linux-toradex.git/drivers/xen/Kconfig, branch master

mm: rename vm_ops->find_special_page() to vm_ops->find_normal_page()

2025-09-13T23:54:53+00:00

...  and hide it behind a kconfig option.  There is really no need for any
!xen code to perform this check.

The naming is a bit off: we want to find the "normal" page when a PTE was
marked "special".  So it's really not "finding a special" page.

Improve the documentation, and add a comment in the code where XEN ends up
performing the pte_mkspecial() through a hypercall.  More details can be
found in commit 923b2919e2c3 ("xen/gntdev: mark userspace PTEs as special
on x86 PV guests").

Link: https://lkml.kernel.org/r/20250811112631.759341-12-david@redhat.com
Signed-off-by: David Hildenbrand 
Reviewed-by: Oscar Salvador 
Reviewed-by: Lorenzo Stoakes 
Reviewed-by: Wei Yang 
Cc: David Vrabel 
Cc: Alistair Popple 
Cc: Al Viro 
Cc: Baolin Wang 
Cc: Barry Song 
Cc: Christian Brauner 
Cc: Christophe Leroy 
Cc: Dan Williams 
Cc: Dev Jain 
Cc: Hugh Dickins 
Cc: Jan Kara 
Cc: Jann Horn 
Cc: Juegren Gross 
Cc: Lance Yang 
Cc: Liam Howlett 
Cc: Madhavan Srinivasan 
Cc: Mariano Pache 
Cc: Matthew Wilcox (Oracle) 
Cc: Michael Ellerman 
Cc: Michal Hocko 
Cc: Mike Rapoport 
Cc: Nicholas Piggin 
Cc: Oleksandr Tyshchenko 
Cc: Ryan Roberts 
Cc: Stefano Stabellini 
Cc: Suren Baghdasaryan 
Cc: Vlastimil Babka 
Cc: Zi Yan 
Signed-off-by: Andrew Morton

xen: Change xen-acpi-processor dom0 dependency

2025-04-07T09:22:40+00:00

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 
Signed-off-by: Jason Andryuk 
Reviewed-by: Juergen Gross 
Tested-by: Jan Beulich 
Signed-off-by: Juergen Gross 
Message-ID: <20250331172913.51240-1-jason.andryuk@amd.com>

xen: Remove dependency between pciback and privcmd

2024-10-18T09:59:04+00:00

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 
Signed-off-by: Jiqian Chen 
Reviewed-by: Juergen Gross 
Message-ID: <20241012084537.1543059-1-Jiqian.Chen@amd.com>
Signed-off-by: Juergen Gross

xen: Fix config option reference in XEN_PRIVCMD definition

2024-10-02T14:14:30+00:00

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 
Reviewed-by: Juergen Gross 
Message-ID: <20240930090650.429813-1-lukas.bulwahn@redhat.com>
Signed-off-by: Juergen Gross

Merge tag 'for-linus-6.12-rc1a-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

2024-09-27T16:55:30+00:00

Pull more xen updates from Juergen Gross:
 "A second round of Xen related changes and features:

   - a small fix of the xen-pciback driver for a warning issued by
     sparse

   - support PCI passthrough when using a PVH dom0

   - enable loading the kernel in PVH mode at arbitrary addresses,
     avoiding conflicts with the memory map when running as a Xen dom0
     using the host memory layout"

* tag 'for-linus-6.12-rc1a-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  x86/pvh: Add 64bit relocation page tables
  x86/kernel: Move page table macros to header
  x86/pvh: Set phys_base when calling xen_prepare_pvh()
  x86/pvh: Make PVH entrypoint PIC for x86-64
  xen: sync elfnote.h from xen tree
  xen/pciback: fix cast to restricted pci_ers_result_t and pci_power_t
  xen/privcmd: Add new syscall to get gsi from dev
  xen/pvh: Setup gsi for passthrough device
  xen/pci: Add a function to reset device for xen

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

2024-09-25T07:54:55+00:00

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//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 
Signed-off-by: Huang Rui 
Signed-off-by: Jiqian Chen 
Reviewed-by: Stefano Stabellini 
Message-ID: <20240924061437.2636766-4-Jiqian.Chen@amd.com>
Signed-off-by: Juergen Gross

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

2024-09-04T04:08:51+00:00

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 
Reviewed-by: Thomas Gleixner 
Acked-by: Sakari Ailus  # for IPU6
Acked-by: Robin Murphy

xen: privcmd: Add support for ioeventfd

2023-10-16T13:18:33+00:00

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 
Reviewed-by: Juergen Gross 
Link: https://lore.kernel.org/r/b20d83efba6453037d0c099912813c79c81f7714.1697439990.git.viresh.kumar@linaro.org
Signed-off-by: Juergen Gross

xen: privcmd: Add support for irqfd

2023-08-22T10:12:50+00:00

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 
Reviewed-by: Juergen Gross 
Link: https://lore.kernel.org/r/8e724ac1f50c2bc1eb8da9b3ff6166f1372570aa.1692697321.git.viresh.kumar@linaro.org
Signed-off-by: Juergen Gross

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

2022-10-12T06:39:50+00:00

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

Signed-off-by: Colin Ian King 
Acked-by: Stefano Stabellini 
Link: https://lore.kernel.org/r/20221007203500.2756787-1-colin.i.king@gmail.com
Signed-off-by: Juergen Gross