On Fri, Sep 11, 2015 at 11:17:33AM +0800, Jason Wang wrote: > Hi: > > This series fixes two issues of fast mmio eventfd: > > 1) A single iodev instance were registerd on two buses: KVM_MMIO_BUS > and KVM_FAST_MMIO_BUS. This will cause double in > ioeventfd_destructor() > 2) A zero length iodev on KVM_MMIO_BUS will never be found but > kvm_io_bus_cmp(). This will lead e.g the eventfd will be trapped by > qemu instead of host. > > 1 is fixed by allocating two instances of iodev. 2 is fixed by ignore > the actual length if the length of iodev is zero in kvm_io_bus_cmp(). > > Please review.
I think we should add a capability for fast mmio. This way, userspace can avoid crashing buggy kernels. > Changes from V3: > > - Don't do search on two buses when trying to do write on > KVM_MMIO_BUS. This fixes a small regression found by vmexit.flat. > - Since we don't do search on two buses, change kvm_io_bus_cmp() to > let it can find zero length iodevs. > - Fix the unnecessary lines in tracepoint patch. > > Changes from V2: > - Tweak styles and comment suggested by Cornelia. > > Changes from v1: > - change ioeventfd_bus_from_flags() to return KVM_FAST_MMIO_BUS when > needed to save lots of unnecessary changes. > > Jason Wang (4): > kvm: factor out core eventfd assign/deassign logic > kvm: fix double free for fast mmio eventfd > kvm: fix zero length mmio searching > kvm: add tracepoint for fast mmio > > arch/x86/kvm/trace.h | 18 ++++++++ > arch/x86/kvm/vmx.c | 1 + > arch/x86/kvm/x86.c | 1 + > virt/kvm/eventfd.c | 124 > ++++++++++++++++++++++++++++++--------------------- > virt/kvm/kvm_main.c | 4 +- > 5 files changed, 96 insertions(+), 52 deletions(-) > > -- > 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
