From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f199.google.com (mail-pl1-f199.google.com [209.85.214.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C97C82ECD3A for ; Fri, 24 Jul 2026 00:48:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784854085; cv=none; b=SoQOWZ4jDz2YSQpDtmUvOxlMCdsxxOjouJ4znvHo6AMAuALhky4+LxX8cJV9E7S+a242QY69wICJOGus3AVh43Py9FLPBs1hlKHfDZtZfhJgYDCmhT3dWurCzMrx80S8NDy74fjq1wqx8/FzTeaI0veSLQthTjy+W2gxq/ICD9I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784854085; c=relaxed/simple; bh=FUCfYbsz9ZyIbrv4tJzgA6QFVNOzaEU/1cTSyaAlIJw=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=kYgwHmifXS8egElO9O69Lh4gGssLLGmj3Sn+pPxJzHnLZ/4zZhL4mFcwzJcjuKzv9R4/+8kmQ/yXGZDhGpb/M7KvrdrVgpjNmrTAsCxvwYqgELKbMDrqgpSBK8eKiHfN2gDfJdjNqDLBo6z4Lmu8i+VrrAwIsFAHJ/SOjj0zK2U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=N0w3arNu; arc=none smtp.client-ip=209.85.214.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="N0w3arNu" Received: by mail-pl1-f199.google.com with SMTP id d9443c01a7336-2caf4173b1cso24706045ad.3 for ; Thu, 23 Jul 2026 17:48:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1784854083; x=1785458883; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:reply-to:from:to:cc:subject:date:message-id :reply-to:content-type; bh=5hCTXU5J5OKjCYOs510ZpnLddxhpdmEInNm/3mj3vgs=; b=N0w3arNu1g1YWrBJHPqgEwHOMELtvrMZl5B3pLAig3HOwGp5StaGi/q/SQafwEHuQe f4xoHnUPsYqbEo3rFZx/N1KP+wFUYWLz+lGNjnW1b23m/DkiZsSoooFr6k22jRBUP9iV l7wPz/N3pGMsZ9hDVDjG2SbaiL2GA0q6ZbZ8YBGUXO2vmlTDld+kch1PuU+X3nbXYOHA U/KipJCw1PEsDT/SsvVNkLzDUCUzMVa5TWvqioq9OnNbxXnj0IaKwB8wdmUtpUNNGkWu tJMLYLLsJrRXc6NYdq0tHdH0kxSjLvjATwRwEEwBJqfseW+9dM8V0kSaeHwkys2ktMCW TFiQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1784854083; x=1785458883; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:reply-to:x-gm-message-state:from:to:cc:subject :date:message-id:reply-to:content-type; bh=5hCTXU5J5OKjCYOs510ZpnLddxhpdmEInNm/3mj3vgs=; b=gW0zNSvnJm89rYeYjyiQ9mSc8g5bGryhJu5Xx6ZvIo4kc2ovRlAH/qCCg7q+GRLC+f e7TCscYAkAEDc23o/+R5Q8vVaIiyiAb5aioov8qc5ZvngSf4tlkhhgNsMoKTUTHVkBJD WWryyJ4QRp1ehG0PljzGRvBlB9xQipkYctJe5+fWXfX4xm18VMMj98u3NXmNuR07QSdg SqaG0d9Q7aEKPjhsOEomq631CYP070sAtVdfImaaiMStaAPeJ8jJRgG0rFaTlcUwkJdE VQUTZLt2cU7Hc0AyXhlBMgqQoZyPA/iKs5/9bXIUsqLzt39AkMXlzUlUTGf5KhEYbGYw U21Q== X-Forwarded-Encrypted: i=1; AHgh+RqT22YVQkgHHAT0n6UmcnqkZJkvFOGhfO4ebuCgk0XMw+90Slq+bniWba14Mwu9FCIsBqM=@vger.kernel.org X-Gm-Message-State: AOJu0YydLpocPoYfaqWhkOYTmNfaXujpIOBXG70paoANrKDLHs5uQ+7x IzsdDPVn5m8ASp6XQKzI3DU/74RSDfzKZRY+217HXfbe/SCI4a5lVe2dAE8Bvbe07Dw4FeZ+zMq GqjrQAg== X-Received: from pgbct6.prod.google.com ([2002:a05:6a02:2106:b0:cb5:f989:9b3e]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a21:6494:b0:3b7:aefe:4367 with SMTP id adf61e73a8af0-3c44b051466mr6208250637.33.1784854082942; Thu, 23 Jul 2026 17:48:02 -0700 (PDT) Reply-To: Sean Christopherson Date: Thu, 23 Jul 2026 17:47:53 -0700 In-Reply-To: <20260724004757.131420-1-seanjc@google.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260724004757.131420-1-seanjc@google.com> X-Mailer: git-send-email 2.55.0.229.g6434b31f56-goog Message-ID: <20260724004757.131420-3-seanjc@google.com> Subject: [PATCH 2/6] KVM: nSVM: Add CLASS()es for automagically handling local kvm_vcpu_map() usage From: Sean Christopherson To: Madhavan Srinivasan , Sean Christopherson , Paolo Bonzini Cc: Nicholas Piggin , linuxppc-dev@lists.ozlabs.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Yosry Ahmed Content-Type: text/plain; charset="UTF-8" Add CLASS() definitions for locally mapping a PFN using kvm_vcpu_map() given a vCPU+gfn pair. In addition to eliminating the need to manually do unmap(), e.g. in error paths, this will allow hardening KVM against double-mapping without having to manually ensure every on-stack declaration is zero-initialized. Use "map local" as the primary terminology as the basic concept is more or less the same as kmap_local(): ensure the current context has a kernel mapping to the underlying memory. Immediately convert the relatively straightforward nested SVM flows, and defer converting the more involved SMM flows to a separate change. No functional change intended. Cc: Yosry Ahmed Signed-off-by: Sean Christopherson --- arch/x86/kvm/svm/nested.c | 18 +++++++----------- arch/x86/kvm/svm/svm.c | 8 +++----- include/linux/kvm_host.h | 19 +++++++++++++++++++ 3 files changed, 29 insertions(+), 16 deletions(-) diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index 5e3e280cd483..73f37b050d0a 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -1086,14 +1086,14 @@ int enter_svm_guest_mode(struct kvm_vcpu *vcpu, u64 vmcb12_gpa, bool from_vmrun) static int nested_svm_copy_vmcb12_to_cache(struct kvm_vcpu *vcpu, u64 vmcb12_gpa) { struct vcpu_svm *svm = to_svm(vcpu); - struct kvm_host_map map; struct vmcb *vmcb12; int r = 0; - if (kvm_vcpu_map(vcpu, gpa_to_gfn(vmcb12_gpa), &map)) + CLASS(kvm_vcpu_map_local, m)(vcpu, gpa_to_gfn(vmcb12_gpa)); + if (m.ret) return -EFAULT; - vmcb12 = map.hva; + vmcb12 = m.map.hva; nested_copy_vmcb_control_to_cache(svm, &vmcb12->control); nested_copy_vmcb_save_to_cache(svm, &vmcb12->save); @@ -1107,7 +1107,6 @@ static int nested_svm_copy_vmcb12_to_cache(struct kvm_vcpu *vcpu, u64 vmcb12_gpa r = -EINVAL; } - kvm_vcpu_unmap(vcpu, &map); return r; } @@ -1251,15 +1250,13 @@ static int nested_svm_vmexit_update_vmcb12(struct kvm_vcpu *vcpu) { struct vcpu_svm *svm = to_svm(vcpu); struct vmcb *vmcb02 = svm->nested.vmcb02.ptr; - struct kvm_host_map map; struct vmcb *vmcb12; - int rc; - rc = kvm_vcpu_map(vcpu, gpa_to_gfn(svm->nested.vmcb12_gpa), &map); - if (rc) - return rc; + CLASS(kvm_vcpu_map_local, m)(vcpu, gpa_to_gfn(svm->nested.vmcb12_gpa)); + if (m.ret) + return m.ret; - vmcb12 = map.hva; + vmcb12 = m.map.hva; vmcb12->save.es = vmcb02->save.es; vmcb12->save.cs = vmcb02->save.cs; @@ -1314,7 +1311,6 @@ static int nested_svm_vmexit_update_vmcb12(struct kvm_vcpu *vcpu) vmcb12->control.exit_int_info_err, KVM_ISA_SVM); - kvm_vcpu_unmap(vcpu, &map); return 0; } diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 91286d46d13a..bf10483c0e8a 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -2216,7 +2216,6 @@ static int vmload_vmsave_interception(struct kvm_vcpu *vcpu, bool vmload) u64 vmcb12_gpa = kvm_rax_read(vcpu); struct vcpu_svm *svm = to_svm(vcpu); struct vmcb *vmcb12; - struct kvm_host_map map; int ret; if (nested_svm_check_permissions(vcpu)) @@ -2227,10 +2226,11 @@ static int vmload_vmsave_interception(struct kvm_vcpu *vcpu, bool vmload) return 1; } - if (kvm_vcpu_map(vcpu, gpa_to_gfn(vmcb12_gpa), &map)) + CLASS(kvm_vcpu_map_local, m)(vcpu, gpa_to_gfn(vmcb12_gpa)); + if (m.ret) return kvm_handle_memory_failure(vcpu, X86EMUL_IO_NEEDED, NULL); - vmcb12 = map.hva; + vmcb12 = m.map.hva; ret = kvm_skip_emulated_instruction(vcpu); @@ -2243,8 +2243,6 @@ static int vmload_vmsave_interception(struct kvm_vcpu *vcpu, bool vmload) svm_copy_vmloadsave_state(vmcb12, svm->vmcb01.ptr); } - kvm_vcpu_unmap(vcpu, &map); - return ret; } diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 9db6eb4023c4..c54dbfdbc346 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -1420,6 +1420,25 @@ static inline void kvm_vcpu_map_mark_dirty(struct kvm_vcpu *vcpu, kvm_vcpu_mark_page_dirty(vcpu, map->gfn); } +typedef struct { + struct kvm_vcpu *vcpu; + struct kvm_host_map map; + int ret; +} kvm_vcpu_local_map_t; + +#define DEFINE_VCPU_MAP_CLASS(ro) \ +DEFINE_CLASS(kvm_vcpu_map_local##ro, kvm_vcpu_local_map_t, \ + if (!_T.ret) kvm_vcpu_unmap(_T.vcpu, &_T.map), \ + ({ \ + kvm_vcpu_local_map_t m = { .vcpu = vcpu }; \ + \ + m.ret = kvm_vcpu_map##ro(vcpu, gfn, &m.map); \ + \ + m; \ + }), struct kvm_vcpu *vcpu, gfn_t gfn); +DEFINE_VCPU_MAP_CLASS(); +DEFINE_VCPU_MAP_CLASS(_readonly); + unsigned long kvm_vcpu_gfn_to_hva(struct kvm_vcpu *vcpu, gfn_t gfn); unsigned long kvm_vcpu_gfn_to_hva_prot(struct kvm_vcpu *vcpu, gfn_t gfn, bool *writable); int kvm_vcpu_read_guest_page(struct kvm_vcpu *vcpu, gfn_t gfn, void *data, int offset, -- 2.55.0.229.g6434b31f56-goog