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>,
"Dr . David Alan Gilbert" <dgilbert@redhat.com>
Subject: Re: [PATCH v3 14/21] KVM: Don't allocate dirty bitmap if dirty ring is enabled
Date: Thu, 9 Jan 2020 11:41:02 -0500 [thread overview]
Message-ID: <20200109164102.GA36997@xz-x1> (raw)
In-Reply-To: <20200109145729.32898-15-peterx@redhat.com>
On Thu, Jan 09, 2020 at 09:57:22AM -0500, Peter Xu wrote:
> 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
>
I think below should be squashed as well into this patch:
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 621b842a9b7b..0806bd12d8ee 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -1308,7 +1308,7 @@ static inline bool memslot_valid_for_gpte(struct kvm_memory_slot *slot,
{
if (!slot || slot->flags & KVM_MEMSLOT_INVALID)
return false;
- if (no_dirty_log && slot->dirty_bitmap)
+ if (no_dirty_log && kvm_slot_dirty_track_enabled(slot))
return false;
return true;
Thanks,
--
Peter Xu
next prev parent reply other threads:[~2020-01-09 16:41 UTC|newest]
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 ` [PATCH v3 14/21] KVM: Don't allocate dirty bitmap if dirty ring is enabled Peter Xu
2020-01-09 16:41 ` Peter Xu [this message]
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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