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* [PATCH v5 0/3] vfio/pci: Request resources and map BARs at enable time
From: Matt Evans @ 2026-05-11 14:58 UTC (permalink / raw)
  To: Alex Williamson, Kevin Tian, Jason Gunthorpe, Ankit Agrawal,
	Alistair Popple, Leon Romanovsky, Kees Cook, Shameer Kolothum,
	Yishai Hadas
  Cc: Alexey Kardashevskiy, Eric Auger, Peter Xu, Vivek Kasireddy,
	Zhi Wang, kvm, linux-kernel, virtualization

Hi,

These patches fix a potential race for concurrent calls to
vfio_pci_core_setup_barmap(), and a DMABUF missing check for resource
before the export.  Discussion on a previous series (different,
replaced by this one) is here:

 https://lore.kernel.org/kvm/20260415181423.1008458-1-mattev@meta.com

Responses in that thread indicated there wasn't a strong historical
reason to require the mapping to be performed on-demand at BAR
reference time.  It's much simpler to move this earlier, to
vfio_pci_core_enable(), and that then avoids having to deal with
concurrent requests later.

The first patch requests PCI resources and pci_iomap() of the BARs
from vfio_pci_core_enable(), moving this out of
vfio_pci_core_setup_barmap().

Some callers rely on vfio_pci_core_setup_barmap() for its ioremap()
effect, and other callers use it for its resource-acquiring effect.
The function turns into a cheap error check that both these actions
have occurred; that maintains the same error behaviour as before the
fix.

The second patch adds a call to vfio_pci_core_setup_barmap() to VFIO
DMABUF export to check the resource is reserved; previously this was
able to export an unrequested resource.  Although patch 1 at first
appears to fix this by requesting resources at enable time, code using
the BAR still needs to check the resource really was acquired.

(FWIW, Leon gave a R-B on v2 in
https://lore.kernel.org/kvm/20260426111606.GC440345@unreal/ though
this repost isn't 100% identical so I didn't propagate it.)

The third patch refactors vfio_pci_core_setup_barmap() plus the various
vdev->barmap[] accesses into vfio_pci_core_get_iomap() which returns
either a pointer to the mapping or an ERR_PTR() describing why it
doesn't exist.  This is used by callers that need the mapping, but
also by other callers to check that the resource/mapping step was
successful.


=== Changes ===

v5:
 - vfio_pci_core_map_bars() releases the region if the subsequent
   pci_iomap() fails
 - vfio_pci_core_disable() correctly tests for NULL/error
 - For nvgrace-gpu, check the result of vfio_pci_core_get_iomap() at
   open time then stash the BAR base for use later on.  Errors are
   checked up-front, and this avoids the perception that a
   later ..._get_iomap() might fail.

v4:
 https://lore.kernel.org/kvm/20260505173835.2324179-1-mattev@meta.com/
 - Reorder patches to put fixes at the front: First, the early BAR
   setup to avoid the race.  Then, add DMABUF check.  Then,
   refactor/tidy.

 - Adjust Fixes: of first patch to point to early VFIO PCI commit, and
   reduce the patch to only the fix (don't add new error checks).
   Use pci_dbg() instead of pci_warn() when setting up BAR
   resources.  Add barmap[] error checking to vfio_pci_core_disable().

 - Add barmap[]/BAR index error checking to vfio_pci_core_get_iomap(),
   and use WARN_ON_ONCE() since the conditions truly shouldn't happen.

v3:
  https://lore.kernel.org/kvm/20260430100340.2787446-1-mattev@meta.com/

 - Remove the separate tracking of the BAR mapping versus the
   acquiring its resource.  Errors from failing iomap vs resource
   reservation are ERR_PTR()-elcoded into barmap[bar].

 - Remove the separate test helper, and add vfio_pci_core_get_iomap().
   This gets the iomap base or is used check for error/failure to
   acquire the resource.  Added comments at call sites explaining
   whether they want to just ensure the resource is reserved versus
   actually use the mapping.

v2:
  https://lore.kernel.org/kvm/20260423182517.2286030-1-mattev@meta.com/

 - Don't fail if resources can't be requested or iomapped, even for
   valid BARs, as this would change the userspace-observable error
   behaviour.  Specifically, if there was an issue with one particular
   BAR which happened to never be used, then userspace would never
   encounter an error for it.  Track iomap and resource-acquisition
   status per BAR.

 - Break out the checks for resource success from those for iomap
   success, in the form of the two new helpers.

 - Third patch to add the check to VFIO DMABUF export, because
   init-time requests can now fail.

v1:
  https://lore.kernel.org/kvm/20260421174143.3883579-1-mattev@meta.com/


Matt Evans (3):
  vfio/pci: Set up BAR resources and maps in vfio_pci_core_enable()
  vfio/pci: Check BAR resources before exporting a DMABUF
  vfio/pci: Replace vfio_pci_core_setup_barmap() with
    vfio_pci_core_get_iomap()

 drivers/vfio/pci/nvgrace-gpu/main.c | 20 +++++++-----
 drivers/vfio/pci/vfio_pci_core.c    | 48 ++++++++++++++++++++++++-----
 drivers/vfio/pci/vfio_pci_dmabuf.c  |  6 ++--
 drivers/vfio/pci/vfio_pci_rdwr.c    | 42 +++++--------------------
 drivers/vfio/pci/virtio/legacy_io.c | 13 ++++----
 include/linux/vfio_pci_core.h       | 20 +++++++++++-
 6 files changed, 91 insertions(+), 58 deletions(-)

-- 
2.47.3


^ permalink raw reply

* [PATCH] vhost/vsock: Refuse the connection immediately when guest isn't ready
From: Polina Vishneva @ 2026-05-11 14:56 UTC (permalink / raw)
  To: linux-kernel
  Cc: netdev, virtualization, kvm, Eugenio Pérez, Jason Wang,
	Michael S. Tsirkin, Stefano Garzarella, Stefan Hajnoczi,
	Polina Vishneva, Denis V . Lunev

From: "Denis V. Lunev" <den@openvz.org>

When the host initiates an AF_VSOCK connect() to a guest that has not
yet loaded the virtio-vsock transport (i.e. still booting), the caller
blocks for VSOCK_DEFAULT_CONNECT_TIMEOUT (2 seconds), because
vhost_transport_do_send_pkt() silently exits when
vhost_vq_get_backend(vq) returns NULL.

If the guest doesn't start listening within this timeout, connect()
returns ETIMEDOUT.

This delay is usually pointless and it doesn't well align with our
behavior at other initialization stages: for example, if a connection is
attempted when the guest driver is already loaded, but when nothing is
listening yet, it returns ECONNRESET immediately without any wait.

Fix this by checking the RX virtqueue backend in
vhost_transport_send_pkt() before queuing. If the backend is NULL,
return -ECONNREFUSED immediately.

Signed-off-by: Denis V. Lunev <den@openvz.org>
Co-developed-by: Polina Vishneva <polina.vishneva@virtuozzo.com>
Signed-off-by: Polina Vishneva <polina.vishneva@virtuozzo.com>
---
 drivers/vhost/vsock.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index 1d8ec6bed53e..a3f218292c3a 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -302,6 +302,16 @@ vhost_transport_send_pkt(struct sk_buff *skb, struct net *net)
 		return -ENODEV;
 	}
 
+	/* Fast-fail if the guest hasn't enabled the RX vq yet. Reading
+	 * private_data without vq->mutex is deliberate: even if the backend becomes
+	 * NULL right after that check, do_send_pkt() checks it under the mutex.
+	 */
+	if (!data_race(READ_ONCE(vsock->vqs[VSOCK_VQ_RX].private_data))) {
+		rcu_read_unlock();
+		kfree_skb(skb);
+		return -ECONNREFUSED;
+	}
+
 	if (virtio_vsock_skb_reply(skb))
 		atomic_inc(&vsock->queued_replies);
 

base-commit: 8ab992f815d6736b5c7a6f5fd7bfe7bc106bb3dc
-- 
2.53.0


^ permalink raw reply related

* Re: [PATCH resend v6 01/30] mm: move vma_alloc_folio_noprof to page_alloc.c
From: Gregory Price @ 2026-05-11 14:47 UTC (permalink / raw)
  To: Michael S. Tsirkin
  Cc: linux-kernel, David Hildenbrand (Arm), Jason Wang, Xuan Zhuo,
	Eugenio Pérez, Muchun Song, Oscar Salvador, Andrew Morton,
	Lorenzo Stoakes, Liam R. Howlett, Vlastimil Babka, Mike Rapoport,
	Suren Baghdasaryan, Michal Hocko, Brendan Jackman,
	Johannes Weiner, Zi Yan, Baolin Wang, Nico Pache, Ryan Roberts,
	Dev Jain, Barry Song, Lance Yang, Hugh Dickins, Matthew Brost,
	Joshua Hahn, Rakie Kim, Byungchul Park, Ying Huang,
	Alistair Popple, Christoph Lameter, David Rientjes,
	Roman Gushchin, Harry Yoo, Axel Rasmussen, Yuanchu Xie, Wei Xu,
	Chris Li, Kairui Song, Kemeng Shi, Nhat Pham, Baoquan He,
	virtualization, linux-mm, Andrea Arcangeli, Liam R. Howlett
In-Reply-To: <a26c5850219e349f8a666282aa8003a82a4819b8.1778489843.git.mst@redhat.com>

On Mon, May 11, 2026 at 05:01:44AM -0400, Michael S. Tsirkin wrote:
> +#ifdef CONFIG_NUMA
> +/**
> + * vma_alloc_folio - Allocate a folio for a VMA.
> + * @gfp: GFP flags.
> + * @order: Order of the folio.
> + * @vma: Pointer to VMA.
> + * @addr: Virtual address of the allocation.  Must be inside @vma.
> + *
> + * Allocate a folio for a specific address in @vma, using the appropriate
> + * NUMA policy.  The caller must hold the mmap_lock of the mm_struct of the
> + * VMA to prevent it from going away.  Should be used for all allocations
> + * for folios that will be mapped into user space, excepting hugetlbfs, and
> + * excepting where direct use of folio_alloc_mpol() is more appropriate.
> + *
> + * Return: The folio on success or NULL if allocation fails.
> + */
> +struct folio *vma_alloc_folio_noprof(gfp_t gfp, int order,
> +		struct vm_area_struct *vma, unsigned long addr)
> +{
> +	struct mempolicy *pol;
> +	pgoff_t ilx;
> +	struct folio *folio;
> +
> +	if (vma->vm_flags & VM_DROPPABLE)
> +		gfp |= __GFP_NOWARN;
> +
> +	pol = get_vma_policy(vma, addr, order, &ilx);
> +	folio = folio_alloc_mpol_noprof(gfp, order, pol, ilx, numa_node_id());
> +	mpol_cond_put(pol);
> +	return folio;
> +}
> +#else
> +struct folio *vma_alloc_folio_noprof(gfp_t gfp, int order,
> +		struct vm_area_struct *vma, unsigned long addr)
> +{
> +	if (vma->vm_flags & VM_DROPPABLE)
> +		gfp |= __GFP_NOWARN;
> +
> +	return folio_alloc_noprof(gfp, order);
> +}
> +#endif

Can this ifdef not reasonably be done in a header?

I know the old path relied on basically mempolicy.c being in/out of
scope based on CONFIG_NUMA, but we should make an attempt at keeping
page_alloc.c clean on this if possible.

~Gregory

^ permalink raw reply

* Re: [PATCH net] vsock/virtio: fix skb overhead accounting to preserve full buf_alloc
From: Stefano Garzarella @ 2026-05-11 13:17 UTC (permalink / raw)
  To: Michael S. Tsirkin
  Cc: netdev, Eric Dumazet, Stefan Hajnoczi, virtualization,
	David S. Miller, Jason Wang, Simon Horman, linux-kernel,
	Paolo Abeni, Xuan Zhuo, kvm, Jakub Kicinski, Eugenio Pérez
In-Reply-To: <20260511084551-mutt-send-email-mst@kernel.org>

On Mon, 11 May 2026 at 14:46, Michael S. Tsirkin <mst@redhat.com> wrote:
>
> On Mon, May 11, 2026 at 12:54:44PM +0200, Stefano Garzarella wrote:
> > On Fri, 8 May 2026 at 12:38, Stefano Garzarella <sgarzare@redhat.com>
> > wrote:
> > >
> > > On Fri, May 08, 2026 at 06:33:13AM -0400, Michael S. Tsirkin wrote:
> > > >On Fri, May 08, 2026 at 12:01:50PM +0200, Stefano Garzarella wrote:
> > > >> On Fri, May 08, 2026 at 05:53:07AM -0400, Michael S. Tsirkin wrote:
> > > >> > On Fri, May 08, 2026 at 11:23:30AM +0200, Stefano Garzarella wrote:
> > > >> > > From: Stefano Garzarella <sgarzare@redhat.com>
> > > >> > >
> > > >> > > After commit 059b7dbd20a6 ("vsock/virtio: fix potential unbounded skb
> > > >> > > queue"), virtio_transport_inc_rx_pkt() subtracts per-skb overhead from
> > > >> > > buf_alloc when checking whether a new packet fits. This reduces the
> > > >> > > effective receive buffer below what the user configured via
> > > >> > > SO_VM_SOCKETS_BUFFER_SIZE, causing legitimate data packets to be
> > > >> > > silently dropped and applications that rely on the full buffer size
> > > >> > > to deadlock.
> > > >> > >
> > > >> > > Also, the reduced space is not communicated to the remote peer, so
> > > >> > > its credit calculation accounts more credit than the receiver will
> > > >> > > actually accept, causing data loss (there is no retransmission).
> > > >> > >
> > > >> > > This also causes failures in tools/testing/vsock/vsock_test.c.
> > > >> > > Test 18 sometimes fails, while test 22 always fails in this way:
> > > >> > >     18 - SOCK_STREAM MSG_ZEROCOPY...hash mismatch
> > > >> > >
> > > >> > >     22 - SOCK_STREAM virtio credit update + SO_RCVLOWAT...send failed:
> > > >> > >     Resource temporarily unavailable
> > > >> > >
> > > >> > > Fix this by introducing virtio_transport_rx_buf_size() to calculate the
> > > >> > > size of the RX buffer based on the overhead. Using it in the acceptance
> > > >> > > check, the advertised buf_alloc, and the credit update decision.
> > > >> > > Use buf_alloc * 2 as total budget (payload + overhead), similar to how
> > > >> > > SO_RCVBUF is doubled to reserve space for sk_buff metadata.
> > > >> > > The function returns buf_alloc as long as overhead fits within the
> > > >> > > reservation, then gradually reduces toward 0 as overhead exceeds
> > > >> > > buf_alloc (e.g. under small-packet flooding), informing the peer to
> > > >> > > slow down.
> > > >> > >
> > > >> > > Fixes: 059b7dbd20a6 ("vsock/virtio: fix potential unbounded skb queue")
> > > >> > > Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
> > > >> >
> > > >> >
> > > >> > unfortunately, this is a bit of a spec violation and there is no guarantee
> > > >> > it helps.
> > > >>
> > > >> Loosing data like we are doing in 059b7dbd20a6 is even worse IMHO.
> > > >>
> > > >> >
> > > >> > a spec violation because the spec says:
> > > >> > Only payload bytes are counted and header bytes are not
> > > >> > included
> > > >> >
> > > >> > and the implication is that a side can not reduce its own buf_alloc.
> > > >> >
> > > >> > no guarantee because the other side is not required to process your
> > > >> > packets, so it might not see your buf alloc reduction.
> > > >> >
> > > >> > as designed in the current spec, you can only increase your buf alloc,
> > > >> > not decrease it.
> > > >>
> > > >> We never enforced this, currently an user can reduce it by
> > > >> SO_VM_SOCKETS_BUFFER_SIZE and we haven't blocked it since virtio-vsock was
> > > >> introduced, should we update the spec?
> > > >
> > > >
> > > >it's not that we need to enforce it, it's that all synchronization
> > > >assumes this. as in, anyone can use an old copy until they run out
> > > >of credits.
> > > >
> > > >
> > > >> >
> > > >> > what can be done:
> > > >> > - more efficient storage for small packets (poc i posted)
> > > >> > - reduce buf alloc ahead of the time
> > > >>
> > > >> That's basically what I'm doing here: I'm using twice the size of
> > > >> `buf_alloc` (just like `SO_RCVBUF` does for other socket types) and telling
> > > >> the other peer just `buf_alloc`.
> > > >>
> > > >> But then, somehow, we have to let the other person know that we're running
> > > >> out of space. With this patch that only happens when the other peer isn't
> > > >> behaving properly, sending so many small packets that the overhead exceeds
> > > >> `buf_alloc`.
> > > >>
> > > >> Stefano
> > > >
> > > >what is "not proper" here, it is up to the application what to send.
> > >
> > > Sure, but here we're just slowing down the application by telling it we
> > > don't have any more space.
> > >
> > > Again, without this patch we are just dropping data, which IMO is even
> > > worse.
> > >
> > > So I think we should merge this for now, while we handle better the EOM.
> > > If you prefer, I can drop the part where we reduce the buf_alloc
> > > advertised to the other peer, but at least we should drop data after
> > > `buf_alloc * 2` IMO.
> >
> > Okay, I thought it over over the weekend, and I agree that this patch
> > still doesn't solve the problem and would still result in packet loss.
> > So, until we resolve the issue permanently, and since 059b7dbd20a6 is
> > coming to stable, I'd like to rework this patch so that we only start
> > dropping packets when the overhead plus the queued bytes exceeds
> > `buf_alloc * 2`.
> > Removing the other changes to reduce the buf_alloc advertised, but
> > terminating the connection so that both peers are aware that something
> > went wrong.
> >
> > Any objections?
> >
> > Stefano
>
> Let's try to first fix it upstream properly please. Discuss backporting
> later.

Commit 059b7dbd20a6 ("vsock/virtio: fix potential unbounded skb
queue") is already in Linus tree and will land soon on stable. Which
issue do you see on having a patch on top of that to close the
connection instead of losing data and breaking our test suite?

IMO we need that change in any case, because the previous code also
discarded packets without any notification, whereas breaking the
connection would be better in that case.

Stefano


^ permalink raw reply

* Re: [PATCH net] vsock/virtio: fix skb overhead accounting to preserve full buf_alloc
From: Michael S. Tsirkin @ 2026-05-11 12:46 UTC (permalink / raw)
  To: Stefano Garzarella
  Cc: netdev, Eric Dumazet, Stefan Hajnoczi, virtualization,
	David S. Miller, Jason Wang, Simon Horman, linux-kernel,
	Paolo Abeni, Xuan Zhuo, kvm, Jakub Kicinski, Eugenio Pérez
In-Reply-To: <CAGxU2F65pw0P1uKOOJpBc4p6KjCz8iePEh9aPybUyECBm1=otg@mail.gmail.com>

On Mon, May 11, 2026 at 12:54:44PM +0200, Stefano Garzarella wrote:
> On Fri, 8 May 2026 at 12:38, Stefano Garzarella <sgarzare@redhat.com> 
> wrote:
> >
> > On Fri, May 08, 2026 at 06:33:13AM -0400, Michael S. Tsirkin wrote:
> > >On Fri, May 08, 2026 at 12:01:50PM +0200, Stefano Garzarella wrote:
> > >> On Fri, May 08, 2026 at 05:53:07AM -0400, Michael S. Tsirkin wrote:
> > >> > On Fri, May 08, 2026 at 11:23:30AM +0200, Stefano Garzarella wrote:
> > >> > > From: Stefano Garzarella <sgarzare@redhat.com>
> > >> > >
> > >> > > After commit 059b7dbd20a6 ("vsock/virtio: fix potential unbounded skb
> > >> > > queue"), virtio_transport_inc_rx_pkt() subtracts per-skb overhead from
> > >> > > buf_alloc when checking whether a new packet fits. This reduces the
> > >> > > effective receive buffer below what the user configured via
> > >> > > SO_VM_SOCKETS_BUFFER_SIZE, causing legitimate data packets to be
> > >> > > silently dropped and applications that rely on the full buffer size
> > >> > > to deadlock.
> > >> > >
> > >> > > Also, the reduced space is not communicated to the remote peer, so
> > >> > > its credit calculation accounts more credit than the receiver will
> > >> > > actually accept, causing data loss (there is no retransmission).
> > >> > >
> > >> > > This also causes failures in tools/testing/vsock/vsock_test.c.
> > >> > > Test 18 sometimes fails, while test 22 always fails in this way:
> > >> > >     18 - SOCK_STREAM MSG_ZEROCOPY...hash mismatch
> > >> > >
> > >> > >     22 - SOCK_STREAM virtio credit update + SO_RCVLOWAT...send failed:
> > >> > >     Resource temporarily unavailable
> > >> > >
> > >> > > Fix this by introducing virtio_transport_rx_buf_size() to calculate the
> > >> > > size of the RX buffer based on the overhead. Using it in the acceptance
> > >> > > check, the advertised buf_alloc, and the credit update decision.
> > >> > > Use buf_alloc * 2 as total budget (payload + overhead), similar to how
> > >> > > SO_RCVBUF is doubled to reserve space for sk_buff metadata.
> > >> > > The function returns buf_alloc as long as overhead fits within the
> > >> > > reservation, then gradually reduces toward 0 as overhead exceeds
> > >> > > buf_alloc (e.g. under small-packet flooding), informing the peer to
> > >> > > slow down.
> > >> > >
> > >> > > Fixes: 059b7dbd20a6 ("vsock/virtio: fix potential unbounded skb queue")
> > >> > > Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
> > >> >
> > >> >
> > >> > unfortunately, this is a bit of a spec violation and there is no guarantee
> > >> > it helps.
> > >>
> > >> Loosing data like we are doing in 059b7dbd20a6 is even worse IMHO.
> > >>
> > >> >
> > >> > a spec violation because the spec says:
> > >> > Only payload bytes are counted and header bytes are not
> > >> > included
> > >> >
> > >> > and the implication is that a side can not reduce its own buf_alloc.
> > >> >
> > >> > no guarantee because the other side is not required to process your
> > >> > packets, so it might not see your buf alloc reduction.
> > >> >
> > >> > as designed in the current spec, you can only increase your buf alloc,
> > >> > not decrease it.
> > >>
> > >> We never enforced this, currently an user can reduce it by
> > >> SO_VM_SOCKETS_BUFFER_SIZE and we haven't blocked it since virtio-vsock was
> > >> introduced, should we update the spec?
> > >
> > >
> > >it's not that we need to enforce it, it's that all synchronization
> > >assumes this. as in, anyone can use an old copy until they run out
> > >of credits.
> > >
> > >
> > >> >
> > >> > what can be done:
> > >> > - more efficient storage for small packets (poc i posted)
> > >> > - reduce buf alloc ahead of the time
> > >>
> > >> That's basically what I'm doing here: I'm using twice the size of
> > >> `buf_alloc` (just like `SO_RCVBUF` does for other socket types) and telling
> > >> the other peer just `buf_alloc`.
> > >>
> > >> But then, somehow, we have to let the other person know that we're running
> > >> out of space. With this patch that only happens when the other peer isn't
> > >> behaving properly, sending so many small packets that the overhead exceeds
> > >> `buf_alloc`.
> > >>
> > >> Stefano
> > >
> > >what is "not proper" here, it is up to the application what to send.
> >
> > Sure, but here we're just slowing down the application by telling it we
> > don't have any more space.
> >
> > Again, without this patch we are just dropping data, which IMO is even
> > worse.
> >
> > So I think we should merge this for now, while we handle better the EOM.
> > If you prefer, I can drop the part where we reduce the buf_alloc
> > advertised to the other peer, but at least we should drop data after
> > `buf_alloc * 2` IMO.
> 
> Okay, I thought it over over the weekend, and I agree that this patch 
> still doesn't solve the problem and would still result in packet loss.
> So, until we resolve the issue permanently, and since 059b7dbd20a6 is 
> coming to stable, I'd like to rework this patch so that we only start 
> dropping packets when the overhead plus the queued bytes exceeds 
> `buf_alloc * 2`.
> Removing the other changes to reduce the buf_alloc advertised, but 
> terminating the connection so that both peers are aware that something 
> went wrong.
> 
> Any objections?
> 
> Stefano

Let's try to first fix it upstream properly please. Discuss backporting
later.

-- 
MST


^ permalink raw reply

* [PATCH v2 10/10] drm/vmwgfx: Remove unused field struct vmwgfx_du_update_plane.old_state
From: Thomas Zimmermann @ 2026-05-11 12:22 UTC (permalink / raw)
  To: mripard, maarten.lankhorst, airlied, airlied, simona, admin,
	gargaditya08, paul, zack.rusin, bcm-kernel-feedback-list
  Cc: dri-devel, linux-hyperv, intel-gfx, intel-xe, linux-mips,
	virtualization, Thomas Zimmermann
In-Reply-To: <20260511122421.114014-1-tzimmermann@suse.de>

Plane updates no longer require the old plane state. Remove the field
from struct vmwgfx_du_update_plane and fix all callers.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/gpu/drm/vmwgfx/vmwgfx_kms.h  |  2 --
 drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c | 12 ++----------
 drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c | 11 ++---------
 3 files changed, 4 insertions(+), 21 deletions(-)

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.h b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.h
index 2224d7d91d1b..8c2072b82062 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.h
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.h
@@ -19,7 +19,6 @@
 /**
  * struct vmw_du_update_plane - Closure structure for vmw_du_helper_plane_update
  * @plane: Plane which is being updated.
- * @old_state: Old state of plane.
  * @dev_priv: Device private.
  * @du: Display unit on which to update the plane.
  * @vfb: Framebuffer which is blitted to display unit.
@@ -102,7 +101,6 @@ struct vmw_du_update_plane {
 				    struct drm_rect *bb);
 
 	struct drm_plane *plane;
-	struct drm_plane_state *old_state;
 	struct vmw_private *dev_priv;
 	struct vmw_display_unit *du;
 	struct vmw_framebuffer *vfb;
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c b/drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c
index c83061cf7455..fa84bc7ab5bb 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c
@@ -530,7 +530,6 @@ static uint32_t vmw_stud_bo_post_clip(struct vmw_du_update_plane  *update,
  */
 static int vmw_sou_plane_update_bo(struct vmw_private *dev_priv,
 				   struct drm_plane *plane,
-				   struct drm_plane_state *old_state,
 				   struct vmw_framebuffer *vfb,
 				   struct vmw_fence_obj **out_fence)
 {
@@ -538,7 +537,6 @@ static int vmw_sou_plane_update_bo(struct vmw_private *dev_priv,
 
 	memset(&bo_update, 0, sizeof(struct vmw_du_update_plane_buffer));
 	bo_update.base.plane = plane;
-	bo_update.base.old_state = old_state;
 	bo_update.base.dev_priv = dev_priv;
 	bo_update.base.du = vmw_crtc_to_du(plane->state->crtc);
 	bo_update.base.vfb = vfb;
@@ -692,7 +690,6 @@ static uint32_t vmw_sou_surface_post_clip(struct vmw_du_update_plane *update,
  */
 static int vmw_sou_plane_update_surface(struct vmw_private *dev_priv,
 					struct drm_plane *plane,
-					struct drm_plane_state *old_state,
 					struct vmw_framebuffer *vfb,
 					struct vmw_fence_obj **out_fence)
 {
@@ -700,7 +697,6 @@ static int vmw_sou_plane_update_surface(struct vmw_private *dev_priv,
 
 	memset(&srf_update, 0, sizeof(struct vmw_du_update_plane_surface));
 	srf_update.base.plane = plane;
-	srf_update.base.old_state = old_state;
 	srf_update.base.dev_priv = dev_priv;
 	srf_update.base.du = vmw_crtc_to_du(plane->state->crtc);
 	srf_update.base.vfb = vfb;
@@ -721,7 +717,6 @@ static void
 vmw_sou_primary_plane_atomic_update(struct drm_plane *plane,
 				    struct drm_atomic_commit *state)
 {
-	struct drm_plane_state *old_state = drm_atomic_get_old_plane_state(state, plane);
 	struct drm_plane_state *new_state = drm_atomic_get_new_plane_state(state, plane);
 	struct drm_crtc *crtc = new_state->crtc;
 	struct vmw_fence_obj *fence = NULL;
@@ -734,12 +729,9 @@ vmw_sou_primary_plane_atomic_update(struct drm_plane *plane,
 			vmw_framebuffer_to_vfb(new_state->fb);
 
 		if (vfb->bo)
-			ret = vmw_sou_plane_update_bo(dev_priv, plane,
-						      old_state, vfb, &fence);
+			ret = vmw_sou_plane_update_bo(dev_priv, plane, vfb, &fence);
 		else
-			ret = vmw_sou_plane_update_surface(dev_priv, plane,
-							   old_state, vfb,
-							   &fence);
+			ret = vmw_sou_plane_update_surface(dev_priv, plane, vfb, &fence);
 		if (ret != 0)
 			DRM_ERROR("Failed to update screen.\n");
 	} else {
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c b/drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c
index f0df2b1c8465..474e3badb80f 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c
@@ -1240,7 +1240,6 @@ vmw_stdu_bo_populate_update_cpu(struct vmw_du_update_plane  *update, void *cmd,
  */
 static int vmw_stdu_plane_update_bo(struct vmw_private *dev_priv,
 				    struct drm_plane *plane,
-				    struct drm_plane_state *old_state,
 				    struct vmw_framebuffer *vfb,
 				    struct vmw_fence_obj **out_fence)
 {
@@ -1248,7 +1247,6 @@ static int vmw_stdu_plane_update_bo(struct vmw_private *dev_priv,
 
 	memset(&bo_update, 0, sizeof(struct vmw_du_update_plane_buffer));
 	bo_update.base.plane = plane;
-	bo_update.base.old_state = old_state;
 	bo_update.base.dev_priv = dev_priv;
 	bo_update.base.du = vmw_crtc_to_du(plane->state->crtc);
 	bo_update.base.vfb = vfb;
@@ -1350,7 +1348,6 @@ vmw_stdu_surface_populate_update(struct vmw_du_update_plane  *update, void *cmd,
  */
 static int vmw_stdu_plane_update_surface(struct vmw_private *dev_priv,
 					 struct drm_plane *plane,
-					 struct drm_plane_state *old_state,
 					 struct vmw_framebuffer *vfb,
 					 struct vmw_fence_obj **out_fence)
 {
@@ -1363,7 +1360,6 @@ static int vmw_stdu_plane_update_surface(struct vmw_private *dev_priv,
 
 	memset(&srf_update, 0, sizeof(struct vmw_du_update_plane));
 	srf_update.plane = plane;
-	srf_update.old_state = old_state;
 	srf_update.dev_priv = dev_priv;
 	srf_update.du = vmw_crtc_to_du(plane->state->crtc);
 	srf_update.vfb = vfb;
@@ -1424,12 +1420,9 @@ vmw_stdu_primary_plane_atomic_update(struct drm_plane *plane,
 			DRM_ERROR("Failed to bind surface to STDU.\n");
 
 		if (vfb->bo)
-			ret = vmw_stdu_plane_update_bo(dev_priv, plane,
-						       old_state, vfb, &fence);
+			ret = vmw_stdu_plane_update_bo(dev_priv, plane, vfb, &fence);
 		else
-			ret = vmw_stdu_plane_update_surface(dev_priv, plane,
-							    old_state, vfb,
-							    &fence);
+			ret = vmw_stdu_plane_update_surface(dev_priv, plane, vfb, &fence);
 		if (ret)
 			DRM_ERROR("Failed to update STDU.\n");
 	} else {
-- 
2.54.0


^ permalink raw reply related

* [PATCH v2 09/10] drm/damage-helper: Rename state parameters in damage helpers
From: Thomas Zimmermann @ 2026-05-11 12:22 UTC (permalink / raw)
  To: mripard, maarten.lankhorst, airlied, airlied, simona, admin,
	gargaditya08, paul, zack.rusin, bcm-kernel-feedback-list
  Cc: dri-devel, linux-hyperv, intel-gfx, intel-xe, linux-mips,
	virtualization, Thomas Zimmermann
In-Reply-To: <20260511122421.114014-1-tzimmermann@suse.de>

Rename some of the state parameters of the damage-helper functions to
align them with each other and other helpers. No functional changes.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/gpu/drm/drm_damage_helper.c | 20 ++++++++++----------
 include/drm/drm_damage_helper.h     |  4 ++--
 2 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/drm_damage_helper.c b/drivers/gpu/drm/drm_damage_helper.c
index 28b847636253..23701e5c51b7 100644
--- a/drivers/gpu/drm/drm_damage_helper.c
+++ b/drivers/gpu/drm/drm_damage_helper.c
@@ -209,7 +209,7 @@ EXPORT_SYMBOL(drm_atomic_helper_dirtyfb);
 /**
  * drm_atomic_helper_damage_iter_init - Initialize the damage iterator.
  * @iter: The iterator to initialize.
- * @state: Plane state from which to iterate the damage clips.
+ * @plane_state: Plane state from which to iterate the damage clips.
  *
  * Initialize an iterator, which clips plane damage
  * &drm_plane_state.fb_damage_clips to plane &drm_plane_state.src. This iterator
@@ -225,26 +225,26 @@ EXPORT_SYMBOL(drm_atomic_helper_dirtyfb);
  */
 void
 drm_atomic_helper_damage_iter_init(struct drm_atomic_helper_damage_iter *iter,
-				   const struct drm_plane_state *state)
+				   const struct drm_plane_state *plane_state)
 {
 	struct drm_rect src;
 	memset(iter, 0, sizeof(*iter));
 
-	if (!state || !state->crtc || !state->fb || !state->visible)
+	if (!plane_state || !plane_state->crtc || !plane_state->fb || !plane_state->visible)
 		return;
 
-	iter->clips = (struct drm_rect *)drm_plane_get_damage_clips(state);
-	iter->num_clips = drm_plane_get_damage_clips_count(state);
+	iter->clips = (struct drm_rect *)drm_plane_get_damage_clips(plane_state);
+	iter->num_clips = drm_plane_get_damage_clips_count(plane_state);
 
 	/* Round down for x1/y1 and round up for x2/y2 to catch all pixels */
-	src = drm_plane_state_src(state);
+	src = drm_plane_state_src(plane_state);
 
 	iter->plane_src.x1 = src.x1 >> 16;
 	iter->plane_src.y1 = src.y1 >> 16;
 	iter->plane_src.x2 = (src.x2 >> 16) + !!(src.x2 & 0xFFFF);
 	iter->plane_src.y2 = (src.y2 >> 16) + !!(src.y2 & 0xFFFF);
 
-	if (!iter->clips || state->ignore_damage_clips) {
+	if (!iter->clips || plane_state->ignore_damage_clips) {
 		iter->clips = NULL;
 		iter->num_clips = 0;
 		iter->full_update = true;
@@ -296,7 +296,7 @@ EXPORT_SYMBOL(drm_atomic_helper_damage_iter_next);
 
 /**
  * drm_atomic_helper_damage_merged - Merged plane damage
- * @state: Plane state from which to iterate the damage clips.
+ * @plane_state: Plane state from which to iterate the damage clips.
  * @rect: Returns the merged damage rectangle
  *
  * This function merges any valid plane damage clips into one rectangle and
@@ -308,7 +308,7 @@ EXPORT_SYMBOL(drm_atomic_helper_damage_iter_next);
  * Returns:
  * True if there is valid plane damage otherwise false.
  */
-bool drm_atomic_helper_damage_merged(const struct drm_plane_state *state,
+bool drm_atomic_helper_damage_merged(const struct drm_plane_state *plane_state,
 				     struct drm_rect *rect)
 {
 	struct drm_atomic_helper_damage_iter iter;
@@ -320,7 +320,7 @@ bool drm_atomic_helper_damage_merged(const struct drm_plane_state *state,
 	rect->x2 = 0;
 	rect->y2 = 0;
 
-	drm_atomic_helper_damage_iter_init(&iter, state);
+	drm_atomic_helper_damage_iter_init(&iter, plane_state);
 	drm_atomic_for_each_plane_damage(&iter, &clip) {
 		rect->x1 = min(rect->x1, clip.x1);
 		rect->y1 = min(rect->y1, clip.y1);
diff --git a/include/drm/drm_damage_helper.h b/include/drm/drm_damage_helper.h
index b5a4de779db6..4a1ac47b9051 100644
--- a/include/drm/drm_damage_helper.h
+++ b/include/drm/drm_damage_helper.h
@@ -73,11 +73,11 @@ int drm_atomic_helper_dirtyfb(struct drm_framebuffer *fb,
 			      unsigned int num_clips);
 void
 drm_atomic_helper_damage_iter_init(struct drm_atomic_helper_damage_iter *iter,
-				   const struct drm_plane_state *state);
+				   const struct drm_plane_state *plane_state);
 bool
 drm_atomic_helper_damage_iter_next(struct drm_atomic_helper_damage_iter *iter,
 				   struct drm_rect *rect);
-bool drm_atomic_helper_damage_merged(const struct drm_plane_state *state,
+bool drm_atomic_helper_damage_merged(const struct drm_plane_state *plane_state,
 				     struct drm_rect *rect);
 
 #endif
-- 
2.54.0


^ permalink raw reply related

* [PATCH v2 08/10] drm/atomic_helper: Do not evaluate plane damage before atomic_check
From: Thomas Zimmermann @ 2026-05-11 12:22 UTC (permalink / raw)
  To: mripard, maarten.lankhorst, airlied, airlied, simona, admin,
	gargaditya08, paul, zack.rusin, bcm-kernel-feedback-list
  Cc: dri-devel, linux-hyperv, intel-gfx, intel-xe, linux-mips,
	virtualization, Thomas Zimmermann
In-Reply-To: <20260511122421.114014-1-tzimmermann@suse.de>

Remove the call to drm_atomic_helper_check_plane_damage() from before
calling the atomic_check helpers. The call has no longer any purpose,
as the actual evaluation happens after running atomic_check.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/gpu/drm/drm_atomic_helper.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 823ce60d45b4..57ffa8c8d641 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -1034,8 +1034,6 @@ drm_atomic_helper_check_planes(struct drm_device *dev,
 
 		drm_atomic_helper_plane_changed(state, old_plane_state, new_plane_state, plane);
 
-		drm_atomic_helper_check_plane_damage(state, old_plane_state, new_plane_state);
-
 		if (!funcs || !funcs->atomic_check)
 			continue;
 
-- 
2.54.0


^ permalink raw reply related

* [PATCH v2 07/10] drm/damage-helper: Remove old state from drm_atomic_helper_damage_merged()
From: Thomas Zimmermann @ 2026-05-11 12:22 UTC (permalink / raw)
  To: mripard, maarten.lankhorst, airlied, airlied, simona, admin,
	gargaditya08, paul, zack.rusin, bcm-kernel-feedback-list
  Cc: dri-devel, linux-hyperv, intel-gfx, intel-xe, linux-mips,
	virtualization, Thomas Zimmermann
In-Reply-To: <20260511122421.114014-1-tzimmermann@suse.de>

Nothing in drm_atomic_helper_damage_merged() requires the old
plane state. Remove the parameter and mass-convert callers.

Most callers now no longer require the old plane state in their plane's
atomic_update helper. Remove it as well.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/gpu/drm/ast/ast_cursor.c           |  3 +--
 drivers/gpu/drm/drm_damage_helper.c        |  4 +---
 drivers/gpu/drm/drm_mipi_dbi.c             |  3 +--
 drivers/gpu/drm/i915/display/intel_plane.c | 11 ++---------
 drivers/gpu/drm/i915/display/intel_psr.c   |  3 +--
 drivers/gpu/drm/sitronix/st7586.c          |  3 +--
 drivers/gpu/drm/tiny/gm12u320.c            |  2 +-
 drivers/gpu/drm/tiny/ili9225.c             |  3 +--
 drivers/gpu/drm/tiny/repaper.c             |  2 +-
 drivers/gpu/drm/tiny/sharp-memory.c        |  3 +--
 drivers/gpu/drm/virtio/virtgpu_plane.c     |  2 +-
 drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c       |  4 +---
 include/drm/drm_damage_helper.h            |  3 +--
 13 files changed, 14 insertions(+), 32 deletions(-)

diff --git a/drivers/gpu/drm/ast/ast_cursor.c b/drivers/gpu/drm/ast/ast_cursor.c
index fd19c45f2abe..12d5f93eec5f 100644
--- a/drivers/gpu/drm/ast/ast_cursor.c
+++ b/drivers/gpu/drm/ast/ast_cursor.c
@@ -251,7 +251,6 @@ static void ast_cursor_plane_helper_atomic_update(struct drm_plane *plane,
 	struct drm_plane_state *plane_state = drm_atomic_get_new_plane_state(state, plane);
 	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
 	struct drm_framebuffer *fb = plane_state->fb;
-	struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(state, plane);
 	struct ast_device *ast = to_ast_device(plane->dev);
 	struct drm_rect damage;
 	u64 dst_off = ast_plane->offset;
@@ -266,7 +265,7 @@ static void ast_cursor_plane_helper_atomic_update(struct drm_plane *plane,
 	 * engine to the offset.
 	 */
 
-	if (drm_atomic_helper_damage_merged(old_plane_state, plane_state, &damage)) {
+	if (drm_atomic_helper_damage_merged(plane_state, &damage)) {
 		const u8 *argb4444 = ast_cursor_plane_get_argb4444(ast_cursor_plane,
 								   shadow_plane_state,
 								   &damage);
diff --git a/drivers/gpu/drm/drm_damage_helper.c b/drivers/gpu/drm/drm_damage_helper.c
index 28f26234523d..28b847636253 100644
--- a/drivers/gpu/drm/drm_damage_helper.c
+++ b/drivers/gpu/drm/drm_damage_helper.c
@@ -296,7 +296,6 @@ EXPORT_SYMBOL(drm_atomic_helper_damage_iter_next);
 
 /**
  * drm_atomic_helper_damage_merged - Merged plane damage
- * @old_state: Old plane state for validation.
  * @state: Plane state from which to iterate the damage clips.
  * @rect: Returns the merged damage rectangle
  *
@@ -309,8 +308,7 @@ EXPORT_SYMBOL(drm_atomic_helper_damage_iter_next);
  * Returns:
  * True if there is valid plane damage otherwise false.
  */
-bool drm_atomic_helper_damage_merged(const struct drm_plane_state *old_state,
-				     const struct drm_plane_state *state,
+bool drm_atomic_helper_damage_merged(const struct drm_plane_state *state,
 				     struct drm_rect *rect)
 {
 	struct drm_atomic_helper_damage_iter iter;
diff --git a/drivers/gpu/drm/drm_mipi_dbi.c b/drivers/gpu/drm/drm_mipi_dbi.c
index 25cf04d029f7..4da201c38c93 100644
--- a/drivers/gpu/drm/drm_mipi_dbi.c
+++ b/drivers/gpu/drm/drm_mipi_dbi.c
@@ -380,7 +380,6 @@ void drm_mipi_dbi_plane_helper_atomic_update(struct drm_plane *plane,
 	struct drm_plane_state *plane_state = plane->state;
 	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
 	struct drm_framebuffer *fb = plane_state->fb;
-	struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(state, plane);
 	struct drm_rect rect;
 	int idx;
 
@@ -388,7 +387,7 @@ void drm_mipi_dbi_plane_helper_atomic_update(struct drm_plane *plane,
 		return;
 
 	if (drm_dev_enter(plane->dev, &idx)) {
-		if (drm_atomic_helper_damage_merged(old_plane_state, plane_state, &rect))
+		if (drm_atomic_helper_damage_merged(plane_state, &rect))
 			mipi_dbi_fb_dirty(&shadow_plane_state->data[0], fb, &rect,
 					  &shadow_plane_state->fmtcnv_state);
 		drm_dev_exit(idx);
diff --git a/drivers/gpu/drm/i915/display/intel_plane.c b/drivers/gpu/drm/i915/display/intel_plane.c
index c181a7d063ec..57107cce9267 100644
--- a/drivers/gpu/drm/i915/display/intel_plane.c
+++ b/drivers/gpu/drm/i915/display/intel_plane.c
@@ -346,7 +346,6 @@ static void intel_plane_clear_hw_state(struct intel_plane_state *plane_state)
 
 static void
 intel_plane_copy_uapi_plane_damage(struct intel_plane_state *new_plane_state,
-				   const struct intel_plane_state *old_uapi_plane_state,
 				   const struct intel_plane_state *new_uapi_plane_state)
 {
 	struct intel_display *display = to_intel_display(new_plane_state);
@@ -356,10 +355,9 @@ intel_plane_copy_uapi_plane_damage(struct intel_plane_state *new_plane_state,
 	if (DISPLAY_VER(display) < 12)
 		return;
 
-	if (!drm_atomic_helper_damage_merged(&old_uapi_plane_state->uapi,
-					     &new_uapi_plane_state->uapi,
+	if (!drm_atomic_helper_damage_merged(&new_uapi_plane_state->uapi,
 					     damage))
-		/* Incase helper fails, mark whole plane region as damage */
+		/* In case the helper fails, mark whole plane region as damage */
 		*damage = drm_plane_state_src(&new_uapi_plane_state->uapi);
 }
 
@@ -815,7 +813,6 @@ static int plane_atomic_check(struct intel_atomic_state *state,
 	const struct intel_plane_state *old_plane_state =
 		intel_atomic_get_old_plane_state(state, plane);
 	const struct intel_plane_state *new_primary_crtc_plane_state;
-	const struct intel_plane_state *old_primary_crtc_plane_state;
 	struct intel_crtc *crtc = intel_crtc_for_pipe(display, plane->pipe);
 	const struct intel_crtc_state *old_crtc_state =
 		intel_atomic_get_old_crtc_state(state, crtc);
@@ -830,15 +827,11 @@ static int plane_atomic_check(struct intel_atomic_state *state,
 
 		new_primary_crtc_plane_state =
 			intel_atomic_get_new_plane_state(state, primary_crtc_plane);
-		old_primary_crtc_plane_state =
-			intel_atomic_get_old_plane_state(state, primary_crtc_plane);
 	} else {
 		new_primary_crtc_plane_state = new_plane_state;
-		old_primary_crtc_plane_state = old_plane_state;
 	}
 
 	intel_plane_copy_uapi_plane_damage(new_plane_state,
-					   old_primary_crtc_plane_state,
 					   new_primary_crtc_plane_state);
 
 	intel_plane_copy_uapi_to_hw_state(new_plane_state,
diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
index 9958230a3dd9..adb936806488 100644
--- a/drivers/gpu/drm/i915/display/intel_psr.c
+++ b/drivers/gpu/drm/i915/display/intel_psr.c
@@ -2970,8 +2970,7 @@ int intel_psr2_sel_fetch_update(struct intel_atomic_state *state,
 		src = drm_plane_state_src(&new_plane_state->uapi);
 		drm_rect_fp_to_int(&src, &src);
 
-		if (!drm_atomic_helper_damage_merged(&old_plane_state->uapi,
-						     &new_plane_state->uapi, &damaged_area))
+		if (!drm_atomic_helper_damage_merged(&new_plane_state->uapi, &damaged_area))
 			continue;
 
 		damaged_area.y1 += new_plane_state->uapi.dst.y1 - src.y1;
diff --git a/drivers/gpu/drm/sitronix/st7586.c b/drivers/gpu/drm/sitronix/st7586.c
index 28b2245f6b79..2cc0312595a4 100644
--- a/drivers/gpu/drm/sitronix/st7586.c
+++ b/drivers/gpu/drm/sitronix/st7586.c
@@ -176,7 +176,6 @@ static void st7586_plane_helper_atomic_update(struct drm_plane *plane,
 	struct drm_plane_state *plane_state = plane->state;
 	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
 	struct drm_framebuffer *fb = plane_state->fb;
-	struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(state, plane);
 	struct drm_rect rect;
 	int idx;
 
@@ -186,7 +185,7 @@ static void st7586_plane_helper_atomic_update(struct drm_plane *plane,
 	if (!drm_dev_enter(plane->dev, &idx))
 		return;
 
-	if (drm_atomic_helper_damage_merged(old_plane_state, plane_state, &rect))
+	if (drm_atomic_helper_damage_merged(plane_state, &rect))
 		st7586_fb_dirty(&shadow_plane_state->data[0], fb, &rect,
 				&shadow_plane_state->fmtcnv_state);
 
diff --git a/drivers/gpu/drm/tiny/gm12u320.c b/drivers/gpu/drm/tiny/gm12u320.c
index d73dfebb4353..880b965e283a 100644
--- a/drivers/gpu/drm/tiny/gm12u320.c
+++ b/drivers/gpu/drm/tiny/gm12u320.c
@@ -582,7 +582,7 @@ static void gm12u320_pipe_update(struct drm_simple_display_pipe *pipe,
 	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(state);
 	struct drm_rect rect;
 
-	if (drm_atomic_helper_damage_merged(old_state, state, &rect))
+	if (drm_atomic_helper_damage_merged(state, &rect))
 		gm12u320_fb_mark_dirty(state->fb, &shadow_plane_state->data[0], &rect);
 }
 
diff --git a/drivers/gpu/drm/tiny/ili9225.c b/drivers/gpu/drm/tiny/ili9225.c
index 5bf52a8fd75b..d821a659a585 100644
--- a/drivers/gpu/drm/tiny/ili9225.c
+++ b/drivers/gpu/drm/tiny/ili9225.c
@@ -185,7 +185,6 @@ static void ili9225_plane_helper_atomic_update(struct drm_plane *plane,
 	struct drm_plane_state *plane_state = plane->state;
 	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
 	struct drm_framebuffer *fb = plane_state->fb;
-	struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(state, plane);
 	struct drm_rect rect;
 	int idx;
 
@@ -195,7 +194,7 @@ static void ili9225_plane_helper_atomic_update(struct drm_plane *plane,
 	if (!drm_dev_enter(drm, &idx))
 		return;
 
-	if (drm_atomic_helper_damage_merged(old_plane_state, plane_state, &rect))
+	if (drm_atomic_helper_damage_merged(plane_state, &rect))
 		ili9225_fb_dirty(&shadow_plane_state->data[0], fb, &rect,
 				 &shadow_plane_state->fmtcnv_state);
 
diff --git a/drivers/gpu/drm/tiny/repaper.c b/drivers/gpu/drm/tiny/repaper.c
index c8270591afc7..531831d2b73f 100644
--- a/drivers/gpu/drm/tiny/repaper.c
+++ b/drivers/gpu/drm/tiny/repaper.c
@@ -837,7 +837,7 @@ static void repaper_pipe_update(struct drm_simple_display_pipe *pipe,
 	if (!pipe->crtc.state->active)
 		return;
 
-	if (drm_atomic_helper_damage_merged(old_state, state, &rect))
+	if (drm_atomic_helper_damage_merged(state, &rect))
 		repaper_fb_dirty(state->fb, shadow_plane_state->data,
 				 &shadow_plane_state->fmtcnv_state);
 }
diff --git a/drivers/gpu/drm/tiny/sharp-memory.c b/drivers/gpu/drm/tiny/sharp-memory.c
index 506e6432e70d..1dacd41ddbaa 100644
--- a/drivers/gpu/drm/tiny/sharp-memory.c
+++ b/drivers/gpu/drm/tiny/sharp-memory.c
@@ -241,7 +241,6 @@ static int sharp_memory_plane_atomic_check(struct drm_plane *plane,
 static void sharp_memory_plane_atomic_update(struct drm_plane *plane,
 					     struct drm_atomic_commit *state)
 {
-	struct drm_plane_state *old_state = drm_atomic_get_old_plane_state(state, plane);
 	struct drm_plane_state *plane_state = plane->state;
 	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
 	struct sharp_memory_device *smd;
@@ -251,7 +250,7 @@ static void sharp_memory_plane_atomic_update(struct drm_plane *plane,
 	if (!smd->crtc.state->active)
 		return;
 
-	if (drm_atomic_helper_damage_merged(old_state, plane_state, &rect))
+	if (drm_atomic_helper_damage_merged(plane_state, &rect))
 		sharp_memory_fb_dirty(plane_state->fb, shadow_plane_state->data,
 				      &rect, &shadow_plane_state->fmtcnv_state);
 }
diff --git a/drivers/gpu/drm/virtio/virtgpu_plane.c b/drivers/gpu/drm/virtio/virtgpu_plane.c
index 73aa70bd4231..24b786e1555e 100644
--- a/drivers/gpu/drm/virtio/virtgpu_plane.c
+++ b/drivers/gpu/drm/virtio/virtgpu_plane.c
@@ -257,7 +257,7 @@ static void virtio_gpu_primary_plane_update(struct drm_plane *plane,
 		return;
 	}
 
-	if (!drm_atomic_helper_damage_merged(old_state, plane->state, &rect))
+	if (!drm_atomic_helper_damage_merged(plane->state, &rect))
 		return;
 
 	bo = gem_to_virtio_gpu_obj(plane->state->fb->obj[0]);
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c b/drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c
index 4139837f4caf..f0df2b1c8465 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c
@@ -977,7 +977,6 @@ vmw_stdu_primary_plane_prepare_fb(struct drm_plane *plane,
 	enum stdu_content_type new_content_type;
 	struct vmw_framebuffer_surface *new_vfbs;
 	uint32_t hdisplay = new_state->crtc_w, vdisplay = new_state->crtc_h;
-	struct drm_plane_state *old_state = plane->state;
 	struct drm_rect rect;
 	int ret;
 
@@ -1101,8 +1100,7 @@ vmw_stdu_primary_plane_prepare_fb(struct drm_plane *plane,
 		struct vmw_surface *surf = vmw_user_object_surface(&vps->uo);
 		struct vmw_resource *res = &surf->res;
 
-		if (!res->res_dirty && drm_atomic_helper_damage_merged(old_state,
-								       new_state,
+		if (!res->res_dirty && drm_atomic_helper_damage_merged(new_state,
 								       &rect)) {
 			/*
 			 * At some point it might be useful to actually translate
diff --git a/include/drm/drm_damage_helper.h b/include/drm/drm_damage_helper.h
index fafe29b50fc6..b5a4de779db6 100644
--- a/include/drm/drm_damage_helper.h
+++ b/include/drm/drm_damage_helper.h
@@ -77,8 +77,7 @@ drm_atomic_helper_damage_iter_init(struct drm_atomic_helper_damage_iter *iter,
 bool
 drm_atomic_helper_damage_iter_next(struct drm_atomic_helper_damage_iter *iter,
 				   struct drm_rect *rect);
-bool drm_atomic_helper_damage_merged(const struct drm_plane_state *old_state,
-				     const struct drm_plane_state *state,
+bool drm_atomic_helper_damage_merged(const struct drm_plane_state *state,
 				     struct drm_rect *rect);
 
 #endif
-- 
2.54.0


^ permalink raw reply related

* [PATCH v2 06/10] drm/damage-helper: Remove old state from drm_atomic_helper_damage_iter_init()
From: Thomas Zimmermann @ 2026-05-11 12:22 UTC (permalink / raw)
  To: mripard, maarten.lankhorst, airlied, airlied, simona, admin,
	gargaditya08, paul, zack.rusin, bcm-kernel-feedback-list
  Cc: dri-devel, linux-hyperv, intel-gfx, intel-xe, linux-mips,
	virtualization, Thomas Zimmermann
In-Reply-To: <20260511122421.114014-1-tzimmermann@suse.de>

Nothing in drm_atomic_helper_damage_iter_init() requires the old
plane state. Remove the parameter and mass-convert callers.

Most callers now no longer require the old plane state in their plane's
atomic_update helper. Remove it as well.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/gpu/drm/ast/ast_mode.c                |  2 +-
 drivers/gpu/drm/drm_damage_helper.c           |  4 +-
 drivers/gpu/drm/drm_fb_dma_helper.c           |  2 +-
 drivers/gpu/drm/gud/gud_pipe.c                |  3 +-
 drivers/gpu/drm/hyperv/hyperv_drm_modeset.c   |  3 +-
 drivers/gpu/drm/mgag200/mgag200_mode.c        |  3 +-
 drivers/gpu/drm/sitronix/st7571.c             |  3 +-
 drivers/gpu/drm/sitronix/st7920.c             |  3 +-
 drivers/gpu/drm/solomon/ssd130x.c             |  9 +--
 drivers/gpu/drm/sysfb/drm_sysfb_modeset.c     |  3 +-
 .../gpu/drm/tests/drm_damage_helper_test.c    | 55 ++++++-------------
 drivers/gpu/drm/tiny/appletbdrm.c             |  8 +--
 drivers/gpu/drm/tiny/bochs.c                  |  3 +-
 drivers/gpu/drm/tiny/cirrus-qemu.c            |  2 +-
 drivers/gpu/drm/udl/udl_modeset.c             |  3 +-
 drivers/gpu/drm/vmwgfx/vmwgfx_kms.c           |  5 +-
 include/drm/drm_damage_helper.h               |  3 +-
 17 files changed, 37 insertions(+), 77 deletions(-)

diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c
index d5ed8c5c7925..6fe3fda6d145 100644
--- a/drivers/gpu/drm/ast/ast_mode.c
+++ b/drivers/gpu/drm/ast/ast_mode.c
@@ -579,7 +579,7 @@ static void ast_primary_plane_helper_atomic_update(struct drm_plane *plane,
 
 	/* if the buffer comes from another device */
 	if (drm_gem_fb_begin_cpu_access(fb, DMA_FROM_DEVICE) == 0) {
-		drm_atomic_helper_damage_iter_init(&iter, old_plane_state, plane_state);
+		drm_atomic_helper_damage_iter_init(&iter, plane_state);
 		drm_atomic_for_each_plane_damage(&iter, &damage) {
 			ast_handle_damage(ast_plane, shadow_plane_state->data, fb, &damage,
 					  &shadow_plane_state->fmtcnv_state);
diff --git a/drivers/gpu/drm/drm_damage_helper.c b/drivers/gpu/drm/drm_damage_helper.c
index f492a59edbeb..28f26234523d 100644
--- a/drivers/gpu/drm/drm_damage_helper.c
+++ b/drivers/gpu/drm/drm_damage_helper.c
@@ -209,7 +209,6 @@ EXPORT_SYMBOL(drm_atomic_helper_dirtyfb);
 /**
  * drm_atomic_helper_damage_iter_init - Initialize the damage iterator.
  * @iter: The iterator to initialize.
- * @old_state: Unused, pass NULL.
  * @state: Plane state from which to iterate the damage clips.
  *
  * Initialize an iterator, which clips plane damage
@@ -226,7 +225,6 @@ EXPORT_SYMBOL(drm_atomic_helper_dirtyfb);
  */
 void
 drm_atomic_helper_damage_iter_init(struct drm_atomic_helper_damage_iter *iter,
-				   const struct drm_plane_state *old_state,
 				   const struct drm_plane_state *state)
 {
 	struct drm_rect src;
@@ -324,7 +322,7 @@ bool drm_atomic_helper_damage_merged(const struct drm_plane_state *old_state,
 	rect->x2 = 0;
 	rect->y2 = 0;
 
-	drm_atomic_helper_damage_iter_init(&iter, old_state, state);
+	drm_atomic_helper_damage_iter_init(&iter, state);
 	drm_atomic_for_each_plane_damage(&iter, &clip) {
 		rect->x1 = min(rect->x1, clip.x1);
 		rect->y1 = min(rect->y1, clip.y1);
diff --git a/drivers/gpu/drm/drm_fb_dma_helper.c b/drivers/gpu/drm/drm_fb_dma_helper.c
index fd71969d2fb1..bbad16d32b6f 100644
--- a/drivers/gpu/drm/drm_fb_dma_helper.c
+++ b/drivers/gpu/drm/drm_fb_dma_helper.c
@@ -138,7 +138,7 @@ void drm_fb_dma_sync_non_coherent(struct drm_device *drm,
 			continue;
 
 		daddr = drm_fb_dma_get_gem_addr(state->fb, state, i);
-		drm_atomic_helper_damage_iter_init(&iter, old_state, state);
+		drm_atomic_helper_damage_iter_init(&iter, state);
 
 		drm_atomic_for_each_plane_damage(&iter, &clip) {
 			/* Ignore x1/x2 values, invalidate complete lines */
diff --git a/drivers/gpu/drm/gud/gud_pipe.c b/drivers/gpu/drm/gud/gud_pipe.c
index 5ef887d8485a..758990cd78aa 100644
--- a/drivers/gpu/drm/gud/gud_pipe.c
+++ b/drivers/gpu/drm/gud/gud_pipe.c
@@ -618,7 +618,6 @@ void gud_plane_atomic_update(struct drm_plane *plane,
 {
 	struct drm_device *drm = plane->dev;
 	struct gud_device *gdrm = to_gud_device(drm);
-	struct drm_plane_state *old_state = drm_atomic_get_old_plane_state(atomic_state, plane);
 	struct drm_plane_state *new_state = drm_atomic_get_new_plane_state(atomic_state, plane);
 	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(new_state);
 	struct drm_framebuffer *fb = new_state->fb;
@@ -647,7 +646,7 @@ void gud_plane_atomic_update(struct drm_plane *plane,
 	if (ret)
 		goto out;
 
-	drm_atomic_helper_damage_iter_init(&iter, old_state, new_state);
+	drm_atomic_helper_damage_iter_init(&iter, new_state);
 	drm_atomic_for_each_plane_damage(&iter, &damage)
 		gud_fb_handle_damage(gdrm, fb, &shadow_plane_state->data[0], &damage);
 
diff --git a/drivers/gpu/drm/hyperv/hyperv_drm_modeset.c b/drivers/gpu/drm/hyperv/hyperv_drm_modeset.c
index 1bbb7de5ab49..9f74365c4d7e 100644
--- a/drivers/gpu/drm/hyperv/hyperv_drm_modeset.c
+++ b/drivers/gpu/drm/hyperv/hyperv_drm_modeset.c
@@ -171,14 +171,13 @@ static void hyperv_plane_atomic_update(struct drm_plane *plane,
 				       struct drm_atomic_commit *state)
 {
 	struct hyperv_drm_device *hv = to_hv(plane->dev);
-	struct drm_plane_state *old_state = drm_atomic_get_old_plane_state(state, plane);
 	struct drm_plane_state *new_state = drm_atomic_get_new_plane_state(state, plane);
 	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(new_state);
 	struct drm_rect damage;
 	struct drm_rect dst_clip;
 	struct drm_atomic_helper_damage_iter iter;
 
-	drm_atomic_helper_damage_iter_init(&iter, old_state, new_state);
+	drm_atomic_helper_damage_iter_init(&iter, new_state);
 	drm_atomic_for_each_plane_damage(&iter, &damage) {
 		dst_clip = new_state->dst;
 
diff --git a/drivers/gpu/drm/mgag200/mgag200_mode.c b/drivers/gpu/drm/mgag200/mgag200_mode.c
index 7e07fc3f1a60..ea121428adf2 100644
--- a/drivers/gpu/drm/mgag200/mgag200_mode.c
+++ b/drivers/gpu/drm/mgag200/mgag200_mode.c
@@ -503,14 +503,13 @@ void mgag200_primary_plane_helper_atomic_update(struct drm_plane *plane,
 	struct drm_device *dev = plane->dev;
 	struct mga_device *mdev = to_mga_device(dev);
 	struct drm_plane_state *plane_state = plane->state;
-	struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(old_state, plane);
 	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
 	struct drm_framebuffer *fb = plane_state->fb;
 	struct drm_atomic_helper_damage_iter iter;
 	struct drm_rect damage;
 
 	mgag200_set_datasiz(mdev, fb->format->format);
-	drm_atomic_helper_damage_iter_init(&iter, old_plane_state, plane_state);
+	drm_atomic_helper_damage_iter_init(&iter, plane_state);
 	drm_atomic_for_each_plane_damage(&iter, &damage) {
 		mgag200_handle_damage(mdev, shadow_plane_state->data, fb, &damage);
 	}
diff --git a/drivers/gpu/drm/sitronix/st7571.c b/drivers/gpu/drm/sitronix/st7571.c
index 20954c33eca9..bc0e59c2600c 100644
--- a/drivers/gpu/drm/sitronix/st7571.c
+++ b/drivers/gpu/drm/sitronix/st7571.c
@@ -342,7 +342,6 @@ static int st7571_primary_plane_helper_atomic_check(struct drm_plane *plane,
 static void st7571_primary_plane_helper_atomic_update(struct drm_plane *plane,
 						      struct drm_atomic_commit *state)
 {
-	struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(state, plane);
 	struct drm_plane_state *plane_state = drm_atomic_get_new_plane_state(state, plane);
 	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
 	struct drm_framebuffer *fb = plane_state->fb;
@@ -362,7 +361,7 @@ static void st7571_primary_plane_helper_atomic_update(struct drm_plane *plane,
 	if (!drm_dev_enter(drm, &idx))
 		goto out_drm_gem_fb_end_cpu_access;
 
-	drm_atomic_helper_damage_iter_init(&iter, old_plane_state, plane_state);
+	drm_atomic_helper_damage_iter_init(&iter, plane_state);
 	drm_atomic_for_each_plane_damage(&iter, &damage) {
 		st7571->pformat->prepare_buffer(st7571,
 						&shadow_plane_state->data[0],
diff --git a/drivers/gpu/drm/sitronix/st7920.c b/drivers/gpu/drm/sitronix/st7920.c
index d320391801f3..7ee45a2b2d3e 100644
--- a/drivers/gpu/drm/sitronix/st7920.c
+++ b/drivers/gpu/drm/sitronix/st7920.c
@@ -390,7 +390,6 @@ static void st7920_primary_plane_atomic_update(struct drm_plane *plane,
 					       struct drm_atomic_commit *state)
 {
 	struct drm_plane_state *plane_state = drm_atomic_get_new_plane_state(state, plane);
-	struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(state, plane);
 	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
 	struct drm_crtc_state *crtc_state = drm_atomic_get_new_crtc_state(state, plane_state->crtc);
 	struct st7920_crtc_state *st7920_crtc_state =  to_st7920_crtc_state(crtc_state);
@@ -407,7 +406,7 @@ static void st7920_primary_plane_atomic_update(struct drm_plane *plane,
 		return;
 
 	if (drm_gem_fb_begin_cpu_access(fb, DMA_FROM_DEVICE) == 0) {
-		drm_atomic_helper_damage_iter_init(&iter, old_plane_state, plane_state);
+		drm_atomic_helper_damage_iter_init(&iter, plane_state);
 		drm_atomic_for_each_plane_damage(&iter, &damage) {
 			dst_clip = plane_state->dst;
 
diff --git a/drivers/gpu/drm/solomon/ssd130x.c b/drivers/gpu/drm/solomon/ssd130x.c
index cae92a3ae8a4..4b55532da31b 100644
--- a/drivers/gpu/drm/solomon/ssd130x.c
+++ b/drivers/gpu/drm/solomon/ssd130x.c
@@ -1198,7 +1198,6 @@ static void ssd130x_primary_plane_atomic_update(struct drm_plane *plane,
 						struct drm_atomic_commit *state)
 {
 	struct drm_plane_state *plane_state = drm_atomic_get_new_plane_state(state, plane);
-	struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(state, plane);
 	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
 	struct drm_crtc_state *crtc_state = drm_atomic_get_new_crtc_state(state, plane_state->crtc);
 	struct ssd130x_crtc_state *ssd130x_crtc_state =  to_ssd130x_crtc_state(crtc_state);
@@ -1216,7 +1215,7 @@ static void ssd130x_primary_plane_atomic_update(struct drm_plane *plane,
 	if (drm_gem_fb_begin_cpu_access(fb, DMA_FROM_DEVICE))
 		goto out_drm_dev_exit;
 
-	drm_atomic_helper_damage_iter_init(&iter, old_plane_state, plane_state);
+	drm_atomic_helper_damage_iter_init(&iter, plane_state);
 	drm_atomic_for_each_plane_damage(&iter, &damage) {
 		dst_clip = plane_state->dst;
 
@@ -1239,7 +1238,6 @@ static void ssd132x_primary_plane_atomic_update(struct drm_plane *plane,
 						struct drm_atomic_commit *state)
 {
 	struct drm_plane_state *plane_state = drm_atomic_get_new_plane_state(state, plane);
-	struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(state, plane);
 	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
 	struct drm_crtc_state *crtc_state = drm_atomic_get_new_crtc_state(state, plane_state->crtc);
 	struct ssd130x_crtc_state *ssd130x_crtc_state =  to_ssd130x_crtc_state(crtc_state);
@@ -1257,7 +1255,7 @@ static void ssd132x_primary_plane_atomic_update(struct drm_plane *plane,
 	if (drm_gem_fb_begin_cpu_access(fb, DMA_FROM_DEVICE))
 		goto out_drm_dev_exit;
 
-	drm_atomic_helper_damage_iter_init(&iter, old_plane_state, plane_state);
+	drm_atomic_helper_damage_iter_init(&iter, plane_state);
 	drm_atomic_for_each_plane_damage(&iter, &damage) {
 		dst_clip = plane_state->dst;
 
@@ -1280,7 +1278,6 @@ static void ssd133x_primary_plane_atomic_update(struct drm_plane *plane,
 						struct drm_atomic_commit *state)
 {
 	struct drm_plane_state *plane_state = drm_atomic_get_new_plane_state(state, plane);
-	struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(state, plane);
 	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
 	struct drm_crtc_state *crtc_state = drm_atomic_get_new_crtc_state(state, plane_state->crtc);
 	struct ssd130x_crtc_state *ssd130x_crtc_state =  to_ssd130x_crtc_state(crtc_state);
@@ -1297,7 +1294,7 @@ static void ssd133x_primary_plane_atomic_update(struct drm_plane *plane,
 	if (drm_gem_fb_begin_cpu_access(fb, DMA_FROM_DEVICE))
 		goto out_drm_dev_exit;
 
-	drm_atomic_helper_damage_iter_init(&iter, old_plane_state, plane_state);
+	drm_atomic_helper_damage_iter_init(&iter, plane_state);
 	drm_atomic_for_each_plane_damage(&iter, &damage) {
 		dst_clip = plane_state->dst;
 
diff --git a/drivers/gpu/drm/sysfb/drm_sysfb_modeset.c b/drivers/gpu/drm/sysfb/drm_sysfb_modeset.c
index d2de29caf89e..9f1ae5ca9a11 100644
--- a/drivers/gpu/drm/sysfb/drm_sysfb_modeset.c
+++ b/drivers/gpu/drm/sysfb/drm_sysfb_modeset.c
@@ -331,7 +331,6 @@ void drm_sysfb_plane_helper_atomic_update(struct drm_plane *plane, struct drm_at
 	struct drm_device *dev = plane->dev;
 	struct drm_sysfb_device *sysfb = to_drm_sysfb_device(dev);
 	struct drm_plane_state *plane_state = drm_atomic_get_new_plane_state(state, plane);
-	struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(state, plane);
 	struct drm_sysfb_plane_state *sysfb_plane_state = to_drm_sysfb_plane_state(plane_state);
 	struct drm_shadow_plane_state *shadow_plane_state = &sysfb_plane_state->base;
 	struct drm_framebuffer *fb = plane_state->fb;
@@ -351,7 +350,7 @@ void drm_sysfb_plane_helper_atomic_update(struct drm_plane *plane, struct drm_at
 	if (!drm_dev_enter(dev, &idx))
 		goto out_drm_gem_fb_end_cpu_access;
 
-	drm_atomic_helper_damage_iter_init(&iter, old_plane_state, plane_state);
+	drm_atomic_helper_damage_iter_init(&iter, plane_state);
 	drm_atomic_for_each_plane_damage(&iter, &damage) {
 		struct iosys_map dst = sysfb->fb_addr;
 		struct drm_rect dst_clip = plane_state->dst;
diff --git a/drivers/gpu/drm/tests/drm_damage_helper_test.c b/drivers/gpu/drm/tests/drm_damage_helper_test.c
index ef931497baf9..2139ec8b0eb0 100644
--- a/drivers/gpu/drm/tests/drm_damage_helper_test.c
+++ b/drivers/gpu/drm/tests/drm_damage_helper_test.c
@@ -20,7 +20,6 @@ struct drm_damage_mock {
 	struct drm_property prop;
 	struct drm_framebuffer fb;
 	struct drm_plane_state state;
-	struct drm_plane_state old_state;
 };
 
 static int drm_damage_helper_init(struct kunit *test)
@@ -37,7 +36,6 @@ static int drm_damage_helper_init(struct kunit *test)
 	mock->state.fb = &mock->fb;
 	mock->state.visible = true;
 
-	mock->old_state.plane = &mock->plane;
 	mock->state.plane = &mock->plane;
 
 	/* just enough so that drm_plane_enable_fb_damage_clips() works */
@@ -124,9 +122,8 @@ static void drm_test_damage_iter_no_damage(struct kunit *test)
 	u32 num_hits = 0;
 
 	/* Plane src same as fb size. */
-	set_plane_src(&mock->old_state, 0, 0, mock->fb.width << 16, mock->fb.height << 16);
 	set_plane_src(&mock->state, 0, 0, mock->fb.width << 16, mock->fb.height << 16);
-	drm_atomic_helper_damage_iter_init(&iter, &mock->old_state, &mock->state);
+	drm_atomic_helper_damage_iter_init(&iter, &mock->state);
 	drm_atomic_for_each_plane_damage(&iter, &clip)
 		num_hits++;
 
@@ -142,11 +139,9 @@ static void drm_test_damage_iter_no_damage_fractional_src(struct kunit *test)
 	u32 num_hits = 0;
 
 	/* Plane src has fractional part. */
-	set_plane_src(&mock->old_state, 0x3fffe, 0x3fffe,
-		      0x3fffe + (1024 << 16), 0x3fffe + (768 << 16));
 	set_plane_src(&mock->state, 0x3fffe, 0x3fffe,
 		      0x3fffe + (1024 << 16), 0x3fffe + (768 << 16));
-	drm_atomic_helper_damage_iter_init(&iter, &mock->old_state, &mock->state);
+	drm_atomic_helper_damage_iter_init(&iter, &mock->state);
 	drm_atomic_for_each_plane_damage(&iter, &clip)
 		num_hits++;
 
@@ -164,9 +159,8 @@ static void drm_test_damage_iter_no_damage_not_visible(struct kunit *test)
 
 	mock->state.visible = false;
 
-	set_plane_src(&mock->old_state, 0, 0, 1024 << 16, 768 << 16);
 	set_plane_src(&mock->state, 0, 0, 1024 << 16, 768 << 16);
-	drm_atomic_helper_damage_iter_init(&iter, &mock->old_state, &mock->state);
+	drm_atomic_helper_damage_iter_init(&iter, &mock->state);
 	drm_atomic_for_each_plane_damage(&iter, &clip)
 		num_hits++;
 
@@ -182,9 +176,8 @@ static void drm_test_damage_iter_no_damage_no_crtc(struct kunit *test)
 
 	mock->state.crtc = NULL;
 
-	set_plane_src(&mock->old_state, 0, 0, 1024 << 16, 768 << 16);
 	set_plane_src(&mock->state, 0, 0, 1024 << 16, 768 << 16);
-	drm_atomic_helper_damage_iter_init(&iter, &mock->old_state, &mock->state);
+	drm_atomic_helper_damage_iter_init(&iter, &mock->state);
 	drm_atomic_for_each_plane_damage(&iter, &clip)
 		num_hits++;
 
@@ -200,9 +193,8 @@ static void drm_test_damage_iter_no_damage_no_fb(struct kunit *test)
 
 	mock->state.fb = NULL;
 
-	set_plane_src(&mock->old_state, 0, 0, 1024 << 16, 768 << 16);
 	set_plane_src(&mock->state, 0, 0, 1024 << 16, 768 << 16);
-	drm_atomic_helper_damage_iter_init(&iter, &mock->old_state, &mock->state);
+	drm_atomic_helper_damage_iter_init(&iter, &mock->state);
 	drm_atomic_for_each_plane_damage(&iter, &clip)
 		num_hits++;
 
@@ -218,13 +210,12 @@ static void drm_test_damage_iter_simple_damage(struct kunit *test)
 	struct drm_rect clip;
 	u32 num_hits = 0;
 
-	set_plane_src(&mock->old_state, 0, 0, 1024 << 16, 768 << 16);
 	set_plane_src(&mock->state, 0, 0, 1024 << 16, 768 << 16);
 	/* Damage set to plane src */
 	set_damage_clip(&damage, 0, 0, 1024, 768);
 	set_damage_blob(&damage_blob, &damage, sizeof(damage));
 	set_plane_damage(&mock->state, &damage_blob);
-	drm_atomic_helper_damage_iter_init(&iter, &mock->old_state, &mock->state);
+	drm_atomic_helper_damage_iter_init(&iter, &mock->state);
 	drm_atomic_for_each_plane_damage(&iter, &clip)
 		num_hits++;
 
@@ -241,12 +232,11 @@ static void drm_test_damage_iter_single_damage(struct kunit *test)
 	struct drm_rect clip;
 	u32 num_hits = 0;
 
-	set_plane_src(&mock->old_state, 0, 0, 1024 << 16, 768 << 16);
 	set_plane_src(&mock->state, 0, 0, 1024 << 16, 768 << 16);
 	set_damage_clip(&damage, 256, 192, 768, 576);
 	set_damage_blob(&damage_blob, &damage, sizeof(damage));
 	set_plane_damage(&mock->state, &damage_blob);
-	drm_atomic_helper_damage_iter_init(&iter, &mock->old_state, &mock->state);
+	drm_atomic_helper_damage_iter_init(&iter, &mock->state);
 	drm_atomic_for_each_plane_damage(&iter, &clip)
 		num_hits++;
 
@@ -263,13 +253,12 @@ static void drm_test_damage_iter_single_damage_intersect_src(struct kunit *test)
 	struct drm_rect clip;
 	u32 num_hits = 0;
 
-	set_plane_src(&mock->old_state, 0, 0, 1024 << 16, 768 << 16);
 	set_plane_src(&mock->state, 0, 0, 1024 << 16, 768 << 16);
 	/* Damage intersect with plane src. */
 	set_damage_clip(&damage, 256, 192, 1360, 768);
 	set_damage_blob(&damage_blob, &damage, sizeof(damage));
 	set_plane_damage(&mock->state, &damage_blob);
-	drm_atomic_helper_damage_iter_init(&iter, &mock->old_state, &mock->state);
+	drm_atomic_helper_damage_iter_init(&iter, &mock->state);
 	drm_atomic_for_each_plane_damage(&iter, &clip)
 		num_hits++;
 
@@ -286,13 +275,12 @@ static void drm_test_damage_iter_single_damage_outside_src(struct kunit *test)
 	struct drm_rect clip;
 	u32 num_hits = 0;
 
-	set_plane_src(&mock->old_state, 0, 0, 1024 << 16, 768 << 16);
 	set_plane_src(&mock->state, 0, 0, 1024 << 16, 768 << 16);
 	/* Damage clip outside plane src */
 	set_damage_clip(&damage, 1360, 1360, 1380, 1380);
 	set_damage_blob(&damage_blob, &damage, sizeof(damage));
 	set_plane_damage(&mock->state, &damage_blob);
-	drm_atomic_helper_damage_iter_init(&iter, &mock->old_state, &mock->state);
+	drm_atomic_helper_damage_iter_init(&iter, &mock->state);
 	drm_atomic_for_each_plane_damage(&iter, &clip)
 		num_hits++;
 
@@ -309,14 +297,12 @@ static void drm_test_damage_iter_single_damage_fractional_src(struct kunit *test
 	u32 num_hits = 0;
 
 	/* Plane src has fractional part. */
-	set_plane_src(&mock->old_state, 0x40002, 0x40002,
-		      0x40002 + (1024 << 16), 0x40002 + (768 << 16));
 	set_plane_src(&mock->state, 0x40002, 0x40002,
 		      0x40002 + (1024 << 16), 0x40002 + (768 << 16));
 	set_damage_clip(&damage, 10, 10, 256, 330);
 	set_damage_blob(&damage_blob, &damage, sizeof(damage));
 	set_plane_damage(&mock->state, &damage_blob);
-	drm_atomic_helper_damage_iter_init(&iter, &mock->old_state, &mock->state);
+	drm_atomic_helper_damage_iter_init(&iter, &mock->state);
 	drm_atomic_for_each_plane_damage(&iter, &clip)
 		num_hits++;
 
@@ -334,15 +320,13 @@ static void drm_test_damage_iter_single_damage_intersect_fractional_src(struct k
 	u32 num_hits = 0;
 
 	/* Plane src has fractional part. */
-	set_plane_src(&mock->old_state, 0x40002, 0x40002,
-		      0x40002 + (1024 << 16), 0x40002 + (768 << 16));
 	set_plane_src(&mock->state, 0x40002, 0x40002,
 		      0x40002 + (1024 << 16), 0x40002 + (768 << 16));
 	/* Damage intersect with plane src. */
 	set_damage_clip(&damage, 10, 1, 1360, 330);
 	set_damage_blob(&damage_blob, &damage, sizeof(damage));
 	set_plane_damage(&mock->state, &damage_blob);
-	drm_atomic_helper_damage_iter_init(&iter, &mock->old_state, &mock->state);
+	drm_atomic_helper_damage_iter_init(&iter, &mock->state);
 	drm_atomic_for_each_plane_damage(&iter, &clip)
 		num_hits++;
 
@@ -361,15 +345,13 @@ static void drm_test_damage_iter_single_damage_outside_fractional_src(struct kun
 	u32 num_hits = 0;
 
 	/* Plane src has fractional part. */
-	set_plane_src(&mock->old_state, 0x40002, 0x40002,
-		      0x40002 + (1024 << 16), 0x40002 + (768 << 16));
 	set_plane_src(&mock->state, 0x40002, 0x40002,
 		      0x40002 + (1024 << 16), 0x40002 + (768 << 16));
 	/* Damage clip outside plane src */
 	set_damage_clip(&damage, 1360, 1360, 1380, 1380);
 	set_damage_blob(&damage_blob, &damage, sizeof(damage));
 	set_plane_damage(&mock->state, &damage_blob);
-	drm_atomic_helper_damage_iter_init(&iter, &mock->old_state, &mock->state);
+	drm_atomic_helper_damage_iter_init(&iter, &mock->state);
 	drm_atomic_for_each_plane_damage(&iter, &clip)
 		num_hits++;
 
@@ -385,14 +367,13 @@ static void drm_test_damage_iter_damage(struct kunit *test)
 	struct drm_rect clip;
 	u32 num_hits = 0;
 
-	set_plane_src(&mock->old_state, 0, 0, 1024 << 16, 768 << 16);
 	set_plane_src(&mock->state, 0, 0, 1024 << 16, 768 << 16);
 	/* 2 damage clips. */
 	set_damage_clip(&damage[0], 20, 30, 200, 180);
 	set_damage_clip(&damage[1], 240, 200, 280, 250);
 	set_damage_blob(&damage_blob, &damage[0], sizeof(damage));
 	set_plane_damage(&mock->state, &damage_blob);
-	drm_atomic_helper_damage_iter_init(&iter, &mock->old_state, &mock->state);
+	drm_atomic_helper_damage_iter_init(&iter, &mock->state);
 	drm_atomic_for_each_plane_damage(&iter, &clip) {
 		if (num_hits == 0)
 			check_damage_clip(test, &clip, 20, 30, 200, 180);
@@ -413,8 +394,6 @@ static void drm_test_damage_iter_damage_one_intersect(struct kunit *test)
 	struct drm_rect clip;
 	u32 num_hits = 0;
 
-	set_plane_src(&mock->old_state, 0x40002, 0x40002,
-		      0x40002 + (1024 << 16), 0x40002 + (768 << 16));
 	set_plane_src(&mock->state, 0x40002, 0x40002,
 		      0x40002 + (1024 << 16), 0x40002 + (768 << 16));
 	/* 2 damage clips, one intersect plane src. */
@@ -422,7 +401,7 @@ static void drm_test_damage_iter_damage_one_intersect(struct kunit *test)
 	set_damage_clip(&damage[1], 2, 2, 1360, 1360);
 	set_damage_blob(&damage_blob, &damage[0], sizeof(damage));
 	set_plane_damage(&mock->state, &damage_blob);
-	drm_atomic_helper_damage_iter_init(&iter, &mock->old_state, &mock->state);
+	drm_atomic_helper_damage_iter_init(&iter, &mock->state);
 	drm_atomic_for_each_plane_damage(&iter, &clip) {
 		if (num_hits == 0)
 			check_damage_clip(test, &clip, 20, 30, 200, 180);
@@ -443,14 +422,13 @@ static void drm_test_damage_iter_damage_one_outside(struct kunit *test)
 	struct drm_rect clip;
 	u32 num_hits = 0;
 
-	set_plane_src(&mock->old_state, 0, 0, 1024 << 16, 768 << 16);
 	set_plane_src(&mock->state, 0, 0, 1024 << 16, 768 << 16);
 	/* 2 damage clips, one outside plane src. */
 	set_damage_clip(&damage[0], 1360, 1360, 1380, 1380);
 	set_damage_clip(&damage[1], 240, 200, 280, 250);
 	set_damage_blob(&damage_blob, &damage[0], sizeof(damage));
 	set_plane_damage(&mock->state, &damage_blob);
-	drm_atomic_helper_damage_iter_init(&iter, &mock->old_state, &mock->state);
+	drm_atomic_helper_damage_iter_init(&iter, &mock->state);
 	drm_atomic_for_each_plane_damage(&iter, &clip)
 		num_hits++;
 
@@ -467,7 +445,6 @@ static void drm_test_damage_iter_damage_ignore(struct kunit *test)
 	struct drm_rect clip;
 	u32 num_hits = 0;
 
-	set_plane_src(&mock->old_state, 0, 0, 1024 << 16, 768 << 16);
 	set_plane_src(&mock->state, 0, 0, 1024 << 16, 768 << 16);
 	/* 2 damage clips, but ignore them. */
 	set_damage_clip(&damage[0], 20, 30, 200, 180);
@@ -475,7 +452,7 @@ static void drm_test_damage_iter_damage_ignore(struct kunit *test)
 	set_damage_blob(&damage_blob, &damage[0], sizeof(damage));
 	set_plane_damage(&mock->state, &damage_blob);
 	mock->state.ignore_damage_clips = true;
-	drm_atomic_helper_damage_iter_init(&iter, &mock->old_state, &mock->state);
+	drm_atomic_helper_damage_iter_init(&iter, &mock->state);
 	drm_atomic_for_each_plane_damage(&iter, &clip) {
 		if (num_hits == 0)
 			check_damage_clip(test, &clip, 0, 0, 1024, 768);
diff --git a/drivers/gpu/drm/tiny/appletbdrm.c b/drivers/gpu/drm/tiny/appletbdrm.c
index 65d1796252e9..8342b56e9d9e 100644
--- a/drivers/gpu/drm/tiny/appletbdrm.c
+++ b/drivers/gpu/drm/tiny/appletbdrm.c
@@ -329,7 +329,7 @@ static int appletbdrm_primary_plane_helper_begin_fb_access(struct drm_plane *pla
 	if (ret)
 		return ret;
 
-	drm_atomic_helper_damage_iter_init(&iter, NULL, new_plane_state);
+	drm_atomic_helper_damage_iter_init(&iter, new_plane_state);
 	drm_atomic_for_each_plane_damage(&iter, &damage) {
 		frames_size += struct_size((struct appletbdrm_frame *)0, buf, rect_size(&damage));
 	}
@@ -381,7 +381,6 @@ static int appletbdrm_primary_plane_helper_atomic_check(struct drm_plane *plane,
 }
 
 static int appletbdrm_flush_damage(struct appletbdrm_device *adev,
-				   struct drm_plane_state *old_state,
 				   struct drm_plane_state *state)
 {
 	struct appletbdrm_plane_state *appletbdrm_state = to_appletbdrm_plane_state(state);
@@ -417,7 +416,7 @@ static int appletbdrm_flush_damage(struct appletbdrm_device *adev,
 
 	frame = (struct appletbdrm_frame *)request->data;
 
-	drm_atomic_helper_damage_iter_init(&iter, old_state, state);
+	drm_atomic_helper_damage_iter_init(&iter, state);
 	drm_atomic_for_each_plane_damage(&iter, &damage) {
 		struct drm_rect dst_clip = state->dst;
 		struct iosys_map dst = IOSYS_MAP_INIT_VADDR(frame->buf);
@@ -484,13 +483,12 @@ static void appletbdrm_primary_plane_helper_atomic_update(struct drm_plane *plan
 	struct appletbdrm_device *adev = drm_to_adev(plane->dev);
 	struct drm_device *drm = plane->dev;
 	struct drm_plane_state *plane_state = plane->state;
-	struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(old_state, plane);
 	int idx;
 
 	if (!drm_dev_enter(drm, &idx))
 		return;
 
-	appletbdrm_flush_damage(adev, old_plane_state, plane_state);
+	appletbdrm_flush_damage(adev, plane_state);
 
 	drm_dev_exit(idx);
 }
diff --git a/drivers/gpu/drm/tiny/bochs.c b/drivers/gpu/drm/tiny/bochs.c
index e2d957e51505..1e19e98694c0 100644
--- a/drivers/gpu/drm/tiny/bochs.c
+++ b/drivers/gpu/drm/tiny/bochs.c
@@ -447,7 +447,6 @@ static void bochs_primary_plane_helper_atomic_update(struct drm_plane *plane,
 	struct drm_device *dev = plane->dev;
 	struct bochs_device *bochs = to_bochs_device(dev);
 	struct drm_plane_state *plane_state = plane->state;
-	struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(state, plane);
 	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
 	struct drm_framebuffer *fb = plane_state->fb;
 	struct drm_atomic_helper_damage_iter iter;
@@ -456,7 +455,7 @@ static void bochs_primary_plane_helper_atomic_update(struct drm_plane *plane,
 	if (!fb || !bochs->stride)
 		return;
 
-	drm_atomic_helper_damage_iter_init(&iter, old_plane_state, plane_state);
+	drm_atomic_helper_damage_iter_init(&iter, plane_state);
 	drm_atomic_for_each_plane_damage(&iter, &damage) {
 		struct iosys_map dst = IOSYS_MAP_INIT_VADDR_IOMEM(bochs->fb_map);
 
diff --git a/drivers/gpu/drm/tiny/cirrus-qemu.c b/drivers/gpu/drm/tiny/cirrus-qemu.c
index 075221b431d3..44ffce563e51 100644
--- a/drivers/gpu/drm/tiny/cirrus-qemu.c
+++ b/drivers/gpu/drm/tiny/cirrus-qemu.c
@@ -350,7 +350,7 @@ static void cirrus_primary_plane_helper_atomic_update(struct drm_plane *plane,
 	if (!old_fb || old_fb->pitches[0] != fb->pitches[0])
 		cirrus_pitch_set(cirrus, fb->pitches[0]);
 
-	drm_atomic_helper_damage_iter_init(&iter, old_plane_state, plane_state);
+	drm_atomic_helper_damage_iter_init(&iter, plane_state);
 	drm_atomic_for_each_plane_damage(&iter, &damage) {
 		unsigned int offset = drm_fb_clip_offset(fb->pitches[0], fb->format, &damage);
 		struct iosys_map dst = IOSYS_MAP_INIT_OFFSET(&vaddr, offset);
diff --git a/drivers/gpu/drm/udl/udl_modeset.c b/drivers/gpu/drm/udl/udl_modeset.c
index 289711035b67..ac981ffca5d9 100644
--- a/drivers/gpu/drm/udl/udl_modeset.c
+++ b/drivers/gpu/drm/udl/udl_modeset.c
@@ -286,7 +286,6 @@ static void udl_primary_plane_helper_atomic_update(struct drm_plane *plane,
 	struct drm_plane_state *plane_state = drm_atomic_get_new_plane_state(state, plane);
 	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
 	struct drm_framebuffer *fb = plane_state->fb;
-	struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(state, plane);
 	struct drm_atomic_helper_damage_iter iter;
 	struct drm_rect damage;
 	int ret, idx;
@@ -301,7 +300,7 @@ static void udl_primary_plane_helper_atomic_update(struct drm_plane *plane,
 	if (!drm_dev_enter(dev, &idx))
 		goto out_drm_gem_fb_end_cpu_access;
 
-	drm_atomic_helper_damage_iter_init(&iter, old_plane_state, plane_state);
+	drm_atomic_helper_damage_iter_init(&iter, plane_state);
 	drm_atomic_for_each_plane_damage(&iter, &damage) {
 		udl_handle_damage(fb, &shadow_plane_state->data[0], &damage);
 	}
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
index 1b407b61f683..32617eb9538e 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
@@ -1733,7 +1733,6 @@ void vmw_kms_lost_device(struct drm_device *dev)
 int vmw_du_helper_plane_update(struct vmw_du_update_plane *update)
 {
 	struct drm_plane_state *state = update->plane->state;
-	struct drm_plane_state *old_state = update->old_state;
 	struct drm_atomic_helper_damage_iter iter;
 	struct drm_rect clip;
 	struct drm_rect bb;
@@ -1750,7 +1749,7 @@ int vmw_du_helper_plane_update(struct vmw_du_update_plane *update)
 	 * Iterate in advance to check if really need plane update and find the
 	 * number of clips that actually are in plane src for fifo allocation.
 	 */
-	drm_atomic_helper_damage_iter_init(&iter, old_state, state);
+	drm_atomic_helper_damage_iter_init(&iter, state);
 	drm_atomic_for_each_plane_damage(&iter, &clip)
 		num_hits++;
 
@@ -1818,7 +1817,7 @@ int vmw_du_helper_plane_update(struct vmw_du_update_plane *update)
 	bb.x2 = INT_MIN;
 	bb.y2 = INT_MIN;
 
-	drm_atomic_helper_damage_iter_init(&iter, old_state, state);
+	drm_atomic_helper_damage_iter_init(&iter, state);
 	drm_atomic_for_each_plane_damage(&iter, &clip) {
 		uint32_t fb_x = clip.x1;
 		uint32_t fb_y = clip.y1;
diff --git a/include/drm/drm_damage_helper.h b/include/drm/drm_damage_helper.h
index e93eaa0fbcb6..fafe29b50fc6 100644
--- a/include/drm/drm_damage_helper.h
+++ b/include/drm/drm_damage_helper.h
@@ -73,8 +73,7 @@ int drm_atomic_helper_dirtyfb(struct drm_framebuffer *fb,
 			      unsigned int num_clips);
 void
 drm_atomic_helper_damage_iter_init(struct drm_atomic_helper_damage_iter *iter,
-				   const struct drm_plane_state *old_state,
-				   const struct drm_plane_state *new_state);
+				   const struct drm_plane_state *state);
 bool
 drm_atomic_helper_damage_iter_next(struct drm_atomic_helper_damage_iter *iter,
 				   struct drm_rect *rect);
-- 
2.54.0


^ permalink raw reply related

* [PATCH v2 04/10] drm/damage-helper: Test src coord in drm_atomic_helper_check_plane_damage()
From: Thomas Zimmermann @ 2026-05-11 12:22 UTC (permalink / raw)
  To: mripard, maarten.lankhorst, airlied, airlied, simona, admin,
	gargaditya08, paul, zack.rusin, bcm-kernel-feedback-list
  Cc: dri-devel, linux-hyperv, intel-gfx, intel-xe, linux-mips,
	virtualization, Thomas Zimmermann
In-Reply-To: <20260511122421.114014-1-tzimmermann@suse.de>

Planes require a full update if the source coordinates change across
atomic commits. Evaluate this during the atomic-check and set the flag
ignore_damage_clips in the plane state, if so. Remove the check from
drm_atomic_helper_damage_iter_init().

This will help with removing the old state from the atomic-commit phase
and simplify atomic_update helpers a bit.

Several unit tests check against the change of the src coordinate. Drop
them as they do no longer make sense. If the src coordinate changes across
commits, atomic helpers will set the plane state's ignore_damage_clips
flag, for which a separate unit test exists.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/gpu/drm/drm_atomic_helper.c           |   4 +-
 drivers/gpu/drm/drm_damage_helper.c           |  20 ++-
 .../gpu/drm/tests/drm_damage_helper_test.c    | 151 ------------------
 include/drm/drm_damage_helper.h               |   3 +-
 4 files changed, 16 insertions(+), 162 deletions(-)

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 4c37299e8ccb..823ce60d45b4 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -1034,7 +1034,7 @@ drm_atomic_helper_check_planes(struct drm_device *dev,
 
 		drm_atomic_helper_plane_changed(state, old_plane_state, new_plane_state, plane);
 
-		drm_atomic_helper_check_plane_damage(state, new_plane_state);
+		drm_atomic_helper_check_plane_damage(state, old_plane_state, new_plane_state);
 
 		if (!funcs || !funcs->atomic_check)
 			continue;
@@ -1066,7 +1066,7 @@ drm_atomic_helper_check_planes(struct drm_device *dev,
 	}
 
 	for_each_oldnew_plane_in_state(state, plane, old_plane_state, new_plane_state, i) {
-		drm_atomic_helper_check_plane_damage(state, new_plane_state);
+		drm_atomic_helper_check_plane_damage(state, old_plane_state, new_plane_state);
 	}
 
 	return ret;
diff --git a/drivers/gpu/drm/drm_damage_helper.c b/drivers/gpu/drm/drm_damage_helper.c
index 945fac8dc27b..f492a59edbeb 100644
--- a/drivers/gpu/drm/drm_damage_helper.c
+++ b/drivers/gpu/drm/drm_damage_helper.c
@@ -55,7 +55,8 @@ static void convert_clip_rect_to_rect(const struct drm_clip_rect *src,
 /**
  * drm_atomic_helper_check_plane_damage - Verify plane damage on atomic_check.
  * @state: The driver state object.
- * @plane_state: Plane state for which to verify damage.
+ * @old_plane_state: Old plane state to verify against.
+ * @new_plane_state: Plane state for which to verify damage.
  *
  * This helper function makes sure that damage from plane state is discarded
  * for full modeset. If there are more reasons a driver would want to do a full
@@ -67,19 +68,23 @@ static void convert_clip_rect_to_rect(const struct drm_clip_rect *src,
  * &drm_plane_state.src as damage.
  */
 void drm_atomic_helper_check_plane_damage(struct drm_atomic_commit *state,
-					  struct drm_plane_state *plane_state)
+					  const struct drm_plane_state *old_plane_state,
+					  struct drm_plane_state *new_plane_state)
 {
 	struct drm_crtc_state *crtc_state;
 
-	if (plane_state->crtc) {
+	if (!drm_rect_equals(&new_plane_state->src, &old_plane_state->src))
+		new_plane_state->ignore_damage_clips = true;
+
+	if (new_plane_state->crtc) {
 		crtc_state = drm_atomic_get_new_crtc_state(state,
-							   plane_state->crtc);
+							   new_plane_state->crtc);
 
 		if (WARN_ON(!crtc_state))
 			return;
 
 		if (drm_atomic_crtc_needs_modeset(crtc_state))
-			plane_state->ignore_damage_clips = true;
+			new_plane_state->ignore_damage_clips = true;
 	}
 }
 EXPORT_SYMBOL(drm_atomic_helper_check_plane_damage);
@@ -204,7 +209,7 @@ EXPORT_SYMBOL(drm_atomic_helper_dirtyfb);
 /**
  * drm_atomic_helper_damage_iter_init - Initialize the damage iterator.
  * @iter: The iterator to initialize.
- * @old_state: Old plane state for validation.
+ * @old_state: Unused, pass NULL.
  * @state: Plane state from which to iterate the damage clips.
  *
  * Initialize an iterator, which clips plane damage
@@ -241,8 +246,7 @@ drm_atomic_helper_damage_iter_init(struct drm_atomic_helper_damage_iter *iter,
 	iter->plane_src.x2 = (src.x2 >> 16) + !!(src.x2 & 0xFFFF);
 	iter->plane_src.y2 = (src.y2 >> 16) + !!(src.y2 & 0xFFFF);
 
-	if (!iter->clips || state->ignore_damage_clips ||
-	    !drm_rect_equals(&state->src, &old_state->src)) {
+	if (!iter->clips || state->ignore_damage_clips) {
 		iter->clips = NULL;
 		iter->num_clips = 0;
 		iter->full_update = true;
diff --git a/drivers/gpu/drm/tests/drm_damage_helper_test.c b/drivers/gpu/drm/tests/drm_damage_helper_test.c
index 64f038a62ffe..ef931497baf9 100644
--- a/drivers/gpu/drm/tests/drm_damage_helper_test.c
+++ b/drivers/gpu/drm/tests/drm_damage_helper_test.c
@@ -155,45 +155,6 @@ static void drm_test_damage_iter_no_damage_fractional_src(struct kunit *test)
 	check_damage_clip(test, &clip, 3, 3, 1028, 772);
 }
 
-static void drm_test_damage_iter_no_damage_src_moved(struct kunit *test)
-{
-	struct drm_damage_mock *mock = test->priv;
-	struct drm_atomic_helper_damage_iter iter;
-	struct drm_rect clip;
-	u32 num_hits = 0;
-
-	/* Plane src moved since old plane state. */
-	set_plane_src(&mock->old_state, 0, 0, 1024 << 16, 768 << 16);
-	set_plane_src(&mock->state, 10 << 16, 10 << 16,
-		      (10 + 1024) << 16, (10 + 768) << 16);
-	drm_atomic_helper_damage_iter_init(&iter, &mock->old_state, &mock->state);
-	drm_atomic_for_each_plane_damage(&iter, &clip)
-		num_hits++;
-
-	KUNIT_EXPECT_EQ_MSG(test, num_hits, 1, "Should return plane src as damage.");
-	check_damage_clip(test, &clip, 10, 10, 1034, 778);
-}
-
-static void drm_test_damage_iter_no_damage_fractional_src_moved(struct kunit *test)
-{
-	struct drm_damage_mock *mock = test->priv;
-	struct drm_atomic_helper_damage_iter iter;
-	struct drm_rect clip;
-	u32 num_hits = 0;
-
-	/* Plane src has fractional part and it moved since old plane state. */
-	set_plane_src(&mock->old_state, 0x3fffe, 0x3fffe,
-		      0x3fffe + (1024 << 16), 0x3fffe + (768 << 16));
-	set_plane_src(&mock->state, 0x40002, 0x40002,
-		      0x40002 + (1024 << 16), 0x40002 + (768 << 16));
-	drm_atomic_helper_damage_iter_init(&iter, &mock->old_state, &mock->state);
-	drm_atomic_for_each_plane_damage(&iter, &clip)
-		num_hits++;
-
-	KUNIT_EXPECT_EQ_MSG(test, num_hits, 1, "Should return plane src as damage.");
-	check_damage_clip(test, &clip, 4, 4, 1029, 773);
-}
-
 static void drm_test_damage_iter_no_damage_not_visible(struct kunit *test)
 {
 	struct drm_damage_mock *mock = test->priv;
@@ -415,58 +376,6 @@ static void drm_test_damage_iter_single_damage_outside_fractional_src(struct kun
 	KUNIT_EXPECT_EQ_MSG(test, num_hits, 0, "Should have no damage.");
 }
 
-static void drm_test_damage_iter_single_damage_src_moved(struct kunit *test)
-{
-	struct drm_damage_mock *mock = test->priv;
-	struct drm_atomic_helper_damage_iter iter;
-	struct drm_property_blob damage_blob;
-	struct drm_mode_rect damage;
-	struct drm_rect clip;
-	u32 num_hits = 0;
-
-	/* Plane src moved since old plane state. */
-	set_plane_src(&mock->old_state, 0, 0, 1024 << 16, 768 << 16);
-	set_plane_src(&mock->state, 10 << 16, 10 << 16,
-		      (10 + 1024) << 16, (10 + 768) << 16);
-	set_damage_clip(&damage, 20, 30, 256, 256);
-	set_damage_blob(&damage_blob, &damage, sizeof(damage));
-	set_plane_damage(&mock->state, &damage_blob);
-	drm_atomic_helper_damage_iter_init(&iter, &mock->old_state, &mock->state);
-	drm_atomic_for_each_plane_damage(&iter, &clip)
-		num_hits++;
-
-	KUNIT_EXPECT_EQ_MSG(test, num_hits, 1,
-			    "Should return plane src as damage.");
-	check_damage_clip(test, &clip, 10, 10, 1034, 778);
-}
-
-static void drm_test_damage_iter_single_damage_fractional_src_moved(struct kunit *test)
-{
-	struct drm_damage_mock *mock = test->priv;
-	struct drm_atomic_helper_damage_iter iter;
-	struct drm_property_blob damage_blob;
-	struct drm_mode_rect damage;
-	struct drm_rect clip;
-	u32 num_hits = 0;
-
-	/* Plane src with fractional part moved since old plane state. */
-	set_plane_src(&mock->old_state, 0x3fffe, 0x3fffe,
-		      0x3fffe + (1024 << 16), 0x3fffe + (768 << 16));
-	set_plane_src(&mock->state, 0x40002, 0x40002,
-		      0x40002 + (1024 << 16), 0x40002 + (768 << 16));
-	/* Damage intersect with plane src. */
-	set_damage_clip(&damage, 20, 30, 1360, 256);
-	set_damage_blob(&damage_blob, &damage, sizeof(damage));
-	set_plane_damage(&mock->state, &damage_blob);
-	drm_atomic_helper_damage_iter_init(&iter, &mock->old_state, &mock->state);
-	drm_atomic_for_each_plane_damage(&iter, &clip)
-		num_hits++;
-
-	KUNIT_EXPECT_EQ_MSG(test, num_hits, 1,
-			    "Should return rounded off plane as damage.");
-	check_damage_clip(test, &clip, 4, 4, 1029, 773);
-}
-
 static void drm_test_damage_iter_damage(struct kunit *test)
 {
 	struct drm_damage_mock *mock = test->priv;
@@ -549,60 +458,6 @@ static void drm_test_damage_iter_damage_one_outside(struct kunit *test)
 	check_damage_clip(test, &clip, 240, 200, 280, 250);
 }
 
-static void drm_test_damage_iter_damage_src_moved(struct kunit *test)
-{
-	struct drm_damage_mock *mock = test->priv;
-	struct drm_atomic_helper_damage_iter iter;
-	struct drm_property_blob damage_blob;
-	struct drm_mode_rect damage[2];
-	struct drm_rect clip;
-	u32 num_hits = 0;
-
-	set_plane_src(&mock->old_state, 0x40002, 0x40002,
-		      0x40002 + (1024 << 16), 0x40002 + (768 << 16));
-	set_plane_src(&mock->state, 0x3fffe, 0x3fffe,
-		      0x3fffe + (1024 << 16), 0x3fffe + (768 << 16));
-	/* 2 damage clips, one outside plane src. */
-	set_damage_clip(&damage[0], 1360, 1360, 1380, 1380);
-	set_damage_clip(&damage[1], 240, 200, 280, 250);
-	set_damage_blob(&damage_blob, &damage[0], sizeof(damage));
-	set_plane_damage(&mock->state, &damage_blob);
-	drm_atomic_helper_damage_iter_init(&iter, &mock->old_state, &mock->state);
-	drm_atomic_for_each_plane_damage(&iter, &clip)
-		num_hits++;
-
-	KUNIT_EXPECT_EQ_MSG(test, num_hits, 1,
-			    "Should return round off plane src as damage.");
-	check_damage_clip(test, &clip, 3, 3, 1028, 772);
-}
-
-static void drm_test_damage_iter_damage_not_visible(struct kunit *test)
-{
-	struct drm_damage_mock *mock = test->priv;
-	struct drm_atomic_helper_damage_iter iter;
-	struct drm_property_blob damage_blob;
-	struct drm_mode_rect damage[2];
-	struct drm_rect clip;
-	u32 num_hits = 0;
-
-	mock->state.visible = false;
-
-	set_plane_src(&mock->old_state, 0x40002, 0x40002,
-		      0x40002 + (1024 << 16), 0x40002 + (768 << 16));
-	set_plane_src(&mock->state, 0x3fffe, 0x3fffe,
-		      0x3fffe + (1024 << 16), 0x3fffe + (768 << 16));
-	/* 2 damage clips, one outside plane src. */
-	set_damage_clip(&damage[0], 1360, 1360, 1380, 1380);
-	set_damage_clip(&damage[1], 240, 200, 280, 250);
-	set_damage_blob(&damage_blob, &damage[0], sizeof(damage));
-	set_plane_damage(&mock->state, &damage_blob);
-	drm_atomic_helper_damage_iter_init(&iter, &mock->old_state, &mock->state);
-	drm_atomic_for_each_plane_damage(&iter, &clip)
-		num_hits++;
-
-	KUNIT_EXPECT_EQ_MSG(test, num_hits, 0, "Should not return any damage.");
-}
-
 static void drm_test_damage_iter_damage_ignore(struct kunit *test)
 {
 	struct drm_damage_mock *mock = test->priv;
@@ -633,8 +488,6 @@ static void drm_test_damage_iter_damage_ignore(struct kunit *test)
 static struct kunit_case drm_damage_helper_tests[] = {
 	KUNIT_CASE(drm_test_damage_iter_no_damage),
 	KUNIT_CASE(drm_test_damage_iter_no_damage_fractional_src),
-	KUNIT_CASE(drm_test_damage_iter_no_damage_src_moved),
-	KUNIT_CASE(drm_test_damage_iter_no_damage_fractional_src_moved),
 	KUNIT_CASE(drm_test_damage_iter_no_damage_not_visible),
 	KUNIT_CASE(drm_test_damage_iter_no_damage_no_crtc),
 	KUNIT_CASE(drm_test_damage_iter_no_damage_no_fb),
@@ -645,13 +498,9 @@ static struct kunit_case drm_damage_helper_tests[] = {
 	KUNIT_CASE(drm_test_damage_iter_single_damage_fractional_src),
 	KUNIT_CASE(drm_test_damage_iter_single_damage_intersect_fractional_src),
 	KUNIT_CASE(drm_test_damage_iter_single_damage_outside_fractional_src),
-	KUNIT_CASE(drm_test_damage_iter_single_damage_src_moved),
-	KUNIT_CASE(drm_test_damage_iter_single_damage_fractional_src_moved),
 	KUNIT_CASE(drm_test_damage_iter_damage),
 	KUNIT_CASE(drm_test_damage_iter_damage_one_intersect),
 	KUNIT_CASE(drm_test_damage_iter_damage_one_outside),
-	KUNIT_CASE(drm_test_damage_iter_damage_src_moved),
-	KUNIT_CASE(drm_test_damage_iter_damage_not_visible),
 	KUNIT_CASE(drm_test_damage_iter_damage_ignore),
 	{ }
 };
diff --git a/include/drm/drm_damage_helper.h b/include/drm/drm_damage_helper.h
index 3661aeab2cd3..e93eaa0fbcb6 100644
--- a/include/drm/drm_damage_helper.h
+++ b/include/drm/drm_damage_helper.h
@@ -65,7 +65,8 @@ struct drm_atomic_helper_damage_iter {
 };
 
 void drm_atomic_helper_check_plane_damage(struct drm_atomic_commit *state,
-					  struct drm_plane_state *plane_state);
+					  const struct drm_plane_state *old_plane_state,
+					  struct drm_plane_state *new_plane_state);
 int drm_atomic_helper_dirtyfb(struct drm_framebuffer *fb,
 			      struct drm_file *file_priv, unsigned int flags,
 			      unsigned int color, struct drm_clip_rect *clips,
-- 
2.54.0


^ permalink raw reply related

* [PATCH v2 05/10] drm/appletbdrm: Allocate request/response buffers in begin_fb_access
From: Thomas Zimmermann @ 2026-05-11 12:22 UTC (permalink / raw)
  To: mripard, maarten.lankhorst, airlied, airlied, simona, admin,
	gargaditya08, paul, zack.rusin, bcm-kernel-feedback-list
  Cc: dri-devel, linux-hyperv, intel-gfx, intel-xe, linux-mips,
	virtualization, Thomas Zimmermann
In-Reply-To: <20260511122421.114014-1-tzimmermann@suse.de>

In atomic_check, damage handling is not fully evaluated. Another
atomic_check helper could trigger a full modeset and thus invalidate
damage clips.

Allocation of the request/response buffers in appletbdrm depends on
correct damage information. Otherwise it might allocate incorrectly
sized buffers. Allocate the buffers in the driver's begin_fb_access
helper. It runs early during the commit when damage clipping has been
fully evaluated.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Aditya Garg <gargaditya08@proton.me>
---
 drivers/gpu/drm/tiny/appletbdrm.c | 50 +++++++++++++++++++------------
 1 file changed, 31 insertions(+), 19 deletions(-)

diff --git a/drivers/gpu/drm/tiny/appletbdrm.c b/drivers/gpu/drm/tiny/appletbdrm.c
index cdd35af49892..65d1796252e9 100644
--- a/drivers/gpu/drm/tiny/appletbdrm.c
+++ b/drivers/gpu/drm/tiny/appletbdrm.c
@@ -315,33 +315,21 @@ static const u32 appletbdrm_primary_plane_formats[] = {
 	DRM_FORMAT_XRGB8888, /* emulated */
 };
 
-static int appletbdrm_primary_plane_helper_atomic_check(struct drm_plane *plane,
-						   struct drm_atomic_commit *state)
+static int appletbdrm_primary_plane_helper_begin_fb_access(struct drm_plane *plane,
+							   struct drm_plane_state *new_plane_state)
 {
-	struct drm_plane_state *new_plane_state = drm_atomic_get_new_plane_state(state, plane);
-	struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(state, plane);
-	struct drm_crtc *new_crtc = new_plane_state->crtc;
-	struct drm_crtc_state *new_crtc_state = NULL;
 	struct appletbdrm_plane_state *appletbdrm_state = to_appletbdrm_plane_state(new_plane_state);
+	size_t frames_size = 0;
 	struct drm_atomic_helper_damage_iter iter;
 	struct drm_rect damage;
-	size_t frames_size = 0;
 	size_t request_size;
 	int ret;
 
-	if (new_crtc)
-		new_crtc_state = drm_atomic_get_new_crtc_state(state, new_crtc);
-
-	ret = drm_atomic_helper_check_plane_state(new_plane_state, new_crtc_state,
-						  DRM_PLANE_NO_SCALING,
-						  DRM_PLANE_NO_SCALING,
-						  false, false);
+	ret = drm_gem_begin_shadow_fb_access(plane, new_plane_state);
 	if (ret)
 		return ret;
-	else if (!new_plane_state->visible)
-		return 0;
 
-	drm_atomic_helper_damage_iter_init(&iter, old_plane_state, new_plane_state);
+	drm_atomic_helper_damage_iter_init(&iter, NULL, new_plane_state);
 	drm_atomic_for_each_plane_damage(&iter, &damage) {
 		frames_size += struct_size((struct appletbdrm_frame *)0, buf, rect_size(&damage));
 	}
@@ -369,6 +357,29 @@ static int appletbdrm_primary_plane_helper_atomic_check(struct drm_plane *plane,
 	return 0;
 }
 
+static int appletbdrm_primary_plane_helper_atomic_check(struct drm_plane *plane,
+							struct drm_atomic_commit *state)
+{
+	struct drm_plane_state *new_plane_state = drm_atomic_get_new_plane_state(state, plane);
+	struct drm_crtc *new_crtc = new_plane_state->crtc;
+	struct drm_crtc_state *new_crtc_state = NULL;
+	int ret;
+
+	if (new_crtc)
+		new_crtc_state = drm_atomic_get_new_crtc_state(state, new_crtc);
+
+	ret = drm_atomic_helper_check_plane_state(new_plane_state, new_crtc_state,
+						  DRM_PLANE_NO_SCALING,
+						  DRM_PLANE_NO_SCALING,
+						  false, false);
+	if (ret)
+		return ret;
+	else if (!new_plane_state->visible)
+		return 0;
+
+	return 0;
+}
+
 static int appletbdrm_flush_damage(struct appletbdrm_device *adev,
 				   struct drm_plane_state *old_state,
 				   struct drm_plane_state *state)
@@ -468,7 +479,7 @@ static int appletbdrm_flush_damage(struct appletbdrm_device *adev,
 }
 
 static void appletbdrm_primary_plane_helper_atomic_update(struct drm_plane *plane,
-						     struct drm_atomic_commit *old_state)
+							  struct drm_atomic_commit *old_state)
 {
 	struct appletbdrm_device *adev = drm_to_adev(plane->dev);
 	struct drm_device *drm = plane->dev;
@@ -552,7 +563,8 @@ static void appletbdrm_primary_plane_destroy_state(struct drm_plane *plane,
 }
 
 static const struct drm_plane_helper_funcs appletbdrm_primary_plane_helper_funcs = {
-	DRM_GEM_SHADOW_PLANE_HELPER_FUNCS,
+	.begin_fb_access = appletbdrm_primary_plane_helper_begin_fb_access,
+	.end_fb_access = drm_gem_end_shadow_fb_access,
 	.atomic_check = appletbdrm_primary_plane_helper_atomic_check,
 	.atomic_update = appletbdrm_primary_plane_helper_atomic_update,
 	.atomic_disable = appletbdrm_primary_plane_helper_atomic_disable,
-- 
2.54.0


^ permalink raw reply related

* [PATCH v2 03/10] drm/ingenic: Remove calls to drm_atomic_helper_check_plane_damage()
From: Thomas Zimmermann @ 2026-05-11 12:22 UTC (permalink / raw)
  To: mripard, maarten.lankhorst, airlied, airlied, simona, admin,
	gargaditya08, paul, zack.rusin, bcm-kernel-feedback-list
  Cc: dri-devel, linux-hyperv, intel-gfx, intel-xe, linux-mips,
	virtualization, Thomas Zimmermann
In-Reply-To: <20260511122421.114014-1-tzimmermann@suse.de>

Atomic helpers call drm_atomic_helper_check_plane_damage() after the
atomic_check anyway. See atomic_helper_check_planes(). Remove the calls
from the planes' atomic_check.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/gpu/drm/ingenic/ingenic-drm-drv.c | 3 ---
 drivers/gpu/drm/ingenic/ingenic-ipu.c     | 8 ++------
 2 files changed, 2 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/ingenic/ingenic-drm-drv.c b/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
index 42c86f195c66..e99b44e3ac92 100644
--- a/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
+++ b/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
@@ -519,9 +519,6 @@ static int ingenic_drm_plane_atomic_check(struct drm_plane *plane,
 	     old_plane_state->fb->format->format != new_plane_state->fb->format->format))
 		crtc_state->mode_changed = true;
 
-	if (priv->soc_info->map_noncoherent)
-		drm_atomic_helper_check_plane_damage(state, new_plane_state);
-
 	return 0;
 }
 
diff --git a/drivers/gpu/drm/ingenic/ingenic-ipu.c b/drivers/gpu/drm/ingenic/ingenic-ipu.c
index 56143a191f36..fd17c642c7ac 100644
--- a/drivers/gpu/drm/ingenic/ingenic-ipu.c
+++ b/drivers/gpu/drm/ingenic/ingenic-ipu.c
@@ -594,7 +594,7 @@ static int ingenic_ipu_plane_atomic_check(struct drm_plane *plane,
 
 	if (!new_plane_state->crtc ||
 	    !crtc_state->mode.hdisplay || !crtc_state->mode.vdisplay)
-		goto out_check_damage;
+		return 0;
 
 	/* Plane must be fully visible */
 	if (new_plane_state->crtc_x < 0 || new_plane_state->crtc_y < 0 ||
@@ -611,7 +611,7 @@ static int ingenic_ipu_plane_atomic_check(struct drm_plane *plane,
 		return -EINVAL;
 
 	if (!osd_changed(new_plane_state, old_plane_state))
-		goto out_check_damage;
+		return 0;
 
 	crtc_state->mode_changed = true;
 
@@ -645,10 +645,6 @@ static int ingenic_ipu_plane_atomic_check(struct drm_plane *plane,
 	ipu_state->denom_w = denom_w;
 	ipu_state->denom_h = denom_h;
 
-out_check_damage:
-	if (ingenic_drm_map_noncoherent(ipu->master))
-		drm_atomic_helper_check_plane_damage(state, new_plane_state);
-
 	return 0;
 }
 
-- 
2.54.0


^ permalink raw reply related

* [PATCH v2 02/10] drm/atomic-helpers: Evaluate plane damage after atomic_check
From: Thomas Zimmermann @ 2026-05-11 12:22 UTC (permalink / raw)
  To: mripard, maarten.lankhorst, airlied, airlied, simona, admin,
	gargaditya08, paul, zack.rusin, bcm-kernel-feedback-list
  Cc: dri-devel, linux-hyperv, intel-gfx, intel-xe, linux-mips,
	virtualization, Thomas Zimmermann
In-Reply-To: <20260511122421.114014-1-tzimmermann@suse.de>

Each plane's and CRTC's atomic_check might trigger a full modeset. As
this affects the plane's damage handling, evaluate damage clips after
running the atomic_check helpers.

Examples can be found in a number of drivers, such as ast, gud, ingenic,
mgag200 or vmwgfx, which all set mode_changed in the CRTC state to true.
Ingenic even reevaluates damage information in its plane's atomic_check.
Doing this after the atomic_check helpers ran benefits all drivers.

There's already a damage evaluation before the calls to atomic_check.
With a few fixes to drivers, this can be removed.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/gpu/drm/drm_atomic_helper.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 51f39edc31ed..4c37299e8ccb 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -1065,6 +1065,10 @@ drm_atomic_helper_check_planes(struct drm_device *dev,
 		}
 	}
 
+	for_each_oldnew_plane_in_state(state, plane, old_plane_state, new_plane_state, i) {
+		drm_atomic_helper_check_plane_damage(state, new_plane_state);
+	}
+
 	return ret;
 }
 EXPORT_SYMBOL(drm_atomic_helper_check_planes);
-- 
2.54.0


^ permalink raw reply related

* [PATCH v2 01/10] drm/damage-helper: Do not alter damage clips on modeset, but ignore them
From: Thomas Zimmermann @ 2026-05-11 12:22 UTC (permalink / raw)
  To: mripard, maarten.lankhorst, airlied, airlied, simona, admin,
	gargaditya08, paul, zack.rusin, bcm-kernel-feedback-list
  Cc: dri-devel, linux-hyperv, intel-gfx, intel-xe, linux-mips,
	virtualization, Thomas Zimmermann, stable
In-Reply-To: <20260511122421.114014-1-tzimmermann@suse.de>

User space supplies rectangles for damage clipping in a plane property.
For full mode sets, we still require a full plane update. In this case,
leave the information as-is and set the ignore_damage_clips flag instead.
The damage iterator will later ignore any damage information.

Also fixes a bug where ignore_damage_clips was not cleared across plane
duplications.

Leaving the damage information as-is might be helpful to drivers that
benefit from it even on full modesets (e.g., for cache management). It
will also help with consolidating the damage-handling logic.

Also add a new unit test that evaluates the ignore_damage_clips flag. It
sets two damage clips plus the flag and tests if the reported damage
covers the entire framebuffer.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: 35ed38d58257 ("drm: Allow drivers to indicate the damage helpers to ignore damage clips")
Cc: dri-devel@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v6.10+
---
 drivers/gpu/drm/drm_atomic_state_helper.c     |  1 +
 drivers/gpu/drm/drm_damage_helper.c           |  6 ++--
 .../gpu/drm/tests/drm_damage_helper_test.c    | 28 +++++++++++++++++++
 3 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/drm_atomic_state_helper.c b/drivers/gpu/drm/drm_atomic_state_helper.c
index cc70508d4fdb..84d5231ccac1 100644
--- a/drivers/gpu/drm/drm_atomic_state_helper.c
+++ b/drivers/gpu/drm/drm_atomic_state_helper.c
@@ -359,6 +359,7 @@ void __drm_atomic_helper_plane_duplicate_state(struct drm_plane *plane,
 	state->fence = NULL;
 	state->commit = NULL;
 	state->fb_damage_clips = NULL;
+	state->ignore_damage_clips = false;
 	state->color_mgmt_changed = false;
 }
 EXPORT_SYMBOL(__drm_atomic_helper_plane_duplicate_state);
diff --git a/drivers/gpu/drm/drm_damage_helper.c b/drivers/gpu/drm/drm_damage_helper.c
index 74a7f4252ecf..945fac8dc27b 100644
--- a/drivers/gpu/drm/drm_damage_helper.c
+++ b/drivers/gpu/drm/drm_damage_helper.c
@@ -78,10 +78,8 @@ void drm_atomic_helper_check_plane_damage(struct drm_atomic_commit *state,
 		if (WARN_ON(!crtc_state))
 			return;
 
-		if (drm_atomic_crtc_needs_modeset(crtc_state)) {
-			drm_property_blob_put(plane_state->fb_damage_clips);
-			plane_state->fb_damage_clips = NULL;
-		}
+		if (drm_atomic_crtc_needs_modeset(crtc_state))
+			plane_state->ignore_damage_clips = true;
 	}
 }
 EXPORT_SYMBOL(drm_atomic_helper_check_plane_damage);
diff --git a/drivers/gpu/drm/tests/drm_damage_helper_test.c b/drivers/gpu/drm/tests/drm_damage_helper_test.c
index 0df2e1a54b0d..64f038a62ffe 100644
--- a/drivers/gpu/drm/tests/drm_damage_helper_test.c
+++ b/drivers/gpu/drm/tests/drm_damage_helper_test.c
@@ -603,6 +603,33 @@ static void drm_test_damage_iter_damage_not_visible(struct kunit *test)
 	KUNIT_EXPECT_EQ_MSG(test, num_hits, 0, "Should not return any damage.");
 }
 
+static void drm_test_damage_iter_damage_ignore(struct kunit *test)
+{
+	struct drm_damage_mock *mock = test->priv;
+	struct drm_atomic_helper_damage_iter iter;
+	struct drm_property_blob damage_blob;
+	struct drm_mode_rect damage[2];
+	struct drm_rect clip;
+	u32 num_hits = 0;
+
+	set_plane_src(&mock->old_state, 0, 0, 1024 << 16, 768 << 16);
+	set_plane_src(&mock->state, 0, 0, 1024 << 16, 768 << 16);
+	/* 2 damage clips, but ignore them. */
+	set_damage_clip(&damage[0], 20, 30, 200, 180);
+	set_damage_clip(&damage[1], 240, 200, 280, 250);
+	set_damage_blob(&damage_blob, &damage[0], sizeof(damage));
+	set_plane_damage(&mock->state, &damage_blob);
+	mock->state.ignore_damage_clips = true;
+	drm_atomic_helper_damage_iter_init(&iter, &mock->old_state, &mock->state);
+	drm_atomic_for_each_plane_damage(&iter, &clip) {
+		if (num_hits == 0)
+			check_damage_clip(test, &clip, 0, 0, 1024, 768);
+		num_hits++;
+	}
+
+	KUNIT_EXPECT_EQ_MSG(test, num_hits, 1, "Should return full-framebuffer damage.");
+}
+
 static struct kunit_case drm_damage_helper_tests[] = {
 	KUNIT_CASE(drm_test_damage_iter_no_damage),
 	KUNIT_CASE(drm_test_damage_iter_no_damage_fractional_src),
@@ -625,6 +652,7 @@ static struct kunit_case drm_damage_helper_tests[] = {
 	KUNIT_CASE(drm_test_damage_iter_damage_one_outside),
 	KUNIT_CASE(drm_test_damage_iter_damage_src_moved),
 	KUNIT_CASE(drm_test_damage_iter_damage_not_visible),
+	KUNIT_CASE(drm_test_damage_iter_damage_ignore),
 	{ }
 };
 
-- 
2.54.0


^ permalink raw reply related

* [PATCH v2 00/10] drm: Improve logic behind damage handling
From: Thomas Zimmermann @ 2026-05-11 12:22 UTC (permalink / raw)
  To: mripard, maarten.lankhorst, airlied, airlied, simona, admin,
	gargaditya08, paul, zack.rusin, bcm-kernel-feedback-list
  Cc: dri-devel, linux-hyperv, intel-gfx, intel-xe, linux-mips,
	virtualization, Thomas Zimmermann

DRM clients can supply information on framebuffer areas to update as
part of each page flip, called damage clipping rectangles. But DRM's
processing of this information is inconsistent and prone to errors.

- There are multiple fields and tests that decide if damage clips
should be taken or ignored.

- Sometimes damage clips are removed behind the back of the DRM client.

- Atomic helpers evaluate damage clipping in the middle of the atomic
check: after connectors and encoders, but before planes and CRTCs. Hence
pipeline stages have an inconsistent view.

- Which leads to drivers (ingenic) doing a re-evaluation if necessary.

- Tests of plane source coordinates only happen during commits. At this
point, the driver should already know if damage clips are to be taken or
not. Because of this, some drivers (appletbdrm) might operate on incorrect
damage information for their internal workings. This also leads to excessive
use of the old plane state.

Got through DRM helpers and drivers to fix up the logic.

- Run all of the atomic checks with the damage information supplied by
DRM clients. Afterwards evaluate plane and CRTC states on whether to
take or ignore damage clips. Do all related tests in a single atomic
helper.

- Do not discard damage clips. Set ignore_damage_clips in struct
drm_plane_state instead. This includes changes to plane source-coordinates.
The damage iterator now only has to look at this flag to detect if it
should use the damage clips. 

- Go over drivers and fix up the damage handling in the plane's
atomic_update helpers. Most drivers no longer need the old plane state
in their update.

- The appletbdrm driver require a fix in how it uses damage information.
Ingenic and vmwgfx can be simplified. These changes make the drivers better
structured.

- Kunit tests require some changes. Drop some obsolete tests and add a new
one for ignore_damage_flags.

Tested with bochs, mgag200, Kunit tests.

v2:
- rebase on latest upstream

Thomas Zimmermann (10):
  drm/damage-helper: Do not alter damage clips on modeset, but ignore
    them
  drm/atomic-helpers: Evaluate plane damage after atomic_check
  drm/ingenic: Remove calls to drm_atomic_helper_check_plane_damage()
  drm/damage-helper: Test src coord in
    drm_atomic_helper_check_plane_damage()
  drm/appletbdrm: Allocate request/response buffers in begin_fb_access
  drm/damage-helper: Remove old state from
    drm_atomic_helper_damage_iter_init()
  drm/damage-helper: Remove old state from
    drm_atomic_helper_damage_merged()
  drm/atomic_helper: Do not evaluate plane damage before atomic_check
  drm/damage-helper: Rename state parameters in damage helpers
  drm/vmwgfx: Remove unused field struct
    vmwgfx_du_update_plane.old_state

 drivers/gpu/drm/ast/ast_cursor.c              |   3 +-
 drivers/gpu/drm/ast/ast_mode.c                |   2 +-
 drivers/gpu/drm/drm_atomic_helper.c           |   6 +-
 drivers/gpu/drm/drm_atomic_state_helper.c     |   1 +
 drivers/gpu/drm/drm_damage_helper.c           |  44 ++--
 drivers/gpu/drm/drm_fb_dma_helper.c           |   2 +-
 drivers/gpu/drm/drm_mipi_dbi.c                |   3 +-
 drivers/gpu/drm/gud/gud_pipe.c                |   3 +-
 drivers/gpu/drm/hyperv/hyperv_drm_modeset.c   |   3 +-
 drivers/gpu/drm/i915/display/intel_plane.c    |  11 +-
 drivers/gpu/drm/i915/display/intel_psr.c      |   3 +-
 drivers/gpu/drm/ingenic/ingenic-drm-drv.c     |   3 -
 drivers/gpu/drm/ingenic/ingenic-ipu.c         |   8 +-
 drivers/gpu/drm/mgag200/mgag200_mode.c        |   3 +-
 drivers/gpu/drm/sitronix/st7571.c             |   3 +-
 drivers/gpu/drm/sitronix/st7586.c             |   3 +-
 drivers/gpu/drm/sitronix/st7920.c             |   3 +-
 drivers/gpu/drm/solomon/ssd130x.c             |   9 +-
 drivers/gpu/drm/sysfb/drm_sysfb_modeset.c     |   3 +-
 .../gpu/drm/tests/drm_damage_helper_test.c    | 200 +++---------------
 drivers/gpu/drm/tiny/appletbdrm.c             |  56 +++--
 drivers/gpu/drm/tiny/bochs.c                  |   3 +-
 drivers/gpu/drm/tiny/cirrus-qemu.c            |   2 +-
 drivers/gpu/drm/tiny/gm12u320.c               |   2 +-
 drivers/gpu/drm/tiny/ili9225.c                |   3 +-
 drivers/gpu/drm/tiny/repaper.c                |   2 +-
 drivers/gpu/drm/tiny/sharp-memory.c           |   3 +-
 drivers/gpu/drm/udl/udl_modeset.c             |   3 +-
 drivers/gpu/drm/virtio/virtgpu_plane.c        |   2 +-
 drivers/gpu/drm/vmwgfx/vmwgfx_kms.c           |   5 +-
 drivers/gpu/drm/vmwgfx/vmwgfx_kms.h           |   2 -
 drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c          |  12 +-
 drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c          |  15 +-
 include/drm/drm_damage_helper.h               |   9 +-
 34 files changed, 124 insertions(+), 311 deletions(-)


base-commit: 680a4832a8182b13ac5d55ab0c03c54ebc2baadd
-- 
2.54.0


^ permalink raw reply

* Re: [PATCH net] vsock/virtio: fix skb overhead accounting to preserve full buf_alloc
From: Stefano Garzarella @ 2026-05-11 10:54 UTC (permalink / raw)
  To: Michael S. Tsirkin
  Cc: netdev, Eric Dumazet, Stefan Hajnoczi, virtualization,
	David S. Miller, Jason Wang, Simon Horman, linux-kernel,
	Paolo Abeni, Xuan Zhuo, kvm, Jakub Kicinski, Eugenio Pérez
In-Reply-To: <af28MAV0LF4qHVmB@sgarzare-redhat>

On Fri, 8 May 2026 at 12:38, Stefano Garzarella <sgarzare@redhat.com> 
wrote:
>
> On Fri, May 08, 2026 at 06:33:13AM -0400, Michael S. Tsirkin wrote:
> >On Fri, May 08, 2026 at 12:01:50PM +0200, Stefano Garzarella wrote:
> >> On Fri, May 08, 2026 at 05:53:07AM -0400, Michael S. Tsirkin wrote:
> >> > On Fri, May 08, 2026 at 11:23:30AM +0200, Stefano Garzarella wrote:
> >> > > From: Stefano Garzarella <sgarzare@redhat.com>
> >> > >
> >> > > After commit 059b7dbd20a6 ("vsock/virtio: fix potential unbounded skb
> >> > > queue"), virtio_transport_inc_rx_pkt() subtracts per-skb overhead from
> >> > > buf_alloc when checking whether a new packet fits. This reduces the
> >> > > effective receive buffer below what the user configured via
> >> > > SO_VM_SOCKETS_BUFFER_SIZE, causing legitimate data packets to be
> >> > > silently dropped and applications that rely on the full buffer size
> >> > > to deadlock.
> >> > >
> >> > > Also, the reduced space is not communicated to the remote peer, so
> >> > > its credit calculation accounts more credit than the receiver will
> >> > > actually accept, causing data loss (there is no retransmission).
> >> > >
> >> > > This also causes failures in tools/testing/vsock/vsock_test.c.
> >> > > Test 18 sometimes fails, while test 22 always fails in this way:
> >> > >     18 - SOCK_STREAM MSG_ZEROCOPY...hash mismatch
> >> > >
> >> > >     22 - SOCK_STREAM virtio credit update + SO_RCVLOWAT...send failed:
> >> > >     Resource temporarily unavailable
> >> > >
> >> > > Fix this by introducing virtio_transport_rx_buf_size() to calculate the
> >> > > size of the RX buffer based on the overhead. Using it in the acceptance
> >> > > check, the advertised buf_alloc, and the credit update decision.
> >> > > Use buf_alloc * 2 as total budget (payload + overhead), similar to how
> >> > > SO_RCVBUF is doubled to reserve space for sk_buff metadata.
> >> > > The function returns buf_alloc as long as overhead fits within the
> >> > > reservation, then gradually reduces toward 0 as overhead exceeds
> >> > > buf_alloc (e.g. under small-packet flooding), informing the peer to
> >> > > slow down.
> >> > >
> >> > > Fixes: 059b7dbd20a6 ("vsock/virtio: fix potential unbounded skb queue")
> >> > > Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
> >> >
> >> >
> >> > unfortunately, this is a bit of a spec violation and there is no guarantee
> >> > it helps.
> >>
> >> Loosing data like we are doing in 059b7dbd20a6 is even worse IMHO.
> >>
> >> >
> >> > a spec violation because the spec says:
> >> > Only payload bytes are counted and header bytes are not
> >> > included
> >> >
> >> > and the implication is that a side can not reduce its own buf_alloc.
> >> >
> >> > no guarantee because the other side is not required to process your
> >> > packets, so it might not see your buf alloc reduction.
> >> >
> >> > as designed in the current spec, you can only increase your buf alloc,
> >> > not decrease it.
> >>
> >> We never enforced this, currently an user can reduce it by
> >> SO_VM_SOCKETS_BUFFER_SIZE and we haven't blocked it since virtio-vsock was
> >> introduced, should we update the spec?
> >
> >
> >it's not that we need to enforce it, it's that all synchronization
> >assumes this. as in, anyone can use an old copy until they run out
> >of credits.
> >
> >
> >> >
> >> > what can be done:
> >> > - more efficient storage for small packets (poc i posted)
> >> > - reduce buf alloc ahead of the time
> >>
> >> That's basically what I'm doing here: I'm using twice the size of
> >> `buf_alloc` (just like `SO_RCVBUF` does for other socket types) and telling
> >> the other peer just `buf_alloc`.
> >>
> >> But then, somehow, we have to let the other person know that we're running
> >> out of space. With this patch that only happens when the other peer isn't
> >> behaving properly, sending so many small packets that the overhead exceeds
> >> `buf_alloc`.
> >>
> >> Stefano
> >
> >what is "not proper" here, it is up to the application what to send.
>
> Sure, but here we're just slowing down the application by telling it we
> don't have any more space.
>
> Again, without this patch we are just dropping data, which IMO is even
> worse.
>
> So I think we should merge this for now, while we handle better the EOM.
> If you prefer, I can drop the part where we reduce the buf_alloc
> advertised to the other peer, but at least we should drop data after
> `buf_alloc * 2` IMO.

Okay, I thought it over over the weekend, and I agree that this patch 
still doesn't solve the problem and would still result in packet loss.
So, until we resolve the issue permanently, and since 059b7dbd20a6 is 
coming to stable, I'd like to rework this patch so that we only start 
dropping packets when the overhead plus the queued bytes exceeds 
`buf_alloc * 2`.
Removing the other changes to reduce the buf_alloc advertised, but 
terminating the connection so that both peers are aware that something 
went wrong.

Any objections?

Stefano


^ permalink raw reply

* [PATCH] vhost-vdpa: Expose ASID group change after DRIVER_OK via backend feature
From: Dragos Tatulea @ 2026-05-11  9:45 UTC (permalink / raw)
  To: virtualization, Dragos Tatulea, Michael S. Tsirkin, Jason Wang,
	Xuan Zhuo, Eugenio Pérez
  Cc: Tariq Toukan, Shahar Shitrit, linux-kernel, kvm, netdev

The commit in the fixes tag blocked VHOST_VDPA_SET_GROUP_ASID operations
once DRIVER_OK is set. That is too strict for devices which can safely
handle this during live migration flows.

Bring back this behavior under a new vhost backend feature flag. The
feature is supported by mlx5 and vdpa_sim devices.

Fixes: 3543b04a4ea3 ("vhost: forbid change vq groups ASID if DRIVER_OK is set")
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Reviewed-by: Shahar Shitrit <shshitrit@nvidia.com>
---
 drivers/vdpa/mlx5/net/mlx5_vnet.c |  3 ++-
 drivers/vdpa/vdpa_sim/vdpa_sim.c  |  3 ++-
 drivers/vhost/vdpa.c              | 13 +++++++++++--
 include/uapi/linux/vhost_types.h  |  4 ++++
 4 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index ad0d5fbbbca8..f89177957c76 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -2906,7 +2906,8 @@ static void unregister_link_notifier(struct mlx5_vdpa_net *ndev)
 
 static u64 mlx5_vdpa_get_backend_features(const struct vdpa_device *vdpa)
 {
-	return BIT_ULL(VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK);
+	return BIT_ULL(VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK) |
+	       BIT_ULL(VHOST_BACKEND_F_GROUP_ASID_AFTER_DRIVER_OK);
 }
 
 static int mlx5_vdpa_set_driver_features(struct vdpa_device *vdev, u64 features)
diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
index 8cb1cc2ea139..253c7fb35ea0 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
@@ -428,7 +428,8 @@ static u64 vdpasim_get_device_features(struct vdpa_device *vdpa)
 
 static u64 vdpasim_get_backend_features(const struct vdpa_device *vdpa)
 {
-	return BIT_ULL(VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK);
+	return BIT_ULL(VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK) |
+	       BIT_ULL(VHOST_BACKEND_F_GROUP_ASID_AFTER_DRIVER_OK);
 }
 
 static int vdpasim_set_driver_features(struct vdpa_device *vdpa, u64 features)
diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 692564b1bcbb..67b3f49fa709 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -682,7 +682,8 @@ static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
 			return -EFAULT;
 		if (idx >= vdpa->ngroups || s.num >= vdpa->nas)
 			return -EINVAL;
-		if (ops->get_status(vdpa) & VIRTIO_CONFIG_S_DRIVER_OK)
+		if ((ops->get_status(vdpa) & VIRTIO_CONFIG_S_DRIVER_OK) &&
+		    !vhost_backend_has_feature(vq, VHOST_BACKEND_F_GROUP_ASID_AFTER_DRIVER_OK))
 			return -EBUSY;
 		if (!ops->set_group_asid)
 			return -EOPNOTSUPP;
@@ -791,7 +792,8 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep,
 				 BIT_ULL(VHOST_BACKEND_F_IOTLB_PERSIST) |
 				 BIT_ULL(VHOST_BACKEND_F_SUSPEND) |
 				 BIT_ULL(VHOST_BACKEND_F_RESUME) |
-				 BIT_ULL(VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK)))
+				 BIT_ULL(VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK) |
+				 BIT_ULL(VHOST_BACKEND_F_GROUP_ASID_AFTER_DRIVER_OK)))
 			return -EOPNOTSUPP;
 		if ((features & BIT_ULL(VHOST_BACKEND_F_SUSPEND)) &&
 		     !vhost_vdpa_can_suspend(v))
@@ -805,6 +807,13 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep,
 		if ((features & BIT_ULL(VHOST_BACKEND_F_DESC_ASID)) &&
 		     !vhost_vdpa_has_desc_group(v))
 			return -EOPNOTSUPP;
+		if (features & BIT_ULL(VHOST_BACKEND_F_GROUP_ASID_AFTER_DRIVER_OK)) {
+			if (!(features & BIT_ULL(VHOST_BACKEND_F_IOTLB_ASID)))
+				return -EINVAL;
+			if (!(vhost_vdpa_get_backend_features(v) &
+				BIT_ULL(VHOST_BACKEND_F_GROUP_ASID_AFTER_DRIVER_OK)))
+				return -EOPNOTSUPP;
+		}
 		if ((features & BIT_ULL(VHOST_BACKEND_F_IOTLB_PERSIST)) &&
 		     !vhost_vdpa_has_persistent_map(v))
 			return -EOPNOTSUPP;
diff --git a/include/uapi/linux/vhost_types.h b/include/uapi/linux/vhost_types.h
index 1c39cc5f5a31..ec1ff8a2e260 100644
--- a/include/uapi/linux/vhost_types.h
+++ b/include/uapi/linux/vhost_types.h
@@ -197,5 +197,9 @@ struct vhost_vdpa_iova_range {
 #define VHOST_BACKEND_F_DESC_ASID    0x7
 /* IOTLB don't flush memory mapping across device reset */
 #define VHOST_BACKEND_F_IOTLB_PERSIST  0x8
+/* Device supports changing the group ASID after DRIVER_OK.
+ * Requires VHOST_BACKEND_F_IOTLB_ASID.
+ */
+#define VHOST_BACKEND_F_GROUP_ASID_AFTER_DRIVER_OK  0x9
 
 #endif
-- 
2.54.0


^ permalink raw reply related

* Re: [PATCH net-next v12 0/4] tun/tap & vhost-net: apply qdisc backpressure on full ptr_ring to reduce TX drops
From: Michael S. Tsirkin @ 2026-05-11  9:10 UTC (permalink / raw)
  To: Simon Schippers
  Cc: willemdebruijn.kernel, jasowang, andrew+netdev, davem, edumazet,
	kuba, pabeni, eperezma, leiyang, stephen, jon, tim.gebauer,
	netdev, linux-kernel, kvm, virtualization
In-Reply-To: <20260510151529.43895-1-simon.schippers@tu-dortmund.de>

On Sun, May 10, 2026 at 05:15:25PM +0200, Simon Schippers wrote:
> This patch series deals with tun/tap & vhost-net which drop incoming
> SKBs whenever their internal ptr_ring buffer is full. Instead, with this 
> patch series, the associated netdev queue is stopped - but only when a
> qdisc is attached. If no qdisc is present the existing behavior is
> preserved. The XDP transmit path is not affected. This patch series
> touches tun/tap and vhost-net, as they share common logic and must be
> updated together. Modifying only one of them would break the other.
> 
> By applying proper backpressure, this change allows the connected qdisc to 
> operate correctly, as reported in [1], and significantly improves
> performance in real-world scenarios, as demonstrated in our paper [2]. For 
> example, we observed a 36% TCP throughput improvement for an OpenVPN 
> connection between Germany and the USA.
> 
> Synthetic pktgen benchmarks indicate a slight regression, and packet
> loss is reduced to near zero. Pktgen benchmarks are provided per commit,
> with the final commit showing the overall performance.

at v12, time to merge this.

Acked-by: Michael S. Tsirkin <mst@redhat.com>

> Thanks!
> 
> [1] Link: https://unix.stackexchange.com/questions/762935/traffic-shaping-ineffective-on-tun-device
> [2] Link: https://cni.etit.tu-dortmund.de/storages/cni-etit/r/Research/Publications/2025/Gebauer_2025_VTCFall/Gebauer_VTCFall2025_AuthorsVersion.pdf
> 
> ---
> Changelog:
> v12:
> Patch 1: 
> - Revert tun_queue_purge() to plain ptr_ring_consume() and instead
>   explicitly wake the queue in __tun_detach() for the ntfile taking
>   over the queue slot (if its ring is empty).
> - Inlined tun_reset_cons_cnt(), because only tun_attach() uses it.
> 
> - Patches 2-4 and cover letter unchanged.
> - Compiled and short pktgen test.
> 
> v11:
> - Renamed __ptr_ring_produce_peek() to __ptr_ring_check_produce()
>   (Sashiko)
> - Add return code -EINVAL to __ptr_ring_check_produce() which lets
>   tun_net_xmit() stop the queue only on -ENOSPC. (MST)
> - Resolve race on tfile->queue_index by locking tx_ring.consumer_lock
>   in __tun_detach(). (Sashiko)
> - Wake the queue in tun_queue_resize() to avoid possible stalls.
> - Other minor adjustments & reran the benchmarks.
> 
> v10: https://lore.kernel.org/netdev/20260506141033.180450-1-simon.schippers@tu-dortmund.de/
> - Changed the term "Transmitted" to "Received" in the benchmarks,
>   as correctly pointed out by MST, and reran the benchmarks.
> 
> Addressed the Sashiko AI review:
> - Avoid a data race on tfile->cons_cnt by always locking.
> - Correctly count the number of consumed packets for vhost-net.
> - Corrected a typo in the commit message of commit 3.
> - Added a missing barrier on the consumer side.
> --> The barriers now follow the "store buffering" principle.
> - No longer return NETDEV_TX_BUSY at all, because it is unsafe.
> --> Result: There are still a few drops with multiple senders, which
>             would be avoided by disabling LLTX.
> 
> V9: https://lore.kernel.org/netdev/20260428123859.19578-1-simon.schippers@tu-dortmund.de/
> - Addressed minor nit by MST in patches 1 and 2.
> - Rebased patch 3 because of commit d748047
>   ("ptr_ring: disable KCSAN warnings").
> - Documented the pair of the smp_mb__after_atomic() in tun_net_xmit()
>   with tun_ring_consume().
>   --> It simply pairs with the test_and_clear_bit() inside of
>       netif_wake_subqueue().
> - Use 1 ptr_ring consumer spinlock instead of 2.
> - Ran pktgen benchmarks with pg_set SHARED for 50 iterations on
>   latest kernel
>   --> No significant performance difference noticed
> 
> V8: https://lore.kernel.org/netdev/20260312130639.138988-1-simon.schippers@tu-dortmund.de/
> - Drop code changes in drivers/net/tap.c; The code there deals with
>   ipvtap/macvtap which are unrelated to the goal of this patch series
>   and I did not realize that before
> -> Greatly simplified logic, 4 instead of 9 commits
> -> No more duplicated logics and distinction in vhost required
> - Only wake after the queue stopped and half of the ring was consumed
>   as suggested by MST
> -> Performance improvements for TAP, but still slightly slower
> - Better benchmarking with pinned threads, XDP drop program for
>   tap+vhost-net and disabling CPU mitigations (and newer Ryzen 5 5600X
>   processor) as suggested by Jason Wang
> 
> V7: https://lore.kernel.org/netdev/20260107210448.37851-1-simon.schippers@tu-dortmund.de/
> - Switch to an approach similar to veth (excluding the recently fixed 
> variant), as suggested by MST, with minor adjustments discussed in V6
> - Rename the cover-letter title
> - Add multithreaded pktgen and iperf3 benchmarks, as suggested by Jason 
> Wang
> - Rework __ptr_ring_consume_created_space() so it can also be used after 
> batched consume
> 
> ...
> 
> ---
> 
> Simon Schippers (4):
>   tun/tap: add ptr_ring consume helper with netdev queue wakeup
>   vhost-net: wake queue of tun/tap after ptr_ring consume
>   ptr_ring: move free-space check into separate helper
>   tun/tap & vhost-net: avoid ptr_ring tail-drop when a qdisc is present
> 
>  drivers/net/tun.c        | 109 ++++++++++++++++++++++++++++++++++++---
>  drivers/vhost/net.c      |  21 +++++---
>  include/linux/if_tun.h   |   3 ++
>  include/linux/ptr_ring.h |  20 ++++++-
>  4 files changed, 139 insertions(+), 14 deletions(-)
> 
> -- 
> 2.43.0


^ permalink raw reply

* [PATCH resend v6 30/30] mm: balloon: use put_page_zeroed for zeroed balloon pages
From: Michael S. Tsirkin @ 2026-05-11  9:04 UTC (permalink / raw)
  To: linux-kernel
  Cc: David Hildenbrand (Arm), Jason Wang, Xuan Zhuo,
	Eugenio Pérez, Muchun Song, Oscar Salvador, Andrew Morton,
	Lorenzo Stoakes, Liam R. Howlett, Vlastimil Babka, Mike Rapoport,
	Suren Baghdasaryan, Michal Hocko, Brendan Jackman,
	Johannes Weiner, Zi Yan, Baolin Wang, Nico Pache, Ryan Roberts,
	Dev Jain, Barry Song, Lance Yang, Hugh Dickins, Matthew Brost,
	Joshua Hahn, Rakie Kim, Byungchul Park, Gregory Price, Ying Huang,
	Alistair Popple, Christoph Lameter, David Rientjes,
	Roman Gushchin, Harry Yoo, Axel Rasmussen, Yuanchu Xie, Wei Xu,
	Chris Li, Kairui Song, Kemeng Shi, Nhat Pham, Baoquan He,
	virtualization, linux-mm, Andrea Arcangeli
In-Reply-To: <cover.1778489843.git.mst@redhat.com>

When a balloon page marked PageZeroed is freed during migration,
use put_page_zeroed() to propagate the zeroed hint to the buddy
allocator. Previously the hint was silently lost via plain put_page().

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Assisted-by: Claude:claude-opus-4-6
---
 mm/balloon.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/mm/balloon.c b/mm/balloon.c
index 96a8f1e20bc6..1bf7eb2642a9 100644
--- a/mm/balloon.c
+++ b/mm/balloon.c
@@ -324,7 +324,12 @@ static int balloon_page_migrate(struct page *newpage, struct page *page,
 	balloon_page_finalize(page);
 	spin_unlock_irqrestore(&balloon_pages_lock, flags);
 
-	put_page(page);
+	if (PageZeroed(page)) {
+		__ClearPageZeroed(page);
+		put_page_zeroed(page);
+	} else {
+		put_page(page);
+	}
 
 	return 0;
 }
-- 
MST


^ permalink raw reply related

* [PATCH resend v6 29/30] virtio_balloon: implement VIRTIO_BALLOON_F_DEVICE_INIT_ON_INFLATE
From: Michael S. Tsirkin @ 2026-05-11  9:04 UTC (permalink / raw)
  To: linux-kernel
  Cc: David Hildenbrand (Arm), Jason Wang, Xuan Zhuo,
	Eugenio Pérez, Muchun Song, Oscar Salvador, Andrew Morton,
	Lorenzo Stoakes, Liam R. Howlett, Vlastimil Babka, Mike Rapoport,
	Suren Baghdasaryan, Michal Hocko, Brendan Jackman,
	Johannes Weiner, Zi Yan, Baolin Wang, Nico Pache, Ryan Roberts,
	Dev Jain, Barry Song, Lance Yang, Hugh Dickins, Matthew Brost,
	Joshua Hahn, Rakie Kim, Byungchul Park, Gregory Price, Ying Huang,
	Alistair Popple, Christoph Lameter, David Rientjes,
	Roman Gushchin, Harry Yoo, Axel Rasmussen, Yuanchu Xie, Wei Xu,
	Chris Li, Kairui Song, Kemeng Shi, Nhat Pham, Baoquan He,
	virtualization, linux-mm, Andrea Arcangeli
In-Reply-To: <cover.1778489843.git.mst@redhat.com>

When the device offers DEVICE_INIT_ON_INFLATE (bit 7), the device
initializes inflated pages and returns a per-page bitmap indicating
which pages were successfully initialized.

The driver appends a device-writable bitmap buffer to each inflate
descriptor chain via virtqueue_add_sgs. After the host acknowledges,
the driver checks bitmap bits (bounded by used_len) and marks pages
with SetPageZeroed.

tell_host() returns used_len from virtqueue_get_buf(). Bitmap reads
are bounded: fill_balloon() and virtballoon_migratepage() only trust
bits within the used_len range.

On deflate, release_pages_balloon checks PageZeroed per page and
uses put_page_zeroed for pages the host initialized, propagating
the zeroed hint to the buddy allocator.

If inflate_vq has fewer than 2 descriptors, probe fails with
-ENOSPC. If PAGE_POISON is negotiated with non-zero poison_val,
the feature is cleared in validate().

See the virtio spec change:
https://lore.kernel.org/all/9c69b992c3dd83dfef3db92cd86b2fd8a0730d48.1777731396.git.mst@redhat.com

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Assisted-by: Claude:claude-opus-4-6
Assisted-by: cursor-agent:GPT-5.4-xhigh
---
 drivers/virtio/virtio_balloon.c     | 102 ++++++++++++++++++++++++----
 include/uapi/linux/virtio_balloon.h |   1 +
 2 files changed, 90 insertions(+), 13 deletions(-)

diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index d1cdb904d60b..284108dbcff1 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -121,6 +121,9 @@ struct virtio_balloon {
 	struct virtqueue *reporting_vq;
 	struct page_reporting_dev_info pr_dev_info;
 
+	/* Bitmap returned by host for DEVICE_INIT_ON_INFLATE */
+	DECLARE_BITMAP(inflate_bitmap, VIRTIO_BALLOON_ARRAY_PFNS_MAX);
+
 	/* State for keeping the wakeup_source active while adjusting the balloon */
 	spinlock_t wakeup_lock;
 	bool processing_wakeup_event;
@@ -181,20 +184,30 @@ static void balloon_ack(struct virtqueue *vq)
 	wake_up(&vb->acked);
 }
 
-static void tell_host(struct virtio_balloon *vb, struct virtqueue *vq)
+static unsigned int tell_host(struct virtio_balloon *vb, struct virtqueue *vq)
 {
-	struct scatterlist sg;
+	struct scatterlist sg_out, sg_in;
+	struct scatterlist *sgs[] = { &sg_out, &sg_in };
 	unsigned int len;
 
-	sg_init_one(&sg, vb->pfns, sizeof(vb->pfns[0]) * vb->num_pfns);
+	sg_init_one(&sg_out, vb->pfns, sizeof(vb->pfns[0]) * vb->num_pfns);
 
-	/* We should always be able to add one buffer to an empty queue. */
-	virtqueue_add_outbuf(vq, &sg, 1, vb, GFP_KERNEL);
+	if (vq == vb->inflate_vq &&
+	    virtio_has_feature(vb->vdev,
+			       VIRTIO_BALLOON_F_DEVICE_INIT_ON_INFLATE)) {
+		unsigned int bitmap_bytes;
+
+		bitmap_bytes = DIV_ROUND_UP(vb->num_pfns, 8);
+		bitmap_zero(vb->inflate_bitmap, vb->num_pfns);
+		sg_init_one(&sg_in, vb->inflate_bitmap, bitmap_bytes);
+		virtqueue_add_sgs(vq, sgs, 1, 1, vb, GFP_KERNEL);
+	} else {
+		virtqueue_add_outbuf(vq, &sg_out, 1, vb, GFP_KERNEL);
+	}
 	virtqueue_kick(vq);
 
-	/* When host has read buffer, this completes via balloon_ack */
 	wait_event(vb->acked, virtqueue_get_buf(vq, &len));
-
+	return len;
 }
 
 static int virtballoon_free_page_report(struct page_reporting_dev_info *pr_dev_info,
@@ -297,8 +310,37 @@ static unsigned int fill_balloon(struct virtio_balloon *vb, size_t num)
 
 	num_allocated_pages = vb->num_pfns;
 	/* Did we get any? */
-	if (vb->num_pfns != 0)
-		tell_host(vb, vb->inflate_vq);
+	if (vb->num_pfns != 0) {
+		unsigned int used_len = tell_host(vb, vb->inflate_vq);
+
+		if (virtio_has_feature(vb->vdev,
+				       VIRTIO_BALLOON_F_DEVICE_INIT_ON_INFLATE)) {
+			unsigned int i;
+			unsigned int valid_bits = used_len * 8;
+
+			for (i = 0; i < vb->num_pfns;
+			     i += VIRTIO_BALLOON_PAGES_PER_PAGE) {
+				unsigned int pfn, j;
+				bool zeroed = true;
+
+				if (i + VIRTIO_BALLOON_PAGES_PER_PAGE > valid_bits)
+					break;
+				for (j = 0; j < VIRTIO_BALLOON_PAGES_PER_PAGE; j++) {
+					if (!test_bit(i + j, vb->inflate_bitmap)) {
+						zeroed = false;
+						break;
+					}
+				}
+				if (zeroed) {
+					pfn = virtio32_to_cpu(vb->vdev,
+							      vb->pfns[i]);
+					__SetPageZeroed(pfn_to_page(pfn >>
+						(PAGE_SHIFT -
+						 VIRTIO_BALLOON_PFN_SHIFT)));
+				}
+			}
+		}
+	}
 	mutex_unlock(&vb->balloon_lock);
 
 	return num_allocated_pages;
@@ -311,7 +353,12 @@ static void release_pages_balloon(struct virtio_balloon *vb,
 
 	list_for_each_entry_safe(page, next, pages, lru) {
 		list_del(&page->lru);
-		put_page(page); /* balloon reference */
+		if (PageZeroed(page)) {
+			__ClearPageZeroed(page);
+			put_page_zeroed(page);
+		} else {
+			put_page(page);
+		}
 	}
 }
 
@@ -858,7 +905,25 @@ static int virtballoon_migratepage(struct balloon_dev_info *vb_dev_info,
 	/* balloon's page migration 1st step  -- inflate "newpage" */
 	vb->num_pfns = VIRTIO_BALLOON_PAGES_PER_PAGE;
 	set_page_pfns(vb, vb->pfns, newpage);
-	tell_host(vb, vb->inflate_vq);
+	{
+		unsigned int used_len = tell_host(vb, vb->inflate_vq);
+
+		if (virtio_has_feature(vb->vdev,
+				       VIRTIO_BALLOON_F_DEVICE_INIT_ON_INFLATE) &&
+		    used_len >= DIV_ROUND_UP(VIRTIO_BALLOON_PAGES_PER_PAGE, 8)) {
+			unsigned int j;
+			bool zeroed = true;
+
+			for (j = 0; j < VIRTIO_BALLOON_PAGES_PER_PAGE; j++) {
+				if (!test_bit(j, vb->inflate_bitmap)) {
+					zeroed = false;
+					break;
+				}
+			}
+			if (zeroed)
+				__SetPageZeroed(newpage);
+		}
+	}
 
 	/* balloon's page migration 2nd step -- deflate "page" */
 	vb->num_pfns = VIRTIO_BALLOON_PAGES_PER_PAGE;
@@ -963,6 +1028,12 @@ static int virtballoon_probe(struct virtio_device *vdev)
 	if (err)
 		goto out_free_vb;
 
+	if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_DEVICE_INIT_ON_INFLATE) &&
+	    virtqueue_get_vring_size(vb->inflate_vq) < 2) {
+		err = -ENOSPC;
+		goto out_del_vqs;
+	}
+
 	if (!virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_DEFLATE_ON_OOM))
 		vb->vb_dev_info.adjust_managed_page_count = true;
 #ifdef CONFIG_BALLOON_MIGRATION
@@ -1188,11 +1259,15 @@ static int virtballoon_validate(struct virtio_device *vdev)
 
 	/* Device fills with poison_val, not zeros; disable zeroed hint */
 	if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_PAGE_POISON) &&
-	    !want_init_on_free())
+	    !want_init_on_free()) {
 		__virtio_clear_bit(vdev, VIRTIO_BALLOON_F_DEVICE_INIT_REPORTED);
+		__virtio_clear_bit(vdev, VIRTIO_BALLOON_F_DEVICE_INIT_ON_INFLATE);
+	}
 
-	if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT))
+	if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) {
 		__virtio_clear_bit(vdev, VIRTIO_BALLOON_F_DEVICE_INIT_REPORTED);
+		__virtio_clear_bit(vdev, VIRTIO_BALLOON_F_DEVICE_INIT_ON_INFLATE);
+	}
 	__virtio_clear_bit(vdev, VIRTIO_F_ACCESS_PLATFORM);
 	return 0;
 }
@@ -1205,6 +1280,7 @@ static unsigned int features[] = {
 	VIRTIO_BALLOON_F_PAGE_POISON,
 	VIRTIO_BALLOON_F_REPORTING,
 	VIRTIO_BALLOON_F_DEVICE_INIT_REPORTED,
+	VIRTIO_BALLOON_F_DEVICE_INIT_ON_INFLATE,
 };
 
 static struct virtio_driver virtio_balloon_driver = {
diff --git a/include/uapi/linux/virtio_balloon.h b/include/uapi/linux/virtio_balloon.h
index 13074631f300..cbaf18e0b17c 100644
--- a/include/uapi/linux/virtio_balloon.h
+++ b/include/uapi/linux/virtio_balloon.h
@@ -38,6 +38,7 @@
 #define VIRTIO_BALLOON_F_PAGE_POISON	4 /* Guest is using page poisoning */
 #define VIRTIO_BALLOON_F_REPORTING	5 /* Page reporting virtqueue */
 #define VIRTIO_BALLOON_F_DEVICE_INIT_REPORTED	6 /* Device initializes reported pages */
+#define VIRTIO_BALLOON_F_DEVICE_INIT_ON_INFLATE	7 /* Device initializes pages on inflate */
 
 /* Size of a PFN in the balloon interface. */
 #define VIRTIO_BALLOON_PFN_SHIFT 12
-- 
MST


^ permalink raw reply related

* [PATCH resend v6 28/30] mm: add put_page_zeroed and folio_put_zeroed
From: Michael S. Tsirkin @ 2026-05-11  9:04 UTC (permalink / raw)
  To: linux-kernel
  Cc: David Hildenbrand (Arm), Jason Wang, Xuan Zhuo,
	Eugenio Pérez, Muchun Song, Oscar Salvador, Andrew Morton,
	Lorenzo Stoakes, Liam R. Howlett, Vlastimil Babka, Mike Rapoport,
	Suren Baghdasaryan, Michal Hocko, Brendan Jackman,
	Johannes Weiner, Zi Yan, Baolin Wang, Nico Pache, Ryan Roberts,
	Dev Jain, Barry Song, Lance Yang, Hugh Dickins, Matthew Brost,
	Joshua Hahn, Rakie Kim, Byungchul Park, Gregory Price, Ying Huang,
	Alistair Popple, Christoph Lameter, David Rientjes,
	Roman Gushchin, Harry Yoo, Axel Rasmussen, Yuanchu Xie, Wei Xu,
	Chris Li, Kairui Song, Kemeng Shi, Nhat Pham, Baoquan He,
	virtualization, linux-mm, Andrea Arcangeli, Liam R. Howlett,
	Youngjun Park, Qi Zheng, Shakeel Butt
In-Reply-To: <cover.1778489843.git.mst@redhat.com>

Add put_page_zeroed() / folio_put_zeroed() for callers that hold
a reference to a page known to be zeroed.

If this drops the last reference, the page goes through
__folio_put_zeroed() which calls free_frozen_pages_zeroed() so
the zeroed hint is preserved.  If someone else still holds a
reference, the hint is simply lost - this is best-effort.

This is useful for balloon drivers during deflation: the host
has already zeroed the pages, and the balloon is typically the
sole owner.  But if the page happens to be shared, silently
dropping the hint is safe and avoids the need for callers to
check the refcount.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Assisted-by: Claude:claude-opus-4-6
---
 include/linux/mm.h | 12 ++++++++++++
 mm/swap.c          | 18 ++++++++++++++++--
 2 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 3b1ca90fd435..4c51b7bd7576 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1913,6 +1913,7 @@ static inline struct folio *virt_to_folio(const void *x)
 }
 
 void __folio_put(struct folio *folio);
+void __folio_put_zeroed(struct folio *folio);
 
 void split_page(struct page *page, unsigned int order);
 void folio_copy(struct folio *dst, struct folio *src);
@@ -2090,6 +2091,17 @@ static inline void folio_put(struct folio *folio)
 		__folio_put(folio);
 }
 
+static inline void folio_put_zeroed(struct folio *folio)
+{
+	if (folio_put_testzero(folio))
+		__folio_put_zeroed(folio);
+}
+
+static inline void put_page_zeroed(struct page *page)
+{
+	folio_put_zeroed(page_folio(page));
+}
+
 /**
  * folio_put_refs - Reduce the reference count on a folio.
  * @folio: The folio.
diff --git a/mm/swap.c b/mm/swap.c
index 5cc44f0de987..8d57223dfe34 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -94,7 +94,7 @@ static void page_cache_release(struct folio *folio)
 		lruvec_unlock_irqrestore(lruvec, flags);
 }
 
-void __folio_put(struct folio *folio)
+static void ___folio_put(struct folio *folio, bool zeroed)
 {
 	if (unlikely(folio_is_zone_device(folio))) {
 		free_zone_device_folio(folio);
@@ -109,10 +109,24 @@ void __folio_put(struct folio *folio)
 	page_cache_release(folio);
 	folio_unqueue_deferred_split(folio);
 	mem_cgroup_uncharge(folio);
-	free_frozen_pages(&folio->page, folio_order(folio));
+	if (zeroed)
+		free_frozen_pages_zeroed(&folio->page, folio_order(folio));
+	else
+		free_frozen_pages(&folio->page, folio_order(folio));
+}
+
+void __folio_put(struct folio *folio)
+{
+	___folio_put(folio, false);
 }
 EXPORT_SYMBOL(__folio_put);
 
+void __folio_put_zeroed(struct folio *folio)
+{
+	___folio_put(folio, true);
+}
+EXPORT_SYMBOL(__folio_put_zeroed);
+
 typedef void (*move_fn_t)(struct lruvec *lruvec, struct folio *folio);
 
 static void lru_add(struct lruvec *lruvec, struct folio *folio)
-- 
MST


^ permalink raw reply related

* [PATCH resend v6 27/30] mm: add free_frozen_pages_zeroed
From: Michael S. Tsirkin @ 2026-05-11  9:04 UTC (permalink / raw)
  To: linux-kernel
  Cc: David Hildenbrand (Arm), Jason Wang, Xuan Zhuo,
	Eugenio Pérez, Muchun Song, Oscar Salvador, Andrew Morton,
	Lorenzo Stoakes, Liam R. Howlett, Vlastimil Babka, Mike Rapoport,
	Suren Baghdasaryan, Michal Hocko, Brendan Jackman,
	Johannes Weiner, Zi Yan, Baolin Wang, Nico Pache, Ryan Roberts,
	Dev Jain, Barry Song, Lance Yang, Hugh Dickins, Matthew Brost,
	Joshua Hahn, Rakie Kim, Byungchul Park, Gregory Price, Ying Huang,
	Alistair Popple, Christoph Lameter, David Rientjes,
	Roman Gushchin, Harry Yoo, Axel Rasmussen, Yuanchu Xie, Wei Xu,
	Chris Li, Kairui Song, Kemeng Shi, Nhat Pham, Baoquan He,
	virtualization, linux-mm, Andrea Arcangeli, Liam R. Howlett
In-Reply-To: <cover.1778489843.git.mst@redhat.com>

Add free_frozen_pages_zeroed(page, order) to free a frozen page
while marking it as zeroed, so the next allocation can skip
redundant zeroing.

An FPI_ZEROED internal flag carries the hint through the free path.
PageZeroed is set after __free_pages_prepare() clears all flags,
so the hint survives on the free list.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Assisted-by: Claude:claude-opus-4-6
---
 include/linux/gfp.h |  1 +
 mm/internal.h       |  1 -
 mm/page_alloc.c     | 21 ++++++++++++++++++++-
 3 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index ee35c5367abc..e0d5743de68d 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -384,6 +384,7 @@ __meminit void *alloc_pages_exact_nid_noprof(int nid, size_t size, gfp_t gfp_mas
 extern void __free_pages(struct page *page, unsigned int order);
 extern void free_pages_nolock(struct page *page, unsigned int order);
 extern void free_pages(unsigned long addr, unsigned int order);
+void free_frozen_pages_zeroed(struct page *page, unsigned int order);
 
 #define __free_page(page) __free_pages((page), 0)
 #define free_page(addr) free_pages((addr), 0)
diff --git a/mm/internal.h b/mm/internal.h
index fa7ffea4d492..0ef6f8221e5c 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -934,7 +934,6 @@ struct page *__alloc_frozen_pages_noprof(gfp_t, unsigned int order, int nid,
 #define __alloc_frozen_pages(...) \
 	alloc_hooks(__alloc_frozen_pages_noprof(__VA_ARGS__))
 void free_frozen_pages(struct page *page, unsigned int order);
-void free_frozen_pages_zeroed(struct page *page, unsigned int order);
 void free_unref_folios(struct folio_batch *fbatch);
 
 #ifdef CONFIG_NUMA
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index ce43f5a3dbaa..8eebe01cda80 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -90,6 +90,13 @@ typedef int __bitwise fpi_t;
 /* Free the page without taking locks. Rely on trylock only. */
 #define FPI_TRYLOCK		((__force fpi_t)BIT(2))
 
+/*
+ * The page contents are known to be zero (e.g., the host zeroed them
+ * during balloon deflate).  Set PageZeroed after free so the next
+ * allocation can skip redundant zeroing.
+ */
+#define FPI_ZEROED		((__force fpi_t)BIT(3))
+
 /* prevent >1 _updater_ of zone percpu pageset ->high and ->batch fields */
 static DEFINE_MUTEX(pcp_batch_high_lock);
 #define MIN_PERCPU_PAGELIST_HIGH_FRACTION (8)
@@ -1596,8 +1603,11 @@ static void __free_pages_ok(struct page *page, unsigned int order,
 	unsigned long pfn = page_to_pfn(page);
 	struct zone *zone = page_zone(page);
 
-	if (__free_pages_prepare(page, order, fpi_flags))
+	if (__free_pages_prepare(page, order, fpi_flags)) {
+		if (fpi_flags & FPI_ZEROED)
+			__SetPageZeroed(page);
 		free_one_page(zone, page, pfn, order, fpi_flags);
+	}
 }
 
 void __meminit __free_pages_core(struct page *page, unsigned int order,
@@ -3000,6 +3010,9 @@ static void __free_frozen_pages(struct page *page, unsigned int order,
 	if (!__free_pages_prepare(page, order, fpi_flags))
 		return;
 
+	if (fpi_flags & FPI_ZEROED)
+		__SetPageZeroed(page);
+
 	/*
 	 * We only track unmovable, reclaimable and movable on pcp lists.
 	 * Place ISOLATE pages on the isolated list because they are being
@@ -3038,6 +3051,12 @@ void free_frozen_pages(struct page *page, unsigned int order)
 	__free_frozen_pages(page, order, FPI_NONE);
 }
 
+void free_frozen_pages_zeroed(struct page *page, unsigned int order)
+{
+	__free_frozen_pages(page, order, FPI_ZEROED);
+}
+EXPORT_SYMBOL(free_frozen_pages_zeroed);
+
 void free_frozen_pages_nolock(struct page *page, unsigned int order)
 {
 	__free_frozen_pages(page, order, FPI_TRYLOCK);
-- 
MST


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* [PATCH resend v6 26/30] virtio_balloon: disable reporting zeroed optimization for confidential guests
From: Michael S. Tsirkin @ 2026-05-11  9:04 UTC (permalink / raw)
  To: linux-kernel
  Cc: David Hildenbrand (Arm), Jason Wang, Xuan Zhuo,
	Eugenio Pérez, Muchun Song, Oscar Salvador, Andrew Morton,
	Lorenzo Stoakes, Liam R. Howlett, Vlastimil Babka, Mike Rapoport,
	Suren Baghdasaryan, Michal Hocko, Brendan Jackman,
	Johannes Weiner, Zi Yan, Baolin Wang, Nico Pache, Ryan Roberts,
	Dev Jain, Barry Song, Lance Yang, Hugh Dickins, Matthew Brost,
	Joshua Hahn, Rakie Kim, Byungchul Park, Gregory Price, Ying Huang,
	Alistair Popple, Christoph Lameter, David Rientjes,
	Roman Gushchin, Harry Yoo, Axel Rasmussen, Yuanchu Xie, Wei Xu,
	Chris Li, Kairui Song, Kemeng Shi, Nhat Pham, Baoquan He,
	virtualization, linux-mm, Andrea Arcangeli
In-Reply-To: <cover.1778489843.git.mst@redhat.com>

In confidential computing environments (TDX, SEV-SNP), the host
is untrusted and may lie about zeroing reported pages. Clear
DEVICE_INIT_REPORTED in validate() so the guest does not skip
re-zeroing based on hints from an untrusted device.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Assisted-by: Claude:claude-opus-4-6
Assisted-by: cursor-agent:GPT-5.4-xhigh
---
 drivers/virtio/virtio_balloon.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index e5d11782ce41..d1cdb904d60b 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -18,6 +18,7 @@
 #include <linux/wait.h>
 #include <linux/mm.h>
 #include <linux/page_reporting.h>
+#include <linux/cc_platform.h>
 
 /*
  * Balloon device works in 4K page units.  So each page is pointed to by
@@ -1190,6 +1191,8 @@ static int virtballoon_validate(struct virtio_device *vdev)
 	    !want_init_on_free())
 		__virtio_clear_bit(vdev, VIRTIO_BALLOON_F_DEVICE_INIT_REPORTED);
 
+	if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT))
+		__virtio_clear_bit(vdev, VIRTIO_BALLOON_F_DEVICE_INIT_REPORTED);
 	__virtio_clear_bit(vdev, VIRTIO_F_ACCESS_PLATFORM);
 	return 0;
 }
-- 
MST


^ permalink raw reply related

* [PATCH resend v6 25/30] virtio_balloon: skip zeroing for host-zeroed reported pages
From: Michael S. Tsirkin @ 2026-05-11  9:04 UTC (permalink / raw)
  To: linux-kernel
  Cc: David Hildenbrand (Arm), Jason Wang, Xuan Zhuo,
	Eugenio Pérez, Muchun Song, Oscar Salvador, Andrew Morton,
	Lorenzo Stoakes, Liam R. Howlett, Vlastimil Babka, Mike Rapoport,
	Suren Baghdasaryan, Michal Hocko, Brendan Jackman,
	Johannes Weiner, Zi Yan, Baolin Wang, Nico Pache, Ryan Roberts,
	Dev Jain, Barry Song, Lance Yang, Hugh Dickins, Matthew Brost,
	Joshua Hahn, Rakie Kim, Byungchul Park, Gregory Price, Ying Huang,
	Alistair Popple, Christoph Lameter, David Rientjes,
	Roman Gushchin, Harry Yoo, Axel Rasmussen, Yuanchu Xie, Wei Xu,
	Chris Li, Kairui Song, Kemeng Shi, Nhat Pham, Baoquan He,
	virtualization, linux-mm, Andrea Arcangeli
In-Reply-To: <cover.1778489843.git.mst@redhat.com>

Implement VIRTIO_BALLOON_F_DEVICE_INIT_REPORTED (per virtio spec
proposal): when negotiated, the device initializes reported pages
(zeros, or poison_val if PAGE_POISON).

Check per-page used length returned by the device to determine
which reported pages were zeroed. If used_len matches the page
size, the device successfully initialized the page (e.g. via
MADV_DONTNEED), and we set the corresponding zeroed_bitmap bit.

Gate host_zeroes_pages on the feature bit and page content:
when PAGE_POISON is negotiated with non-zero poison_val, the
device fills with poison not zeros, so pages are not zeroed.

Clear the feature in validate() if REPORTING is not present
or if PAGE_POISON is active with non-zero poison_val.

See the virtio spec change:
https://github.com/oasis-tcs/virtio-spec/issues/244

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Assisted-by: Claude:claude-opus-4-6
Assisted-by: cursor-agent:GPT-5.4-xhigh
---
 drivers/virtio/virtio_balloon.c     | 22 ++++++++++++++++++++--
 include/uapi/linux/virtio_balloon.h |  1 +
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index fdfd828657dd..e5d11782ce41 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -204,6 +204,8 @@ static int virtballoon_free_page_report(struct page_reporting_dev_info *pr_dev_i
 	struct virtqueue *vq = vb->reporting_vq;
 	unsigned int i, err;
 
+	bitmap_zero(pr_dev_info->zeroed_bitmap, nents);
+
 	/* We should always be able to add these buffers to an empty queue. */
 	for (i = 0; i < nents; i++) {
 		struct scatterlist one;
@@ -223,10 +225,14 @@ static int virtballoon_free_page_report(struct page_reporting_dev_info *pr_dev_i
 
 		/* When host has read buffer, this completes via balloon_ack */
 		for (i = 0; i < nents; i++) {
-			unsigned int unused;
+			struct scatterlist *entry;
+			unsigned int used_len;
 
 			wait_event(vb->acked,
-				   virtqueue_get_buf(vq, &unused));
+				   (entry = virtqueue_get_buf(vq, &used_len)));
+			if (used_len == entry->length)
+				set_bit(entry - sg,
+					pr_dev_info->zeroed_bitmap);
 		}
 	}
 
@@ -1048,6 +1054,9 @@ static int virtballoon_probe(struct virtio_device *vdev)
 #endif
 
 		vb->pr_dev_info.capacity = capacity;
+		vb->pr_dev_info.host_zeroes_pages =
+			virtio_has_feature(vdev,
+					   VIRTIO_BALLOON_F_DEVICE_INIT_REPORTED);
 		err = page_reporting_register(&vb->pr_dev_info);
 		if (err)
 			goto out_unregister_oom;
@@ -1173,6 +1182,14 @@ static int virtballoon_validate(struct virtio_device *vdev)
 	else if (!virtio_has_feature(vdev, VIRTIO_BALLOON_F_PAGE_POISON))
 		__virtio_clear_bit(vdev, VIRTIO_BALLOON_F_REPORTING);
 
+	if (!virtio_has_feature(vdev, VIRTIO_BALLOON_F_REPORTING))
+		__virtio_clear_bit(vdev, VIRTIO_BALLOON_F_DEVICE_INIT_REPORTED);
+
+	/* Device fills with poison_val, not zeros; disable zeroed hint */
+	if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_PAGE_POISON) &&
+	    !want_init_on_free())
+		__virtio_clear_bit(vdev, VIRTIO_BALLOON_F_DEVICE_INIT_REPORTED);
+
 	__virtio_clear_bit(vdev, VIRTIO_F_ACCESS_PLATFORM);
 	return 0;
 }
@@ -1184,6 +1201,7 @@ static unsigned int features[] = {
 	VIRTIO_BALLOON_F_FREE_PAGE_HINT,
 	VIRTIO_BALLOON_F_PAGE_POISON,
 	VIRTIO_BALLOON_F_REPORTING,
+	VIRTIO_BALLOON_F_DEVICE_INIT_REPORTED,
 };
 
 static struct virtio_driver virtio_balloon_driver = {
diff --git a/include/uapi/linux/virtio_balloon.h b/include/uapi/linux/virtio_balloon.h
index ee35a372805d..13074631f300 100644
--- a/include/uapi/linux/virtio_balloon.h
+++ b/include/uapi/linux/virtio_balloon.h
@@ -37,6 +37,7 @@
 #define VIRTIO_BALLOON_F_FREE_PAGE_HINT	3 /* VQ to report free pages */
 #define VIRTIO_BALLOON_F_PAGE_POISON	4 /* Guest is using page poisoning */
 #define VIRTIO_BALLOON_F_REPORTING	5 /* Page reporting virtqueue */
+#define VIRTIO_BALLOON_F_DEVICE_INIT_REPORTED	6 /* Device initializes reported pages */
 
 /* Size of a PFN in the balloon interface. */
 #define VIRTIO_BALLOON_PFN_SHIFT 12
-- 
MST


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