From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH] KVM: MMU: fix huge page adapted on non-PAE host Date: Mon, 28 May 2012 13:57:25 +0300 Message-ID: <4FC35A15.6080000@redhat.com> References: <4FC316E3.6080607@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Marcelo Tosatti , LKML , KVM To: Xiao Guangrong Return-path: In-Reply-To: <4FC316E3.6080607@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 05/28/2012 09:10 AM, Xiao Guangrong wrote: > The huge page size is 4M on non-PAE host, but 2M page size is used in > transparent_hugepage_adjust(), so the page we get after adjust the > mapping level is not the head page, the BUG_ON() will be triggered > > > diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c > index 72102e0..be3cea4 100644 > --- a/arch/x86/kvm/mmu.c > +++ b/arch/x86/kvm/mmu.c > @@ -2595,8 +2595,7 @@ static void transparent_hugepage_adjust(struct kvm_vcpu *vcpu, > *gfnp = gfn; > kvm_release_pfn_clean(pfn); > pfn &= ~mask; > - if (!get_page_unless_zero(pfn_to_page(pfn))) > - BUG(); > + kvm_get_pfn(pfn); > *pfnp = pfn; > } > } Shouldn't we adjust mask instead? -- error compiling committee.c: too many arguments to function