On Wed, Feb 22, 2017 at 7:13 AM, Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: > 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. > I renamed the helpers to make it less likely that someone would repeat my little buglet. I can submit a patch that just has the differences, but I think it should go in through your tree. Would that work? --Andy -- Andy Lutomirski AMA Capital Management, LLC
