xen: Change xen-acpi-processor dom0 dependency

xen-acpi-processor functions under a PVH dom0 with only a
xen_initial_domain() runtime check. Change the Kconfig dependency from
PV dom0 to generic do

xen: Change xen-acpi-processor dom0 dependency

xen-acpi-processor functions under a PVH dom0 with only a
xen_initial_domain() runtime check. Change the Kconfig dependency from
PV dom0 to generic dom0 to reflect that.

Suggested-by: Jan Beulich <[email protected]>
Signed-off-by: Jason Andryuk <[email protected]>
Reviewed-by: Juergen Gross <[email protected]>
Tested-by: Jan Beulich <[email protected]>
Signed-off-by: Juergen Gross <[email protected]>
Message-ID: <[email protected]>

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xen: Remove dependency between pciback and privcmd

Commit 2fae6bb7be32 ("xen/privcmd: Add new syscall to get gsi from dev")
adds a weak reverse dependency to the config XEN_PRIVCMD definition, that

xen: Remove dependency between pciback and privcmd

Commit 2fae6bb7be32 ("xen/privcmd: Add new syscall to get gsi from dev")
adds a weak reverse dependency to the config XEN_PRIVCMD definition, that
dependency causes xen-privcmd can't be loaded on domU, because dependent
xen-pciback isn't always be loaded successfully on domU.

To solve above problem, remove that dependency, and do not call
pcistub_get_gsi_from_sbdf() directly, instead add a hook in
drivers/xen/apci.c, xen-pciback register the real call function, then in
privcmd_ioctl_pcidev_get_gsi call that hook.

Fixes: 2fae6bb7be32 ("xen/privcmd: Add new syscall to get gsi from dev")
Reported-by: Marek Marczykowski-Górecki <[email protected]>
Signed-off-by: Jiqian Chen <[email protected]>
Reviewed-by: Juergen Gross <[email protected]>
Message-ID: <[email protected]>
Signed-off-by: Juergen Gross <[email protected]>

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xen: Fix config option reference in XEN_PRIVCMD definition

Commit 2fae6bb7be32 ("xen/privcmd: Add new syscall to get gsi from dev")
adds a weak reverse dependency to the config XEN_PRIVCMD definitio

xen: Fix config option reference in XEN_PRIVCMD definition

Commit 2fae6bb7be32 ("xen/privcmd: Add new syscall to get gsi from dev")
adds a weak reverse dependency to the config XEN_PRIVCMD definition,
referring to CONFIG_XEN_PCIDEV_BACKEND. In Kconfig files, one refers to
config options without the CONFIG prefix, though. So in its current form,
this does not create the reverse dependency as intended, but is an
attribute with no effect.

Refer to the intended config option XEN_PCIDEV_BACKEND in the XEN_PRIVCMD
definition.

Fixes: 2fae6bb7be32 ("xen/privcmd: Add new syscall to get gsi from dev")
Signed-off-by: Lukas Bulwahn <[email protected]>
Reviewed-by: Juergen Gross <[email protected]>
Message-ID: <[email protected]>
Signed-off-by: Juergen Gross <[email protected]>

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xen/privcmd: Add new syscall to get gsi from dev

On PVH dom0, when passthrough a device to domU, QEMU and xl tools
want to use gsi number to do pirq mapping, see QEMU code
xen_pt_realize->xc_physdev

xen/privcmd: Add new syscall to get gsi from dev

On PVH dom0, when passthrough a device to domU, QEMU and xl tools
want to use gsi number to do pirq mapping, see QEMU code
xen_pt_realize->xc_physdev_map_pirq, and xl code
pci_add_dm_done->xc_physdev_map_pirq, but in current codes, the gsi
number is got from file /sys/bus/pci/devices/<sbdf>/irq, that is
wrong, because irq is not equal with gsi, they are in different
spaces, so pirq mapping fails.
And in current linux codes, there is no method to get gsi
for userspace.

For above purpose, record gsi of pcistub devices when init
pcistub and add a new syscall into privcmd to let userspace
can get gsi when they have a need.

Signed-off-by: Jiqian Chen <[email protected]>
Signed-off-by: Huang Rui <[email protected]>
Signed-off-by: Jiqian Chen <[email protected]>
Reviewed-by: Stefano Stabellini <[email protected]>
Message-ID: <[email protected]>
Signed-off-by: Juergen Gross <[email protected]>

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dma-mapping: clearly mark DMA ops as an architecture feature

DMA ops are a helper for architectures and not for drivers to override
the DMA implementation.

Unfortunately driver authors keep ignorin

dma-mapping: clearly mark DMA ops as an architecture feature

DMA ops are a helper for architectures and not for drivers to override
the DMA implementation.

Unfortunately driver authors keep ignoring this. Make the fact more
clear by renaming the symbol to ARCH_HAS_DMA_OPS and having the two drivers
overriding their dma_ops depend on that. These drivers should probably be
marked broken, but we can give them a bit of a grace period for that.

Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
Acked-by: Sakari Ailus <[email protected]> # for IPU6
Acked-by: Robin Murphy <[email protected]>

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xen: privcmd: Add support for ioeventfd

Virtio guests send VIRTIO_MMIO_QUEUE_NOTIFY notification when they need
to notify the backend of an update to the status of the virtqueue. The
backend or anot

xen: privcmd: Add support for ioeventfd

Virtio guests send VIRTIO_MMIO_QUEUE_NOTIFY notification when they need
to notify the backend of an update to the status of the virtqueue. The
backend or another entity, polls the MMIO address for updates to know
when the notification is sent.

It works well if the backend does this polling by itself. But as we move
towards generic backend implementations, we end up implementing this in
a separate user-space program.

Generally, the Virtio backends are implemented to work with the Eventfd
based mechanism. In order to make such backends work with Xen, another
software layer needs to do the polling and send an event via eventfd to
the backend once the notification from guest is received. This results
in an extra context switch.

This is not a new problem in Linux though. It is present with other
hypervisors like KVM, etc. as well. The generic solution implemented in
the kernel for them is to provide an IOCTL call to pass the address to
poll and eventfd, which lets the kernel take care of polling and raise
an event on the eventfd, instead of handling this in user space (which
involves an extra context switch).

This patch adds similar support for xen.

Inspired by existing implementations for KVM, etc..

This also copies ioreq.h header file (only struct ioreq and related
macros) from Xen's source tree (Top commit 5d84f07fe6bf ("xen/pci: drop
remaining uses of bool_t")).

Signed-off-by: Viresh Kumar <[email protected]>
Reviewed-by: Juergen Gross <[email protected]>
Link: https://lore.kernel.org/r/b20d83efba6453037d0c099912813c79c81f7714.1697439990.git.viresh.kumar@linaro.org
Signed-off-by: Juergen Gross <[email protected]>

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xen: privcmd: Add support for irqfd

Xen provides support for injecting interrupts to the guests via the
HYPERVISOR_dm_op() hypercall. The same is used by the Virtio based
device backend implementati

xen: privcmd: Add support for irqfd

Xen provides support for injecting interrupts to the guests via the
HYPERVISOR_dm_op() hypercall. The same is used by the Virtio based
device backend implementations, in an inefficient manner currently.

Generally, the Virtio backends are implemented to work with the Eventfd
based mechanism. In order to make such backends work with Xen, another
software layer needs to poll the Eventfds and raise an interrupt to the
guest using the Xen based mechanism. This results in an extra context
switch.

This is not a new problem in Linux though. It is present with other
hypervisors like KVM, etc. as well. The generic solution implemented in
the kernel for them is to provide an IOCTL call to pass the interrupt
details and eventfd, which lets the kernel take care of polling the
eventfd and raising of the interrupt, instead of handling this in user
space (which involves an extra context switch).

This patch adds support to inject a specific interrupt to guest using
the eventfd mechanism, by preventing the extra context switch.

Inspired by existing implementations for KVM, etc..

Signed-off-by: Viresh Kumar <[email protected]>
Reviewed-by: Juergen Gross <[email protected]>
Link: https://lore.kernel.org/r/8e724ac1f50c2bc1eb8da9b3ff6166f1372570aa.1692697321.git.viresh.kumar@linaro.org
Signed-off-by: Juergen Gross <[email protected]>

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xen: Kconfig: Fix spelling mistake "Maxmium" -> "Maximum"

There is a spelling mistake in a Kconfig description. Fix it.

Signed-off-by: Colin Ian King <[email protected]>
Acked-by: Stefano Stab

xen: Kconfig: Fix spelling mistake "Maxmium" -> "Maximum"

There is a spelling mistake in a Kconfig description. Fix it.

Signed-off-by: Colin Ian King <[email protected]>
Acked-by: Stefano Stabellini <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Juergen Gross <[email protected]>

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xen: don't require virtio with grants for non-PV guests

Commit fa1f57421e0b ("xen/virtio: Enable restricted memory access using
Xen grant mappings") introduced a new requirement for using virtio
dev

xen: don't require virtio with grants for non-PV guests

Commit fa1f57421e0b ("xen/virtio: Enable restricted memory access using
Xen grant mappings") introduced a new requirement for using virtio
devices: the backend now needs to support the VIRTIO_F_ACCESS_PLATFORM
feature.

This is an undue requirement for non-PV guests, as those can be operated
with existing backends without any problem, as long as those backends
are running in dom0.

Per default allow virtio devices without grant support for non-PV
guests.

On Arm require VIRTIO_F_ACCESS_PLATFORM for devices having been listed
in the device tree to use grants.

Add a new config item to always force use of grants for virtio.

Fixes: fa1f57421e0b ("xen/virtio: Enable restricted memory access using Xen grant mappings")
Reported-by: Viresh Kumar <[email protected]>
Signed-off-by: Juergen Gross <[email protected]>
Reviewed-by: Oleksandr Tyshchenko <[email protected]>
Tested-by: Oleksandr Tyshchenko <[email protected]> # Arm64 guest using Xen
Reviewed-by: Stefano Stabellini <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Juergen Gross <[email protected]>

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xen/grant-dma-ops: Retrieve the ID of backend's domain for DT devices

Use the presence of "iommus" property pointed to the IOMMU node with
recently introduced "xen,grant-dma" compatible as a clear i

xen/grant-dma-ops: Retrieve the ID of backend's domain for DT devices

Use the presence of "iommus" property pointed to the IOMMU node with
recently introduced "xen,grant-dma" compatible as a clear indicator
of enabling Xen grant mappings scheme for that device and read the ID
of Xen domain where the corresponding backend is running. The domid
(domain ID) is used as an argument to the Xen grant mapping APIs.

To avoid the deferred probe timeout which takes place after reusing
generic IOMMU device tree bindings (because the IOMMU device never
becomes available) enable recently introduced stub IOMMU driver by
selecting XEN_GRANT_DMA_IOMMU.

Also introduce xen_is_grant_dma_device() to check whether xen-grant
DMA ops need to be set for a passed device.

Remove the hardcoded domid 0 in xen_grant_setup_dma_ops().

Signed-off-by: Oleksandr Tyshchenko <[email protected]>
Reviewed-by: Stefano Stabellini <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Juergen Gross <[email protected]>

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xen/grant-dma-iommu: Introduce stub IOMMU driver

In order to reuse generic IOMMU device tree bindings by Xen grant
DMA-mapping layer we need to add this stub driver from a fw_devlink
perspective (gr

xen/grant-dma-iommu: Introduce stub IOMMU driver

In order to reuse generic IOMMU device tree bindings by Xen grant
DMA-mapping layer we need to add this stub driver from a fw_devlink
perspective (grant-dma-ops cannot be converted into the proper
IOMMU driver).

Otherwise, just reusing IOMMU bindings (without having a corresponding
driver) leads to the deferred probe timeout afterwards, because
the IOMMU device never becomes available.

This stub driver does nothing except registering empty iommu_ops,
the upper layer "of_iommu" will treat this as NO_IOMMU condition
and won't return -EPROBE_DEFER.

As this driver is quite different from the most hardware IOMMU
implementations and only needed in Xen guests, place it in drivers/xen
directory. The subsequent commit will make use of it.

Signed-off-by: Oleksandr Tyshchenko <[email protected]>
Reviewed-by: Stefano Stabellini <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Juergen Gross <[email protected]>

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xen/virtio: Enable restricted memory access using Xen grant mappings

In order to support virtio in Xen guests add a config option XEN_VIRTIO
enabling the user to specify whether in all Xen guests vi

xen/virtio: Enable restricted memory access using Xen grant mappings

In order to support virtio in Xen guests add a config option XEN_VIRTIO
enabling the user to specify whether in all Xen guests virtio should
be able to access memory via Xen grant mappings only on the host side.

Also set PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS feature from the guest
initialization code on Arm and x86 if CONFIG_XEN_VIRTIO is enabled.

Signed-off-by: Juergen Gross <[email protected]>
Signed-off-by: Oleksandr Tyshchenko <[email protected]>
Reviewed-by: Stefano Stabellini <[email protected]>
Reviewed-by: Boris Ostrovsky <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Juergen Gross <[email protected]>

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xen/grant-dma-ops: Add option to restrict memory access under Xen

Introduce Xen grant DMA-mapping layer which contains special DMA-mapping
routines for providing grant references as DMA addresses to

xen/grant-dma-ops: Add option to restrict memory access under Xen

Introduce Xen grant DMA-mapping layer which contains special DMA-mapping
routines for providing grant references as DMA addresses to be used by
frontends (e.g. virtio) in Xen guests.

Add the needed functionality by providing a special set of DMA ops
handling the needed grant operations for the I/O pages.

The subsequent commit will introduce the use case for xen-grant DMA ops
layer to enable using virtio devices in Xen guests in a safe manner.

Signed-off-by: Juergen Gross <[email protected]>
Signed-off-by: Oleksandr Tyshchenko <[email protected]>
Reviewed-by: Stefano Stabellini <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Juergen Gross <[email protected]>

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arm/xen: Read extended regions from DT and init Xen resource

This patch implements arch_xen_unpopulated_init() on Arm where
the extended regions (if any) are gathered from DT and inserted
into speci

arm/xen: Read extended regions from DT and init Xen resource

This patch implements arch_xen_unpopulated_init() on Arm where
the extended regions (if any) are gathered from DT and inserted
into specific Xen resource to be used as unused address space
for Xen scratch pages by unpopulated-alloc code.

The extended region (safe range) is a region of guest physical
address space which is unused and could be safely used to create
grant/foreign mappings instead of wasting real RAM pages from
the domain memory for establishing these mappings.

The extended regions are chosen by the hypervisor at the domain
creation time and advertised to it via "reg" property under
hypervisor node in the guest device-tree. As region 0 is reserved
for grant table space (always present), the indexes for extended
regions are 1...N.

If arch_xen_unpopulated_init() fails for some reason the default
behaviour will be restored (allocate xenballooned pages).

This patch also removes XEN_UNPOPULATED_ALLOC dependency on x86.

Signed-off-by: Oleksandr Tyshchenko <[email protected]>
Reviewed-by: Stefano Stabellini <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Juergen Gross <[email protected]>

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xen/privcmd: make option visible in Kconfig

This configuration option provides a misc device as an API to userspace.
Make this API usable without having to select the module as a transitive
dependen

xen/privcmd: make option visible in Kconfig

This configuration option provides a misc device as an API to userspace.
Make this API usable without having to select the module as a transitive
dependency.

This also fixes an issue where localyesconfig would select
CONFIG_XEN_PRIVCMD=m because it was not visible and defaulted to
building as module.

[boris: clarified help message per Jan's suggestion]

Based-on-patch-by: Thomas Weißschuh <[email protected]>
Signed-off-by: Juergen Gross <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Jan Beulich <[email protected]>
Reviewed-by: Thomas Weißschuh <[email protected]>
Signed-off-by: Boris Ostrovsky <[email protected]>

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xen-pciback: allow compiling on other archs than x86

Xen-pciback driver was designed to be built for x86 only. But it
can also be used by other architectures, e.g. Arm.

Currently PCI backend implem

xen-pciback: allow compiling on other archs than x86

Xen-pciback driver was designed to be built for x86 only. But it
can also be used by other architectures, e.g. Arm.

Currently PCI backend implements multiple functionalities at a time,
such as:
1. It is used as a database for assignable PCI devices, e.g. xl
pci-assignable-{add|remove|list} manipulates that list. So, whenever
the toolstack needs to know which PCI devices can be passed through
it reads that from the relevant sysfs entries of the pciback.
2. It is used to hold the unbound PCI devices list, e.g. when passing
through a PCI device it needs to be unbound from the relevant device
driver and bound to pciback (strictly speaking it is not required
that the device is bound to pciback, but pciback is again used as a
database of the passed through PCI devices, so we can re-bind the
devices back to their original drivers when guest domain shuts down)
3. Device reset for the devices being passed through
4. Para-virtualised use-cases support

The para-virtualised part of the driver is not always needed as some
architectures, e.g. Arm or x86 PVH Dom0, are not using backend-frontend
model for PCI device passthrough.

For such use-cases make the very first step in splitting the
xen-pciback driver into two parts: Xen PCI stub and PCI PV backend
drivers.

For that add new configuration options CONFIG_XEN_PCI_STUB and
CONFIG_XEN_PCIDEV_STUB, so the driver can be limited in its
functionality, e.g. no support for para-virtualised scenario.
x86 platform will continue using CONFIG_XEN_PCIDEV_BACKEND for the
fully featured backend driver.

Signed-off-by: Oleksandr Andrushchenko <[email protected]>
Signed-off-by: Anastasiia Lukianenko <[email protected]>
Reviewed-by: Stefano Stabellini <[email protected]>
Reviewed-by: Juergen Gross <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Boris Ostrovsky <[email protected]>

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xen/x86: allow PVH Dom0 without XEN_PV=y

Decouple XEN_DOM0 from XEN_PV, converting some existing uses of XEN_DOM0
to a new XEN_PV_DOM0. (I'm not convinced all are really / should really
be PV-specif

xen/x86: allow PVH Dom0 without XEN_PV=y

Decouple XEN_DOM0 from XEN_PV, converting some existing uses of XEN_DOM0
to a new XEN_PV_DOM0. (I'm not convinced all are really / should really
be PV-specific, but for starters I've tried to be conservative.)

For PVH Dom0 the hypervisor populates MADT with only x2APIC entries, so
without x2APIC support enabled in the kernel things aren't going to work
very well. (As opposed, DomU-s would only ever see LAPIC entries in MADT
as of now.) Note that this then requires PVH Dom0 to be 64-bit, as
X86_X2APIC depends on X86_64.

In the course of this xen_running_on_version_or_later() needs to be
available more broadly. Move it from a PV-specific to a generic file,
considering that what it does isn't really PV-specific at all anyway.

Note that xen/interface/version.h cannot be included on its own; in
enlighten.c, which uses SCHEDOP_* anyway, include xen/interface/sched.h
first to resolve the apparently sole missing type (xen_ulong_t).

Signed-off-by: Jan Beulich <[email protected]>
Reviewed-by: Juergen Gross <[email protected]>

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Juergen Gross <[email protected]>

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swiotlb-xen: this is PV-only on x86

The code is unreachable for HVM or PVH, and it also makes little sense
in auto-translated environments. On Arm, with
xen_{create,destroy}_contiguous_region() both

swiotlb-xen: this is PV-only on x86

The code is unreachable for HVM or PVH, and it also makes little sense
in auto-translated environments. On Arm, with
xen_{create,destroy}_contiguous_region() both being stubs, I have a hard
time seeing what good the Xen specific variant does - the generic one
ought to be fine for all purposes there. Still Arm code explicitly
references symbols here, so the code will continue to be included there.

Instead of making PCI_XEN's "select" conditional, simply drop it -
SWIOTLB_XEN will be available unconditionally in the PV case anyway, and
is - as explained above - dead code in non-PV environments.

This in turn allows dropping the stubs for
xen_{create,destroy}_contiguous_region(), the former of which was broken
anyway - it failed to set the DMA handle output.

Signed-off-by: Jan Beulich <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Reviewed-by: Stefano Stabellini <[email protected]>

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Juergen Gross <[email protected]>

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xen/pvcalls: backend can be a module

It's not clear to me why only the frontend has been tristate. Switch the
backend to be, too.

Signed-off-by: Jan Beulich <[email protected]>
Acked-by: Stefano St

xen/pvcalls: backend can be a module

It's not clear to me why only the frontend has been tristate. Switch the
backend to be, too.

Signed-off-by: Jan Beulich <[email protected]>
Acked-by: Stefano Stabellini <[email protected]>

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Juergen Gross <[email protected]>

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xen: Remove support for PV ACPI cpu/memory hotplug

Commit 76fc253723ad ("xen/acpi-stub: Disable it b/c the acpi_processor_add
is no longer called.") declared as BROKEN support for Xen ACPI stub (whi

xen: Remove support for PV ACPI cpu/memory hotplug

Commit 76fc253723ad ("xen/acpi-stub: Disable it b/c the acpi_processor_add
is no longer called.") declared as BROKEN support for Xen ACPI stub (which
is required for xen-acpi-{cpu|memory}-hotplug) and suggested that this
is temporary and will be soon fixed. This was in March 2013.

Further, commit cfafae940381 ("xen: rename dom0_op to platform_op")
renamed an interface used by memory hotplug code without updating that
code (as it was BROKEN and therefore not compiled). This was
in November 2015 and has gone unnoticed for over 5 year.

It is now clear that this code is of no interest to anyone and therefore
should be removed.

Signed-off-by: Boris Ostrovsky <[email protected]>
Acked-by: Rafael J. Wysocki <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Juergen Gross <[email protected]>

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xen/x86: make XEN_BALLOON_MEMORY_HOTPLUG_LIMIT depend on MEMORY_HOTPLUG

The Xen memory hotplug limit should depend on the memory hotplug
generic option, rather than the Xen balloon configuration. It

xen/x86: make XEN_BALLOON_MEMORY_HOTPLUG_LIMIT depend on MEMORY_HOTPLUG

The Xen memory hotplug limit should depend on the memory hotplug
generic option, rather than the Xen balloon configuration. It's
possible to have a kernel with generic memory hotplug enabled, but
without Xen balloon enabled, at which point memory hotplug won't work
correctly due to the size limitation of the p2m.

Rename the option to XEN_MEMORY_HOTPLUG_LIMIT since it's no longer
tied to ballooning.

Fixes: 9e2369c06c8a18 ("xen: add helpers to allocate unpopulated memory")
Signed-off-by: Roger Pau Monné <[email protected]>
Reviewed-by: Boris Ostrovsky <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Boris Ostrovsky <[email protected]>

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xen: add helpers to allocate unpopulated memory

To be used in order to create foreign mappings. This is based on the
ZONE_DEVICE facility which is used by persistent memory devices in
order to creat

xen: add helpers to allocate unpopulated memory

To be used in order to create foreign mappings. This is based on the
ZONE_DEVICE facility which is used by persistent memory devices in
order to create struct pages and kernel virtual mappings for the IOMEM
areas of such devices. Note that on kernels without support for
ZONE_DEVICE Xen will fallback to use ballooned pages in order to
create foreign mappings.

The newly added helpers use the same parameters as the existing
{alloc/free}_xenballooned_pages functions, which allows for in-place
replacement of the callers. Once a memory region has been added to be
used as scratch mapping space it will no longer be released, and pages
returned are kept in a linked list. This allows to have a buffer of
pages and prevents resorting to frequent additions and removals of
regions.

If enabled (because ZONE_DEVICE is supported) the usage of the new
functionality untangles Xen balloon and RAM hotplug from the usage of
unpopulated physical memory ranges to map foreign pages, which is the
correct thing to do in order to avoid mappings of foreign pages depend
on memory hotplug.

Note the driver is currently not enabled on Arm platforms because it
would interfere with the identity mapping required on some platforms.

Signed-off-by: Roger Pau Monné <[email protected]>
Reviewed-by: Juergen Gross <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Juergen Gross <[email protected]>

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x86/xen: remove 32-bit Xen PV guest support

Xen is requiring 64-bit machines today and since Xen 4.14 it can be
built without 32-bit PV guest support. There is no need to carry the
burden of 32-bit

x86/xen: remove 32-bit Xen PV guest support

Xen is requiring 64-bit machines today and since Xen 4.14 it can be
built without 32-bit PV guest support. There is no need to carry the
burden of 32-bit PV guest support in the kernel any longer, as new
guests can be either HVM or PVH, or they can use a 64 bit kernel.

Remove the 32-bit Xen PV support from the kernel.

Signed-off-by: Juergen Gross <[email protected]>
Reviewed-by: Boris Ostrovsky <[email protected]>
Signed-off-by: Juergen Gross <[email protected]>

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dma-mapping: make support for dma ops optional

Avoid the overhead of the dma ops support for tiny builds that only
use the direct mapping.

Signed-off-by: Christoph Hellwig <[email protected]>
Tested-by: A

dma-mapping: make support for dma ops optional

Avoid the overhead of the dma ops support for tiny builds that only
use the direct mapping.

Signed-off-by: Christoph Hellwig <[email protected]>
Tested-by: Alexey Kardashevskiy <[email protected]>
Reviewed-by: Alexey Kardashevskiy <[email protected]>

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xen: enable BALLOON_MEMORY_HOTPLUG by default

Without it a PVH dom0 is mostly useless, as it would balloon down huge
amounts of RAM in order get physical address space to map foreign
memory and gran

xen: enable BALLOON_MEMORY_HOTPLUG by default

Without it a PVH dom0 is mostly useless, as it would balloon down huge
amounts of RAM in order get physical address space to map foreign
memory and grants, ultimately leading to an out of memory situation.

Such option is also needed for HVM or PVH driver domains, since they
also require mapping grants into physical memory regions.

Suggested-by: Ian Jackson <[email protected]>
Signed-off-by: Roger Pau Monné <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Juergen Gross <[email protected]>
Signed-off-by: Boris Ostrovsky <[email protected]>

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