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Peter Anvin" , Hugh Dickins , Jeff Layton , "J . Bruce Fields" , Andrew Morton , Shuah Khan , Mike Rapoport , Steven Price , "Maciej S . Szmigiero" , Vlastimil Babka , Vishal Annapurve , Yu Zhang , "Kirill A . Shutemov" , luto@kernel.org, jun.nakajima@intel.com, dave.hansen@intel.com, ak@linux.intel.com, david@redhat.com, aarcange@redhat.com, ddutile@redhat.com, dhildenb@redhat.com, Quentin Perret , Michael Roth , mhocko@suse.com, Muchun Song , wei.w.wang@intel.com, isaku.yamahata@gmail.com Subject: Re: [PATCH v8 2/8] KVM: Extend the memslot to support fd-based private memory Message-ID: <20220929224516.GA2260388@ls.amr.corp.intel.com> References: <20220915142913.2213336-1-chao.p.peng@linux.intel.com> <20220915142913.2213336-3-chao.p.peng@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20220915142913.2213336-3-chao.p.peng@linux.intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 15, 2022 at 10:29:07PM +0800, Chao Peng wrote: ... > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index 584a5bab3af3..12dc0dc57b06 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c ... > @@ -4622,6 +4622,33 @@ static int kvm_vm_ioctl_get_stats_fd(struct kvm *kvm) > return fd; > } > > +#define SANITY_CHECK_MEM_REGION_FIELD(field) \ > +do { \ > + BUILD_BUG_ON(offsetof(struct kvm_user_mem_region, field) != \ > + offsetof(struct kvm_userspace_memory_region, field)); \ > + BUILD_BUG_ON(sizeof_field(struct kvm_user_mem_region, field) != \ > + sizeof_field(struct kvm_userspace_memory_region, field)); \ > +} while (0) > + > +#define SANITY_CHECK_MEM_REGION_EXT_FIELD(field) \ > +do { \ > + BUILD_BUG_ON(offsetof(struct kvm_user_mem_region, field) != \ > + offsetof(struct kvm_userspace_memory_region_ext, field)); \ > + BUILD_BUG_ON(sizeof_field(struct kvm_user_mem_region, field) != \ > + sizeof_field(struct kvm_userspace_memory_region_ext, field)); \ > +} while (0) > + > +static void kvm_sanity_check_user_mem_region_alias(void) > +{ > + SANITY_CHECK_MEM_REGION_FIELD(slot); > + SANITY_CHECK_MEM_REGION_FIELD(flags); > + SANITY_CHECK_MEM_REGION_FIELD(guest_phys_addr); > + SANITY_CHECK_MEM_REGION_FIELD(memory_size); > + SANITY_CHECK_MEM_REGION_FIELD(userspace_addr); > + SANITY_CHECK_MEM_REGION_EXT_FIELD(private_offset); > + SANITY_CHECK_MEM_REGION_EXT_FIELD(private_fd); > +} > + > static long kvm_vm_ioctl(struct file *filp, > unsigned int ioctl, unsigned long arg) > { > @@ -4645,14 +4672,20 @@ static long kvm_vm_ioctl(struct file *filp, > break; > } > case KVM_SET_USER_MEMORY_REGION: { > - struct kvm_userspace_memory_region kvm_userspace_mem; > + struct kvm_user_mem_region mem; > + unsigned long size = sizeof(struct kvm_userspace_memory_region); > + > + kvm_sanity_check_user_mem_region_alias(); > > r = -EFAULT; > - if (copy_from_user(&kvm_userspace_mem, argp, > - sizeof(kvm_userspace_mem))) > + if (copy_from_user(&mem, argp, size); > + goto out; > + > + r = -EINVAL; > + if (mem.flags & KVM_MEM_PRIVATE) > goto out; Nit: It's better to check if padding is zero. Maybe rename it to reserved. + if (mem.pad1 || memchr_inv(mem.pad2, 0, sizeof(mem.pad2))) + goto out; -- Isaku Yamahata