[v2,0/7] xen/console: cleanup console input switch logic

Message

Denis Mukhin March 31, 2025, 11:05 p.m. UTC

Currently, on x86, console input can be rotated in round-robin manner
only between dom0, PV shim, and Xen itself. On Arm the input rotation
can include domUs with vpl011.
  
The patch series introduces the concept of "console focus", which is
defined as the ID of the domain that currently owns the physical console
input.
  
The patch series originates from the NS16550 UART emulator series [1]
for x86, which requires ability to switch physical console input to a
PVH/HVM domain with an emulated UART.
 
The main idea is introducing a per-domain permission flag that is set
during domain initialization and used by the console driver to switch
the input across permitted domains.

Patch 1 introduces a new domain permission flag to mark ownership of the
console input for the console driver.
 
Patches 2, 3 prepare console driver to allow console input rotation
across multiple domains based on the new permission flag. Patch 3
depends on patch 2.

Patches 4, 5 perform mechanical renames to fit the usage in the code.
 
Patch 6 cleans up the console input switch logic; depends on patches
3, 4, 5.

Patch 7 simplifies the existing vUART code by using newly introduced APIs,
depends on patch 5.

[1] https://lore.kernel.org/xen-devel/[e-mail]/
[2] Link to CI: https://gitlab.com/xen-project/people/dmukhin/xen/-/pipelines/1745537898
[3] Link to v1: https://lore.kernel.org/xen-devel/[e-mail]/ 

Denis Mukhin (7):
  xen/console: introduce console input permission
  xen/domain: introduce domid_alloc()
  xen/domain: introduce domid_top()
  xen/console: rename switch_serial_input() to console_switch_input()
  xen/console: rename console_rx to console_focus
  xen/console: introduce console_set_focus()
  xen/console: introduce console_get_focus()

 xen/arch/arm/dom0less-build.c      |  15 ++--
 xen/arch/arm/domain_build.c        |  19 +++--
 xen/arch/arm/include/asm/setup.h   |   2 -
 xen/arch/arm/setup.c               |   2 -
 xen/arch/arm/vpl011.c              |   7 +-
 xen/arch/ppc/include/asm/setup.h   |   2 -
 xen/arch/riscv/include/asm/setup.h |   2 -
 xen/arch/x86/include/asm/setup.h   |   2 -
 xen/arch/x86/pv/shim.c             |   2 +
 xen/arch/x86/setup.c               |   8 +-
 xen/common/domain.c                |  70 +++++++++++++++++
 xen/common/domctl.c                |  45 +----------
 xen/drivers/char/console.c         | 121 ++++++++++++++++-------------
 xen/include/xen/console.h          |   3 +-
 xen/include/xen/domain.h           |   4 +
 xen/include/xen/sched.h            |   8 +-
 16 files changed, 186 insertions(+), 126 deletions(-)