From mboxrd@z Thu Jan 1 00:00:00 1970 From: Xiao Guangrong Subject: Re: [PATCH 2/5] mmu: pass execonly value when initializing rsvd bits Date: Wed, 29 Jun 2016 11:07:56 +0800 Message-ID: <57733B8C.6050504@linux.intel.com> References: <1467088360-10186-1-git-send-email-bsd@redhat.com> <1467088360-10186-3-git-send-email-bsd@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Cc: pbonzini@redhat.com, linux-kernel@vger.kernel.org To: Bandan Das , kvm@vger.kernel.org Return-path: In-Reply-To: <1467088360-10186-3-git-send-email-bsd@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 06/28/2016 12:32 PM, Bandan Das wrote: > In reset_tdp_shadow_zero_bits_mask, we always pass false > when initializing the reserved bits. By initializing with the > correct value of ept exec only, the host can correctly > identify if the guest pte is valid. Note that > kvm_init_shadow_ept_mmu() already knows about execonly. > > Signed-off-by: Bandan Das > --- > arch/x86/kvm/mmu.c | 12 ++++++++---- > 1 file changed, 8 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c > index a50af79..875d4f7 100644 > --- a/arch/x86/kvm/mmu.c > +++ b/arch/x86/kvm/mmu.c > @@ -3831,23 +3831,27 @@ static inline bool boot_cpu_is_amd(void) > > /* > * the direct page table on host, use as much mmu features as > - * possible, however, kvm currently does not do execution-protection. > + * possible > */ > static void > reset_tdp_shadow_zero_bits_mask(struct kvm_vcpu *vcpu, > struct kvm_mmu *context) > { It is not necessary. reset_tdp_shadow_zero_bits_mask() is used for the guest without nested-ept, host never sets shadow execute-only actively. For the nested ept guest, kvm_init_shadow_ept_mmu() has already handled xonly case perfectly.