[0/2] Add API for making parts of a MMIO page R/O and use it in XHCI console

Message

Marek Marczykowski-Górecki March 27, 2023, 10:09 a.m. UTC

On older systems, XHCI xcap had a layout that no other (interesting) registers
were placed on the same page as the debug capability, so Linux was fine with
making the whole page R/O. But at least on Tiger Lake and Alder Lake, Linux
needs to write to some other registers on the same page too.

Add a generic API for making just parts of an MMIO page R/O and use it to fix
USB3 console with share=yes or share=hwdom options. More details in commit
messages.

Marek Marczykowski-Górecki (2):
  x86/mm: add API for marking only part of a MMIO page read only
  drivers/char: Use sub-page ro API to make just xhci dbc cap RO

 xen/arch/x86/hvm/emulate.c      |   2 +-
 xen/arch/x86/hvm/hvm.c          |   3 +-
 xen/arch/x86/include/asm/mm.h   |  22 ++++-
 xen/arch/x86/mm.c               | 181 +++++++++++++++++++++++++++++++++-
 xen/arch/x86/pv/ro-page-fault.c |   1 +-
 xen/drivers/char/xhci-dbc.c     |  38 ++++++-
 6 files changed, 243 insertions(+), 4 deletions(-)

base-commit: b1f11273d5a774cc88a3685c96c2e7cf6385e3b6