On 21/02/2017 20:14, Andy Lutomirski wrote: > The first four patches here are intended to be straightforward > cleanups and to make a better base for Thomas' GDT series. They may > be a slight speedup, too, because they remove an STR instruction > from the VMX entry path. > > The last two patches are a reasonably large speedup but need careful > review. > > FWIW, I can see lots of additional easy-ish speedups here. For example: > > - The GDT reload on VM exit isn't really needed at all. Instead let's > just change the kernel limit to 0xFFFF. Doing that naively would > waste memory, but doing it carefully on top of Thomas' series would > be straightforward and almost free. > > - RDMSR from MSR_GS_BASE is totally pointless. > > - Once I or someone finishes the FSGSBASE series, we get a big speedup > there. > > - The LDT reload code should be split up and optimized better, I think. > > Changes from v1: > - Fix some changelog typos. > - Fix the bug that Paolo found. > - Rename the helpers to make their usage more obvious. > - Move clearing __tss_limit_invalid into force_reload_TR() as a tiny > optimization. > - Add a test case. It doesn't test all the machinations, but at least > it checks basic functionality. > > Andy Lutomirski (7): > x86/asm: Define the kernel TSS limit in a macro > x86/kvm/vmx: Don't fetch the TSS base from the GDT > x86/kvm/vmx: Get rid of segment_base() on 64-bit kernels > x86/kvm/vmx: Simplify segment_base() > x86/asm/64: Drop __cacheline_aligned from struct x86_hw_tss > x86/kvm/vmx: Defer TR reload after VM exit > selftests/x86: Add a basic selftest for ioperm > > arch/x86/include/asm/desc.h | 62 +++++++++++-- > arch/x86/include/asm/processor.h | 12 ++- > arch/x86/kernel/ioport.c | 11 +++ > arch/x86/kernel/process.c | 10 ++ > arch/x86/kvm/vmx.c | 63 ++++++------- > tools/testing/selftests/x86/Makefile | 2 +- > tools/testing/selftests/x86/ioperm.c | 171 +++++++++++++++++++++++++++++++++++ > 7 files changed, 284 insertions(+), 47 deletions(-) > create mode 100644 tools/testing/selftests/x86/ioperm.c > I pushed and tagged before seeing this v2. :( The differences seem to be x86-only, so I suppose Ingo can handle them if you resubmit. Paolo
