From 6e6a6ca7d9097d1aa68089379cdaa7553dad7a25 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Fri, 24 Jul 2020 12:57:37 +1000 Subject: confidential guest support: Move side effect out of machine_set_memory_encryption() When the "memory-encryption" property is set, we also disable KSM merging for the guest, since it won't accomplish anything. We want that, but doing it in the property set function itself is thereoretically incorrect, in the unlikely event of some configuration environment that set the property then cleared it again before constructing the guest. More importantly, it makes some other cleanups we want more difficult. So, instead move this logic to machine_run_board_init() conditional on the final value of the property. Signed-off-by: David Gibson Reviewed-by: Richard Henderson Reviewed-by: Greg Kurz Reviewed-by: Cornelia Huck --- hw/core/machine.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) (limited to 'hw/core/machine.c') diff --git a/hw/core/machine.c b/hw/core/machine.c index 5d6163ab70..919067b5c9 100644 --- a/hw/core/machine.c +++ b/hw/core/machine.c @@ -437,14 +437,6 @@ static void machine_set_memory_encryption(Object *obj, const char *value, g_free(ms->memory_encryption); ms->memory_encryption = g_strdup(value); - - /* - * With memory encryption, the host can't see the real contents of RAM, - * so there's no point in it trying to merge areas. - */ - if (value) { - machine_set_mem_merge(obj, false, errp); - } } static bool machine_get_nvdimm(Object *obj, Error **errp) @@ -1166,6 +1158,15 @@ void machine_run_board_init(MachineState *machine) cc->deprecation_note); } + if (machine->memory_encryption) { + /* + * With memory encryption, the host can't see the real + * contents of RAM, so there's no point in it trying to merge + * areas. + */ + machine_set_mem_merge(OBJECT(machine), false, &error_abort); + } + machine_class->init(machine); phase_advance(PHASE_MACHINE_INITIALIZED); } -- cgit v1.2.3-55-g7522 From e0292d7c62673546c01d5c6b245735fdfef81840 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Fri, 4 Dec 2020 12:51:51 +1100 Subject: confidential guest support: Rework the "memory-encryption" property Currently the "memory-encryption" property is only looked at once we get to kvm_init(). Although protection of guest memory from the hypervisor isn't something that could really ever work with TCG, it's not conceptually tied to the KVM accelerator. In addition, the way the string property is resolved to an object is almost identical to how a QOM link property is handled. So, create a new "confidential-guest-support" link property which sets this QOM interface link directly in the machine. For compatibility we keep the "memory-encryption" property, but now implemented in terms of the new property. Signed-off-by: David Gibson Reviewed-by: Greg Kurz Reviewed-by: Cornelia Huck --- accel/kvm/kvm-all.c | 5 +++-- accel/kvm/sev-stub.c | 5 +++-- hw/core/machine.c | 43 +++++++++++++++++++++++++++++++++++++------ include/hw/boards.h | 2 +- include/sysemu/sev.h | 2 +- target/i386/sev.c | 32 ++------------------------------ 6 files changed, 47 insertions(+), 42 deletions(-) (limited to 'hw/core/machine.c') diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c index 3526e88b6c..88a6b8c19e 100644 --- a/accel/kvm/kvm-all.c +++ b/accel/kvm/kvm-all.c @@ -2184,8 +2184,9 @@ static int kvm_init(MachineState *ms) * if memory encryption object is specified then initialize the memory * encryption context. */ - if (ms->memory_encryption) { - ret = sev_guest_init(ms->memory_encryption); + if (ms->cgs) { + /* FIXME handle mechanisms other than SEV */ + ret = sev_kvm_init(ms->cgs); if (ret < 0) { goto err; } diff --git a/accel/kvm/sev-stub.c b/accel/kvm/sev-stub.c index 5db9ab8f00..3d4787ae4a 100644 --- a/accel/kvm/sev-stub.c +++ b/accel/kvm/sev-stub.c @@ -15,7 +15,8 @@ #include "qemu-common.h" #include "sysemu/sev.h" -int sev_guest_init(const char *id) +int sev_kvm_init(ConfidentialGuestSupport *cgs) { - return -1; + /* SEV can't be selected if it's not compiled */ + g_assert_not_reached(); } diff --git a/hw/core/machine.c b/hw/core/machine.c index 919067b5c9..f45a795478 100644 --- a/hw/core/machine.c +++ b/hw/core/machine.c @@ -32,6 +32,7 @@ #include "hw/mem/nvdimm.h" #include "migration/global_state.h" #include "migration/vmstate.h" +#include "exec/confidential-guest-support.h" GlobalProperty hw_compat_5_2[] = {}; const size_t hw_compat_5_2_len = G_N_ELEMENTS(hw_compat_5_2); @@ -427,16 +428,37 @@ static char *machine_get_memory_encryption(Object *obj, Error **errp) { MachineState *ms = MACHINE(obj); - return g_strdup(ms->memory_encryption); + if (ms->cgs) { + return g_strdup(object_get_canonical_path_component(OBJECT(ms->cgs))); + } + + return NULL; } static void machine_set_memory_encryption(Object *obj, const char *value, Error **errp) { - MachineState *ms = MACHINE(obj); + Object *cgs = + object_resolve_path_component(object_get_objects_root(), value); + + if (!cgs) { + error_setg(errp, "No such memory encryption object '%s'", value); + return; + } - g_free(ms->memory_encryption); - ms->memory_encryption = g_strdup(value); + object_property_set_link(obj, "confidential-guest-support", cgs, errp); +} + +static void machine_check_confidential_guest_support(const Object *obj, + const char *name, + Object *new_target, + Error **errp) +{ + /* + * So far the only constraint is that the target has the + * TYPE_CONFIDENTIAL_GUEST_SUPPORT interface, and that's checked + * by the QOM core + */ } static bool machine_get_nvdimm(Object *obj, Error **errp) @@ -836,6 +858,15 @@ static void machine_class_init(ObjectClass *oc, void *data) object_class_property_set_description(oc, "suppress-vmdesc", "Set on to disable self-describing migration"); + object_class_property_add_link(oc, "confidential-guest-support", + TYPE_CONFIDENTIAL_GUEST_SUPPORT, + offsetof(MachineState, cgs), + machine_check_confidential_guest_support, + OBJ_PROP_LINK_STRONG); + object_class_property_set_description(oc, "confidential-guest-support", + "Set confidential guest scheme to support"); + + /* For compatibility */ object_class_property_add_str(oc, "memory-encryption", machine_get_memory_encryption, machine_set_memory_encryption); object_class_property_set_description(oc, "memory-encryption", @@ -1158,9 +1189,9 @@ void machine_run_board_init(MachineState *machine) cc->deprecation_note); } - if (machine->memory_encryption) { + if (machine->cgs) { /* - * With memory encryption, the host can't see the real + * With confidential guests, the host can't see the real * contents of RAM, so there's no point in it trying to merge * areas. */ diff --git a/include/hw/boards.h b/include/hw/boards.h index 85af4faf76..a46dfe5d1a 100644 --- a/include/hw/boards.h +++ b/include/hw/boards.h @@ -270,7 +270,7 @@ struct MachineState { bool iommu; bool suppress_vmdesc; bool enable_graphics; - char *memory_encryption; + ConfidentialGuestSupport *cgs; char *ram_memdev_id; /* * convenience alias to ram_memdev_id backend memory region diff --git a/include/sysemu/sev.h b/include/sysemu/sev.h index 7335e59867..3b5b1aacf1 100644 --- a/include/sysemu/sev.h +++ b/include/sysemu/sev.h @@ -16,7 +16,7 @@ #include "sysemu/kvm.h" -int sev_guest_init(const char *id); +int sev_kvm_init(ConfidentialGuestSupport *cgs); int sev_encrypt_flash(uint8_t *ptr, uint64_t len, Error **errp); int sev_inject_launch_secret(const char *hdr, const char *secret, uint64_t gpa, Error **errp); diff --git a/target/i386/sev.c b/target/i386/sev.c index 8d4e1ea262..fa962d533c 100644 --- a/target/i386/sev.c +++ b/target/i386/sev.c @@ -335,26 +335,6 @@ static const TypeInfo sev_guest_info = { } }; -static SevGuestState * -lookup_sev_guest_info(const char *id) -{ - Object *obj; - SevGuestState *info; - - obj = object_resolve_path_component(object_get_objects_root(), id); - if (!obj) { - return NULL; - } - - info = (SevGuestState *) - object_dynamic_cast(obj, TYPE_SEV_GUEST); - if (!info) { - return NULL; - } - - return info; -} - bool sev_enabled(void) { @@ -682,10 +662,9 @@ sev_vm_state_change(void *opaque, int running, RunState state) } } -int -sev_guest_init(const char *id) +int sev_kvm_init(ConfidentialGuestSupport *cgs) { - SevGuestState *sev; + SevGuestState *sev = SEV_GUEST(cgs); char *devname; int ret, fw_error; uint32_t ebx; @@ -698,13 +677,6 @@ sev_guest_init(const char *id) return -1; } - sev = lookup_sev_guest_info(id); - if (!sev) { - error_report("%s: '%s' is not a valid '%s' object", - __func__, id, TYPE_SEV_GUEST); - goto err; - } - sev_guest = sev; sev->state = SEV_STATE_UNINIT; -- cgit v1.2.3-55-g7522 From 9f88a7a3df11a5aaa6212ea535d40d5f92561683 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Thu, 4 Jun 2020 14:20:24 +1000 Subject: confidential guest support: Alter virtio default properties for protected guests The default behaviour for virtio devices is not to use the platforms normal DMA paths, but instead to use the fact that it's running in a hypervisor to directly access guest memory. That doesn't work if the guest's memory is protected from hypervisor access, such as with AMD's SEV or POWER's PEF. So, if a confidential guest mechanism is enabled, then apply the iommu_platform=on option so it will go through normal DMA mechanisms. Those will presumably have some way of marking memory as shared with the hypervisor or hardware so that DMA will work. Signed-off-by: David Gibson Reviewed-by: Dr. David Alan Gilbert Reviewed-by: Cornelia Huck Reviewed-by: Greg Kurz --- hw/core/machine.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'hw/core/machine.c') diff --git a/hw/core/machine.c b/hw/core/machine.c index f45a795478..970046f438 100644 --- a/hw/core/machine.c +++ b/hw/core/machine.c @@ -33,6 +33,8 @@ #include "migration/global_state.h" #include "migration/vmstate.h" #include "exec/confidential-guest-support.h" +#include "hw/virtio/virtio.h" +#include "hw/virtio/virtio-pci.h" GlobalProperty hw_compat_5_2[] = {}; const size_t hw_compat_5_2_len = G_N_ELEMENTS(hw_compat_5_2); @@ -1196,6 +1198,17 @@ void machine_run_board_init(MachineState *machine) * areas. */ machine_set_mem_merge(OBJECT(machine), false, &error_abort); + + /* + * Virtio devices can't count on directly accessing guest + * memory, so they need iommu_platform=on to use normal DMA + * mechanisms. That requires also disabling legacy virtio + * support for those virtio pci devices which allow it. + */ + object_register_sugar_prop(TYPE_VIRTIO_PCI, "disable-legacy", + "on", true); + object_register_sugar_prop(TYPE_VIRTIO_DEVICE, "iommu_platform", + "on", false); } machine_class->init(machine); -- cgit v1.2.3-55-g7522