@@ -113,6 +113,7 @@
KVM_ARCH_REQ_FLAGS(31, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP)
#define KVM_REQ_HV_TLB_FLUSH \
KVM_ARCH_REQ_FLAGS(32, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP)
+#define KVM_REQ_UPDATE_PROTECTED_GUEST_STATE KVM_ARCH_REQ(34)
#define CR0_RESERVED_BITS \
(~(unsigned long)(X86_CR0_PE | X86_CR0_MP | X86_CR0_EM | X86_CR0_TS \
@@ -290,6 +290,11 @@ static_assert((X2AVIC_MAX_PHYSICAL_ID & AVIC_PHYSICAL_MAX_INDEX_MASK) == X2AVIC_
#define SVM_SEV_FEAT_DEBUG_SWAP BIT(5)
#define SVM_SEV_FEAT_SNP_ACTIVE BIT(0)
+#define SVM_SEV_FEAT_RESTRICTED_INJECTION BIT(3)
+#define SVM_SEV_FEAT_ALTERNATE_INJECTION BIT(4)
+#define SVM_SEV_FEAT_INT_INJ_MODES \
+ (SVM_SEV_FEAT_RESTRICTED_INJECTION | \
+ SVM_SEV_FEAT_ALTERNATE_INJECTION)
struct vmcb_seg {
u16 selector;
@@ -650,6 +650,7 @@ static int sev_launch_update_data(struct kvm *kvm, struct kvm_sev_cmd *argp)
static int sev_es_sync_vmsa(struct vcpu_svm *svm)
{
+ struct kvm_sev_info *sev = &to_kvm_svm(svm->vcpu.kvm)->sev_info;
struct sev_es_save_area *save = svm->sev_es.vmsa;
/* Check some debug related fields before encrypting the VMSA */
@@ -698,6 +699,12 @@ static int sev_es_sync_vmsa(struct vcpu_svm *svm)
if (sev_snp_guest(svm->vcpu.kvm))
save->sev_features |= SVM_SEV_FEAT_SNP_ACTIVE;
+ /*
+ * Save the VMSA synced SEV features. For now, they are the same for
+ * all vCPUs, so just save each time.
+ */
+ sev->sev_features = save->sev_features;
+
pr_debug("Virtual Machine Save Area (VMSA):\n");
print_hex_dump_debug("", DUMP_PREFIX_NONE, 16, 1, save, sizeof(*save), false);
@@ -3076,6 +3083,11 @@ static int sev_es_validate_vmgexit(struct vcpu_svm *svm)
if (!kvm_ghcb_sw_scratch_is_valid(svm))
goto vmgexit_err;
break;
+ case SVM_VMGEXIT_AP_CREATION:
+ if (lower_32_bits(control->exit_info_1) != SVM_VMGEXIT_AP_DESTROY)
+ if (!kvm_ghcb_rax_is_valid(svm))
+ goto vmgexit_err;
+ break;
case SVM_VMGEXIT_NMI_COMPLETE:
case SVM_VMGEXIT_AP_HLT_LOOP:
case SVM_VMGEXIT_AP_JUMP_TABLE:
@@ -3295,6 +3307,202 @@ static int snp_complete_psc(struct kvm_vcpu *vcpu)
return 1; /* resume */
}
+static int __sev_snp_update_protected_guest_state(struct kvm_vcpu *vcpu)
+{
+ struct vcpu_svm *svm = to_svm(vcpu);
+ hpa_t cur_pa;
+
+ WARN_ON(!mutex_is_locked(&svm->sev_es.snp_vmsa_mutex));
+
+ /* Save off the current VMSA PA for later checks */
+ cur_pa = svm->sev_es.vmsa_pa;
+
+ /* Mark the vCPU as offline and not runnable */
+ vcpu->arch.pv.pv_unhalted = false;
+ vcpu->arch.mp_state = KVM_MP_STATE_HALTED;
+
+ /* Clear use of the VMSA */
+ svm->sev_es.vmsa_pa = INVALID_PAGE;
+ svm->vmcb->control.vmsa_pa = INVALID_PAGE;
+
+ /*
+ * sev->sev_es.vmsa holds the virtual address of the VMSA initially
+ * allocated by the host. If the guest specified a new a VMSA via
+ * AP_CREATION, it will have been pinned to avoid future issues
+ * with things like page migration support. Make sure to un-pin it
+ * before switching to a newer guest-specified VMSA.
+ */
+ if (cur_pa != __pa(svm->sev_es.vmsa) && VALID_PAGE(cur_pa))
+ kvm_release_pfn_dirty(__phys_to_pfn(cur_pa));
+
+ if (VALID_PAGE(svm->sev_es.snp_vmsa_gpa)) {
+ gfn_t gfn = gpa_to_gfn(svm->sev_es.snp_vmsa_gpa);
+ struct kvm_memory_slot *slot;
+ kvm_pfn_t pfn;
+
+ slot = gfn_to_memslot(vcpu->kvm, gfn);
+ if (!slot)
+ return -EINVAL;
+
+ /*
+ * The new VMSA will be private memory guest memory, so
+ * retrieve the PFN from the gmem backend, and leave the ref
+ * count of the associated folio elevated to ensure it won't
+ * ever be migrated.
+ */
+ if (kvm_gmem_get_pfn(vcpu->kvm, slot, gfn, &pfn, NULL))
+ return -EINVAL;
+
+ /* Use the new VMSA */
+ svm->sev_es.vmsa_pa = pfn_to_hpa(pfn);
+ svm->vmcb->control.vmsa_pa = svm->sev_es.vmsa_pa;
+
+ /* Mark the vCPU as runnable */
+ vcpu->arch.pv.pv_unhalted = false;
+ vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
+
+ svm->sev_es.snp_vmsa_gpa = INVALID_PAGE;
+ }
+
+ /*
+ * When replacing the VMSA during SEV-SNP AP creation,
+ * mark the VMCB dirty so that full state is always reloaded.
+ */
+ vmcb_mark_all_dirty(svm->vmcb);
+
+ return 0;
+}
+
+/*
+ * Invoked as part of svm_vcpu_reset() processing of an init event.
+ */
+void sev_snp_init_protected_guest_state(struct kvm_vcpu *vcpu)
+{
+ struct vcpu_svm *svm = to_svm(vcpu);
+ int ret;
+
+ if (!sev_snp_guest(vcpu->kvm))
+ return;
+
+ mutex_lock(&svm->sev_es.snp_vmsa_mutex);
+
+ if (!svm->sev_es.snp_ap_create)
+ goto unlock;
+
+ svm->sev_es.snp_ap_create = false;
+
+ ret = __sev_snp_update_protected_guest_state(vcpu);
+ if (ret)
+ vcpu_unimpl(vcpu, "snp: AP state update on init failed\n");
+
+unlock:
+ mutex_unlock(&svm->sev_es.snp_vmsa_mutex);
+}
+
+static int sev_snp_ap_creation(struct vcpu_svm *svm)
+{
+ struct kvm_sev_info *sev = &to_kvm_svm(svm->vcpu.kvm)->sev_info;
+ struct kvm_vcpu *vcpu = &svm->vcpu;
+ struct kvm_vcpu *target_vcpu;
+ struct vcpu_svm *target_svm;
+ unsigned int request;
+ unsigned int apic_id;
+ bool kick;
+ int ret;
+
+ request = lower_32_bits(svm->vmcb->control.exit_info_1);
+ apic_id = upper_32_bits(svm->vmcb->control.exit_info_1);
+
+ /* Validate the APIC ID */
+ target_vcpu = kvm_get_vcpu_by_id(vcpu->kvm, apic_id);
+ if (!target_vcpu) {
+ vcpu_unimpl(vcpu, "vmgexit: invalid AP APIC ID [%#x] from guest\n",
+ apic_id);
+ return -EINVAL;
+ }
+
+ ret = 0;
+
+ target_svm = to_svm(target_vcpu);
+
+ /*
+ * The target vCPU is valid, so the vCPU will be kicked unless the
+ * request is for CREATE_ON_INIT. For any errors at this stage, the
+ * kick will place the vCPU in an non-runnable state.
+ */
+ kick = true;
+
+ mutex_lock(&target_svm->sev_es.snp_vmsa_mutex);
+
+ target_svm->sev_es.snp_vmsa_gpa = INVALID_PAGE;
+ target_svm->sev_es.snp_ap_create = true;
+
+ /* Interrupt injection mode shouldn't change for AP creation */
+ if (request < SVM_VMGEXIT_AP_DESTROY) {
+ u64 sev_features;
+
+ sev_features = vcpu->arch.regs[VCPU_REGS_RAX];
+ sev_features ^= sev->sev_features;
+ if (sev_features & SVM_SEV_FEAT_INT_INJ_MODES) {
+ vcpu_unimpl(vcpu, "vmgexit: invalid AP injection mode [%#lx] from guest\n",
+ vcpu->arch.regs[VCPU_REGS_RAX]);
+ ret = -EINVAL;
+ goto out;
+ }
+ }
+
+ switch (request) {
+ case SVM_VMGEXIT_AP_CREATE_ON_INIT:
+ kick = false;
+ fallthrough;
+ case SVM_VMGEXIT_AP_CREATE:
+ if (!page_address_valid(vcpu, svm->vmcb->control.exit_info_2)) {
+ vcpu_unimpl(vcpu, "vmgexit: invalid AP VMSA address [%#llx] from guest\n",
+ svm->vmcb->control.exit_info_2);
+ ret = -EINVAL;
+ goto out;
+ }
+
+ /*
+ * Malicious guest can RMPADJUST a large page into VMSA which
+ * will hit the SNP erratum where the CPU will incorrectly signal
+ * an RMP violation #PF if a hugepage collides with the RMP entry
+ * of VMSA page, reject the AP CREATE request if VMSA address from
+ * guest is 2M aligned.
+ */
+ if (IS_ALIGNED(svm->vmcb->control.exit_info_2, PMD_SIZE)) {
+ vcpu_unimpl(vcpu,
+ "vmgexit: AP VMSA address [%llx] from guest is unsafe as it is 2M aligned\n",
+ svm->vmcb->control.exit_info_2);
+ ret = -EINVAL;
+ goto out;
+ }
+
+ target_svm->sev_es.snp_vmsa_gpa = svm->vmcb->control.exit_info_2;
+ break;
+ case SVM_VMGEXIT_AP_DESTROY:
+ break;
+ default:
+ vcpu_unimpl(vcpu, "vmgexit: invalid AP creation request [%#x] from guest\n",
+ request);
+ ret = -EINVAL;
+ break;
+ }
+
+out:
+ if (kick) {
+ if (target_vcpu->arch.mp_state == KVM_MP_STATE_UNINITIALIZED)
+ target_vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
+
+ kvm_make_request(KVM_REQ_UPDATE_PROTECTED_GUEST_STATE, target_vcpu);
+ kvm_vcpu_kick(target_vcpu);
+ }
+
+ mutex_unlock(&target_svm->sev_es.snp_vmsa_mutex);
+
+ return ret;
+}
+
static int sev_handle_vmgexit_msr_protocol(struct vcpu_svm *svm)
{
struct vmcb_control_area *control = &svm->vmcb->control;
@@ -3545,6 +3753,15 @@ int sev_handle_vmgexit(struct kvm_vcpu *vcpu)
vcpu->run->vmgexit.ghcb_msr = ghcb_gpa;
vcpu->arch.complete_userspace_io = snp_complete_psc;
break;
+ case SVM_VMGEXIT_AP_CREATION:
+ ret = sev_snp_ap_creation(svm);
+ if (ret) {
+ ghcb_set_sw_exit_info_1(svm->sev_es.ghcb, 2);
+ ghcb_set_sw_exit_info_2(svm->sev_es.ghcb, GHCB_ERR_INVALID_INPUT);
+ }
+
+ ret = 1;
+ break;
case SVM_VMGEXIT_UNSUPPORTED_EVENT:
vcpu_unimpl(vcpu,
"vmgexit: unsupported event - exit_info_1=%#llx, exit_info_2=%#llx\n",
@@ -3711,6 +3928,8 @@ void sev_es_vcpu_reset(struct vcpu_svm *svm)
set_ghcb_msr(svm, GHCB_MSR_SEV_INFO(GHCB_VERSION_MAX,
GHCB_VERSION_MIN,
sev_enc_bit));
+
+ mutex_init(&svm->sev_es.snp_vmsa_mutex);
}
void sev_es_prepare_switch_to_guest(struct sev_es_save_area *hostsa)
@@ -1402,6 +1402,9 @@ static void svm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
svm->spec_ctrl = 0;
svm->virt_spec_ctrl = 0;
+ if (init_event)
+ sev_snp_init_protected_guest_state(vcpu);
+
init_vmcb(vcpu);
if (!init_event)
@@ -96,6 +96,7 @@ struct kvm_sev_info {
atomic_t migration_in_progress;
u64 snp_init_flags;
void *snp_context; /* SNP guest context page */
+ u64 sev_features; /* Features set at VMSA creation */
};
struct kvm_svm {
@@ -212,6 +213,10 @@ struct vcpu_sev_es_state {
bool ghcb_sa_free;
u64 ghcb_registered_gpa;
+
+ struct mutex snp_vmsa_mutex; /* Used to handle concurrent updates of VMSA. */
+ gpa_t snp_vmsa_gpa;
+ bool snp_ap_create;
};
struct vcpu_svm {
@@ -687,7 +692,7 @@ void avic_refresh_virtual_apic_mode(struct kvm_vcpu *vcpu);
#define GHCB_VERSION_MAX 2ULL
#define GHCB_VERSION_MIN 1ULL
-#define GHCB_HV_FT_SUPPORTED GHCB_HV_FT_SNP
+#define GHCB_HV_FT_SUPPORTED (GHCB_HV_FT_SNP | GHCB_HV_FT_SNP_AP_CREATION)
extern unsigned int max_sev_asid;
@@ -717,6 +722,7 @@ void sev_es_prepare_switch_to_guest(struct sev_es_save_area *hostsa);
void sev_es_unmap_ghcb(struct vcpu_svm *svm);
struct page *snp_safe_alloc_page(struct kvm_vcpu *vcpu);
void handle_rmp_page_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u64 error_code);
+void sev_snp_init_protected_guest_state(struct kvm_vcpu *vcpu);
/* vmenter.S */
@@ -10660,6 +10660,14 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
if (kvm_check_request(KVM_REQ_UPDATE_CPU_DIRTY_LOGGING, vcpu))
static_call(kvm_x86_update_cpu_dirty_logging)(vcpu);
+
+ if (kvm_check_request(KVM_REQ_UPDATE_PROTECTED_GUEST_STATE, vcpu)) {
+ kvm_vcpu_reset(vcpu, true);
+ if (vcpu->arch.mp_state != KVM_MP_STATE_RUNNABLE) {
+ r = 1;
+ goto out;
+ }
+ }
}
if (kvm_check_request(KVM_REQ_EVENT, vcpu) || req_int_win ||
@@ -12871,6 +12879,9 @@ static inline bool kvm_vcpu_has_events(struct kvm_vcpu *vcpu)
return true;
#endif
+ if (kvm_test_request(KVM_REQ_UPDATE_PROTECTED_GUEST_STATE, vcpu))
+ return true;
+
if (kvm_arch_interrupt_allowed(vcpu) &&
(kvm_cpu_has_interrupt(vcpu) ||
kvm_guest_apic_has_interrupt(vcpu)))