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From: Peter Xu <peterx@redhat.com>
To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Christophe de Dinechin <dinechin@redhat.com>,
	"Michael S . Tsirkin" <mst@redhat.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Sean Christopherson <sean.j.christopherson@intel.com>,
	Yan Zhao <yan.y.zhao@intel.com>,
	Alex Williamson <alex.williamson@redhat.com>,
	Jason Wang <jasowang@redhat.com>,
	Kevin Kevin <kevin.tian@intel.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	peterx@redhat.com,
	"Dr . David Alan Gilbert" <dgilbert@redhat.com>
Subject: [PATCH v3 14/21] KVM: Don't allocate dirty bitmap if dirty ring is enabled
Date: Thu,  9 Jan 2020 09:57:22 -0500
Message-ID: <20200109145729.32898-15-peterx@redhat.com> (raw)
In-Reply-To: <20200109145729.32898-1-peterx@redhat.com>

Because kvm dirty rings and kvm dirty log is used in an exclusive way,
Let's avoid creating the dirty_bitmap when kvm dirty ring is enabled.
At the meantime, since the dirty_bitmap will be conditionally created
now, we can't use it as a sign of "whether this memory slot enabled
dirty tracking".  Change users like that to check against the kvm
memory slot flags.

Note that there still can be chances where the kvm memory slot got its
dirty_bitmap allocated, _if_ the memory slots are created before
enabling of the dirty rings and at the same time with the dirty
tracking capability enabled, they'll still with the dirty_bitmap.
However it should not hurt much (e.g., the bitmaps will always be
freed if they are there), and the real users normally won't trigger
this because dirty bit tracking flag should in most cases only be
applied to kvm slots only before migration starts, that should be far
latter than kvm initializes (VM starts).

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 include/linux/kvm_host.h | 5 +++++
 virt/kvm/kvm_main.c      | 5 +++--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index c96161c6a0c9..ab2a169b1264 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -353,6 +353,11 @@ struct kvm_memory_slot {
 	u8 as_id;
 };
 
+static inline bool kvm_slot_dirty_track_enabled(struct kvm_memory_slot *slot)
+{
+	return slot->flags & KVM_MEM_LOG_DIRTY_PAGES;
+}
+
 static inline unsigned long kvm_dirty_bitmap_bytes(struct kvm_memory_slot *memslot)
 {
 	return ALIGN(memslot->npages, BITS_PER_LONG) / 8;
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index f0f766183cb2..46da3169944f 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1120,7 +1120,8 @@ int __kvm_set_memory_region(struct kvm *kvm,
 	}
 
 	/* Allocate page dirty bitmap if needed */
-	if ((new.flags & KVM_MEM_LOG_DIRTY_PAGES) && !new.dirty_bitmap) {
+	if ((new.flags & KVM_MEM_LOG_DIRTY_PAGES) && !new.dirty_bitmap &&
+	    !kvm->dirty_ring_size) {
 		if (kvm_create_dirty_bitmap(&new) < 0)
 			goto out_free;
 	}
@@ -2309,7 +2310,7 @@ static void mark_page_dirty_in_slot(struct kvm *kvm,
 				    struct kvm_memory_slot *memslot,
 				    gfn_t gfn)
 {
-	if (memslot && memslot->dirty_bitmap) {
+	if (memslot && kvm_slot_dirty_track_enabled(memslot)) {
 		unsigned long rel_gfn = gfn - memslot->base_gfn;
 		u32 slot = (memslot->as_id << 16) | memslot->id;
 
-- 
2.24.1


  parent reply index

Thread overview: 82+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-09 14:57 [PATCH v3 00/21] KVM: Dirty ring interface Peter Xu
2020-01-09 14:57 ` [PATCH v3 01/21] vfio: introduce vfio_iova_rw to read/write a range of IOVAs Peter Xu
2020-01-09 14:57 ` [PATCH v3 02/21] drm/i915/gvt: subsitute kvm_read/write_guest with vfio_iova_rw Peter Xu
2020-01-09 14:57 ` [PATCH v3 03/21] KVM: Remove kvm_read_guest_atomic() Peter Xu
2020-01-09 14:57 ` [PATCH v3 04/21] KVM: Add build-time error check on kvm_run size Peter Xu
2020-01-09 14:57 ` [PATCH v3 05/21] KVM: X86: Change parameter for fast_page_fault tracepoint Peter Xu
2020-01-09 14:57 ` [PATCH v3 06/21] KVM: X86: Don't take srcu lock in init_rmode_identity_map() Peter Xu
2020-01-09 14:57 ` [PATCH v3 07/21] KVM: Cache as_id in kvm_memory_slot Peter Xu
2020-01-09 14:57 ` [PATCH v3 08/21] KVM: X86: Drop x86_set_memory_region() Peter Xu
2020-01-09 14:57 ` [PATCH v3 09/21] KVM: X86: Don't track dirty for KVM_SET_[TSS_ADDR|IDENTITY_MAP_ADDR] Peter Xu
2020-01-19  9:01   ` Paolo Bonzini
2020-01-20  6:45     ` Peter Xu
2020-01-21 15:56   ` Sean Christopherson
2020-01-21 16:14     ` Paolo Bonzini
2020-01-28  5:50     ` Peter Xu
2020-01-28 18:24       ` Sean Christopherson
2020-01-31 15:08         ` Peter Xu
2020-01-31 19:33           ` Sean Christopherson
2020-01-31 20:28             ` Peter Xu
2020-01-31 20:36               ` Sean Christopherson
2020-01-31 20:55                 ` Peter Xu
2020-01-31 21:29                   ` Sean Christopherson
2020-01-31 22:16                     ` Peter Xu
2020-01-31 22:20                       ` Sean Christopherson
2020-01-09 14:57 ` [PATCH v3 10/21] KVM: Pass in kvm pointer into mark_page_dirty_in_slot() Peter Xu
2020-01-09 14:57 ` [PATCH v3 11/21] KVM: Move running VCPU from ARM to common code Peter Xu
2020-01-09 14:57 ` [PATCH v3 12/21] KVM: X86: Implement ring-based dirty memory tracking Peter Xu
2020-01-09 16:29   ` Michael S. Tsirkin
2020-01-09 16:56     ` Alex Williamson
2020-01-09 19:21       ` Peter Xu
2020-01-09 19:36         ` Michael S. Tsirkin
2020-01-09 19:15     ` Peter Xu
2020-01-09 19:35       ` Michael S. Tsirkin
2020-01-09 20:19         ` Peter Xu
2020-01-09 22:18           ` Michael S. Tsirkin
2020-01-10 15:29             ` Peter Xu
2020-01-12  6:24               ` Michael S. Tsirkin
2020-01-14 20:01         ` Peter Xu
2020-01-15  6:50           ` Michael S. Tsirkin
2020-01-15 15:20             ` Peter Xu
2020-01-19  9:09       ` Paolo Bonzini
2020-01-19 10:12         ` Michael S. Tsirkin
2020-01-20  7:29           ` Peter Xu
2020-01-20  7:47             ` Michael S. Tsirkin
2020-01-21  8:29               ` Peter Xu
2020-01-21 10:25                 ` Paolo Bonzini
2020-01-21 10:24             ` Paolo Bonzini
2020-01-11  4:49   ` kbuild test robot
2020-01-11 23:19   ` kbuild test robot
2020-01-15  6:47   ` Michael S. Tsirkin
2020-01-15 15:27     ` Peter Xu
2020-01-16  8:38   ` Michael S. Tsirkin
2020-01-16 16:27     ` Peter Xu
2020-01-17  9:50       ` Michael S. Tsirkin
2020-01-20  6:48         ` Peter Xu
2020-01-09 14:57 ` [PATCH v3 13/21] KVM: Make dirty ring exclusive to dirty bitmap log Peter Xu
2020-01-09 14:57 ` Peter Xu [this message]
2020-01-09 16:41   ` [PATCH v3 14/21] KVM: Don't allocate dirty bitmap if dirty ring is enabled Peter Xu
2020-01-09 14:57 ` [PATCH v3 15/21] KVM: selftests: Always clear dirty bitmap after iteration Peter Xu
2020-01-09 14:57 ` [PATCH v3 16/21] KVM: selftests: Sync uapi/linux/kvm.h to tools/ Peter Xu
2020-01-09 14:57 ` [PATCH v3 17/21] KVM: selftests: Use a single binary for dirty/clear log test Peter Xu
2020-01-09 14:57 ` [PATCH v3 18/21] KVM: selftests: Introduce after_vcpu_run hook for dirty " Peter Xu
2020-01-09 14:57 ` [PATCH v3 19/21] KVM: selftests: Add dirty ring buffer test Peter Xu
2020-01-09 14:57 ` [PATCH v3 20/21] KVM: selftests: Let dirty_log_test async for dirty ring test Peter Xu
2020-01-09 14:57 ` [PATCH v3 21/21] KVM: selftests: Add "-c" parameter to dirty log test Peter Xu
2020-01-09 15:59 ` [PATCH v3 00/21] KVM: Dirty ring interface Michael S. Tsirkin
2020-01-09 16:17   ` Peter Xu
2020-01-09 16:40     ` Michael S. Tsirkin
2020-01-09 17:08       ` Peter Xu
2020-01-09 19:08         ` Michael S. Tsirkin
2020-01-09 19:39           ` Peter Xu
2020-01-09 20:42             ` Paolo Bonzini
2020-01-09 22:28             ` Michael S. Tsirkin
2020-01-10 15:10               ` Peter Xu
2020-01-09 16:47 ` Alex Williamson
2020-01-09 17:58   ` Peter Xu
2020-01-09 19:13     ` Michael S. Tsirkin
2020-01-09 19:23       ` Peter Xu
2020-01-09 19:37         ` Michael S. Tsirkin
2020-01-09 20:51       ` Paolo Bonzini
2020-01-09 22:21         ` Michael S. Tsirkin
2020-01-19  9:11 ` Paolo Bonzini

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