On Thu, May 16, 2024 at 02:33:47PM +0000, Srivatsa Vaddagiri wrote: > This adds support to launch hypervisor-assisted confidential guests, > where guest's memory is protected from a potentially untrusted host. > Hypervisor can setup host's page-tables so that it loses access to guest > memory. > > Since some guest drivers may need to communicate data with their host > counterparts via shared memory, optionally allow setting aside some part > of the confidential guest's memory as "shared". The size of this shared > memory is specified via the optional "swiotlb-size" parameter. > > -machine virt,confidential-guest-support=prot0 \ > -object arm-confidential-guest,id=prot0,swiotlb-size=16777216 > > The size of this shared memory is indicated to the guest in size/reg > property of device-tree node "/reserved-memory/restricted_dma_reserved". > A memory-region property is added to device-tree node representing > virtio-pcie hub, so that all DMA allocations requested by guest's virtio-pcie > device drivers are satisfied from the shared swiotlb region.
For reference, there is another series proposing confidential guest support for the 'virt' machine on AArch64 with KVM https://lists.nongnu.org/archive/html/qemu-devel/2024-04/msg02742.html I've no idea how closely your impl matches the KVM proposed impl. ie whether we need 2 distinct "ConfidentialGuest" subclasses for KVM vs Gunyah, or whether 1 can cope with both. If we do need 2 distinct subclasses for each hypervisor, then calling this Gunyah targetted object 'arm-confidential-guest' is too broad of an name. > > Signed-off-by: Srivatsa Vaddagiri <quic_svadd...@quicinc.com> > --- > qapi/qom.json | 14 +++++ > include/hw/arm/virt.h | 1 + > hw/arm/virt.c | 141 +++++++++++++++++++++++++++++++++++++++++- > 3 files changed, 155 insertions(+), 1 deletion(-) > > diff --git a/qapi/qom.json b/qapi/qom.json > index 38dde6d785..9b3cd7ce22 100644 > --- a/qapi/qom.json > +++ b/qapi/qom.json > @@ -874,6 +874,18 @@ > 'base': 'RngProperties', > 'data': { '*filename': 'str' } } > > +## > +# @ArmConfidentialGuestProperties: > +# > +# Properties for arm-confidential-guest objects. > +# > +# @swiotlb-size: swiotlb size > +# > +# Since: 2.12 > +## > +{ 'struct': 'ArmConfidentialGuestProperties', > + 'data': { 'swiotlb-size' : 'uint64' } } > + > ## > # @SevGuestProperties: > # > @@ -997,6 +1009,7 @@ > { 'name': 'secret_keyring', > 'if': 'CONFIG_SECRET_KEYRING' }, > 'sev-guest', > + 'arm-confidential-guest', > 'thread-context', > 's390-pv-guest', > 'throttle-group', > @@ -1067,6 +1080,7 @@ > 'secret_keyring': { 'type': 'SecretKeyringProperties', > 'if': 'CONFIG_SECRET_KEYRING' }, > 'sev-guest': 'SevGuestProperties', > + 'arm-confidential-guest': 'ArmConfidentialGuestProperties', > 'thread-context': 'ThreadContextProperties', > 'throttle-group': 'ThrottleGroupProperties', > 'tls-creds-anon': 'TlsCredsAnonProperties', > diff --git a/include/hw/arm/virt.h b/include/hw/arm/virt.h > index bb486d36b1..1e23f20972 100644 > --- a/include/hw/arm/virt.h > +++ b/include/hw/arm/virt.h > @@ -165,6 +165,7 @@ struct VirtMachineState { > uint32_t clock_phandle; > uint32_t gic_phandle; > uint32_t msi_phandle; > + uint32_t restricted_dma_phandle; > uint32_t iommu_phandle; > int psci_conduit; > hwaddr highest_gpa; > diff --git a/hw/arm/virt.c b/hw/arm/virt.c > index 3c93c0c0a6..2a3eb4075d 100644 > --- a/hw/arm/virt.c > +++ b/hw/arm/virt.c > @@ -84,6 +84,9 @@ > #include "hw/virtio/virtio-iommu.h" > #include "hw/char/pl011.h" > #include "qemu/guest-random.h" > +#include "sysemu/cpus.h" > +#include "exec/confidential-guest-support.h" > +#include "qom/object_interfaces.h" > > static GlobalProperty arm_virt_compat[] = { > { TYPE_VIRTIO_IOMMU_PCI, "aw-bits", "48" }, > @@ -1545,6 +1548,11 @@ static void create_pcie(VirtMachineState *vms) > nr_pcie_buses - 1); > qemu_fdt_setprop(ms->fdt, nodename, "dma-coherent", NULL, 0); > > + if (vms->restricted_dma_phandle) { > + qemu_fdt_setprop_cell(ms->fdt, nodename, "memory-region", > + vms->restricted_dma_phandle); > + } > + > if (vms->msi_phandle) { > qemu_fdt_setprop_cells(ms->fdt, nodename, "msi-map", > 0, vms->msi_phandle, 0, 0x10000); > @@ -2065,6 +2073,129 @@ static void virt_cpu_post_init(VirtMachineState *vms, > MemoryRegion *sysmem) > } > } > > +#define TYPE_ARM_CONFIDENTIAL_GUEST "arm-confidential-guest" > +OBJECT_DECLARE_SIMPLE_TYPE(ArmConfidentialGuestState, ARM_CONFIDENTIAL_GUEST) > + > +struct ArmConfidentialGuestState { > + ConfidentialGuestSupport parent_obj; > + > + hwaddr swiotlb_size; > +}; > + > +static ArmConfidentialGuestState *acg; > + > +static void > +arm_confidential_guest_instance_init(Object *obj) > +{ > + ArmConfidentialGuestState *acg = ARM_CONFIDENTIAL_GUEST(obj); > + > + object_property_add_uint64_ptr(obj, "swiotlb-size", &acg->swiotlb_size, > + OBJ_PROP_FLAG_READWRITE); > +} > + > +static const TypeInfo confidential_guest_info = { > + .parent = TYPE_CONFIDENTIAL_GUEST_SUPPORT, > + .name = TYPE_ARM_CONFIDENTIAL_GUEST, > + .instance_size = sizeof(ArmConfidentialGuestState), > + .instance_init = arm_confidential_guest_instance_init, > + .interfaces = (InterfaceInfo[]) { > + { TYPE_USER_CREATABLE }, > + { } > + } > +}; > + > +static void > +confidential_guest_register_types(void) > +{ > + type_register_static(&confidential_guest_info); > +} > +type_init(confidential_guest_register_types); > + > +static int confidential_guest_init(MachineState *ms) > +{ > + ConfidentialGuestSupport *cgs = ms->cgs; > + ArmConfidentialGuestState *obj = (ArmConfidentialGuestState *) > + object_dynamic_cast(OBJECT(cgs), TYPE_ARM_CONFIDENTIAL_GUEST); > + const AccelOpsClass *ops = cpus_get_accel(); > + > + if (!obj) { > + return 0; > + } > + > + if (!ops->check_capability || > + !ops->check_capability(CONFIDENTIAL_GUEST_SUPPORTED)) { > + error_report("confidential guests are not supported"); > + return -1; > + } > + > + if (obj->swiotlb_size > ms->ram_size) { > + error_report("swiotlb_size exceeds RAM size"); > + return -1; > + } > + > + acg = obj; > + cgs->ready = true; > + > + return 0; > +} > + > +static void fdt_add_reserved_memory(VirtMachineState *vms) > +{ > + MachineState *ms = MACHINE(vms); > + hwaddr membase = vms->memmap[VIRT_MEM].base; > + hwaddr memsize = ms->ram_size; > + hwaddr resv_start; > + const char compat[] = "restricted-dma-pool"; > + const AccelOpsClass *ops = cpus_get_accel(); > + char *nodename; > + > + if (!acg || !acg->swiotlb_size) { > + return; > + } > + > + nodename = g_strdup_printf("/reserved-memory"); > + > + qemu_fdt_add_subnode(ms->fdt, nodename); > + qemu_fdt_setprop_cell(ms->fdt, nodename, "#address-cells", 2); > + qemu_fdt_setprop_cell(ms->fdt, nodename, "#size-cells", 2); > + qemu_fdt_setprop(ms->fdt, nodename, "ranges", NULL, 0); > + g_free(nodename); > + > + resv_start = membase + memsize - acg->swiotlb_size; > + if (ops->check_capability && > + > ops->check_capability(CONFIDENTIAL_GUEST_CAN_SHARE_MEM_WITH_HOST)) { > + /* > + * Indicate only the size of swiotlb buffer needed. Guest will > + * determine where in its private memory the buffer will be placed > and > + * will use appropriate (hypervisor) APIs to share that with host. > + */ > + nodename = > g_strdup_printf("/reserved-memory/restricted_dma_reserved"); > + qemu_fdt_add_subnode(ms->fdt, nodename); > + qemu_fdt_setprop_cell(ms->fdt, nodename, "size", acg->swiotlb_size); > + qemu_fdt_setprop_cell(ms->fdt, nodename, "alignment", 4096); > + } else { > + /* > + * On hypervisors that don't support APIs for guest to share > + * its (private) memory with host, indicate to the guest where in its > + * address space shared memory can be found. Host should make > arrangents > + * with hypervisor to assign some memory to guest at the indicated > range > + * and mark it as shared. > + */ > + nodename = > g_strdup_printf("/reserved-memory/restricted_dma_reserved@%" > + PRIx64, resv_start); > + qemu_fdt_add_subnode(ms->fdt, nodename); > + qemu_fdt_setprop_sized_cells(ms->fdt, nodename, "reg", > + 2, resv_start, > + 2, acg->swiotlb_size); > + } > + > + vms->restricted_dma_phandle = qemu_fdt_alloc_phandle(ms->fdt); > + qemu_fdt_setprop_cell(ms->fdt, nodename, "phandle", > + vms->restricted_dma_phandle); > + qemu_fdt_setprop(ms->fdt, nodename, "compatible", compat, > sizeof(compat)); > + g_free(nodename); > +} > + > static void machvirt_init(MachineState *machine) > { > VirtMachineState *vms = VIRT_MACHINE(machine); > @@ -2075,7 +2206,7 @@ static void machvirt_init(MachineState *machine) > MemoryRegion *secure_sysmem = NULL; > MemoryRegion *tag_sysmem = NULL; > MemoryRegion *secure_tag_sysmem = NULL; > - int n, virt_max_cpus; > + int n, virt_max_cpus, ret; > bool firmware_loaded; > bool aarch64 = true; > bool has_ged = !vmc->no_ged; > @@ -2084,6 +2215,12 @@ static void machvirt_init(MachineState *machine) > > possible_cpus = mc->possible_cpu_arch_ids(machine); > > + ret = confidential_guest_init(machine); > + if (ret != 0) { > + error_report("Failed to initialize confidential guest"); > + exit(1); > + } > + > /* > * In accelerated mode, the memory map is computed earlier in kvm_type() > * to create a VM with the right number of IPA bits. > @@ -2195,6 +2332,8 @@ static void machvirt_init(MachineState *machine) > > create_fdt(vms); > > + fdt_add_reserved_memory(vms); > + > assert(possible_cpus->len == max_cpus); > for (n = 0; n < possible_cpus->len; n++) { > Object *cpuobj; > -- > 2.25.1 > > With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
