• Xiao Guangrong's avatar
    KVM: MMU: mmio page fault support · ce88decf
    Xiao Guangrong authored
    The idea is from Avi:
    | We could cache the result of a miss in an spte by using a reserved bit, and
    | checking the page fault error code (or seeing if we get an ept violation or
    | ept misconfiguration), so if we get repeated mmio on a page, we don't need to
    | search the slot list/tree.
    | (https://lkml.org/lkml/2011/2/22/221)
    When the page fault is caused by mmio, we cache the info in the shadow page
    table, and also set the reserved bits in the shadow page table, so if the mmio
    is caused again, we can quickly identify it and emulate it directly
    Searching mmio gfn in memslots is heavy since we need to walk all memeslots, it
    can be reduced by this feature, and also avoid walking guest page table for
    soft mmu.
    [jan: fix operator precedence issue]
    Signed-off-by: default avatarXiao Guangrong <xiaoguangrong@cn.fujitsu.com>
    Signed-off-by: default avatarJan Kiszka <jan.kiszka@siemens.com>
    Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
kvm_main.c 59.8 KB