From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f202.google.com (mail-pl1-f202.google.com [209.85.214.202]) (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 7D418233704 for ; Thu, 12 Feb 2026 21:16:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770930976; cv=none; b=gHimBgmGtBLPXqPZ4jWhWal2VjXQ9ljcGoRXyRzpIDhh+IHZrlwy/2nHqp5pBZsFgBgZGd7SCCOdDRCzNARQ/w/u6vPSZCDHxlNaoD6KkbSVP/XNK5QliyF0DGnynpDzNOZce8sddf6eapPdGQTLpPDb2esJAXN3pKn6aKIXMMA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770930976; c=relaxed/simple; bh=RSWfWpGpbRWBApx+ZLjfLxtlxtxcLASQxHTXl2x+rn0=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=kVM/qaE/8ykmDfT4oMLe8Ejb/csRt0pFVHagazmich+WcktLpev4JQo35rjwmoabZw/CdveNOT7ybNWsQITBrW/6IUDQNskacmIOmCJbVUC1tf+D166DMwbmMSj3XDQluQ0j0g5ZL+gEZF/lU5PQCoVe18OprX3J5reWcUsrVv8= 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=b9u9yKc2; arc=none smtp.client-ip=209.85.214.202 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="b9u9yKc2" Received: by mail-pl1-f202.google.com with SMTP id d9443c01a7336-2aaf2f3bef6so2427115ad.0 for ; Thu, 12 Feb 2026 13:16:15 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1770930975; x=1771535775; darn=vger.kernel.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=ntbMRWd9O7mWHdd1+6mPGyqg89FrBxm9Fcl2fFR7Emc=; b=b9u9yKc2RWylriHX5/NmeNl2KUtXeYA+F34ULcTFmFW/F7wxXyA+w+kt3VckSuzl5f BirWvA3eMktD7AmR/jKKOPxzIF9nCkxXSHPGwE7mfdaoBe9kxTq1cq6+GkoImgc+T6yk aHnLpp87uvxonBGdPrunm+71roiK0lr7l7YCX+L1yz1cz54cJyIDWuj1YnFrcNLJwq/O VXsxDzBeqdJ2VX1YhwLM68GrjtefCM1emUBzUqCm3x+oqj7o2piJGcjdDSmFm3+DgAOn TfS12k79tMPhldauj3s1NjFGTfxyX7FjhC/ZO7/iIGcijjmS0Zm6cGjhZ4n14dU+Ou2m MnDw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1770930975; x=1771535775; 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=ntbMRWd9O7mWHdd1+6mPGyqg89FrBxm9Fcl2fFR7Emc=; b=OczPBhZX1x6k/FM/GzGGBqUclJeoWAko6kNKdXpLC1naOQPo9RBIgQX87ygeO/elNR W7QhYMz+8EjnAzPCmMUhbu4o1WHActdGY9nFEmVUVbSZ9NIMfelHt+IAJI1nWLHQCbAV L3LinlW1fdZCOdHNWrK4S6DLZkqHiAvFOh2nZ5xKdapD0BCclaJfx+e/mryBbGZU8RqU M7Uou2jETRTdjaCR3XoiXq86OGVXiZ/GRED0HmMDldYpaWGgkAMiCCNqn+PNbOCp71d+ W2fWxMQxSrPvq0CynO8DgXMpIjTCEMH2mNUmBYU5Wc7NmCmpzhArsSBaadJWE1i3vooq mdgg== X-Forwarded-Encrypted: i=1; AJvYcCVu9vbnb59TOs/0Fhs6xkCI9lY384Rd0uZ5WZsEk1kol5GJ3LsNEYtIX+Ph4tPl1Erf3ixFsILKCVKYa5s=@vger.kernel.org X-Gm-Message-State: AOJu0Yx6jorQ9UrI/QydYCuoBeQyqv6TlFrUTcV3fxYaVCvfz5vWQZq7 KeWS2LNtxtM8nmw5yb1/RVCwcyv4k2+LH9CyJsjCL8wXUTHtp4s1l8ukF3oyH5cJRQoWq6dF9yQ oNAFWJA== X-Received: from plbki7.prod.google.com ([2002:a17:903:687:b0:29f:fca:3bd4]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:903:18b:b0:2a9:4700:2a94 with SMTP id d9443c01a7336-2ab4cf4ab54mr3274265ad.10.1770930974454; Thu, 12 Feb 2026 13:16:14 -0800 (PST) Date: Thu, 12 Feb 2026 13:16:13 -0800 In-Reply-To: <20260122045755.205203-3-chengkev@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260122045755.205203-1-chengkev@google.com> <20260122045755.205203-3-chengkev@google.com> Message-ID: Subject: Re: [PATCH V3 2/5] KVM: SVM: Inject #UD for STGI if EFER.SVME=0 and SVM Lock and DEV are not available From: Sean Christopherson To: Kevin Cheng Cc: pbonzini@redhat.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, yosry.ahmed@linux.dev Content-Type: text/plain; charset="us-ascii" On Thu, Jan 22, 2026, Kevin Cheng wrote: > The AMD APM states that STGI causes a #UD if SVM is not enabled and > neither SVM Lock nor the device exclusion vector (DEV) are supported. > Support for DEV is part of the SKINIT architecture. Fix the STGI exit > handler by injecting #UD when these conditions are met. This is entirely pointless. SVML and SKINIT can never bet set in guest caps. There are many things that are documented in the SDM/APM that don't have "correct" handling in KVM, because they're completely unsupported. _If_ this is causing someone enough heartburn to want to "fix", just add a comment in nested_svm_check_permissions() stating that KVM doesn't support SVML or SKINIT.