From nobody Sun Feb 8 23:25:14 2026 Received: from mail-pj1-f73.google.com (mail-pj1-f73.google.com [209.85.216.73]) (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 48F8713C800 for ; Thu, 4 Apr 2024 23:40:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.73 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712274015; cv=none; b=eWONwe4J6azNiDaZpHTVtK5MDeBOCeGNkQi+vSPczzh4vP5+sr8VWbPWF8N3LDvd+4JuBtUPFYsr49NkfDSVASV9hPx5XhbAmncFx6cDy5JPF6jWzBUm5HDH9SMWHWVyOWKlVE/IQs0kSIZ1SX4DrATCX8MvIZG5bPHYzbBzu9I= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712274015; c=relaxed/simple; bh=ShNXKTKxsoV1gidL/jCEGh1UXFa8beTlPBREvu3TALk=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=o8Tu44bm6S6ViLtoN0fjTW4/HpbIUK318zOkShU8SsJ9hz5y5YO1Ye2ACcDshiApXJGW1ufb5Zn9eOqvG8fVpTF398CLbwIZhNpyjV1rz4FbmZRNmuNER/ubtI1F/lu4iZcfueqnLLegN8Y7UjqgUrfdOIFs5BZredR6nb4c8ic= 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=OHR03Hm4; arc=none smtp.client-ip=209.85.216.73 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="OHR03Hm4" Received: by mail-pj1-f73.google.com with SMTP id 98e67ed59e1d1-2a2fec91d48so467184a91.2 for ; Thu, 04 Apr 2024 16:40:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1712274013; x=1712878813; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=++a/hvLgm2LFaPeq7sJT2WCGQZL19kelVmxT81YyZ+I=; b=OHR03Hm4Yz6teVrcBEDj7uZYxtI/wK8o3p/VJxPH9QSOOUt441UucrN3CFoJG9ytlh 8Wp2XnVg0rlKEsBzmbVjJx9XVoNcjdo5ZqA/FFlK8QagQeW9y+GucU1zKp/Z+1opadLG oS2vQ8Seofa5U36TUJzSoDqjbKbHld7YeqMGv3XgNF+p/l6eBpq04VfD7pfumuKv/fmp Rv89YUjYDuuR0ORxarFdlWX6/2SNNpTjfb1K/J4PkxeZaYNrqr9alRLOkgunNWw3gCRl m0u14fFC/k3WmbI3ykFb6CV44CyVeSKXM/usj/1iatqCLZkdNB5QZL56a8D3ezMoRi8E p7Vg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1712274013; x=1712878813; h=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; bh=++a/hvLgm2LFaPeq7sJT2WCGQZL19kelVmxT81YyZ+I=; b=kN0ZmvU8JDJx3gIRuqqldksRbuaD0bhwxa566kd1pP0hE8ruwEPR97ylFDCTJKQ+2A qABGE3gqmlck58rFSJZRixpuw+T3+TpcOpXUjD/USGUQDRykK3bnUDkrcvdZd/TeTjEr 6iB2dlEl4tPnuWeBTd3WUMniTRvNqWyaTigBwdQVdUdh/Oo0no6UixpL7cZp7YN/1oTz FR7uUWm9O1fWBXWubkztLcliinOxg23c0qtAtgEdLfJUaSDSCy6bIggTpNaMKPXetUw4 8RgKUvEkVb9W3fJMadNjKw2UTY7k/qzjW42K9T2ehyBU7VrVOPgVV8wT7PTVdGBNLsOZ r6Dg== X-Forwarded-Encrypted: i=1; AJvYcCVoiylRZodpDPKLTsDo2HA5zrB0+P4stby0h+FbL/xYdpLD+/qJfMpSq5zsi1vqoOzdqOUqkC88p3TKtQje9a1mGusccWWByeFvRzdc X-Gm-Message-State: AOJu0YyXOhjFky7EKdkx1VCKc5V+ovZIYWB6xDE58aFboYj/L4HuOMmD w1v7JpugxmQ3IKrhrAi+BqnAi2manPa5o9KTVUxsSZ5rrP+Nx9yvPn8r4f5zLTtRtF6Mi/Qoj1z P8g== X-Google-Smtp-Source: AGHT+IFXyQGRwEJ/4fWcQaCNTSSexyUuvyDvbAc15+ionqqlW/lDl07k9yVGUcTvt59QeDxRQ5kPXvAaaLQ= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a17:903:41c9:b0:1e0:bae4:490e with SMTP id u9-20020a17090341c900b001e0bae4490emr38806ple.13.1712274013568; Thu, 04 Apr 2024 16:40:13 -0700 (PDT) Reply-To: Sean Christopherson Date: Thu, 4 Apr 2024 16:40:03 -0700 In-Reply-To: <20240404234004.911293-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240404234004.911293-1-seanjc@google.com> X-Mailer: git-send-email 2.44.0.478.gd926399ef9-goog Message-ID: <20240404234004.911293-2-seanjc@google.com> Subject: [PATCH 5.15 1/2] KVM: x86: Bail to userspace if emulation of atomic user access faults From: Sean Christopherson To: stable@vger.kernel.org, Greg Kroah-Hartman Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Sean Christopherson , Paolo Bonzini , David Matlack , Pasha Tatashin , Michael Krebs , Jim Mattson Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Upstream commit 5d6c7de6446e9ab3fb41d6f7d82770e50998f3de. Exit to userspace when emulating an atomic guest access if the CMPXCHG on the userspace address faults. Emulating the access as a write and thus likely treating it as emulated MMIO is wrong, as KVM has already confirmed there is a valid, writable memslot. Signed-off-by: Sean Christopherson Message-Id: <20220202004945.2540433-6-seanjc@google.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/x86.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index aa6f700f8c5f..a9c26397dcfd 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -7105,7 +7105,7 @@ static int emulator_cmpxchg_emulated(struct x86_emula= te_ctxt *ctxt, } =20 if (r < 0) - goto emul_write; + return X86EMUL_UNHANDLEABLE; if (r) return X86EMUL_CMPXCHG_FAILED; =20 --=20 2.44.0.478.gd926399ef9-goog