| Message ID | 20240322181116.1228416-16-pbonzini@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | x86, kvm: common confidential computing subset | expand |
On 22/3/24 19:11, Paolo Bonzini wrote: > KVM is introducing a new API to create confidential guests, which > will be used by TDX and SEV-SNP but is also available for SEV and > SEV-ES. The API uses the VM type argument to KVM_CREATE_VM to > identify which confidential computing technology to use. > > Since there are no other expected uses of VM types, delegate > mc->kvm_type() for x86 boards to the confidential-guest-support s/mc/cgs/ here and in subject? > object pointed to by ms->cgs. > > For example, if a sev-guest object is specified to confidential-guest-support, > like, > > qemu -machine ...,confidential-guest-support=sev0 \ > -object sev-guest,id=sev0,... > > it will check if a VM type KVM_X86_SEV_VM or KVM_X86_SEV_ES_VM > is supported, and if so use them together with the KVM_SEV_INIT2 > function of the KVM_MEMORY_ENCRYPT_OP ioctl. If not, it will fall back to > KVM_SEV_INIT and KVM_SEV_ES_INIT. > > This is a preparatory work towards TDX and SEV-SNP support, but it > will also enable support for VMSA features such as DebugSwap, which > are only available via KVM_SEV_INIT2. > > Co-developed-by: Xiaoyao Li <xiaoyao.li@intel.com> > Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com> > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> > --- > target/i386/confidential-guest.h | 19 ++++++++++++++ > target/i386/kvm/kvm_i386.h | 2 ++ > hw/i386/x86.c | 11 ++++++++ > target/i386/kvm/kvm.c | 44 ++++++++++++++++++++++++++++++++ > 4 files changed, 76 insertions(+)
On Mon, Mar 25, 2024 at 10:29 AM Philippe Mathieu-Daudé <philmd@linaro.org> wrote: > > On 22/3/24 19:11, Paolo Bonzini wrote: > > KVM is introducing a new API to create confidential guests, which > > will be used by TDX and SEV-SNP but is also available for SEV and > > SEV-ES. The API uses the VM type argument to KVM_CREATE_VM to > > identify which confidential computing technology to use. > > > > Since there are no other expected uses of VM types, delegate > > mc->kvm_type() for x86 boards to the confidential-guest-support > > s/mc/cgs/ here and in subject? No, this refers to x86_kvm_type(), which is the implementation mc->kvm_type. As the commit message says, mc->kvm_type() is delegated to cgs->kvm_type(), via kvm_get_vm_type(). Paolo > > object pointed to by ms->cgs. > > > > For example, if a sev-guest object is specified to confidential-guest-support, > > like, > > > > qemu -machine ...,confidential-guest-support=sev0 \ > > -object sev-guest,id=sev0,... > > > > it will check if a VM type KVM_X86_SEV_VM or KVM_X86_SEV_ES_VM > > is supported, and if so use them together with the KVM_SEV_INIT2 > > function of the KVM_MEMORY_ENCRYPT_OP ioctl. If not, it will fall back to > > KVM_SEV_INIT and KVM_SEV_ES_INIT. > > > > This is a preparatory work towards TDX and SEV-SNP support, but it > > will also enable support for VMSA features such as DebugSwap, which > > are only available via KVM_SEV_INIT2. > > > > Co-developed-by: Xiaoyao Li <xiaoyao.li@intel.com> > > Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com> > > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> > > --- > > target/i386/confidential-guest.h | 19 ++++++++++++++ > > target/i386/kvm/kvm_i386.h | 2 ++ > > hw/i386/x86.c | 11 ++++++++ > > target/i386/kvm/kvm.c | 44 ++++++++++++++++++++++++++++++++ > > 4 files changed, 76 insertions(+) >
diff --git a/target/i386/confidential-guest.h b/target/i386/confidential-guest.h index ca12d5a8fba..532e172a60b 100644 --- a/target/i386/confidential-guest.h +++ b/target/i386/confidential-guest.h @@ -36,5 +36,24 @@ struct X86ConfidentialGuest { struct X86ConfidentialGuestClass { /* <private> */ ConfidentialGuestSupportClass parent; + + /* <public> */ + int (*kvm_type)(X86ConfidentialGuest *cg); }; + +/** + * x86_confidential_guest_kvm_type: + * + * Calls #X86ConfidentialGuestClass.unplug callback of @plug_handler. + */ +static inline int x86_confidential_guest_kvm_type(X86ConfidentialGuest *cg) +{ + X86ConfidentialGuestClass *klass = X86_CONFIDENTIAL_GUEST_GET_CLASS(cg); + + if (klass->kvm_type) { + return klass->kvm_type(cg); + } else { + return 0; + } +} #endif diff --git a/target/i386/kvm/kvm_i386.h b/target/i386/kvm/kvm_i386.h index 30fedcffea3..6b44844d95d 100644 --- a/target/i386/kvm/kvm_i386.h +++ b/target/i386/kvm/kvm_i386.h @@ -37,6 +37,7 @@ bool kvm_hv_vpindex_settable(void); bool kvm_enable_sgx_provisioning(KVMState *s); bool kvm_hyperv_expand_features(X86CPU *cpu, Error **errp); +int kvm_get_vm_type(MachineState *ms); void kvm_arch_reset_vcpu(X86CPU *cs); void kvm_arch_after_reset_vcpu(X86CPU *cpu); void kvm_arch_do_init_vcpu(X86CPU *cs); @@ -49,6 +50,7 @@ void kvm_request_xsave_components(X86CPU *cpu, uint64_t mask); #ifdef CONFIG_KVM +bool kvm_is_vm_type_supported(int type); bool kvm_has_adjust_clock_stable(void); bool kvm_has_exception_payload(void); void kvm_synchronize_all_tsc(void); diff --git a/hw/i386/x86.c b/hw/i386/x86.c index 84a48019770..3d5b51e92db 100644 --- a/hw/i386/x86.c +++ b/hw/i386/x86.c @@ -1381,6 +1381,16 @@ static void machine_set_sgx_epc(Object *obj, Visitor *v, const char *name, qapi_free_SgxEPCList(list); } +static int x86_kvm_type(MachineState *ms, const char *vm_type) +{ + /* + * No x86 machine has a kvm-type property. If one is added that has + * it, it should call kvm_get_vm_type() directly or not use it at all. + */ + assert(vm_type == NULL); + return kvm_enabled() ? kvm_get_vm_type(ms) : 0; +} + static void x86_machine_initfn(Object *obj) { X86MachineState *x86ms = X86_MACHINE(obj); @@ -1405,6 +1415,7 @@ static void x86_machine_class_init(ObjectClass *oc, void *data) mc->cpu_index_to_instance_props = x86_cpu_index_to_props; mc->get_default_cpu_node_id = x86_get_default_cpu_node_id; mc->possible_cpu_arch_ids = x86_possible_cpu_arch_ids; + mc->kvm_type = x86_kvm_type; x86mc->save_tsc_khz = true; x86mc->fwcfg_dma_enabled = true; nc->nmi_monitor_handler = x86_nmi; diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c index 0ec69109a2b..b599a7fae36 100644 --- a/target/i386/kvm/kvm.c +++ b/target/i386/kvm/kvm.c @@ -31,6 +31,7 @@ #include "sysemu/kvm_int.h" #include "sysemu/runstate.h" #include "kvm_i386.h" +#include "../confidential-guest.h" #include "sev.h" #include "xen-emu.h" #include "hyperv.h" @@ -161,6 +162,49 @@ static KVMMSRHandlers msr_handlers[KVM_MSR_FILTER_MAX_RANGES]; static RateLimit bus_lock_ratelimit_ctrl; static int kvm_get_one_msr(X86CPU *cpu, int index, uint64_t *value); +static const char *vm_type_name[] = { + [KVM_X86_DEFAULT_VM] = "default", +}; + +bool kvm_is_vm_type_supported(int type) +{ + uint32_t machine_types; + + /* + * old KVM doesn't support KVM_CAP_VM_TYPES but KVM_X86_DEFAULT_VM + * is always supported + */ + if (type == KVM_X86_DEFAULT_VM) { + return true; + } + + machine_types = kvm_check_extension(KVM_STATE(current_machine->accelerator), + KVM_CAP_VM_TYPES); + return !!(machine_types & BIT(type)); +} + +int kvm_get_vm_type(MachineState *ms) +{ + int kvm_type = KVM_X86_DEFAULT_VM; + + if (ms->cgs) { + if (!object_dynamic_cast(OBJECT(ms->cgs), TYPE_X86_CONFIDENTIAL_GUEST)) { + error_report("configuration type %s not supported for x86 guests", + object_get_typename(OBJECT(ms->cgs))); + exit(1); + } + kvm_type = x86_confidential_guest_kvm_type( + X86_CONFIDENTIAL_GUEST(ms->cgs)); + } + + if (!kvm_is_vm_type_supported(kvm_type)) { + error_report("vm-type %s not supported by KVM", vm_type_name[kvm_type]); + exit(1); + } + + return kvm_type; +} + bool kvm_has_smm(void) { return kvm_vm_check_extension(kvm_state, KVM_CAP_X86_SMM);
KVM is introducing a new API to create confidential guests, which will be used by TDX and SEV-SNP but is also available for SEV and SEV-ES. The API uses the VM type argument to KVM_CREATE_VM to identify which confidential computing technology to use. Since there are no other expected uses of VM types, delegate mc->kvm_type() for x86 boards to the confidential-guest-support object pointed to by ms->cgs. For example, if a sev-guest object is specified to confidential-guest-support, like, qemu -machine ...,confidential-guest-support=sev0 \ -object sev-guest,id=sev0,... it will check if a VM type KVM_X86_SEV_VM or KVM_X86_SEV_ES_VM is supported, and if so use them together with the KVM_SEV_INIT2 function of the KVM_MEMORY_ENCRYPT_OP ioctl. If not, it will fall back to KVM_SEV_INIT and KVM_SEV_ES_INIT. This is a preparatory work towards TDX and SEV-SNP support, but it will also enable support for VMSA features such as DebugSwap, which are only available via KVM_SEV_INIT2. Co-developed-by: Xiaoyao Li <xiaoyao.li@intel.com> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> --- target/i386/confidential-guest.h | 19 ++++++++++++++ target/i386/kvm/kvm_i386.h | 2 ++ hw/i386/x86.c | 11 ++++++++ target/i386/kvm/kvm.c | 44 ++++++++++++++++++++++++++++++++ 4 files changed, 76 insertions(+)