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Shutemov" X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231030_091053_212058_CC64B482 X-CRM114-Status: GOOD ( 20.01 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Oct 30, 2023, Chao Gao wrote: > On Fri, Oct 27, 2023 at 11:21:55AM -0700, Sean Christopherson wrote: > >From: Chao Peng > > > >In confidential computing usages, whether a page is private or shared is > >necessary information for KVM to perform operations like page fault > >handling, page zapping etc. There are other potential use cases for > >per-page memory attributes, e.g. to make memory read-only (or no-exec, > >or exec-only, etc.) without having to modify memslots. > > > >Introduce two ioctls (advertised by KVM_CAP_MEMORY_ATTRIBUTES) to allow > >userspace to operate on the per-page memory attributes. > > - KVM_SET_MEMORY_ATTRIBUTES to set the per-page memory attributes to > > a guest memory range. > > > - KVM_GET_SUPPORTED_MEMORY_ATTRIBUTES to return the KVM supported > > memory attributes. > > This ioctl() is already removed. So, the changelog is out-of-date and needs > an update. Doh, I lost track of this and the fixup for KVM_CAP_MEMORY_ATTRIBUTES below. > >+:Capability: KVM_CAP_MEMORY_ATTRIBUTES > >+:Architectures: x86 > >+:Type: vm ioctl > >+:Parameters: struct kvm_memory_attributes(in) > > ^ add one space here? Ah, yeah, that does appear to be the standard. > > > >+static bool kvm_pre_set_memory_attributes(struct kvm *kvm, > >+ struct kvm_gfn_range *range) > >+{ > >+ /* > >+ * Unconditionally add the range to the invalidation set, regardless of > >+ * whether or not the arch callback actually needs to zap SPTEs. E.g. > >+ * if KVM supports RWX attributes in the future and the attributes are > >+ * going from R=>RW, zapping isn't strictly necessary. Unconditionally > >+ * adding the range allows KVM to require that MMU invalidations add at > >+ * least one range between begin() and end(), e.g. allows KVM to detect > >+ * bugs where the add() is missed. Rexlaing the rule *might* be safe, > > ^^^^^^^^ Relaxing > > >@@ -4640,6 +4850,17 @@ static int kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg) > > case KVM_CAP_BINARY_STATS_FD: > > case KVM_CAP_SYSTEM_EVENT_DATA: > > return 1; > >+#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES > >+ case KVM_CAP_MEMORY_ATTRIBUTES: > >+ u64 attrs = kvm_supported_mem_attributes(kvm); > >+ > >+ r = -EFAULT; > >+ if (copy_to_user(argp, &attrs, sizeof(attrs))) > >+ goto out; > >+ r = 0; > >+ break; > > This cannot work, e.g., no @argp in this function and is fixed by a later commit: > > fcbef1e5e5d2 ("KVM: Add KVM_CREATE_GUEST_MEMFD ioctl() for guest-specific backing memory") I'll post a fixup patch for all of these, thanks much! _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel