From mboxrd@z Thu Jan 1 00:00:00 1970 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 805D4C2BD09 for ; Mon, 24 Jun 2024 15:49:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type:Cc:To:From: Subject:Message-ID:References:Mime-Version:In-Reply-To:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=w0TfFi1A5eAUOELglH+ORGjDb5xIqjGuRnaKSa2m3Gs=; b=cnJfCtk9VHxHudh/S4ckylODzz oZvDtJ5bGTTk+JcMWQ7CBtzXggidPqRqaGKm9m+u3fhjCCLkd+YJmgDA4OTazmilvrIUsTkFSIfE4 gsL64QKThtRsIoaZcz4NL5SDGgBYlUKuCFHC6LKBC70hTY+NFPXXeqlC3LtGHNQdvkz29jzWWZzHd HOG2uzV+BNr1p7iZV5h/YY2IoQWit+wuNAroM1UgQVmNLCOUSssAYs+EkvimpfP7oyvLeD4HmERLM r0+KLVwndnNTCmxSGAN5hkgtnPE9ycEjxYq89SeRSWio92GBSKYPAi0Fwu/29UrTwflufudurZfcB WKFiGnbw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sLlwE-0000000HNLC-0wYs; Mon, 24 Jun 2024 15:49:02 +0000 Received: from mail-yb1-xb4a.google.com ([2607:f8b0:4864:20::b4a]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1sLlw9-0000000HNJp-1hMa for linux-arm-kernel@lists.infradead.org; Mon, 24 Jun 2024 15:48:58 +0000 Received: by mail-yb1-xb4a.google.com with SMTP id 3f1490d57ef6-e02c3d0f784so8522222276.0 for ; Mon, 24 Jun 2024 08:48:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1719244136; x=1719848936; darn=lists.infradead.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=w0TfFi1A5eAUOELglH+ORGjDb5xIqjGuRnaKSa2m3Gs=; b=097Is5Jwg9M++paS3e2W1+/7W5//SwaF3IfVGexcJ99ZPjIYjC8daZc3UcOLJZJ6ze KthVBzqALRaCpp8+2YH/75DsyEWVQ2wbTWpVDULaibJPxfJy6blv0/78oTdymBm+auUu burrNxvaoD7L37/Get71cvfr2YjOrg+pUpM0KiwmAw0fcKZ7AKqVu3WjXxZkOZd8yE4/ pQy/pdMZqSpFIO9J2SfypQmK4uuiJuLy8ueRC7RFAEUm/QFgp/96lWft9iCDSVtoV8NG 3zvIp65c+LElByzge1Ai3NwO/C0a8LohBSIjwr+USe6eyuZm2FRUBw5DnaFRUhEqGn5J SVrQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1719244136; x=1719848936; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=w0TfFi1A5eAUOELglH+ORGjDb5xIqjGuRnaKSa2m3Gs=; b=hQECLuuGbsH9Rn7ZKpvKJflSGRWb/RpEkRqE4KlN7YHDCBPvJLED3OBTpgvW2jz/tT P/rLjfFssjnvuOW1KHKBzXFy5rcVrxyOxM12A6kk7I5ySYNsT/G87w+iUUOjxEW3golu 9yi3du3Y5HxgOpcIL0aFVsu6gcPsYLnDbZzsfZv1sirE+zy/I0cVuvBCumU5k+YrF59b +Q+EzkwTLW0W9hiQDYLpmwk98MCEg3v9oomJveuwaduQVBHqUiZLUCXOZL3fiqZ5qtoP eEn6SxPSCrbzDVrlpsIZf+CY+LY01qHvSG3HyM4oROIUZS6vGd32Y/svfoSQtop5bzYj bANg== X-Forwarded-Encrypted: i=1; AJvYcCVgSGSGdi+AMDLcVyVqoRNalNxWIyeaZU7xP9yj2ULR37Unpv2M6z5SJ4/jIFWm4TQV7JOsM1lYejS8mV2zOk4wf5NxwIFqlFkF6rbIJHnKU0KnClw= X-Gm-Message-State: AOJu0Yy51sUCsQ9uHgqe6BtULZKEBr/wTyKKLYhqRE7XWPCAERRdPVqV I9wgjAAGRdcg4IdhYECnJwq47b9lT21M15O0k2s8oV0SEUJbvneQQosT210YbryEFjYp8fjy+nY DNA== X-Google-Smtp-Source: AGHT+IF8kv5cg7jBtfLj5KChqQb0E4AVt+N3NAFysUC46dBIyhEpZe/ChMcBWGfHF7p7NpzSNPuuniqMZ0A= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a05:6902:705:b0:df4:8ecb:ae57 with SMTP id 3f1490d57ef6-e030108f81cmr16300276.10.1719244135814; Mon, 24 Jun 2024 08:48:55 -0700 (PDT) Date: Mon, 24 Jun 2024 08:48:54 -0700 In-Reply-To: <20240208151837.35068-2-shameerali.kolothum.thodi@huawei.com> Mime-Version: 1.0 References: <20240208151837.35068-1-shameerali.kolothum.thodi@huawei.com> <20240208151837.35068-2-shameerali.kolothum.thodi@huawei.com> Message-ID: Subject: Re: [RFC PATCH v2 1/7] KVM: Add generic infrastructure to support pinned VMIDs From: Sean Christopherson To: Shameer Kolothum Cc: kvmarm@lists.linux.dev, iommu@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linuxarm@huawei.com, kevin.tian@intel.com, jgg@ziepe.ca, alex.williamson@redhat.com, maz@kernel.org, oliver.upton@linux.dev, will@kernel.org, robin.murphy@arm.com, jean-philippe@linaro.org, jonathan.cameron@huawei.com Content-Type: text/plain; charset="us-ascii" X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240624_084857_468807_FF465CC7 X-CRM114-Status: GOOD ( 21.07 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Feb 08, 2024, Shameer Kolothum wrote: > Provide generic helper functions to get/put pinned VMIDs if the arch > supports it. IMO, this has no business being in generic KVM. Multiple architectures have constructs that are _similar_ ARM's VMID, but AFAICT the exact semantics are very ARM specific. I.e. odds are very good that the only thing that can actually use kvm_pinned_vmid_get() is the SMMU, because the concept won't fit any other architecture. The other issue is that other architectures support building KVM as a module, which makes it much more difficult to guarantee the safety of these hooks. > Signed-off-by: Shameer Kolothum > --- > include/linux/kvm_host.h | 18 ++++++++++++++++++ > virt/kvm/Kconfig | 3 +++ > virt/kvm/kvm_main.c | 23 +++++++++++++++++++++++ > 3 files changed, 44 insertions(+) > > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > index 7e7fd25b09b3..610e239bea46 100644 > --- a/include/linux/kvm_host.h > +++ b/include/linux/kvm_host.h > @@ -2311,6 +2311,24 @@ static inline void kvm_handle_signal_exit(struct kvm_vcpu *vcpu) > } > #endif /* CONFIG_KVM_XFER_TO_GUEST_WORK */ > > +#ifdef CONFIG_HAVE_KVM_PINNED_VMID > +int kvm_arch_pinned_vmid_get(struct kvm *kvm); > +void kvm_arch_pinned_vmid_put(struct kvm *kvm); > +#endif > + > +#ifdef CONFIG_HAVE_KVM_PINNED_VMID > +int kvm_pinned_vmid_get(struct kvm *kvm); > +void kvm_pinned_vmid_put(struct kvm *kvm); > +#else > +static inline int kvm_pinned_vmid_get(struct kvm *kvm) > +{ > + return -EINVAL; > +} > + > +static inline void kvm_pinned_vmid_put(struct kvm *kvm) > +{ > +} > +#endif > /* > * If more than one page is being (un)accounted, @virt must be the address of > * the first page of a block of pages what were allocated together (i.e > diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig > index 184dab4ee871..a3052c8e3ac4 100644 > --- a/virt/kvm/Kconfig > +++ b/virt/kvm/Kconfig > @@ -108,3 +108,6 @@ config KVM_GENERIC_PRIVATE_MEM > select KVM_GENERIC_MEMORY_ATTRIBUTES > select KVM_PRIVATE_MEM > bool > + > +config HAVE_KVM_PINNED_VMID > + bool > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index 10bfc88a69f7..f84d6da5f464 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -3918,6 +3918,29 @@ bool kvm_vcpu_wake_up(struct kvm_vcpu *vcpu) > } > EXPORT_SYMBOL_GPL(kvm_vcpu_wake_up); > > +#ifdef CONFIG_HAVE_KVM_PINNED_VMID > +int kvm_pinned_vmid_get(struct kvm *kvm) > +{ > + int ret; > + > + if (!kvm_get_kvm_safe(kvm)) > + return -ENOENT; > + ret = kvm_arch_pinned_vmid_get(kvm); > + if (ret < 0) > + kvm_put_kvm(kvm); > + > + return ret; > +} > +EXPORT_SYMBOL_GPL(kvm_pinned_vmid_get); > + > +void kvm_pinned_vmid_put(struct kvm *kvm) > +{ > + kvm_arch_pinned_vmid_put(kvm); > + kvm_put_kvm(kvm); > +} > +EXPORT_SYMBOL_GPL(kvm_pinned_vmid_put); > +#endif > + > #ifndef CONFIG_S390 > /* > * Kick a sleeping VCPU, or a guest VCPU in guest mode, into host kernel mode. > -- > 2.34.1 >