From patchwork Tue Aug 13 15:01:18 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roy Hopkins X-Patchwork-Id: 13762184 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D4C2AC531DD for ; Tue, 13 Aug 2024 15:02:52 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sdt1z-00046c-Q1; Tue, 13 Aug 2024 11:01:51 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sdt1y-00041G-FG for qemu-devel@nongnu.org; Tue, 13 Aug 2024 11:01:50 -0400 Received: from smtp-out1.suse.de ([195.135.223.130]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1sdt1w-0002Fd-Dg for qemu-devel@nongnu.org; Tue, 13 Aug 2024 11:01:50 -0400 Received: from imap1.dmz-prg2.suse.org (imap1.dmz-prg2.suse.org [IPv6:2a07:de40:b281:104:10:150:64:97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 2B21922831; Tue, 13 Aug 2024 15:01:47 +0000 (UTC) Authentication-Results: smtp-out1.suse.de; none Received: from imap1.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id 5BCE413ADB; Tue, 13 Aug 2024 15:01:46 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id iJlCFFp1u2Z/NAAAD6G6ig (envelope-from ); Tue, 13 Aug 2024 15:01:46 +0000 To: qemu-devel@nongnu.org Cc: Roy Hopkins , Paolo Bonzini , =?utf-8?q?Daniel_P_=2E_Berrang=C3=A9?= , Stefano Garzarella , Marcelo Tosatti , "Michael S . Tsirkin" , Cornelia Huck , Marcel Apfelbaum , Sergio Lopez , Eduardo Habkost , Alistair Francis , Peter Xu , David Hildenbrand , Igor Mammedov , Tom Lendacky , Michael Roth , Ani Sinha , =?utf-8?q?J=C3=B6rg_Roedel?= Subject: [PATCH v5 16/16] sev: Provide sev_features flags from IGVM VMSA to KVM_SEV_INIT2 Date: Tue, 13 Aug 2024 16:01:18 +0100 Message-ID: <1e7ce4cc6112d888206290155e30dca5a7ef382b.1723560001.git.roy.hopkins@suse.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: References: MIME-Version: 1.0 X-Rspamd-Pre-Result: action=no action; module=replies; Message is reply to one we originated X-Spamd-Result: default: False [-4.00 / 50.00]; REPLY(-4.00)[]; TAGGED_RCPT(0.00)[] X-Rspamd-Queue-Id: 2B21922831 X-Rspamd-Pre-Result: action=no action; module=replies; Message is reply to one we originated X-Rspamd-Action: no action X-Rspamd-Server: rspamd1.dmz-prg2.suse.org Received-SPF: pass client-ip=195.135.223.130; envelope-from=roy.hopkins@suse.com; helo=smtp-out1.suse.de X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-to: Roy Hopkins X-Patchwork-Original-From: Roy Hopkins via From: Roy Hopkins Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org IGVM files can contain an initial VMSA that should be applied to each vcpu as part of the initial guest state. The sev_features flags are provided as part of the VMSA structure. However, KVM only allows sev_features to be set during initialization and not as the guest is being prepared for launch. This patch queries KVM for the supported set of sev_features flags and processes the IGVM file during kvm_init to determine any sev_features flags set in the IGVM file. These are then provided in the call to KVM_SEV_INIT2 to ensure the guest state matches that specified in the IGVM file. This does cause the IGVM file to be processed twice. Firstly to extract the sev_features then secondly to actually configure the guest. However, the first pass is largely ignored meaning the overhead is minimal. Signed-off-by: Roy Hopkins Acked-by: Michael S. Tsirkin --- target/i386/sev.c | 160 ++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 141 insertions(+), 19 deletions(-) diff --git a/target/i386/sev.c b/target/i386/sev.c index 8af3c785d3..578c4c5ea8 100644 --- a/target/i386/sev.c +++ b/target/i386/sev.c @@ -117,6 +117,8 @@ struct SevCommonState { uint32_t cbitpos; uint32_t reduced_phys_bits; bool kernel_hashes; + uint64_t sev_features; + uint64_t supported_sev_features; /* runtime state */ uint8_t api_major; @@ -492,7 +494,40 @@ static void sev_apply_cpu_context(CPUState *cpu) } } -static int check_vmsa_supported(hwaddr gpa, const struct sev_es_save_area *vmsa, +static int check_sev_features(SevCommonState *sev_common, uint64_t sev_features, + Error **errp) +{ + /* + * Ensure SEV_FEATURES is configured for correct SEV hardware and that + * the requested features are supported. If SEV-SNP is enabled then + * that feature must be enabled, otherwise it must be cleared. + */ + if (sev_snp_enabled() && !(sev_features & SVM_SEV_FEAT_SNP_ACTIVE)) { + error_setg( + errp, + "%s: SEV_SNP is enabled but is not enabled in VMSA sev_features", + __func__); + return -1; + } else if (!sev_snp_enabled() && + (sev_features & SVM_SEV_FEAT_SNP_ACTIVE)) { + error_setg( + errp, + "%s: SEV_SNP is not enabled but is enabled in VMSA sev_features", + __func__); + return -1; + } + if (sev_features & ~sev_common->supported_sev_features) { + error_setg(errp, + "%s: VMSA contains unsupported sev_features: %lX, " + "supported features: %lX", + __func__, sev_features, sev_common->supported_sev_features); + return -1; + } + return 0; +} + +static int check_vmsa_supported(SevCommonState *sev_common, hwaddr gpa, + const struct sev_es_save_area *vmsa, Error **errp) { struct sev_es_save_area vmsa_check; @@ -558,24 +593,10 @@ static int check_vmsa_supported(hwaddr gpa, const struct sev_es_save_area *vmsa, vmsa_check.x87_fcw = 0; vmsa_check.mxcsr = 0; - if (sev_snp_enabled()) { - if (vmsa_check.sev_features != SVM_SEV_FEAT_SNP_ACTIVE) { - error_setg(errp, - "%s: sev_features in the VMSA contains an unsupported " - "value. For SEV-SNP, sev_features must be set to %x.", - __func__, SVM_SEV_FEAT_SNP_ACTIVE); - return -1; - } - vmsa_check.sev_features = 0; - } else { - if (vmsa_check.sev_features != 0) { - error_setg(errp, - "%s: sev_features in the VMSA contains an unsupported " - "value. For SEV-ES and SEV, sev_features must be " - "set to 0.", __func__); - return -1; - } + if (check_sev_features(sev_common, vmsa_check.sev_features, errp) < 0) { + return -1; } + vmsa_check.sev_features = 0; if (!buffer_is_zero(&vmsa_check, sizeof(vmsa_check))) { error_setg(errp, @@ -1729,6 +1750,39 @@ static int sev_snp_kvm_type(X86ConfidentialGuest *cg) return KVM_X86_SNP_VM; } +static int sev_init_supported_features(ConfidentialGuestSupport *cgs, + SevCommonState *sev_common, Error **errp) +{ + X86ConfidentialGuestClass *x86_klass = + X86_CONFIDENTIAL_GUEST_GET_CLASS(cgs); + /* + * Older kernels do not support query or setting of sev_features. In this + * case the set of supported features must be zero to match the settings + * in the kernel. + */ + if (x86_klass->kvm_type(X86_CONFIDENTIAL_GUEST(sev_common)) == + KVM_X86_DEFAULT_VM) { + sev_common->supported_sev_features = 0; + return 0; + } + + /* Query KVM for the supported set of sev_features */ + struct kvm_device_attr attr = { + .group = KVM_X86_GRP_SEV, + .attr = KVM_X86_SEV_VMSA_FEATURES, + .addr = (unsigned long)&sev_common->supported_sev_features, + }; + if (kvm_ioctl(kvm_state, KVM_GET_DEVICE_ATTR, &attr) < 0) { + error_setg(errp, "%s: failed to query supported sev_features", + __func__); + return -1; + } + if (sev_snp_enabled()) { + sev_common->supported_sev_features |= SVM_SEV_FEAT_SNP_ACTIVE; + } + return 0; +} + static int sev_common_kvm_init(ConfidentialGuestSupport *cgs, Error **errp) { char *devname; @@ -1809,6 +1863,10 @@ static int sev_common_kvm_init(ConfidentialGuestSupport *cgs, Error **errp) } } + if (sev_init_supported_features(cgs, sev_common, errp) < 0) { + return -1; + } + trace_kvm_sev_init(); switch (x86_klass->kvm_type(X86_CONFIDENTIAL_GUEST(sev_common))) { case KVM_X86_DEFAULT_VM: @@ -1820,6 +1878,39 @@ static int sev_common_kvm_init(ConfidentialGuestSupport *cgs, Error **errp) case KVM_X86_SEV_ES_VM: case KVM_X86_SNP_VM: { struct kvm_sev_init args = { 0 }; + MachineState *machine = MACHINE(qdev_get_machine()); + X86MachineState *x86machine = X86_MACHINE(qdev_get_machine()); + + /* + * If configuration is provided via an IGVM file then the IGVM file + * might contain configuration of the initial vcpu context. For SEV + * the vcpu context includes the sev_features which should be applied + * to the vcpu. + * + * KVM does not synchronize sev_features from CPU state. Instead it + * requires sev_features to be provided as part of this initialization + * call which is subsequently automatically applied to the VMSA of + * each vcpu. + * + * The IGVM file is normally processed after initialization. Therefore + * we need to pre-process it here to extract sev_features in order to + * provide it to KVM_SEV_INIT2. Each cgs_* function that is called by + * the IGVM processor detects this pre-process by observing the state + * as SEV_STATE_UNINIT. + */ + if (x86machine->igvm) { + if (IGVM_CFG_GET_CLASS(x86machine->igvm) + ->process(x86machine->igvm, machine->cgs, errp) == -1) { + return -1; + } + /* + * KVM maintains a bitmask of allowed sev_features. This does not + * include SVM_SEV_FEAT_SNP_ACTIVE which is set accordingly by KVM + * itself. Therefore we need to clear this flag. + */ + args.vmsa_features = sev_common->sev_features & + ~SVM_SEV_FEAT_SNP_ACTIVE; + } ret = sev_ioctl(sev_common->sev_fd, KVM_SEV_INIT2, &args, &fw_error); break; @@ -2424,6 +2515,24 @@ static int cgs_set_guest_state(hwaddr gpa, uint8_t *ptr, uint64_t len, SevCommonState *sev_common = SEV_COMMON(MACHINE(qdev_get_machine())->cgs); SevCommonStateClass *klass = SEV_COMMON_GET_CLASS(sev_common); + if (sev_common->state == SEV_STATE_UNINIT) { + /* Pre-processing of IGVM file called from sev_common_kvm_init() */ + if ((cpu_index == 0) && (memory_type == CGS_PAGE_TYPE_VMSA)) { + const struct sev_es_save_area *sa = + (const struct sev_es_save_area *)ptr; + if (len < sizeof(*sa)) { + error_setg(errp, "%s: invalid VMSA length encountered", + __func__); + return -1; + } + if (check_sev_features(sev_common, sa->sev_features, errp) < 0) { + return -1; + } + sev_common->sev_features = sa->sev_features; + } + return 0; + } + if (!sev_enabled()) { error_setg(errp, "%s: attempt to configure guest memory, but SEV " "is not enabled", __func__); @@ -2443,7 +2552,8 @@ static int cgs_set_guest_state(hwaddr gpa, uint8_t *ptr, uint64_t len, __func__); return -1; } - if (check_vmsa_supported(gpa, (const struct sev_es_save_area *)ptr, + if (check_vmsa_supported(sev_common, gpa, + (const struct sev_es_save_area *)ptr, errp) < 0) { return -1; } @@ -2500,6 +2610,12 @@ static int cgs_get_mem_map_entry(int index, struct e820_entry *table; int num_entries; + SevCommonState *sev_common = SEV_COMMON(MACHINE(qdev_get_machine())->cgs); + if (sev_common->state == SEV_STATE_UNINIT) { + /* Pre-processing of IGVM file called from sev_common_kvm_init() */ + return 1; + } + num_entries = e820_get_table(&table); if ((index < 0) || (index >= num_entries)) { return 1; @@ -2531,6 +2647,12 @@ static int cgs_set_guest_policy(ConfidentialGuestPolicyType policy_type, uint32_t policy_data1_size, void *policy_data2, uint32_t policy_data2_size, Error **errp) { + SevCommonState *sev_common = SEV_COMMON(MACHINE(qdev_get_machine())->cgs); + if (sev_common->state == SEV_STATE_UNINIT) { + /* Pre-processing of IGVM file called from sev_common_kvm_init() */ + return 0; + } + if (policy_type != GUEST_POLICY_SEV) { error_setg(errp, "%s: Invalid guest policy type provided for SEV: %d", __func__, policy_type);