On 20/12/2017 08:29, Haozhong Zhang wrote: > Some reserved pages, such as those from NVDIMM DAX devices, are not > for MMIO, and can be mapped with cached memory type for better > performance. However, the above check misconceives those pages as > MMIO. Because KVM maps MMIO pages with UC memory type, the > performance of guest accesses to those pages would be harmed. > Therefore, we check the host memory type in addition and only treat > UC/UC-/WC pages as MMIO. > > Changes in v6: > * Rename the function in patch 1 to pat_immune_to_uc_mtrr(). > * Consider WC memory type in patch 1. > > Changes in v5: > * Rename pat_pfn_is_uc() into pat_pfn_is_uc_or_uc_minus() to avoid > confusion. > * Drop converters between kvm_pfn_t and pfn_t, because they are not > necessary. pat_pfn_is_uc_or_uc_minus() does not need flags in > pfn_t, so we can only pass a raw unsigned long to it. > > Changes in v4: > * Mask pfn_t and kvm_pfn_t specific flags in conversion. > > Changes in v3: > * Move cache mode check to pat.c as pat_pfn_is_uc() > * Reintroduce converters between kvm_pfn_t and pfn_t. > > Changes in v2: > * Switch to lookup_memtype() to get host memory type. > * Rewrite the comment in KVM MMU patch. > * Remove v1 patch 2, which is not necessary in v2. > > Haozhong Zhang (2): > x86/mm: add a function to check if a pfn is UC/UC-/WC > KVM: MMU: consider host cache mode in MMIO page check > > arch/x86/include/asm/pat.h | 2 ++ > arch/x86/kvm/mmu.c | 13 ++++++++++++- > arch/x86/mm/pat.c | 19 +++++++++++++++++++ > 3 files changed, 33 insertions(+), 1 deletion(-) > Thanks, I applied this series. I only changed the function name to pat_pfn_immune_to_uc_mtrr. Thanks, Paolo
