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 | 4 +- xen/arch/x86/include/asm/mm.h | 23 +++- xen/arch/x86/mm.c | 261 +++++++++++++++++++++++++++++++++- xen/arch/x86/pv/ro-page-fault.c | 6 +- xen/drivers/char/xhci-dbc.c | 36 +++-- 6 files changed, 313 insertions(+), 19 deletions(-) base-commit: b25b28ede1cba43eda1e0b84ad967683b8196847 -- git-series 0.9.1
