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 C760B3126B0 for ; Tue, 18 Nov 2025 23:28:24 +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=1763508506; cv=none; b=YTrswV5NtDmpWB4lEXPOl7r8ZgY07vwR44awo1UBhiEaCT2z2qAtUebpyHZO4nNWAbrl/SIvbdm0AiycWvXFF5LUoxxQTpGl5z3tFU9fyB6rdIdgw/UwUJXhW6nMSyP0BA04MlvtwmwXzsyn/K0aJoxTz4sodmmuyoOtpUvqAOo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763508506; c=relaxed/simple; bh=RKdmMC42/iIVW4UaIPvvt7Lznoqyt8RCKocFexndvlo=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=HlW0TthVkR1D+Q6FNKS3RrPIprv/12UHDSHE6UutEHAOLDgTHABX81igkMoMJB23mbVxtEqJX5ouuwWPeoXk2PxIhskddduSr2v33TPqzlV+PAO0tAdgWkbe6/tQsJpecgO0E4Pp+RphyzaEEVg3w/xfVamSgxY14YgTBd5eg+w= 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=2tsiYycA; 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="2tsiYycA" Received: by mail-pl1-f202.google.com with SMTP id d9443c01a7336-297dfae179bso148189695ad.1 for ; Tue, 18 Nov 2025 15:28:24 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1763508504; x=1764113304; darn=vger.kernel.org; h=content-transfer-encoding:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:from:to:cc:subject:date:message-id :reply-to; bh=FDLwWg9J1rvmjJToyLqj0Znttc1W1NHhLEmVjPp5KVk=; b=2tsiYycAEdq7/qodl+/DbeIFb+mxEbHXDxtBaScQdo6Nydy/cDVfpv2fmB9qMw/F6A BRJgmks8mYOAQRI+0N7fS59qC+J1SnZLXnjgv2g5e9Kpok5qhlrT1vrL/3FvN99NMR99 uN6C43eIEiNutsaczjjIob3Coaq85RGZBu7c5KKpKPv8ZNOQaEjZX1KA11/D9PjhvbLK wQSjod7uuGmEChD+xgY5X6WUdaQCEQG7+kPpRvcxg0/geeDT3VgLMh6hsbBzLpzCHYyr KFRZ4HCqphcAI/qvz+Dc+KDXWGdjZQjQz9o793wTSREAcrrS/EuTbeozhz6nmw+Z020R Kkkg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1763508504; x=1764113304; h=content-transfer-encoding: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=FDLwWg9J1rvmjJToyLqj0Znttc1W1NHhLEmVjPp5KVk=; b=AG50LSF3xQEHKr3YhBqEjXmagBBrCeRdc9xkBwQGGSD3Aut5XzP6HQ61mw5aldJ/VK KV3lq69hUewxTCjRDaMz0AQ+y/iUChwXqFunvIYEhyzROKwe0DIQZnSThfja/rKy4zkp x4VQ5+B+THhO5GY1ToyF1OS5yilbcgyCa1jPfbzVnqNIwB2zlFHu6V8oWFJnetl/cMQB bOQcoxGQLrgfuzhVIcAhyN37H7ZUsMsUTP4bvwN1fPWV/+/CPWWoe3vVoKmYc5zuoK3J auCg4b+syvAbmtMHeOk/tCMxNLmzANhdpGyebcHLqgAcoVHtitZU/O0mjSzFlgDXPAKc QzLg== X-Forwarded-Encrypted: i=1; AJvYcCWIo1GEZTLELuXczGtgRny84zYIhpuyLupylk3qRZlh1etWQJFvpNLsiCXM5OHR6HAsj2pG8yPeTk1BNEI=@vger.kernel.org X-Gm-Message-State: AOJu0YxjQbo45c7IfRMZacPPc8pE4cdD2ZoaL51v8wbqC3ZRpYr+5+2s MRVoiY5a4PXRVp8p31xA7IFj6tbigpV94UP4+aYXTRR7etxIWtuwSAuV6CAMxGg/YSjvqlvoRvy e1s6Zzg== X-Google-Smtp-Source: AGHT+IH0bu0OBswoopYcZzWlNO7RR5DVt2xehpznuFywGpO6c6WAdcd0Fqy753Gyg7xe4xkiody224xp/pI= X-Received: from plhz15.prod.google.com ([2002:a17:902:d9cf:b0:298:3e35:3e78]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:903:2c03:b0:297:f2d6:17b2 with SMTP id d9443c01a7336-29a054a622dmr8506545ad.40.1763508503765; Tue, 18 Nov 2025 15:28:23 -0800 (PST) Date: Tue, 18 Nov 2025 15:27:50 -0800 In-Reply-To: <20251030223757.2950309-1-yosry.ahmed@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20251030223757.2950309-1-yosry.ahmed@linux.dev> X-Mailer: git-send-email 2.52.0.rc1.455.g30608eb744-goog Message-ID: <176350814750.2284663.7850374301770413168.b4-ty@google.com> Subject: Re: [PATCH] KVM: x86: Document a virtualization gap for GIF on AMD CPUs From: Sean Christopherson To: Sean Christopherson , Yosry Ahmed Cc: Paolo Bonzini , Jim Mattson , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable On Thu, 30 Oct 2025 22:37:57 +0000, Yosry Ahmed wrote: > According to the APM Volume #2, Section 15.17, Table 15-10 (24593=E2=80= =94Rev. > 3.42=E2=80=94March 2024), When "GIF=3D=3D0", an "Debug exception or trap,= due to > breakpoint register match" should be "Ignored and discarded". >=20 > KVM lacks any handling of this. Even when vGIF is enabled and vGIF=3D=3D0= , > the CPU does not ignore #DBs and relies on the VMM to do so. >=20 > [...] Applied to kvm-x86 svm, thanks! [1/1] KVM: x86: Document a virtualization gap for GIF on AMD CPUs https://github.com/kvm-x86/linux/commit/9f4ce4878878 -- https://github.com/kvm-x86/linux/tree/next