From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH v4 08/10] ARM: KVM: Handle guest faults in KVM Date: Tue, 09 Aug 2011 14:24:50 +0300 Message-ID: <4E411902.9010406@redhat.com> References: <20110806103821.27198.41231.stgit@localhost6.localdomain6> <20110806103957.27198.28802.stgit@localhost6.localdomain6> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org, catalin.marinas@arm.com, tech@virtualopensystems.com, android-virt@lists.cs.columbia.edu To: Christoffer Dall Return-path: Received: from mx1.redhat.com ([209.132.183.28]:48606 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753134Ab1HILZM (ORCPT ); Tue, 9 Aug 2011 07:25:12 -0400 In-Reply-To: <20110806103957.27198.28802.stgit@localhost6.localdomain6> Sender: kvm-owner@vger.kernel.org List-ID: On 08/06/2011 01:39 PM, Christoffer Dall wrote: > Handles the guest faults in KVM by mapping in corresponding user pages > in the 2nd stage page tables. > > Introduces new ARM-specific kernel memory types, PAGE_KVM_GUEST and > pgprot_guest variables used to map 2nd stage memory for KVM guests. > > > > +static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, > + gfn_t gfn, struct kvm_memory_slot *memslot) > +{ > + pfn_t pfn; > + pgd_t *pgd; > + pud_t *pud; > + pmd_t *pmd; > + pte_t *pte, new_pte; > + > + pfn = gfn_to_pfn(vcpu->kvm, gfn); > + > + if (is_error_pfn(pfn)) { > + kvm_err(-EFAULT, "Guest gfn %u (0x%08lx) does not have " > + "corresponding host mapping", > + gfn, gfn<< PAGE_SHIFT); > + return -EFAULT; > + } > + > + /* Create 2nd stage page table mapping - Level 1 */ > + pgd = vcpu->kvm->arch.pgd + pgd_index(fault_ipa); > + pud = pud_offset(pgd, fault_ipa); > + if (pud_none(*pud)) { > + pmd = pmd_alloc_one(NULL, fault_ipa); > + if (!pmd) { > + kvm_err(-ENOMEM, "Cannot allocate 2nd stage pmd"); > + return -ENOMEM; > + } > + pud_populate(NULL, pud, pmd); > + pmd += pmd_index(fault_ipa); Don't we need locking here? Another vcpu may have executed pud_populate concurrently. > + } else > + pmd = pmd_offset(pud, fault_ipa); > + > + /* Create 2nd stage page table mapping - Level 2 */ > + if (pmd_none(*pmd)) { > + pte = pte_alloc_one_kernel(NULL, fault_ipa); > + if (!pte) { > + kvm_err(-ENOMEM, "Cannot allocate 2nd stage pte"); > + return -ENOMEM; > + } > + pmd_populate_kernel(NULL, pmd, pte); > + pte += pte_index(fault_ipa); > + } else > + pte = pte_offset_kernel(pmd, fault_ipa); > + > + /* Create 2nd stage page table mapping - Level 3 */ > + new_pte = pfn_pte(pfn, PAGE_KVM_GUEST); > + set_pte_ext(pte, new_pte, 0); > + > + return 0; > +} > + > +#define HSR_ABT_FS (0x3f) > -- error compiling committee.c: too many arguments to function