From nobody Sun Feb 8 19:35:27 2026 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8CEBF276038 for ; Thu, 6 Mar 2025 20:29:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741292977; cv=none; b=KJSwjOKg0sqjfTEU7XSnQEio6lj/cFyvEqlTl53oMlzkzNbWVbm4SU8At1zVy4O0IgmRtBvJW/1R+x/KamfGRq6vrZcq4cki18SIAtJNQprXzWcVkrDv0q0X1ssn/Uu9GWprPIvCzkEc+3hcK6p5tPrGdGeKV2HHO2v9UdQTXqc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741292977; c=relaxed/simple; bh=8vyu3XmUOc6y+9UctpvXG0VUwJYWY/BqkHoBpdSAYZ4=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=hsTeFQdC9aXxE4snjpjyk3LDBrDINApjxudFal6vc0M3yicd8ZxP9Ohiq5h9a15/gtTsBvmEk3VRP2TKDdTzeyJJ6Zt5K6bGzz6oOT0l0cvlVG0tb6WLMAPr9hZyijR0kPKJ791NEzMpnBhokXDnKydM3iAh4uEsdCx1sSCaVcE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=EG2nMqfr; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="EG2nMqfr" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1741292974; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=jc3bU+07/m9HQ5f3AAk7LB5X6YU1cmlau9q/eqDjROY=; b=EG2nMqfri01p7slaqSFq/p1uqm45mAmiGjNsVfytm3CgT58iOJNrJMDeRcpkBgYnvITjj8 bShIjAjqO0vvdU9FyQ1P33OwtOsKD8hJF0KLgqoaRKqJXf6SUshNTz9QXQL/rYni/oetun P7tLx5Pm8NJ18A695sOx0WaTIr+EmrI= Received: from mail-wm1-f70.google.com (mail-wm1-f70.google.com [209.85.128.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-224-CpOiqkVeMiiLKl63CXFhnA-1; Thu, 06 Mar 2025 15:29:27 -0500 X-MC-Unique: CpOiqkVeMiiLKl63CXFhnA-1 X-Mimecast-MFC-AGG-ID: CpOiqkVeMiiLKl63CXFhnA_1741292966 Received: by mail-wm1-f70.google.com with SMTP id 5b1f17b1804b1-438e4e9a53fso6738145e9.1 for ; Thu, 06 Mar 2025 12:29:27 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1741292965; x=1741897765; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=jc3bU+07/m9HQ5f3AAk7LB5X6YU1cmlau9q/eqDjROY=; b=GmufNcpHIaPiKJSZD1J0DMDg8UCt8Psh5UEQjqXcpI6AmeivE5AYq4g805d4FptyXQ 870rY/ujIsUgHYuzGbSY3nG3Y7hRTNqDRm7iU11sbC+mKNH+S0lG5YlZHlfiJPNMEgfO dNMCWgYxnT7UJ/qXOn2QXA+GrUVEKU1v6XyJ1JqlkmeFpajAja9bdnZTrtahVkJ07ThR zg2IOwY6ullukpBuogviCkaWmvF/rahCUqNta9BXTisORWWWTop+afewiA6x1Bb+yBOg H/ZSpCf+KWQFAk9BmSlEokJ2UIGv8IvZi8LN2c0rKu7po7DQX2x4moJi2QIPwB+QSGzJ H0sQ== X-Gm-Message-State: AOJu0YzmVfIaOeFK3FN0ICwXkm/euvJJGNrOMBqg4XamdW22QPoHQdWA yN3fDxCA6BO3Migk72kigEn8QquueVX+CHahUeXvY1M05JdsKrd3hox7O3dqtrthPXGSIJcYWA0 lkT3av6I3+cVLe1yZWXXqaL6GBiFLk2MuW73eKVhqkD79E+qz1iAplG21p/lgKPxx/I2Pc07Jp2 6a6XwgvUGn7FWii/D5N6XNpzoJvyNhWkCcK/O0Sjc8KD+jumPN X-Gm-Gg: ASbGncu3C0U3MmSRrpIbJx/XXRXQWuco1KJuNK9CtkGTyJj70LtAd7jTYL4tHjAVb/K wLap+GP7jpHkeidzmDc90GEiZfxmh34DWhlS1OPHpGPGI56hLBpdmEJpBr1sn4xN93apMXN4umx lVkW+iUyGqTa79AGReIzwdbcSq916iXgzfaVeIJDMDWmOeFy8+1Q0DndofvrB3KGACq5mxzFkMt UGaVB8V/C7VCDYKFRraNZ7ub2pfbbH6ZtZfDtcc95bSKezMLbgx66UcyMlWOMIKNMqhHnw2EjtB 7B04ninYq1U5Z/yTUJ4= X-Received: by 2002:a05:600c:1c92:b0:43b:c284:5bc2 with SMTP id 5b1f17b1804b1-43c54a13899mr8094665e9.0.1741292964980; Thu, 06 Mar 2025 12:29:24 -0800 (PST) X-Google-Smtp-Source: AGHT+IEAQSfTDDfEGt7kCQUl09IKwMyDuCnJFvs3A/ftPMnIhst0AXXgvlmr3jiXxVdhzI638oXcqg== X-Received: by 2002:a05:600c:1c92:b0:43b:c284:5bc2 with SMTP id 5b1f17b1804b1-43c54a13899mr8094515e9.0.1741292964495; Thu, 06 Mar 2025 12:29:24 -0800 (PST) Received: from [192.168.10.48] ([151.95.119.44]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-43bd435c836sm59321245e9.37.2025.03.06.12.29.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 06 Mar 2025 12:29:23 -0800 (PST) From: Paolo Bonzini To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: seanjc@google.com Subject: [PATCH] KVM: x86: block KVM_CAP_SYNC_REGS if guest state is protected Date: Thu, 6 Mar 2025 21:29:22 +0100 Message-ID: <20250306202923.646075-1-pbonzini@redhat.com> X-Mailer: git-send-email 2.48.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" KVM_CAP_SYNC_REGS does not make sense for VMs with protected guest state, since the register values cannot actually be written. Return 0 when using the VM-level KVM_CHECK_EXTENSION ioctl, and accordingly return -EINVAL from KVM_RUN if the valid/dirty fields are nonzero. However, on exit from KVM_RUN userspace could have placed a nonzero value into kvm_run->kvm_valid_regs, so check guest_state_protected again and skip store_regs() in that case. Signed-off-by: Paolo Bonzini Reviewed-by: Pankaj Gupta --- arch/x86/kvm/x86.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index aaa067b79095..b416eec5c167 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4586,6 +4586,11 @@ static bool kvm_is_vm_type_supported(unsigned long t= ype) return type < 32 && (kvm_caps.supported_vm_types & BIT(type)); } =20 +static inline u32 kvm_sync_valid_fields(struct kvm *kvm) +{ + return kvm && kvm->arch.has_protected_state ? 0 : KVM_SYNC_X86_VALID_FIEL= DS; +} + int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) { int r =3D 0; @@ -4694,7 +4699,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, lon= g ext) break; #endif case KVM_CAP_SYNC_REGS: - r =3D KVM_SYNC_X86_VALID_FIELDS; + r =3D kvm_sync_valid_fields(kvm); break; case KVM_CAP_ADJUST_CLOCK: r =3D KVM_CLOCK_VALID_FLAGS; @@ -11503,6 +11508,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) { struct kvm_queued_exception *ex =3D &vcpu->arch.exception; struct kvm_run *kvm_run =3D vcpu->run; + u32 sync_valid_fields; int r; =20 r =3D kvm_mmu_post_init_vm(vcpu->kvm); @@ -11548,8 +11554,9 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) goto out; } =20 - if ((kvm_run->kvm_valid_regs & ~KVM_SYNC_X86_VALID_FIELDS) || - (kvm_run->kvm_dirty_regs & ~KVM_SYNC_X86_VALID_FIELDS)) { + sync_valid_fields =3D kvm_sync_valid_fields(vcpu->kvm); + if ((kvm_run->kvm_valid_regs & ~sync_valid_fields) || + (kvm_run->kvm_dirty_regs & ~sync_valid_fields)) { r =3D -EINVAL; goto out; } @@ -11607,7 +11614,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) =20 out: kvm_put_guest_fpu(vcpu); - if (kvm_run->kvm_valid_regs) + if (kvm_run->kvm_valid_regs && likely(!vcpu->arch.guest_state_protected)) store_regs(vcpu); post_kvm_run_save(vcpu); kvm_vcpu_srcu_read_unlock(vcpu); --=20 2.48.1