From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [PATCH 4/6] kvm: nVMX: support EPT accessed/dirty bits Date: Fri, 14 Apr 2017 13:17:56 +0800 Message-ID: References: <1490867732-16743-1-git-send-email-pbonzini@redhat.com> <1490867732-16743-5-git-send-email-pbonzini@redhat.com> <317734077.12913155.1491954869446.JavaMail.zimbra@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, david@redhat.com To: Bandan Das Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 13/04/2017 07:02, Bandan Das wrote: >> For EPT it is, you're right it's fishy. The "nested_access" should be >> computed in translate_nested_gpa, which is where kvm->arch.nested_mmu >> (non-EPT) requests to access kvm->arch.mmu (EPT). > > Thanks for the clarification. Is it the case when L1 runs L2 without > EPT ? I can't figure out the case where translate_nested_gpa will actually > be called. It happens when L2 instruction are emulated by L0, for example when L1 is passing through I/O ports to L2 and L2 runs an "insb" instruction. I think this case is not covered by vmx.flat. Paolo > FNAME(walk_addr_nested) calls walk_addr_generic > with &vcpu->arch.nested_mmu and init_kvm_nested_mmu() sets gva_to_gpa() > with the appropriate "_nested" functions. But the gva_to_gpa() pointers > don't seem to get invoked at all for the nested case. > > BTW, just noticed that setting PFERR_USER_MASK is redundant since > translate_nested_gpa does it too.