From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bandan Das Subject: Re: [PATCH v2 0/3] nVMX: Emulated Page Modification Logging for Nested Virtualization Date: Tue, 09 May 2017 12:03:27 -0400 Message-ID: References: <20170505192515.27833-1-bsd@redhat.com> Mime-Version: 1.0 Content-Type: text/plain Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org To: Paolo Bonzini Return-path: In-Reply-To: (Paolo Bonzini's message of "Tue, 9 May 2017 17:22:22 +0200") Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org Paolo Bonzini writes: > On 05/05/2017 21:25, Bandan Das wrote: >> v2: >> 2/3: Clear out all bits except bit 12 >> 3/3: Slightly modify an existing comment, honor L0's >> PML setting when clearing it for L1 >> >> v1: >> http://www.spinics.net/lists/kvm/msg149247.html >> >> These patches implement PML on top of EPT A/D emulation >> (ae1e2d1082ae). >> >> When dirty bit is being set, we write the gpa to the >> buffer provided by L1. If the index overflows, we just >> change the exit reason before running L1. > > I tested this with api/dirty-log-perf, and nested PML is more than 3 > times faster than pml=0. I want to do a few more tests because I don't > see any PML full exits in the L1 trace, but it seems to be a nice > improvement! Thanks for testing! Regarding the PML full exits, I did notice their absence. I induced it artifically in my testing with a lower index and it seemed to work fine. > Paolo > >> Bandan Das (3): >> kvm: x86: Add a hook for arch specific dirty logging emulation >> nVMX: Implement emulated Page Modification Logging >> nVMX: Advertise PML to L1 hypervisor >> >> arch/x86/include/asm/kvm_host.h | 2 + >> arch/x86/kvm/mmu.c | 15 +++++++ >> arch/x86/kvm/mmu.h | 1 + >> arch/x86/kvm/paging_tmpl.h | 4 ++ >> arch/x86/kvm/vmx.c | 97 ++++++++++++++++++++++++++++++++++++++--- >> 5 files changed, 112 insertions(+), 7 deletions(-) >>