From patchwork Thu Mar 6 20:29:22 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paolo Bonzini X-Patchwork-Id: 14005307 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 A9597270EB8 for ; Thu, 6 Mar 2025 20:29:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741292970; cv=none; b=t72jYX/ECdr/BLarBsWHcMMinxXF0cQ7nMcudfQTWorfBogoiCLusZTgl9o2EnnmKbGpGzLG9WFVxxciH/0FaMchElb9zQaATcwD4WGqq3zFLoUfrI6ABC5YLtaYmlSUcqgCkDdzCKCqmhFprXJ//PkXRGHDHnlij1JCm/Mopu0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741292970; c=relaxed/simple; bh=8vyu3XmUOc6y+9UctpvXG0VUwJYWY/BqkHoBpdSAYZ4=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=h8LXJ8YY640vVJyRk2dFjBec8KGVaaiQzgEMj13Hvm152ge8ANCamsM9DDaeICYZGpYqhHqOoqHHv6Px1SAYvHsZ+vrwy61adKZ7A7jW0vNRcwD6QB7wXueSqsjXgGUpc9bXIddKmU4L9AEZe2jWWU0+n6dSmYP7i3ERW2XNbEw= 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=d7zvUKZC; arc=none smtp.client-ip=170.10.129.124 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="d7zvUKZC" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1741292967; 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=d7zvUKZChUQiUFsy6MXREKw1wK+yz7LVShCIYy4sipA891i6nOkbKlNHN4UaygEl8Wp7fs XS5Inv1y0Ddzy1DK9YyGdb3o6rGfgQIQmdtzQBcz76z/SsWbWURiphZ2CSRiiUZMzxFHP0 4dXyn3Et+KNDduBIsB50DgezFBvwkJs= Received: from mail-wm1-f71.google.com (mail-wm1-f71.google.com [209.85.128.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-359-7_9-8wuCMMmjEGO0x_UUyg-1; Thu, 06 Mar 2025 15:29:26 -0500 X-MC-Unique: 7_9-8wuCMMmjEGO0x_UUyg-1 X-Mimecast-MFC-AGG-ID: 7_9-8wuCMMmjEGO0x_UUyg_1741292965 Received: by mail-wm1-f71.google.com with SMTP id 5b1f17b1804b1-4394c0a58e7so6775995e9.0 for ; Thu, 06 Mar 2025 12:29:26 -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=jwnFGw5CV4uoEwNEt/OLE05GCHtO9otw3JQYDgNPSn4elkCqZ9sOprByvzS6Vk6p3P TMUd/yePsbN2dgfy8Wr1TM11UZyN+ymWyMp4UDcguvTdmYp6ZQJMGQMRs5d7oNvljWel zNZpFLjZ8vjfkOARDOx+l0Q64P/tRmRwKb0oPAm1SUDfW2hki33LRasJo5kkCw+t9C3O 0dKupr4ArI36W/fxfcf9Gx9kA3EW2bs/HOEFUlaIYpRtUmt3FGRSbJiu1h3IXQcEg7Y+ bqe2Vb6Fa9JcAXdKozRK9vJNVxRHDSSbP5CZkKeXQwx/53Bp4Xu5OV9te7nTYvcGhfM1 v3Sg== X-Forwarded-Encrypted: i=1; AJvYcCXBdXF6fqgmr5HUhS8XbDfojrERRXmaPQkY66irRePS4O5xDW3RH2j65g/TT9lX5Jq6/oQ=@vger.kernel.org X-Gm-Message-State: AOJu0Yy0+lf5VAlRWzTm+78qjHr/UtCEeuaZV7lqj5jWPfnXPqrDUb7a BnJneR8VWXAVQNMYKiTauMxzTTqNFbp+8gbz4xMuzWQc3sf4qOPR/lnI6jmXMVJrLXy6/LV4hZw gXCkiSfPga0aVoSda1ckfkg/wG8iyyb3neEwVFFRn/KQpPWMIKA== X-Gm-Gg: ASbGnctGVXxWxZ1afPXLPi1qY2/GYbgV/uzjCy/gRd+VJ2A8liDADlz9YvsvhQfftx5 9schbZ1F6MDw0lgmIgqK0tSXHUGuatPGkrNyONJgUl7o7XdmewX8icPOCIx/tBJnGfmND7gU+Zq RzSNHsSN/rmGPytK/IOcq8k2gVlbBOusSPkC1IBDBjx0t2DwpcpRCIoG6awH41j7aQwCDmr5h+B sW9Iac/eIkQfuc38IL+yWj1ZjopwtBw99dY/xJQSdvX3dt9qlpn/V6RtwzHV2c0qzlbDy5JYxQY /c+uqmX0RLvEscm2sYo= X-Received: by 2002:a05:600c:1c92:b0:43b:c284:5bc2 with SMTP id 5b1f17b1804b1-43c54a13899mr8094625e9.0.1741292964887; 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: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 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 type) return type < 32 && (kvm_caps.supported_vm_types & BIT(type)); } +static inline u32 kvm_sync_valid_fields(struct kvm *kvm) +{ + return kvm && kvm->arch.has_protected_state ? 0 : KVM_SYNC_X86_VALID_FIELDS; +} + int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) { int r = 0; @@ -4694,7 +4699,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) break; #endif case KVM_CAP_SYNC_REGS: - r = KVM_SYNC_X86_VALID_FIELDS; + r = kvm_sync_valid_fields(kvm); break; case KVM_CAP_ADJUST_CLOCK: r = KVM_CLOCK_VALID_FLAGS; @@ -11503,6 +11508,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) { struct kvm_queued_exception *ex = &vcpu->arch.exception; struct kvm_run *kvm_run = vcpu->run; + u32 sync_valid_fields; int r; r = kvm_mmu_post_init_vm(vcpu->kvm); @@ -11548,8 +11554,9 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) goto out; } - if ((kvm_run->kvm_valid_regs & ~KVM_SYNC_X86_VALID_FIELDS) || - (kvm_run->kvm_dirty_regs & ~KVM_SYNC_X86_VALID_FIELDS)) { + sync_valid_fields = kvm_sync_valid_fields(vcpu->kvm); + if ((kvm_run->kvm_valid_regs & ~sync_valid_fields) || + (kvm_run->kvm_dirty_regs & ~sync_valid_fields)) { r = -EINVAL; goto out; } @@ -11607,7 +11614,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) 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);