| Message ID | 20231115071519.2864957-5-xiaoyao.li@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | QEMU Guest memfd + QEMU TDX support | expand |
On 15.11.23 08:14, Xiaoyao Li wrote: > Add a new member "require_guest_memfd" to memory backends. When it's set > to true, it enables RAM_GUEST_MEMFD in ram_flags, thus private kvm > guest_memfd will be allocated during RAMBlock allocation. > > Memory backend's @require_guest_memfd is wired with @require_guest_memfd > field of MachineState. MachineState::require_guest_memfd is supposed to > be set by any VMs that requires KVM guest memfd as private memory, e.g., > TDX VM. > > Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com> I'm confused, why do we need this if it's going to be the same for all memory backends right now?
On 11/16/2023 2:14 AM, David Hildenbrand wrote: > On 15.11.23 08:14, Xiaoyao Li wrote: >> Add a new member "require_guest_memfd" to memory backends. When it's set >> to true, it enables RAM_GUEST_MEMFD in ram_flags, thus private kvm >> guest_memfd will be allocated during RAMBlock allocation. >> >> Memory backend's @require_guest_memfd is wired with @require_guest_memfd >> field of MachineState. MachineState::require_guest_memfd is supposed to >> be set by any VMs that requires KVM guest memfd as private memory, e.g., >> TDX VM. >> >> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com> > > I'm confused, why do we need this if it's going to be the same for all > memory backends right now? > I want to provide a elegant (in my sense) way to configure "the need of guest memfd" instead of checking x86machinestate->vm_type in physmem.c
On 16.11.23 03:53, Xiaoyao Li wrote: > On 11/16/2023 2:14 AM, David Hildenbrand wrote: >> On 15.11.23 08:14, Xiaoyao Li wrote: >>> Add a new member "require_guest_memfd" to memory backends. When it's set >>> to true, it enables RAM_GUEST_MEMFD in ram_flags, thus private kvm >>> guest_memfd will be allocated during RAMBlock allocation. >>> >>> Memory backend's @require_guest_memfd is wired with @require_guest_memfd >>> field of MachineState. MachineState::require_guest_memfd is supposed to >>> be set by any VMs that requires KVM guest memfd as private memory, e.g., >>> TDX VM. >>> >>> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com> >> >> I'm confused, why do we need this if it's going to be the same for all >> memory backends right now? >> > > I want to provide a elegant (in my sense) way to configure "the need of > guest memfd" instead of checking x86machinestate->vm_type in physmem.c > It's suboptimal right now, but I guess you want to avoid looking up the machine e.g., in ram_backend_memory_alloc(). I'd suggest s/require_guest_memfd/guest_memfd/gc in "struct HostMemoryBackend". Apart from that LGTM.
On 11/20/2023 5:30 PM, David Hildenbrand wrote: > On 16.11.23 03:53, Xiaoyao Li wrote: >> On 11/16/2023 2:14 AM, David Hildenbrand wrote: >>> On 15.11.23 08:14, Xiaoyao Li wrote: >>>> Add a new member "require_guest_memfd" to memory backends. When it's >>>> set >>>> to true, it enables RAM_GUEST_MEMFD in ram_flags, thus private kvm >>>> guest_memfd will be allocated during RAMBlock allocation. >>>> >>>> Memory backend's @require_guest_memfd is wired with >>>> @require_guest_memfd >>>> field of MachineState. MachineState::require_guest_memfd is supposed to >>>> be set by any VMs that requires KVM guest memfd as private memory, >>>> e.g., >>>> TDX VM. >>>> >>>> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com> >>> >>> I'm confused, why do we need this if it's going to be the same for all >>> memory backends right now? >>> >> >> I want to provide a elegant (in my sense) way to configure "the need of >> guest memfd" instead of checking x86machinestate->vm_type in physmem.c >> > > It's suboptimal right now, but I guess you want to avoid looking up the > machine e.g., in ram_backend_memory_alloc(). > > I'd suggest s/require_guest_memfd/guest_memfd/gc in "struct > HostMemoryBackend". sure! > Apart from that LGTM. >
diff --git a/backends/hostmem-file.c b/backends/hostmem-file.c index 361d4a8103ef..d5ea2879f321 100644 --- a/backends/hostmem-file.c +++ b/backends/hostmem-file.c @@ -84,6 +84,7 @@ file_backend_memory_alloc(HostMemoryBackend *backend, Error **errp) ram_flags |= fb->readonly ? RAM_READONLY_FD : 0; ram_flags |= fb->rom == ON_OFF_AUTO_ON ? RAM_READONLY : 0; ram_flags |= backend->reserve ? 0 : RAM_NORESERVE; + ram_flags |= backend->require_guest_memfd ? RAM_GUEST_MEMFD : 0; ram_flags |= fb->is_pmem ? RAM_PMEM : 0; ram_flags |= RAM_NAMED_FILE; memory_region_init_ram_from_file(&backend->mr, OBJECT(backend), name, diff --git a/backends/hostmem-memfd.c b/backends/hostmem-memfd.c index 3fc85c3db81b..011e2311f088 100644 --- a/backends/hostmem-memfd.c +++ b/backends/hostmem-memfd.c @@ -55,6 +55,7 @@ memfd_backend_memory_alloc(HostMemoryBackend *backend, Error **errp) name = host_memory_backend_get_name(backend); ram_flags = backend->share ? RAM_SHARED : 0; ram_flags |= backend->reserve ? 0 : RAM_NORESERVE; + ram_flags |= backend->require_guest_memfd ? RAM_GUEST_MEMFD : 0; memory_region_init_ram_from_fd(&backend->mr, OBJECT(backend), name, backend->size, ram_flags, fd, 0, errp); g_free(name); diff --git a/backends/hostmem-ram.c b/backends/hostmem-ram.c index b8e55cdbd0f8..7d2e1327f8c8 100644 --- a/backends/hostmem-ram.c +++ b/backends/hostmem-ram.c @@ -30,6 +30,7 @@ ram_backend_memory_alloc(HostMemoryBackend *backend, Error **errp) name = host_memory_backend_get_name(backend); ram_flags = backend->share ? RAM_SHARED : 0; ram_flags |= backend->reserve ? 0 : RAM_NORESERVE; + ram_flags |= backend->require_guest_memfd ? RAM_GUEST_MEMFD : 0; memory_region_init_ram_flags_nomigrate(&backend->mr, OBJECT(backend), name, backend->size, ram_flags, errp); g_free(name); diff --git a/backends/hostmem.c b/backends/hostmem.c index 747e7838c031..2deb2b78bcb8 100644 --- a/backends/hostmem.c +++ b/backends/hostmem.c @@ -279,6 +279,7 @@ static void host_memory_backend_init(Object *obj) /* TODO: convert access to globals to compat properties */ backend->merge = machine_mem_merge(machine); backend->dump = machine_dump_guest_core(machine); + backend->require_guest_memfd = machine_require_guest_memfd(machine); backend->reserve = true; backend->prealloc_threads = machine->smp.cpus; } diff --git a/hw/core/machine.c b/hw/core/machine.c index 0c1739814124..b1b0a46ea52f 100644 --- a/hw/core/machine.c +++ b/hw/core/machine.c @@ -1189,6 +1189,11 @@ bool machine_mem_merge(MachineState *machine) return machine->mem_merge; } +bool machine_require_guest_memfd(MachineState *machine) +{ + return machine->require_guest_memfd; +} + static char *cpu_slot_to_string(const CPUArchId *cpu) { GString *s = g_string_new(NULL); diff --git a/include/hw/boards.h b/include/hw/boards.h index a7359992980a..227aded07209 100644 --- a/include/hw/boards.h +++ b/include/hw/boards.h @@ -30,6 +30,7 @@ bool machine_usb(MachineState *machine); int machine_phandle_start(MachineState *machine); bool machine_dump_guest_core(MachineState *machine); bool machine_mem_merge(MachineState *machine); +bool machine_require_guest_memfd(MachineState *machine); HotpluggableCPUList *machine_query_hotpluggable_cpus(MachineState *machine); void machine_set_cpu_numa_node(MachineState *machine, const CpuInstanceProperties *props, @@ -364,6 +365,7 @@ struct MachineState { char *dt_compatible; bool dump_guest_core; bool mem_merge; + bool require_guest_memfd; bool usb; bool usb_disabled; char *firmware; diff --git a/include/sysemu/hostmem.h b/include/sysemu/hostmem.h index 39326f1d4f9c..92f7fd469639 100644 --- a/include/sysemu/hostmem.h +++ b/include/sysemu/hostmem.h @@ -66,6 +66,7 @@ struct HostMemoryBackend { uint64_t size; bool merge, dump, use_canonical_path; bool prealloc, is_mapped, share, reserve; + bool require_guest_memfd; uint32_t prealloc_threads; ThreadContext *prealloc_context; DECLARE_BITMAP(host_nodes, MAX_NODES + 1);
Add a new member "require_guest_memfd" to memory backends. When it's set to true, it enables RAM_GUEST_MEMFD in ram_flags, thus private kvm guest_memfd will be allocated during RAMBlock allocation. Memory backend's @require_guest_memfd is wired with @require_guest_memfd field of MachineState. MachineState::require_guest_memfd is supposed to be set by any VMs that requires KVM guest memfd as private memory, e.g., TDX VM. Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com> --- backends/hostmem-file.c | 1 + backends/hostmem-memfd.c | 1 + backends/hostmem-ram.c | 1 + backends/hostmem.c | 1 + hw/core/machine.c | 5 +++++ include/hw/boards.h | 2 ++ include/sysemu/hostmem.h | 1 + 7 files changed, 12 insertions(+)