When in-place conversion is enabled, both the shared memory and private memory must come from the same guest_memfd instance. Thus, the memory-backend-memfd options must in turn correspond to a guest_memfd instance, e.g. guest-memfd=on must be specified. Since there is no use-case for enabling in-place conversion without setting guest-memfd=on, just set it automatically if in-place conversion is enabled.
Signed-off-by: Michael Roth <[email protected]> --- backends/hostmem-memfd.c | 34 ++++++++++++++++++++++++---------- qapi/qom.json | 5 +++-- 2 files changed, 27 insertions(+), 12 deletions(-) diff --git a/backends/hostmem-memfd.c b/backends/hostmem-memfd.c index de51cf738a..85ed973082 100644 --- a/backends/hostmem-memfd.c +++ b/backends/hostmem-memfd.c @@ -19,6 +19,9 @@ #include "qom/object.h" #include "migration/cpr.h" #include "system/kvm.h" +#include "qapi/qapi-visit-common.h" +#include "hw/core/boards.h" +#include "hw/core/qdev.h" OBJECT_DECLARE_SIMPLE_TYPE(HostMemoryBackendMemfd, MEMORY_BACKEND_MEMFD) @@ -35,7 +38,7 @@ struct HostMemoryBackendMemfd { * private pages. Instead, this flag marks the memory backend will * 100% use the guest-memfd pages in-place. */ - bool guest_memfd; + OnOffAuto guest_memfd; }; static bool @@ -43,6 +46,7 @@ memfd_backend_memory_alloc(HostMemoryBackend *backend, Error **errp) { HostMemoryBackendMemfd *m = MEMORY_BACKEND_MEMFD(backend); g_autofree char *name = host_memory_backend_get_name(backend); + MachineState *machine = MACHINE(qdev_get_machine()); int fd = cpr_find_fd(name, 0); uint32_t ram_flags; @@ -55,7 +59,9 @@ memfd_backend_memory_alloc(HostMemoryBackend *backend, Error **errp) goto have_fd; } - if (m->guest_memfd) { + if (m->guest_memfd == ON_OFF_AUTO_ON || + (m->guest_memfd == ON_OFF_AUTO_AUTO && + machine_require_guest_memfd_convert_in_place(machine))) { /* * NOTE: guest-memfd ignores seal=on/off because it always * implicitly seals the FD by definition. @@ -91,16 +97,24 @@ have_fd: backend->size, ram_flags, fd, 0, errp); } -static bool -memfd_backend_get_guest_memfd(Object *o, Error **errp) +static void +memfd_backend_get_guest_memfd(Object *o, Visitor *v, + const char *value, void *opaque, + Error **errp) { - return MEMORY_BACKEND_MEMFD(o)->guest_memfd; + HostMemoryBackendMemfd *m = MEMORY_BACKEND_MEMFD(o); + + visit_type_OnOffAuto(v, value, &m->guest_memfd, errp); } static void -memfd_backend_set_guest_memfd(Object *o, bool value, Error **errp) +memfd_backend_set_guest_memfd(Object *o, Visitor *v, + const char *value, void *opaque, + Error **errp) { - MEMORY_BACKEND_MEMFD(o)->guest_memfd = value; + HostMemoryBackendMemfd *m = MEMORY_BACKEND_MEMFD(o); + + visit_type_OnOffAuto(v, value, &m->guest_memfd, errp); } static bool @@ -191,9 +205,9 @@ memfd_backend_class_init(ObjectClass *oc, const void *data) "Huge pages size (ex: 2M, 1G)"); } - object_class_property_add_bool(oc, "guest-memfd", - memfd_backend_get_guest_memfd, - memfd_backend_set_guest_memfd); + object_class_property_add(oc, "guest-memfd", "OnOffAuto", + memfd_backend_get_guest_memfd, + memfd_backend_set_guest_memfd, NULL, NULL); object_class_property_set_description(oc, "guest-memfd", "Use guest memfd"); diff --git a/qapi/qom.json b/qapi/qom.json index 20d6fefb04..32df7cb794 100644 --- a/qapi/qom.json +++ b/qapi/qom.json @@ -772,7 +772,8 @@ # resizing of the memory (default: true) # # @guest-memfd: if true, use guest-memfd to back the memory region. -# (default: false, since: 11.2) +# (default: true for Confidential VMs with in-place conversion, +# false otherwise, since: 11.2) # # Since: 2.12 ## @@ -781,7 +782,7 @@ 'data': { '*hugetlb': 'bool', '*hugetlbsize': 'size', '*seal': 'bool', - '*guest-memfd': 'bool' }, + '*guest-memfd': 'OnOffAuto' }, 'if': 'CONFIG_LINUX' } ## -- 2.43.0
