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Ip=[165.204.84.17]; Helo=[satlexmb07.amd.com] X-MS-Exchange-CrossTenant-AuthSource: BN2PEPF0000A893.namprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH8PR12MB6868 Received-SPF: permerror client-ip=2a01:111:f403:c107::9; envelope-from=Michael.Roth@amd.com; helo=PH7PR06CU001.outbound.protection.outlook.com X-Spam_score_int: -23 X-Spam_score: -2.4 X-Spam_bar: -- X-Spam_report: (-2.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.341, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org From: Xiaoyao Li With the mmap support of guest memfd, KVM allows userspace to create guest memfd serving as normal non-private memory for X86 DEFAULT VM. However, KVM doesn't support private memory attribute for X86 DEFAULT VM. Make kvm_guest_memfd_supported not rely on KVM_MEMORY_ATTRIBUTE_PRIVATE and check KVM_MEMORY_ATTRIBUTE_PRIVATE separately when the machine requires guest_memfd to serve as private memory. This allows QEMU to create guest memfd with mmap to serve as the memory backend for X86 DEFAULT VM. Signed-off-by: Xiaoyao Li Signed-off-by: Peter Xu Reviewed-by: Fabiano Rosas Reviewed-by: Michael Roth Reviewed-by: David Hildenbrand Signed-off-by: Michael Roth --- accel/kvm/kvm-all.c | 8 ++++++-- accel/stubs/kvm-stub.c | 5 +++++ include/system/kvm.h | 1 + system/physmem.c | 9 +++++++++ 4 files changed, 21 insertions(+), 2 deletions(-) diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c index 83cbd120a8..cdc7554082 100644 --- a/accel/kvm/kvm-all.c +++ b/accel/kvm/kvm-all.c @@ -1627,6 +1627,11 @@ int kvm_set_memory_attributes_shared(hwaddr start, uint64_t size) return kvm_set_memory_attributes(start, size, 0); } +bool kvm_private_memory_attribute_supported(void) +{ + return !!(kvm_supported_memory_attributes & KVM_MEMORY_ATTRIBUTE_PRIVATE); +} + /* Called with KVMMemoryListener.slots_lock held */ static void kvm_set_phys_mem(KVMMemoryListener *kml, MemoryRegionSection *section, bool add) @@ -3058,8 +3063,7 @@ static int kvm_init(AccelState *as, MachineState *ms) kvm_supported_memory_attributes = kvm_vm_check_extension(s, KVM_CAP_MEMORY_ATTRIBUTES); kvm_guest_memfd_supported = kvm_vm_check_extension(s, KVM_CAP_GUEST_MEMFD) && - kvm_vm_check_extension(s, KVM_CAP_USER_MEMORY2) && - (kvm_supported_memory_attributes & KVM_MEMORY_ATTRIBUTE_PRIVATE); + kvm_vm_check_extension(s, KVM_CAP_USER_MEMORY2); kvm_pre_fault_memory_supported = kvm_vm_check_extension(s, KVM_CAP_PRE_FAULT_MEMORY); if (s->kernel_irqchip_split == ON_OFF_AUTO_AUTO) { diff --git a/accel/stubs/kvm-stub.c b/accel/stubs/kvm-stub.c index 32b4b07403..3d34e3b99d 100644 --- a/accel/stubs/kvm-stub.c +++ b/accel/stubs/kvm-stub.c @@ -143,3 +143,8 @@ int kvm_create_guest_memfd(uint64_t size, uint64_t flags, Error **errp) { return -ENOSYS; } + +bool kvm_private_memory_attribute_supported(void) +{ + return false; +} diff --git a/include/system/kvm.h b/include/system/kvm.h index 714b8c7b01..d29624034c 100644 --- a/include/system/kvm.h +++ b/include/system/kvm.h @@ -551,6 +551,7 @@ int kvm_create_guest_memfd(uint64_t size, uint64_t flags, Error **errp); int kvm_set_memory_attributes_private(hwaddr start, uint64_t size); int kvm_set_memory_attributes_shared(hwaddr start, uint64_t size); +bool kvm_private_memory_attribute_supported(void); int kvm_convert_memory(hwaddr start, hwaddr size, bool to_private); diff --git a/system/physmem.c b/system/physmem.c index bd5f41cb02..1b3f327ed5 100644 --- a/system/physmem.c +++ b/system/physmem.c @@ -2192,6 +2192,15 @@ static void ram_block_add(RAMBlock *new_block, Error **errp) object_get_typename(OBJECT(current_machine->cgs))); goto out_free; } + + if (!kvm_private_memory_attribute_supported()) { + error_setg(errp, "cannot set up private guest memory for %s: " + "KVM does not support private memory attribute", + object_get_typename(OBJECT(current_machine->cgs))); + qemu_mutex_unlock_ramlist(); + goto out_free; + } + assert(new_block->guest_memfd < 0); ret = ram_block_coordinated_discard_require(true); -- 2.43.0