32 kvm_dirty_ring_get_rsvd_entries(void); int kvm_dirty_ring_alloc(struct kvm_dirty_ring *ring, int index, u32 size); diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 6fab55e58111..f51eb9419bfc 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -779,6 +779,7 @@ struct kvm { pid_t userspace_pid; unsigned int max_halt_poll_ns; u32 dirty_ring_size; + bool dirty_ring_with_bitmap; bool vm_bugged; bool vm_dead; diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 0d5d4419139a..c87b5882d7ae 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -1178,6 +1178,7 @@ struct kvm_ppc_resize_hpt { #define KVM_CAP_S390_ZPCI_OP 221 #define KVM_CAP_S390_CPU_TOPOLOGY 222 #define KVM_CAP_DIRTY_LOG_RING_ACQ_REL 223 +#define KVM_CAP_DIRTY_LOG_RING_WITH_BITMAP 224 #ifdef KVM_CAP_IRQ_ROUTING diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig index 800f9470e36b..228be1145cf3 100644 --- a/virt/kvm/Kconfig +++ b/virt/kvm/Kconfig @@ -33,6 +33,14 @@ config HAVE_KVM_DIRTY_RING_ACQ_REL bool select HAVE_KVM_DIRTY_RING +# Only architectures that need to dirty memory outside of a vCPU +# context should select this, advertising to userspace the +# requirement to use a dirty bitmap in addition to the vCPU dirty +# ring. +config HAVE_KVM_DIRTY_RING_WITH_BITMAP + bool + depends on HAVE_KVM_DIRTY_RING + config HAVE_KVM_EVENTFD bool select EVENTFD diff --git a/virt/kvm/dirty_ring.c b/virt/kvm/dirty_ring.c index fecbb7d75ad2..f95cbcdd74ff 100644 --- a/virt/kvm/dirty_ring.c +++ b/virt/kvm/dirty_ring.c @@ -21,6 +21,18 @@ u32 kvm_dirty_ring_get_rsvd_entries(void) return KVM_DIRTY_RING_RSVD_ENTRIES + kvm_cpu_dirty_log_size(); } +bool kvm_use_dirty_bitmap(struct kvm *kvm) +{ + lockdep_assert_held(&kvm->slots_lock); + + return !kvm->dirty_ring_size || kvm->dirty_ring_with_bitmap; +} + +bool __weak kvm_arch_allow_write_without_running_vcpu(struct kvm *kvm) +{ + return false; +} + static u32 kvm_dirty_ring_used(struct kvm_dirty_ring *ring) { return READ_ONCE(ring->dirty_index) - READ_ONCE(ring->reset_index); diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index c865d7d82685..5f32752b7d96 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1617,7 +1617,7 @@ static int kvm_prepare_memory_region(struct kvm *kvm, new->dirty_bitmap = NULL; else if (old && old->dirty_bitmap) new->dirty_bitmap = old->dirty_bitmap; - else if (!kvm->dirty_ring_size) { + else if (kvm_use_dirty_bitmap(kvm)) { r = kvm_alloc_dirty_bitmap(new); if (r) return r; @@ -2060,8 +2060,8 @@ int kvm_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log, unsigned long n; unsigned long any = 0; - /* Dirty ring tracking is exclusive to dirty log tracking */ - if (kvm->dirty_ring_size) + /* Dirty ring tracking may be exclusive to dirty log tracking */ + if (!kvm_use_dirty_bitmap(kvm)) return -ENXIO; *memslot = NULL; @@ -2125,8 +2125,8 @@ static int kvm_get_dirty_log_protect(struct kvm *kvm, struct kvm_dirty_log *log) unsigned long *dirty_bitmap_buffer; bool flush; - /* Dirty ring tracking is exclusive to dirty log tracking */ - if (kvm->dirty_ring_size) + /* Dirty ring tracking may be exclusive to dirty log tracking */ + if (!kvm_use_dirty_bitmap(kvm)) return -ENXIO; as_id = log->slot >> 16; @@ -2237,8 +2237,8 @@ static int kvm_clear_dirty_log_protect(struct kvm *kvm, unsigned long *dirty_bitmap_buffer; bool flush; - /* Dirty ring tracking is exclusive to dirty log tracking */ - if (kvm->dirty_ring_size) + /* Dirty ring tracking may be exclusive to dirty log tracking */ + if (!kvm_use_dirty_bitmap(kvm)) return -ENXIO; as_id = log->slot >> 16; @@ -3305,7 +3305,10 @@ void mark_page_dirty_in_slot(struct kvm *kvm, struct kvm_vcpu *vcpu = kvm_get_running_vcpu(); #ifdef CONFIG_HAVE_KVM_DIRTY_RING - if (WARN_ON_ONCE(!vcpu) || WARN_ON_ONCE(vcpu->kvm != kvm)) + if (WARN_ON_ONCE(vcpu && vcpu->kvm != kvm)) + return; + + if (WARN_ON_ONCE(!kvm_arch_allow_write_without_running_vcpu(kvm) && !vcpu)) return; #endif @@ -3313,7 +3316,7 @@ void mark_page_dirty_in_slot(struct kvm *kvm, unsigned long rel_gfn = gfn - memslot->base_gfn; u32 slot = (memslot->as_id << 16) | memslot->id; - if (kvm->dirty_ring_size) + if (kvm->dirty_ring_size && vcpu) kvm_dirty_ring_push(vcpu, slot, rel_gfn); else set_bit_le(rel_gfn, memslot->dirty_bitmap); @@ -4482,6 +4485,9 @@ static long kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg) return KVM_DIRTY_RING_MAX_ENTRIES * sizeof(struct kvm_dirty_gfn); #else return 0; +#endif +#ifdef CONFIG_HAVE_KVM_DIRTY_RING_WITH_BITMAP + case KVM_CAP_DIRTY_LOG_RING_WITH_BITMAP: #endif case KVM_CAP_BINARY_STATS_FD: case KVM_CAP_SYSTEM_EVENT_DATA: @@ -4558,6 +4564,20 @@ int __attribute__((weak)) kvm_vm_ioctl_enable_cap(struct kvm *kvm, return -EINVAL; } +static bool kvm_are_all_memslots_empty(struct kvm *kvm) +{ + int i; + + lockdep_assert_held(&kvm->slots_lock); + + for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) { + if (!kvm_memslots_empty(__kvm_memslots(kvm, i))) + return false; + } + + return true; +} + static int kvm_vm_ioctl_enable_cap_generic(struct kvm *kvm, struct kvm_enable_cap *cap) { @@ -4588,6 +4608,29 @@ static int kvm_vm_ioctl_enable_cap_generic(struct kvm *kvm, return -EINVAL; return kvm_vm_ioctl_enable_dirty_log_ring(kvm, cap->args[0]); + case KVM_CAP_DIRTY_LOG_RING_WITH_BITMAP: { + int r = -EINVAL; + + if (!IS_ENABLED(CONFIG_HAVE_KVM_DIRTY_RING_WITH_BITMAP) || + !kvm->dirty_ring_size) + return r; + + mutex_lock(&kvm->slots_lock); + + /* + * For simplicity, allow enabling ring+bitmap if and only if + * there are no memslots, e.g. to ensure all memslots allocate + * a bitmap after the capability is enabled. + */ + if (kvm_are_all_memslots_empty(kvm)) { + kvm->dirty_ring_with_bitmap = true; + r = 0; + } + + mutex_unlock(&kvm->slots_lock); + + return r; + } default: return kvm_vm_ioctl_enable_cap(kvm, cap); } From patchwork Tue Nov 8 04:10:36 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gavin Shan X-Patchwork-Id: 13035833 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8D6F6C433FE for ; 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Mon, 07 Nov 2022 23:12:44 -0500 X-MC-Unique: z9OyzPdtN5SllLq5UrND9Q-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 426403C01DF0; Tue, 8 Nov 2022 04:12:43 +0000 (UTC) Received: from gshan.redhat.com (vpn2-54-78.bne.redhat.com [10.64.54.78]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 026554EA47; Tue, 8 Nov 2022 04:12:36 +0000 (UTC) From: Gavin Shan To: kvmarm@lists.linux.dev Cc: kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, shuah@kernel.org, catalin.marinas@arm.com, andrew.jones@linux.dev, ajones@ventanamicro.com, bgardon@google.com, dmatlack@google.com, will@kernel.org, suzuki.poulose@arm.com, alexandru.elisei@arm.com, pbonzini@redhat.com, maz@kernel.org, peterx@redhat.com, oliver.upton@linux.dev, seanjc@google.com, zhenyzha@redhat.com, shan.gavin@gmail.com Subject: [PATCH v9 4/7] KVM: arm64: Enable ring-based dirty memory tracking Date: Tue, 8 Nov 2022 12:10:36 +0800 Message-Id: <20221108041039.111145-5-gshan@redhat.com> In-Reply-To: <20221108041039.111145-1-gshan@redhat.com> References: <20221108041039.111145-1-gshan@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Enable ring-based dirty memory tracking on arm64 by selecting CONFIG_HAVE_KVM_DIRTY_{RING_ACQ_REL, RING_WITH_BITMAP} and providing the ring buffer's physical page offset (KVM_DIRTY_LOG_PAGE_OFFSET). Besides, ARM64 specific kvm_arch_allow_write_without_running_vcpu() is added to override the generic one, to keep the site of saving vgic/its tables out of the no-running-vcpu radar. Signed-off-by: Gavin Shan --- Documentation/virt/kvm/api.rst | 2 +- arch/arm64/include/uapi/asm/kvm.h | 1 + arch/arm64/kvm/Kconfig | 2 ++ arch/arm64/kvm/arm.c | 3 +++ arch/arm64/kvm/vgic/vgic-its.c | 20 ++++++++++++++++++++ include/kvm/arm_vgic.h | 1 + 6 files changed, 28 insertions(+), 1 deletion(-) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 1f1b09aa6db4..773e4b202f47 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -7921,7 +7921,7 @@ regardless of what has actually been exposed through the CPUID leaf. 8.29 KVM_CAP_DIRTY_LOG_RING/KVM_CAP_DIRTY_LOG_RING_ACQ_REL ---------------------------------------------------------- -:Architectures: x86 +:Architectures: x86, arm64 :Parameters: args[0] - size of the dirty log ring KVM is capable of tracking dirty memory using ring buffers that are diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h index 316917b98707..a7a857f1784d 100644 --- a/arch/arm64/include/uapi/asm/kvm.h +++ b/arch/arm64/include/uapi/asm/kvm.h @@ -43,6 +43,7 @@ #define __KVM_HAVE_VCPU_EVENTS #define KVM_COALESCED_MMIO_PAGE_OFFSET 1 +#define KVM_DIRTY_LOG_PAGE_OFFSET 64 #define KVM_REG_SIZE(id) \ (1U << (((id) & KVM_REG_SIZE_MASK) >> KVM_REG_SIZE_SHIFT)) diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig index 815cc118c675..066b053e9eb9 100644 --- a/arch/arm64/kvm/Kconfig +++ b/arch/arm64/kvm/Kconfig @@ -32,6 +32,8 @@ menuconfig KVM select KVM_VFIO select HAVE_KVM_EVENTFD select HAVE_KVM_IRQFD + select HAVE_KVM_DIRTY_RING_ACQ_REL + select HAVE_KVM_DIRTY_RING_WITH_BITMAP select HAVE_KVM_MSI select HAVE_KVM_IRQCHIP select HAVE_KVM_IRQ_ROUTING diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 94d33e296e10..6b097605e38c 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -746,6 +746,9 @@ static int check_vcpu_requests(struct kvm_vcpu *vcpu) if (kvm_check_request(KVM_REQ_SUSPEND, vcpu)) return kvm_vcpu_suspend(vcpu); + + if (kvm_dirty_ring_check_request(vcpu)) + return 0; } return 1; diff --git a/arch/arm64/kvm/vgic/vgic-its.c b/arch/arm64/kvm/vgic/vgic-its.c index 733b53055f97..94a666dd1443 100644 --- a/arch/arm64/kvm/vgic/vgic-its.c +++ b/arch/arm64/kvm/vgic/vgic-its.c @@ -2743,6 +2743,7 @@ static int vgic_its_has_attr(struct kvm_device *dev, static int vgic_its_ctrl(struct kvm *kvm, struct vgic_its *its, u64 attr) { const struct vgic_its_abi *abi = vgic_its_get_abi(its); + struct vgic_dist *dist = &kvm->arch.vgic; int ret = 0; if (attr == KVM_DEV_ARM_VGIC_CTRL_INIT) /* Nothing to do */ @@ -2762,7 +2763,9 @@ static int vgic_its_ctrl(struct kvm *kvm, struct vgic_its *its, u64 attr) vgic_its_reset(kvm, its); break; case KVM_DEV_ARM_ITS_SAVE_TABLES: + dist->save_its_tables_in_progress = true; ret = abi->save_tables(its); + dist->save_its_tables_in_progress = false; break; case KVM_DEV_ARM_ITS_RESTORE_TABLES: ret = abi->restore_tables(its); @@ -2775,6 +2778,23 @@ static int vgic_its_ctrl(struct kvm *kvm, struct vgic_its *its, u64 attr) return ret; } +/* + * kvm_arch_allow_write_without_running_vcpu - allow writing guest memory + * without the running VCPU when dirty ring is enabled. + * + * The running VCPU is required to track dirty guest pages when dirty ring + * is enabled. Otherwise, the backup bitmap should be used to track the + * dirty guest pages. When vgic/its tables are being saved, the backup + * bitmap is used to track the dirty guest pages due to the missed running + * VCPU in the period. + */ +bool kvm_arch_allow_write_without_running_vcpu(struct kvm *kvm) +{ + struct vgic_dist *dist = &kvm->arch.vgic; + + return dist->save_its_tables_in_progress; +} + static int vgic_its_set_attr(struct kvm_device *dev, struct kvm_device_attr *attr) { diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h index 4df9e73a8bb5..9270cd87da3f 100644 --- a/include/kvm/arm_vgic.h +++ b/include/kvm/arm_vgic.h @@ -263,6 +263,7 @@ struct vgic_dist { struct vgic_io_device dist_iodev; bool has_its; + bool save_its_tables_in_progress; /* * Contains the attributes and gpa of the LPI configuration table. From patchwork Tue Nov 8 04:10:37 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gavin Shan X-Patchwork-Id: 13035834 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6E6A7C4332F for ; Tue, 8 Nov 2022 04:14:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233376AbiKHEOK (ORCPT ); Mon, 7 Nov 2022 23:14:10 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43630 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233128AbiKHENw (ORCPT ); Mon, 7 Nov 2022 23:13:52 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 568EB1742D for ; Mon, 7 Nov 2022 20:12:55 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1667880774; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=AKNjwXr1+6lA46ix04voPDpp+Bnwo29abQuhxfN937w=; b=Jl9bbvlXic1p5IUAztl3gjbDyodwq/WIcmh2AzFXS8G1jRDKKglATlp3pM46pMYK4Kn0E5 g6/jBxJ9Uv/tkJoiYV08/MKa2MvR46gVJrJsWHMohHV4dvTE6/VdpCTQl7XTrc8YiCbrLJ Dc/ULoeFuqva2dDe3vn1/8oDqrBQYWo= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-608-LqMmuS3hNWqybkzDsJuPdA-1; Mon, 07 Nov 2022 23:12:51 -0500 X-MC-Unique: LqMmuS3hNWqybkzDsJuPdA-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id BFB31833A09; Tue, 8 Nov 2022 04:12:49 +0000 (UTC) Received: from gshan.redhat.com (vpn2-54-78.bne.redhat.com [10.64.54.78]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D486C35429; Tue, 8 Nov 2022 04:12:43 +0000 (UTC) From: Gavin Shan To: kvmarm@lists.linux.dev Cc: kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, shuah@kernel.org, catalin.marinas@arm.com, andrew.jones@linux.dev, ajones@ventanamicro.com, bgardon@google.com, dmatlack@google.com, will@kernel.org, suzuki.poulose@arm.com, alexandru.elisei@arm.com, pbonzini@redhat.com, maz@kernel.org, peterx@redhat.com, oliver.upton@linux.dev, seanjc@google.com, zhenyzha@redhat.com, shan.gavin@gmail.com Subject: [PATCH v9 5/7] KVM: selftests: Use host page size to map ring buffer in dirty_log_test Date: Tue, 8 Nov 2022 12:10:37 +0800 Message-Id: <20221108041039.111145-6-gshan@redhat.com> In-Reply-To: <20221108041039.111145-1-gshan@redhat.com> References: <20221108041039.111145-1-gshan@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org In vcpu_map_dirty_ring(), the guest's page size is used to figure out the offset in the virtual area. It works fine when we have same page sizes on host and guest. However, it fails when the page sizes on host and guest are different on arm64, like below error messages indicates. # ./dirty_log_test -M dirty-ring -m 7 Setting log mode to: 'dirty-ring' Test iterations: 32, interval: 10 (ms) Testing guest mode: PA-bits:40, VA-bits:48, 64K pages guest physical test memory offset: 0xffbffc0000 vcpu stops because vcpu is kicked out... Notifying vcpu to continue vcpu continues now. ==== Test Assertion Failure ==== lib/kvm_util.c:1477: addr == MAP_FAILED pid=9000 tid=9000 errno=0 - Success 1 0x0000000000405f5b: vcpu_map_dirty_ring at kvm_util.c:1477 2 0x0000000000402ebb: dirty_ring_collect_dirty_pages at dirty_log_test.c:349 3 0x00000000004029b3: log_mode_collect_dirty_pages at dirty_log_test.c:478 4 (inlined by) run_test at dirty_log_test.c:778 5 (inlined by) run_test at dirty_log_test.c:691 6 0x0000000000403a57: for_each_guest_mode at guest_modes.c:105 7 0x0000000000401ccf: main at dirty_log_test.c:921 8 0x0000ffffb06ec79b: ?? ??:0 9 0x0000ffffb06ec86b: ?? ??:0 10 0x0000000000401def: _start at ??:? Dirty ring mapped private Fix the issue by using host's page size to map the ring buffer. Signed-off-by: Gavin Shan --- tools/testing/selftests/kvm/lib/kvm_util.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c index f1cb1627161f..89a1a420ebd5 100644 --- a/tools/testing/selftests/kvm/lib/kvm_util.c +++ b/tools/testing/selftests/kvm/lib/kvm_util.c @@ -1506,7 +1506,7 @@ struct kvm_reg_list *vcpu_get_reg_list(struct kvm_vcpu *vcpu) void *vcpu_map_dirty_ring(struct kvm_vcpu *vcpu) { - uint32_t page_size = vcpu->vm->page_size; + uint32_t page_size = getpagesize(); uint32_t size = vcpu->vm->dirty_ring_size; TEST_ASSERT(size > 0, "Should enable dirty ring first"); From patchwork Tue Nov 8 04:10:38 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gavin Shan X-Patchwork-Id: 13035835 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id F0D9FC433FE for ; Tue, 8 Nov 2022 04:14:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233410AbiKHEOb (ORCPT ); Mon, 7 Nov 2022 23:14:31 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43640 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233335AbiKHEN5 (ORCPT ); Mon, 7 Nov 2022 23:13:57 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 577651928B for ; Mon, 7 Nov 2022 20:13:03 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1667880782; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=cNQilMgvXDneE1h9HbtAPKvGFLnkNGwhukg91aqJDGY=; b=MSU9eagOVHK+bscPpBS/qHYAyF9c2EZ1ERzI+JkXe6yzMvRv4OfoOEmzCE4T/paw1jQ+y+ PxBlwgo7iEwbjZT4DUa9Syd4JrgjhK7J8MWgOcHl+pTFx+5qgkZtTy5+2+IvYMSKLdh9/I arOYsC+KlkRPHdJc7rpBigQtrxTQyHI= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-98-5Ab_Qd9BPAycxwXYtVQzpA-1; Mon, 07 Nov 2022 23:12:57 -0500 X-MC-Unique: 5Ab_Qd9BPAycxwXYtVQzpA-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 4720E833A06; Tue, 8 Nov 2022 04:12:56 +0000 (UTC) Received: from gshan.redhat.com (vpn2-54-78.bne.redhat.com [10.64.54.78]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 4E7AC4EA48; Tue, 8 Nov 2022 04:12:50 +0000 (UTC) From: Gavin Shan To: kvmarm@lists.linux.dev Cc: kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, shuah@kernel.org, catalin.marinas@arm.com, andrew.jones@linux.dev, ajones@ventanamicro.com, bgardon@google.com, dmatlack@google.com, will@kernel.org, suzuki.poulose@arm.com, alexandru.elisei@arm.com, pbonzini@redhat.com, maz@kernel.org, peterx@redhat.com, oliver.upton@linux.dev, seanjc@google.com, zhenyzha@redhat.com, shan.gavin@gmail.com Subject: [PATCH v9 6/7] KVM: selftests: Clear dirty ring states between two modes in dirty_log_test Date: Tue, 8 Nov 2022 12:10:38 +0800 Message-Id: <20221108041039.111145-7-gshan@redhat.com> In-Reply-To: <20221108041039.111145-1-gshan@redhat.com> References: <20221108041039.111145-1-gshan@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org There are two states, which need to be cleared before next mode is executed. Otherwise, we will hit failure as the following messages indicate. - The variable 'dirty_ring_vcpu_ring_full' shared by main and vcpu thread. It's indicating if the vcpu exit due to full ring buffer. The value can be carried from previous mode (VM_MODE_P40V48_4K) to current one (VM_MODE_P40V48_64K) when VM_MODE_P40V48_16K isn't supported. - The current ring buffer index needs to be reset before next mode (VM_MODE_P40V48_64K) is executed. Otherwise, the stale value is carried from previous mode (VM_MODE_P40V48_4K). # ./dirty_log_test -M dirty-ring Setting log mode to: 'dirty-ring' Test iterations: 32, interval: 10 (ms) Testing guest mode: PA-bits:40, VA-bits:48, 4K pages guest physical test memory offset: 0xffbfffc000 : Dirtied 995328 pages Total bits checked: dirty (1012434), clear (7114123), track_next (966700) Testing guest mode: PA-bits:40, VA-bits:48, 64K pages guest physical test memory offset: 0xffbffc0000 vcpu stops because vcpu is kicked out... vcpu continues now. Notifying vcpu to continue Iteration 1 collected 0 pages vcpu stops because dirty ring is full... vcpu continues now. vcpu stops because dirty ring is full... vcpu continues now. vcpu stops because dirty ring is full... ==== Test Assertion Failure ==== dirty_log_test.c:369: cleared == count pid=10541 tid=10541 errno=22 - Invalid argument 1 0x0000000000403087: dirty_ring_collect_dirty_pages at dirty_log_test.c:369 2 0x0000000000402a0b: log_mode_collect_dirty_pages at dirty_log_test.c:492 3 (inlined by) run_test at dirty_log_test.c:795 4 (inlined by) run_test at dirty_log_test.c:705 5 0x0000000000403a37: for_each_guest_mode at guest_modes.c:100 6 0x0000000000401ccf: main at dirty_log_test.c:938 7 0x0000ffff9ecd279b: ?? ??:0 8 0x0000ffff9ecd286b: ?? ??:0 9 0x0000000000401def: _start at ??:? Reset dirty pages (0) mismatch with collected (35566) Fix the issues by clearing 'dirty_ring_vcpu_ring_full' and the ring buffer index before next new mode is to be executed. Signed-off-by: Gavin Shan --- tools/testing/selftests/kvm/dirty_log_test.c | 27 ++++++++++++-------- 1 file changed, 17 insertions(+), 10 deletions(-) diff --git a/tools/testing/selftests/kvm/dirty_log_test.c b/tools/testing/selftests/kvm/dirty_log_test.c index b5234d6efbe1..8758c10ec850 100644 --- a/tools/testing/selftests/kvm/dirty_log_test.c +++ b/tools/testing/selftests/kvm/dirty_log_test.c @@ -226,13 +226,15 @@ static void clear_log_create_vm_done(struct kvm_vm *vm) } static void dirty_log_collect_dirty_pages(struct kvm_vcpu *vcpu, int slot, - void *bitmap, uint32_t num_pages) + void *bitmap, uint32_t num_pages, + uint32_t *unused) { kvm_vm_get_dirty_log(vcpu->vm, slot, bitmap); } static void clear_log_collect_dirty_pages(struct kvm_vcpu *vcpu, int slot, - void *bitmap, uint32_t num_pages) + void *bitmap, uint32_t num_pages, + uint32_t *unused) { kvm_vm_get_dirty_log(vcpu->vm, slot, bitmap); kvm_vm_clear_dirty_log(vcpu->vm, slot, bitmap, 0, num_pages); @@ -329,10 +331,9 @@ static void dirty_ring_continue_vcpu(void) } static void dirty_ring_collect_dirty_pages(struct kvm_vcpu *vcpu, int slot, - void *bitmap, uint32_t num_pages) + void *bitmap, uint32_t num_pages, + uint32_t *ring_buf_idx) { - /* We only have one vcpu */ - static uint32_t fetch_index = 0; uint32_t count = 0, cleared; bool continued_vcpu = false; @@ -349,7 +350,8 @@ static void dirty_ring_collect_dirty_pages(struct kvm_vcpu *vcpu, int slot, /* Only have one vcpu */ count = dirty_ring_collect_one(vcpu_map_dirty_ring(vcpu), - slot, bitmap, num_pages, &fetch_index); + slot, bitmap, num_pages, + ring_buf_idx); cleared = kvm_vm_reset_dirty_ring(vcpu->vm); @@ -406,7 +408,8 @@ struct log_mode { void (*create_vm_done)(struct kvm_vm *vm); /* Hook to collect the dirty pages into the bitmap provided */ void (*collect_dirty_pages) (struct kvm_vcpu *vcpu, int slot, - void *bitmap, uint32_t num_pages); + void *bitmap, uint32_t num_pages, + uint32_t *ring_buf_idx); /* Hook to call when after each vcpu run */ void (*after_vcpu_run)(struct kvm_vcpu *vcpu, int ret, int err); void (*before_vcpu_join) (void); @@ -471,13 +474,14 @@ static void log_mode_create_vm_done(struct kvm_vm *vm) } static void log_mode_collect_dirty_pages(struct kvm_vcpu *vcpu, int slot, - void *bitmap, uint32_t num_pages) + void *bitmap, uint32_t num_pages, + uint32_t *ring_buf_idx) { struct log_mode *mode = &log_modes[host_log_mode]; TEST_ASSERT(mode->collect_dirty_pages != NULL, "collect_dirty_pages() is required for any log mode!"); - mode->collect_dirty_pages(vcpu, slot, bitmap, num_pages); + mode->collect_dirty_pages(vcpu, slot, bitmap, num_pages, ring_buf_idx); } static void log_mode_after_vcpu_run(struct kvm_vcpu *vcpu, int ret, int err) @@ -696,6 +700,7 @@ static void run_test(enum vm_guest_mode mode, void *arg) struct kvm_vcpu *vcpu; struct kvm_vm *vm; unsigned long *bmap; + uint32_t ring_buf_idx = 0; if (!log_mode_supported()) { print_skip("Log mode '%s' not supported", @@ -771,6 +776,7 @@ static void run_test(enum vm_guest_mode mode, void *arg) host_dirty_count = 0; host_clear_count = 0; host_track_next_count = 0; + WRITE_ONCE(dirty_ring_vcpu_ring_full, false); pthread_create(&vcpu_thread, NULL, vcpu_worker, vcpu); @@ -778,7 +784,8 @@ static void run_test(enum vm_guest_mode mode, void *arg) /* Give the vcpu thread some time to dirty some pages */ usleep(p->interval * 1000); log_mode_collect_dirty_pages(vcpu, TEST_MEM_SLOT_INDEX, - bmap, host_num_pages); + bmap, host_num_pages, + &ring_buf_idx); /* * See vcpu_sync_stop_requested definition for details on why From patchwork Tue Nov 8 04:10:39 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gavin Shan X-Patchwork-Id: 13035836 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 36F3CC433FE for ; Tue, 8 Nov 2022 04:14:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233452AbiKHEOm (ORCPT ); Mon, 7 Nov 2022 23:14:42 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43646 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233379AbiKHEOM (ORCPT ); Mon, 7 Nov 2022 23:14:12 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DDECD22B3A for ; 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Tue, 8 Nov 2022 04:13:02 +0000 (UTC) Received: from gshan.redhat.com (vpn2-54-78.bne.redhat.com [10.64.54.78]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D584735429; Tue, 8 Nov 2022 04:12:56 +0000 (UTC) From: Gavin Shan To: kvmarm@lists.linux.dev Cc: kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, shuah@kernel.org, catalin.marinas@arm.com, andrew.jones@linux.dev, ajones@ventanamicro.com, bgardon@google.com, dmatlack@google.com, will@kernel.org, suzuki.poulose@arm.com, alexandru.elisei@arm.com, pbonzini@redhat.com, maz@kernel.org, peterx@redhat.com, oliver.upton@linux.dev, seanjc@google.com, zhenyzha@redhat.com, shan.gavin@gmail.com Subject: [PATCH v9 7/7] KVM: selftests: Automate choosing dirty ring size in dirty_log_test Date: Tue, 8 Nov 2022 12:10:39 +0800 Message-Id: <20221108041039.111145-8-gshan@redhat.com> In-Reply-To: <20221108041039.111145-1-gshan@redhat.com> References: <20221108041039.111145-1-gshan@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org In the dirty ring case, we rely on vcpu exit due to full dirty ring state. On ARM64 system, there are 4096 host pages when the host page size is 64KB. In this case, the vcpu never exits due to the full dirty ring state. The similar case is 4KB page size on host and 64KB page size on guest. The vcpu corrupts same set of host pages, but the dirty page information isn't collected in the main thread. This leads to infinite loop as the following log shows. # ./dirty_log_test -M dirty-ring -c 65536 -m 5 Setting log mode to: 'dirty-ring' Test iterations: 32, interval: 10 (ms) Testing guest mode: PA-bits:40, VA-bits:48, 4K pages guest physical test memory offset: 0xffbffe0000 vcpu stops because vcpu is kicked out... Notifying vcpu to continue vcpu continues now. Iteration 1 collected 576 pages Fix the issue by automatically choosing the best dirty ring size, to ensure vcpu exit due to full dirty ring state. The option '-c' becomes a hint to the dirty ring count, instead of the value of it. Signed-off-by: Gavin Shan --- tools/testing/selftests/kvm/dirty_log_test.c | 26 +++++++++++++++++--- 1 file changed, 22 insertions(+), 4 deletions(-) diff --git a/tools/testing/selftests/kvm/dirty_log_test.c b/tools/testing/selftests/kvm/dirty_log_test.c index 8758c10ec850..a87e5f78ebf1 100644 --- a/tools/testing/selftests/kvm/dirty_log_test.c +++ b/tools/testing/selftests/kvm/dirty_log_test.c @@ -24,6 +24,9 @@ #include "guest_modes.h" #include "processor.h" +#define DIRTY_MEM_BITS 30 /* 1G */ +#define PAGE_SHIFT_4K 12 + /* The memory slot index to track dirty pages */ #define TEST_MEM_SLOT_INDEX 1 @@ -273,6 +276,24 @@ static bool dirty_ring_supported(void) static void dirty_ring_create_vm_done(struct kvm_vm *vm) { + uint64_t pages; + uint32_t limit; + + /* + * We rely on vcpu exit due to full dirty ring state. Adjust + * the ring buffer size to ensure we're able to reach the + * full dirty ring state. + */ + pages = (1ul << (DIRTY_MEM_BITS - vm->page_shift)) + 3; + pages = vm_adjust_num_guest_pages(vm->mode, pages); + if (vm->page_size < getpagesize()) + pages = vm_num_host_pages(vm->mode, pages); + + limit = 1 << (31 - __builtin_clz(pages)); + test_dirty_ring_count = 1 << (31 - __builtin_clz(test_dirty_ring_count)); + test_dirty_ring_count = min(limit, test_dirty_ring_count); + pr_info("dirty ring count: 0x%x\n", test_dirty_ring_count); + /* * Switch to dirty ring mode after VM creation but before any * of the vcpu creation. @@ -685,9 +706,6 @@ static struct kvm_vm *create_vm(enum vm_guest_mode mode, struct kvm_vcpu **vcpu, return vm; } -#define DIRTY_MEM_BITS 30 /* 1G */ -#define PAGE_SHIFT_4K 12 - struct test_params { unsigned long iterations; unsigned long interval; @@ -830,7 +848,7 @@ static void help(char *name) printf("usage: %s [-h] [-i iterations] [-I interval] " "[-p offset] [-m mode]\n", name); puts(""); - printf(" -c: specify dirty ring size, in number of entries\n"); + printf(" -c: hint to dirty ring size, in number of entries\n"); printf(" (only useful for dirty-ring test; default: %"PRIu32")\n", TEST_DIRTY_RING_COUNT); printf(" -i: specify iteration counts (default: %"PRIu64")\n",