kernel/linux.git/include/xen/interface, branch master

hvc/xen: Check console connection flag

2026-04-10T09:06:17+00:00

When the console out buffer is filled, __write_console() will return 0 as it cannot send any data. domU_write_console() will then spin in `while (len)` as len doesn't decrement until xenconsoled attaches. This would block a domU and nullify the parallelism of Hyperlaunch until dom0 userspace starts xenconsoled, which empties the buffer. Xen 4.21 added a connection field to the xen console page. This is set to XENCONSOLE_DISCONNECTED (1) when a domain is built, and xenconsoled will set it to XENCONSOLE_CONNECTED (0) when it connects. Update the hvc_xen driver to check the field. When the field is disconnected, drop the write with -ENOTCONN. We only drop the write when the field is XENCONSOLE_DISCONNECTED (1) to try for maximum compatibility. The Xen toolstack has historically zero initialized the console, so it should see XENCONSOLE_CONNECTED (0) by default. If an implemenation used uninitialized memory, only checking for XENCONSOLE_DISCONNECTED could have the lowest chance of not connecting. This lets the hyperlaunched domU boot without stalling. Once dom0 starts xenconsoled, xl console can be used to access the domU's hvc0. Paritally sync console.h from xen.git to bring in the new field. Reviewed-by: Stefano Stabellini Signed-off-by: Jason Andryuk Signed-off-by: Juergen Gross Message-ID: <20260318235326.14568-1-jason.andryuk@amd.com>

xen/mcelog: Add __nonstring annotations for unterminated strings

2025-03-14T10:15:16+00:00

When a character array without a terminating NUL character has a static initializer, GCC 15's -Wunterminated-string-initialization will only warn if the array lacks the "nonstring" attribute[1]. Mark the arrays with __nonstring to and correctly identify the char array as "not a C string" and thereby eliminate the warning. Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117178 [1] Cc: Juergen Gross Cc: Stefano Stabellini Cc: Oleksandr Tyshchenko Cc: xen-devel@lists.xenproject.org Signed-off-by: Kees Cook Acked-by: Juergen Gross Message-ID: <20250310222234.work.473-kees@kernel.org> Signed-off-by: Juergen Gross

xen: sync elfnote.h from xen tree

2024-09-25T12:15:04+00:00

Sync Xen's elfnote.h header from xen.git to pull in the XEN_ELFNOTE_PHYS32_RELOC define. xen commit dfc9fab00378 ("x86/PVH: Support relocatable dom0 kernels") This is a copy except for the removal of the emacs editor config at the end of the file. Signed-off-by: Jason Andryuk Reviewed-by: Juergen Gross Message-ID: <20240823193630.2583107-2-jason.andryuk@amd.com> Signed-off-by: Juergen Gross

xen/pci: Add a function to reset device for xen

2024-09-25T07:54:40+00:00

When device on dom0 side has been reset, the vpci on Xen side won't get notification, so that the cached state in vpci is all out of date with the real device state. To solve that problem, add a new function to clear all vpci device state when device is reset on dom0 side. And call that function in pcistub_init_device. Because when using "pci-assignable-add" to assign a passthrough device in Xen, it will reset passthrough device and the vpci state will out of date, and then device will fail to restore bar state. Signed-off-by: Jiqian Chen Signed-off-by: Huang Rui Signed-off-by: Jiqian Chen Reviewed-by: Stefano Stabellini Message-ID: <20240924061437.2636766-2-Jiqian.Chen@amd.com> Signed-off-by: Juergen Gross

xen: update PV-device interface headers

2024-01-09T10:46:24+00:00

Update the Xen PV-device interface headers in order to avoid undefined behavior with flexible arrays being defined with one array element. Reported-by: Pry Mar Signed-off-by: Juergen Gross Acked-by: Stefano Stabellini Link: https://lore.kernel.org/r/20231205115121.11627-1-jgross@suse.com Signed-off-by: Juergen Gross

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

x86/PVH: obtain VGA console info in Dom0

2023-03-14T14:20:51+00:00

A new platform-op was added to Xen to allow obtaining the same VGA console information PV Dom0 is handed. Invoke the new function and have the output data processed by xen_init_vga(). Signed-off-by: Jan Beulich Reviewed-by: Juergen Gross Link: https://lore.kernel.org/r/8f315e92-7bda-c124-71cc-478ab9c5e610@suse.com Signed-off-by: Juergen Gross

x86/xen: Add support for HVMOP_set_evtchn_upcall_vector

2022-08-12T09:28:21+00:00

Implement support for the HVMOP_set_evtchn_upcall_vector hypercall in order to set the per-vCPU event channel vector callback on Linux and use it in preference of HVM_PARAM_CALLBACK_IRQ. If the per-VCPU vector setup is successful on BSP, use this method for the APs. If not, fallback to the global vector-type callback. Also register callback_irq at per-vCPU event channel setup to trick toolstack to think the domain is enlightened. Suggested-by: "Roger Pau Monné" Signed-off-by: Jane Malalane Reviewed-by: Boris Ostrovsky Link: https://lore.kernel.org/r/20220729070416.23306-1-jane.malalane@citrix.com Signed-off-by: Juergen Gross

xen: sync xs_wire.h header with upstream xen

2022-05-19T12:44:05+00:00

Sync the xs_wire.h header file in Linux with the one in Xen. Signed-off-by: Stefano Stabellini Reviewed-by: Boris Ostrovsky Link: https://lore.kernel.org/r/20220513211938.719341-1-sstabellini@kernel.org Signed-off-by: Juergen Gross

xen: update ring.h

2022-05-19T12:21:53+00:00

Update include/xen/interface/io/ring.h to its newest version. Switch the two improper use cases of RING_HAS_UNCONSUMED_RESPONSES() to XEN_RING_NR_UNCONSUMED_RESPONSES() in order to avoid the nasty XEN_RING_HAS_UNCONSUMED_IS_BOOL #define. Signed-off-by: Juergen Gross Reviewed-by: Boris Ostrovsky Signed-off-by: Juergen Gross