From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752527AbeBFCqB (ORCPT ); Mon, 5 Feb 2018 21:46:01 -0500 Received: from mail-ot0-f195.google.com ([74.125.82.195]:32935 "EHLO mail-ot0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752187AbeBFCpv (ORCPT ); Mon, 5 Feb 2018 21:45:51 -0500 X-Google-Smtp-Source: AH8x226DWxPnkAI7296EZei9k06P1fOU9jRSLLCH0vfzxdnCSz2hf3FgGx1vcOKvTuB0NNjNnDtKGvWEifAPG44oAxA= MIME-Version: 1.0 In-Reply-To: <1510584031-36240-3-git-send-email-pbonzini@redhat.com> References: <1510584031-36240-1-git-send-email-pbonzini@redhat.com> <1510584031-36240-3-git-send-email-pbonzini@redhat.com> From: Wanpeng Li Date: Tue, 6 Feb 2018 10:45:50 +0800 Message-ID: Subject: Re: [PATCH 2/5] KVM: x86: add support for UMIP To: Paolo Bonzini Cc: LKML , kvm , Radim Krcmar Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2017-11-13 22:40 GMT+08:00 Paolo Bonzini : > Add the CPUID bits, make the CR4.UMIP bit not reserved anymore, and > add UMIP support for instructions that are already emulated by KVM. > > Signed-off-by: Paolo Bonzini > --- > arch/x86/include/asm/kvm_host.h | 2 +- > arch/x86/kvm/cpuid.c | 4 ++-- > arch/x86/kvm/emulate.c | 8 ++++++++ > arch/x86/kvm/x86.c | 3 +++ > 4 files changed, 14 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > index c73e493adf07..1b005ccf4d0b 100644 > --- a/arch/x86/include/asm/kvm_host.h > +++ b/arch/x86/include/asm/kvm_host.h > @@ -86,7 +86,7 @@ > | X86_CR4_PGE | X86_CR4_PCE | X86_CR4_OSFXSR | X86_CR4_PCIDE \ > | X86_CR4_OSXSAVE | X86_CR4_SMEP | X86_CR4_FSGSBASE \ > | X86_CR4_OSXMMEXCPT | X86_CR4_LA57 | X86_CR4_VMXE \ > - | X86_CR4_SMAP | X86_CR4_PKE)) > + | X86_CR4_SMAP | X86_CR4_PKE | X86_CR4_UMIP)) > > #define CR8_RESERVED_BITS (~(unsigned long)X86_CR8_TPR) > > diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c > index 0099e10eb045..77fb8732b47b 100644 > --- a/arch/x86/kvm/cpuid.c > +++ b/arch/x86/kvm/cpuid.c > @@ -387,8 +387,8 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function, > > /* cpuid 7.0.ecx*/ > const u32 kvm_cpuid_7_0_ecx_x86_features = > - F(AVX512VBMI) | F(LA57) | F(PKU) | > - 0 /*OSPKE*/ | F(AVX512_VPOPCNTDQ); > + F(AVX512VBMI) | F(LA57) | F(PKU) | 0 /*OSPKE*/ | > + F(AVX512_VPOPCNTDQ) | F(UMIP); > > /* cpuid 7.0.edx*/ > const u32 kvm_cpuid_7_0_edx_x86_features = > diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c > index d90cdc77e077..d27339332ac8 100644 > --- a/arch/x86/kvm/emulate.c > +++ b/arch/x86/kvm/emulate.c > @@ -3725,6 +3725,10 @@ static int emulate_store_desc_ptr(struct x86_emulate_ctxt *ctxt, > { > struct desc_ptr desc_ptr; > > + if ((ctxt->ops->get_cr(ctxt, 4) & X86_CR4_UMIP) && > + ctxt->ops->cpl(ctxt) > 0) > + return emulate_gp(ctxt, 0); > + > if (ctxt->mode == X86EMUL_MODE_PROT64) > ctxt->op_bytes = 8; > get(ctxt, &desc_ptr); > @@ -3784,6 +3788,10 @@ static int em_lidt(struct x86_emulate_ctxt *ctxt) > > static int em_smsw(struct x86_emulate_ctxt *ctxt) > { > + if ((ctxt->ops->get_cr(ctxt, 4) & X86_CR4_UMIP) && > + ctxt->ops->cpl(ctxt) > 0) > + return emulate_gp(ctxt, 0); > + > if (ctxt->dst.type == OP_MEM) > ctxt->dst.bytes = 2; > ctxt->dst.val = ctxt->ops->get_cr(ctxt, 0); > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 03869eb7fcd6..cda567aadd28 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -791,6 +791,9 @@ int kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4) > if (!guest_cpuid_has(vcpu, X86_FEATURE_LA57) && (cr4 & X86_CR4_LA57)) > return 1; > > + if (!guest_cpuid_has(vcpu, X86_FEATURE_UMIP) && (cr4 & X86_CR4_UMIP)) > + return 1; There is a scenario here, UMIP CPUID is not exposed to the guest since it depends on SECONDARY_EXEC_DESC is set, however, SECONDARY_EXEC_DESC depends on guest sets the X86_CR4_UMIP bit, the function kvm_set_cr4() will inject a #GP and fails to set X86_CR4_UMIP bit since UMIP CPUID is not exposed to the guest. This scenario can be observed when running kvm-unit-tests/umip.flat in the L1. Regards, Wanpeng Li