From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcelo Tosatti Subject: Re: [PATCH v4 3/5] KVM: x86: clean up reexecute_instruction Date: Fri, 4 Jan 2013 20:21:35 -0200 Message-ID: <20130104222135.GA13481@amt.cnet> References: <50E6DEDC.7040800@linux.vnet.ibm.com> <50E6DF5C.2000103@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Gleb Natapov , LKML , KVM To: Xiao Guangrong Return-path: Content-Disposition: inline In-Reply-To: <50E6DF5C.2000103@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On Fri, Jan 04, 2013 at 09:55:40PM +0800, Xiao Guangrong wrote: > Little cleanup for reexecute_instruction, also use gpa_to_gfn in > retry_instruction > > Signed-off-by: Xiao Guangrong > --- > arch/x86/kvm/x86.c | 13 ++++++------- > 1 files changed, 6 insertions(+), 7 deletions(-) > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 1c9c834..ad39018 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -4761,19 +4761,18 @@ static bool reexecute_instruction(struct kvm_vcpu *vcpu, gva_t gva) > if (tdp_enabled) > return false; > > + gpa = kvm_mmu_gva_to_gpa_read(vcpu, gva, NULL); > + if (gpa == UNMAPPED_GVA) > + return true; /* let cpu generate fault */ > + Why change from _system to _read here? Purely cleanup patch should have no logical changes. BTW, there is not much logic in using reexecute_instruction() at for x86_decode_insn (checks in reexecute_instruction() assume write to the cr2, for instance). Fault propagation for x86_decode_insn seems completly broken (which is perhaps why reexecute_instruction() there survived). > /* > * if emulation was due to access to shadowed page table > * and it failed try to unshadow page and re-enter the > * guest to let CPU execute the instruction. > */ > - if (kvm_mmu_unprotect_page_virt(vcpu, gva)) > + if (kvm_mmu_unprotect_page(vcpu->kvm, gpa_to_gfn(gpa))) > return true; > > - gpa = kvm_mmu_gva_to_gpa_system(vcpu, gva, NULL); > - > - if (gpa == UNMAPPED_GVA) > - return true; /* let cpu generate fault */ > - > /* > * Do not retry the unhandleable instruction if it faults on the > * readonly host memory, otherwise it will goto a infinite loop: > @@ -4828,7 +4827,7 @@ static bool retry_instruction(struct x86_emulate_ctxt *ctxt, > if (!vcpu->arch.mmu.direct_map) > gpa = kvm_mmu_gva_to_gpa_write(vcpu, cr2, NULL); > > - kvm_mmu_unprotect_page(vcpu->kvm, gpa >> PAGE_SHIFT); > + kvm_mmu_unprotect_page(vcpu->kvm, gpa_to_gfn(gpa)); > > return true; > } > -- > 1.7.7.6