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Tue, 2 Aug 2022 13:19:55 +0000 (UTC) X-FDA: 79754710350.18.A7DD435 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf17.hostedemail.com (Postfix) with ESMTP id 978F4400FB for ; Tue, 2 Aug 2022 13:19:54 +0000 (UTC) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id C36376134A; Tue, 2 Aug 2022 13:19:53 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A4184C433D7; Tue, 2 Aug 2022 13:19:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1659446393; bh=QpcAUsewd/+KMI+EaDJ9tjM4TNeoV2RTu8Kl+bvpWxA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=IW6a0pBIbsC5aevWoSvnCQw/mnUVKyYeXk22PgTJrLMOVjWuVKvxYHoJNu+XaOHGT KX/BQQ3WevV4ImfzdxOhGW2VvY68hI7gVN/iEIHt4jCIbkg9PPG8z1MmmB0XAkbvIx KQj5HmrDrwJWCvn8lpneqdu+BnUuBHv4yyh2zAWwr6x4k3iPI0CUjrfehS0MDbVOHZ qWdDrluYFRNt0jpoza17eCzqQ5KF410Es93UkKJfyJ02SOiyeUoYdtuG6ixRfnaTeU yxaUdedITpu2h5PZVWrj3BGH71at0ojTMovVf9bB5drUTA7vDAfZRPzmjToDJTzB6R kGakJmiL3h0Dw== Date: Tue, 2 Aug 2022 16:19:49 +0300 From: Jarkko Sakkinen To: Ashish Kalra Cc: x86@kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-coco@lists.linux.dev, linux-mm@kvack.org, linux-crypto@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com, jroedel@suse.de, thomas.lendacky@amd.com, hpa@zytor.com, ardb@kernel.org, pbonzini@redhat.com, seanjc@google.com, vkuznets@redhat.com, jmattson@google.com, luto@kernel.org, dave.hansen@linux.intel.com, slp@redhat.com, pgonda@google.com, peterz@infradead.org, srinivas.pandruvada@linux.intel.com, rientjes@google.com, dovmurik@linux.ibm.com, tobin@ibm.com, bp@alien8.de, michael.roth@amd.com, vbabka@suse.cz, kirill@shutemov.name, ak@linux.intel.com, tony.luck@intel.com, marcorr@google.com, sathyanarayanan.kuppuswamy@linux.intel.com, alpergun@google.com, dgilbert@redhat.com Subject: Re: [PATCH Part2 v6 24/49] KVM: SVM: Add KVM_SEV_SNP_LAUNCH_START command Message-ID: References: <6d5c899030b113755e6c093e8bb9ad123280edc6.1655761627.git.ashish.kalra@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6d5c899030b113755e6c093e8bb9ad123280edc6.1655761627.git.ashish.kalra@amd.com> ARC-Authentication-Results: i=1; imf17.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=IW6a0pBI; spf=pass (imf17.hostedemail.com: domain of jarkko@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=jarkko@kernel.org; dmarc=pass (policy=none) header.from=kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1659446394; a=rsa-sha256; cv=none; b=M6X1wwmUZ6rb0UkpoQvFyUD1GDUIqnZ4NYVJMh3N0XRdsX+QwzVUcnrL5/u2KJncA5Jc0z 4JPmtcKf3jGiGqUtTxkYJ9nXwp4F8cL+eU6jVI9a3Ppq9XHRk9DsVHnF7gbgriYNc36938 YuGiLUl6zq6B8BBV2ModoaPyAOna9KU= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1659446394; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=wl/BFNqog6CYy/pdnLpBpcm/jPMLkXUcMKMLpu0Pfaw=; b=SbmvSWK2XwGKG0kDRZ/aznI/6EVmB/UNOTnnrkF2II69fTAVOYjOjYf74smI8BUvb/KtXy Wq98d3bcmqVU34Hq9AnulWgd7rx360Qpj/1Ul7HvZbWJWYSKKJmTEb7IA6T0I7vu1D0yPu SsrL5p29nv9cWl/7znDCfJiBYteV4kw= X-Stat-Signature: snuwhtyntom66agt8tba5169qbwxao6f X-Rspamd-Queue-Id: 978F4400FB X-Rspam-User: Authentication-Results: imf17.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=IW6a0pBI; spf=pass (imf17.hostedemail.com: domain of jarkko@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=jarkko@kernel.org; dmarc=pass (policy=none) header.from=kernel.org X-Rspamd-Server: rspam04 X-HE-Tag: 1659446394-863770 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, Jun 20, 2022 at 11:07:35PM +0000, Ashish Kalra wrote: > From: Brijesh Singh > > KVM_SEV_SNP_LAUNCH_START begins the launch process for an SEV-SNP guest. > The command initializes a cryptographic digest context used to construct > the measurement of the guest. If the guest is expected to be migrated, > the command also binds a migration agent (MA) to the guest. > > For more information see the SEV-SNP specification. > > Signed-off-by: Brijesh Singh > --- > .../virt/kvm/x86/amd-memory-encryption.rst | 24 ++++ > arch/x86/kvm/svm/sev.c | 115 +++++++++++++++++- > arch/x86/kvm/svm/svm.h | 1 + > include/uapi/linux/kvm.h | 10 ++ > 4 files changed, 147 insertions(+), 3 deletions(-) > > diff --git a/Documentation/virt/kvm/x86/amd-memory-encryption.rst b/Documentation/virt/kvm/x86/amd-memory-encryption.rst > index 903023f524af..878711f2dca6 100644 > --- a/Documentation/virt/kvm/x86/amd-memory-encryption.rst > +++ b/Documentation/virt/kvm/x86/amd-memory-encryption.rst > @@ -462,6 +462,30 @@ The flags bitmap is defined as:: > If the specified flags is not supported then return -EOPNOTSUPP, and the supported > flags are returned. > > +19. KVM_SNP_LAUNCH_START > +------------------------ > + > +The KVM_SNP_LAUNCH_START command is used for creating the memory encryption > +context for the SEV-SNP guest. To create the encryption context, user must > +provide a guest policy, migration agent (if any) and guest OS visible > +workarounds value as defined SEV-SNP specification. > + > +Parameters (in): struct kvm_snp_launch_start > + > +Returns: 0 on success, -negative on error > + > +:: > + > + struct kvm_sev_snp_launch_start { > + __u64 policy; /* Guest policy to use. */ > + __u64 ma_uaddr; /* userspace address of migration agent */ > + __u8 ma_en; /* 1 if the migtation agent is enabled */ > + __u8 imi_en; /* set IMI to 1. */ > + __u8 gosvw[16]; /* guest OS visible workarounds */ > + }; > + > +See the SEV-SNP specification for further detail on the launch input. > + > References > ========== > > diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c > index 813bda7f7b55..9e6fc7a94ed7 100644 > --- a/arch/x86/kvm/svm/sev.c > +++ b/arch/x86/kvm/svm/sev.c > @@ -21,6 +21,7 @@ > #include > #include > #include > +#include > > #include "x86.h" > #include "svm.h" > @@ -73,6 +74,8 @@ static unsigned int nr_asids; > static unsigned long *sev_asid_bitmap; > static unsigned long *sev_reclaim_asid_bitmap; > > +static int snp_decommission_context(struct kvm *kvm); > + > struct enc_region { > struct list_head list; > unsigned long npages; > @@ -98,12 +101,17 @@ static int sev_flush_asids(int min_asid, int max_asid) > down_write(&sev_deactivate_lock); > > wbinvd_on_all_cpus(); > - ret = sev_guest_df_flush(&error); > + > + if (sev_snp_enabled) > + ret = snp_guest_df_flush(&error); > + else > + ret = sev_guest_df_flush(&error); > > up_write(&sev_deactivate_lock); > > if (ret) > - pr_err("SEV: DF_FLUSH failed, ret=%d, error=%#x\n", ret, error); > + pr_err("SEV%s: DF_FLUSH failed, ret=%d, error=%#x\n", > + sev_snp_enabled ? "-SNP" : "", ret, error); > > return ret; > } > @@ -1825,6 +1833,74 @@ int sev_vm_move_enc_context_from(struct kvm *kvm, unsigned int source_fd) > return ret; > } > > +static void *snp_context_create(struct kvm *kvm, struct kvm_sev_cmd *argp) > +{ > + struct sev_data_snp_gctx_create data = {}; > + void *context; > + int rc; > + > + /* Allocate memory for context page */ Nit: this comment has very little value, if any. It's just stating the obvious. Instead, I'd add a description for the function: /* * Allocate and initialize a digest for the guest measurement. */ static void *snp_context_create(struct kvm *kvm, struct kvm_sev_cmd *argp) This would be much more helpful to get a grasp on "what I'm looking at". > + context = snp_alloc_firmware_page(GFP_KERNEL_ACCOUNT); > + if (!context) > + return NULL; > + > + data.gctx_paddr = __psp_pa(context); > + rc = __sev_issue_cmd(argp->sev_fd, SEV_CMD_SNP_GCTX_CREATE, &data, &argp->error); > + if (rc) { > + snp_free_firmware_page(context); > + return NULL; > + } > + > + return context; > +} > + > +static int snp_bind_asid(struct kvm *kvm, int *error) > +{ > + struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info; > + struct sev_data_snp_activate data = {0}; > + > + data.gctx_paddr = __psp_pa(sev->snp_context); > + data.asid = sev_get_asid(kvm); > + return sev_issue_cmd(kvm, SEV_CMD_SNP_ACTIVATE, &data, error); > +} > + > +static int snp_launch_start(struct kvm *kvm, struct kvm_sev_cmd *argp) > +{ > + struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info; > + struct sev_data_snp_launch_start start = {0}; > + struct kvm_sev_snp_launch_start params; > + int rc; > + > + if (!sev_snp_guest(kvm)) > + return -ENOTTY; > + > + if (copy_from_user(¶ms, (void __user *)(uintptr_t)argp->data, sizeof(params))) > + return -EFAULT; > + > + sev->snp_context = snp_context_create(kvm, argp); > + if (!sev->snp_context) > + return -ENOTTY; > + > + start.gctx_paddr = __psp_pa(sev->snp_context); > + start.policy = params.policy; > + memcpy(start.gosvw, params.gosvw, sizeof(params.gosvw)); > + rc = __sev_issue_cmd(argp->sev_fd, SEV_CMD_SNP_LAUNCH_START, &start, &argp->error); > + if (rc) > + goto e_free_context; > + > + sev->fd = argp->sev_fd; > + rc = snp_bind_asid(kvm, &argp->error); > + if (rc) > + goto e_free_context; > + > + return 0; > + > +e_free_context: > + snp_decommission_context(kvm); > + > + return rc; > +} > + > int sev_mem_enc_ioctl(struct kvm *kvm, void __user *argp) > { > struct kvm_sev_cmd sev_cmd; > @@ -1915,6 +1991,9 @@ int sev_mem_enc_ioctl(struct kvm *kvm, void __user *argp) > case KVM_SEV_RECEIVE_FINISH: > r = sev_receive_finish(kvm, &sev_cmd); > break; > + case KVM_SEV_SNP_LAUNCH_START: > + r = snp_launch_start(kvm, &sev_cmd); > + break; > default: > r = -EINVAL; > goto out; > @@ -2106,6 +2185,28 @@ int sev_vm_copy_enc_context_from(struct kvm *kvm, unsigned int source_fd) > return ret; > } > > +static int snp_decommission_context(struct kvm *kvm) > +{ > + struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info; > + struct sev_data_snp_decommission data = {}; > + int ret; > + > + /* If context is not created then do nothing */ > + if (!sev->snp_context) > + return 0; > + > + data.gctx_paddr = __sme_pa(sev->snp_context); > + ret = snp_guest_decommission(&data, NULL); > + if (WARN_ONCE(ret, "failed to release guest context")) > + return ret; > + > + /* free the context page now */ > + snp_free_firmware_page(sev->snp_context); > + sev->snp_context = NULL; > + > + return 0; > +} > + > void sev_vm_destroy(struct kvm *kvm) > { > struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info; > @@ -2147,7 +2248,15 @@ void sev_vm_destroy(struct kvm *kvm) > } > } > > - sev_unbind_asid(kvm, sev->handle); > + if (sev_snp_guest(kvm)) { > + if (snp_decommission_context(kvm)) { > + WARN_ONCE(1, "Failed to free SNP guest context, leaking asid!\n"); > + return; > + } > + } else { > + sev_unbind_asid(kvm, sev->handle); > + } > + > sev_asid_free(sev); > } > > diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h > index 2f45589ee596..71c011af098e 100644 > --- a/arch/x86/kvm/svm/svm.h > +++ b/arch/x86/kvm/svm/svm.h > @@ -91,6 +91,7 @@ struct kvm_sev_info { > struct misc_cg *misc_cg; /* For misc cgroup accounting */ > atomic_t migration_in_progress; > u64 snp_init_flags; > + void *snp_context; /* SNP guest context page */ > }; > > struct kvm_svm { > diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h > index 0f912cefc544..0cb119d66ae5 100644 > --- a/include/uapi/linux/kvm.h > +++ b/include/uapi/linux/kvm.h > @@ -1812,6 +1812,7 @@ enum sev_cmd_id { > > /* SNP specific commands */ > KVM_SEV_SNP_INIT, > + KVM_SEV_SNP_LAUNCH_START, > > KVM_SEV_NR_MAX, > }; > @@ -1919,6 +1920,15 @@ struct kvm_snp_init { > __u64 flags; > }; > > +struct kvm_sev_snp_launch_start { > + __u64 policy; > + __u64 ma_uaddr; > + __u8 ma_en; > + __u8 imi_en; > + __u8 gosvw[16]; > + __u8 pad[6]; > +}; > + > #define KVM_DEV_ASSIGN_ENABLE_IOMMU (1 << 0) > #define KVM_DEV_ASSIGN_PCI_2_3 (1 << 1) > #define KVM_DEV_ASSIGN_MASK_INTX (1 << 2) > -- > 2.25.1 > BR, Jarkko