While working on Qubes OS Marek found out that there were some PAT hacks in the Linux i195 driver. I decided to make Xen use Linux’s PAT to see if it solved the graphics glitches that were observed; it did. This required a substantial amount of preliminary work that is useful even without using Linux’s PAT.
Patches 1 through 9 are the preliminary work and I would like them to be accepted into upstream Xen. Patch 9 does break ABI by rejecting the unused PAT entries, but this will only impact buggy PV guests and can be disabled with a Xen command-line option. Patch 10 actually switches to Linux’s PAT and is NOT intended to be merged (at least for now) as it would at a minimum break migration of PV guests from hosts that do not have the patch. Only patches 9 and 10 actually change Xen’s observable behavior. Patches 1, 2, and 7 are prerequisites, and patches 3 through 6 are cleanups. Patch 8 makes changing the PAT much less error-prone, as problems with the PAT or with the associated _PAGE_* constants will be detected at compile time. Demi Marie Obenour (10): x86: Add memory type constants x86/mm: Avoid hard-coding PAT in get_page_from_l1e() x86: Replace PAT_* with X86_MT_* x86: Replace MTRR_* constants with X86_MT_* constants x86: Replace EPT_EMT_* constants with X86_MT_* x86: Remove MEMORY_NUM_TYPES and NO_HARDCODE_MEM_TYPE x86: Derive XEN_MSR_PAT from its individual entries x86/mm: make code robust to future PAT changes x86/mm: Reject invalid cacheability in PV guests by default x86: Use Linux's PAT xen/arch/x86/cpu/mtrr/generic.c | 10 +- xen/arch/x86/cpu/mtrr/main.c | 26 +++--- xen/arch/x86/e820.c | 4 +- xen/arch/x86/hvm/hvm.c | 12 +-- xen/arch/x86/hvm/mtrr.c | 100 ++++++++++---------- xen/arch/x86/hvm/vmx/vmcs.c | 2 +- xen/arch/x86/hvm/vmx/vmx.c | 18 ++-- xen/arch/x86/include/asm/hvm/vmx/vmcs.h | 2 +- xen/arch/x86/include/asm/hvm/vmx/vmx.h | 9 -- xen/arch/x86/include/asm/mtrr.h | 22 +---- xen/arch/x86/include/asm/page.h | 4 +- xen/arch/x86/include/asm/processor.h | 11 ++- xen/arch/x86/include/asm/x86-defns.h | 11 +++ xen/arch/x86/mm.c | 118 ++++++++++++++++++++++-- xen/arch/x86/mm/hap/nested_ept.c | 4 +- xen/arch/x86/mm/p2m-ept.c | 51 +++++----- xen/arch/x86/mm/shadow/multi.c | 8 +- 17 files changed, 253 insertions(+), 159 deletions(-) -- Sincerely, Demi Marie Obenour (she/her/hers) Invisible Things Lab
