From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 4A4EE3AA9DA for ; Sun, 19 Jul 2026 15:48:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784476092; cv=none; b=GutibzfBRWlTHeTSyLHD1s8NcfHM3s7hxXCXCHPq7wb3lQ2TY1vBfe7XIPrp9z5xnOQfM8yAK6fJGg0IrjQr5sOdyhNPmXyyIH5THzs94Q15lK1IQ1o2L1mCT3h5ESI0Ii1IKJUbieK/eOoZ6RaQX96LNCDG3J4V9syijm9KgM8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784476092; c=relaxed/simple; bh=Cyrtv8mN6joNkVTYO5UTB0S31EfN+o/0iDq22RmQj50=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=GQfTytN+xeeTgaAFU+2uz8zToGUSy4juqKBDyW/fuT3QTe1R59uWZ+XCan7dF9N0qiDNyCfj3sKjzH7DovX5t7OqoD+aMjtPGS7OZ0RV+adgXt653i90x4Yy1cGsxBtFyE7J62TBksJV48lh+L6ocoWtI1o8dOZO6O9ALC8I9cY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ep6LUGB/; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="ep6LUGB/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AE0E51F000E9; Sun, 19 Jul 2026 15:48:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784476091; bh=gnzCcA6tppyCDk8OtNCFSbbls8ksCEv5tPbmwlYGUAI=; h=From:To:Cc:Subject:Date:Reply-To; b=ep6LUGB/JBRZuEtprQrBodL35Z2reO5G819/+ryePDucPMkTClOQrvD093oRHPm45 OTgIGoarfHebRUZC3pMJGv4vB8Gr/P9+OIVGHHaTfJJIwUTSnWjfks9RPSQJryZ853 x3kkQhS3ryM/WbDvCY2i3MLN3H6Ose9ERjqHMvoc= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-64172: KVM: SVM: Disable AVIC IPI virtualization on Hygon Family 18h (erratum #1235) Date: Sun, 19 Jul 2026 17:40:34 +0200 Message-ID: <2026071936-CVE-2026-64172-c960@gregkh> X-Mailer: git-send-email 2.55.0 Reply-To: , Precedence: bulk X-Mailing-List: linux-cve-announce@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2699; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=aSLSqAVfxvDvqs1MkyDTHoF7BwIZPXg0MNdveo2bAfk=; b=owGbwMvMwCRo6H6F97bub03G02pJDFkx72tOv2V9v7Ck9+SD3IQHr204t+xx+JtbrXrqqqk5D 89PvVD+jlgWBkEmBlkxRZYv23iO7q84pOhlaHsaZg4rE8gQBi5OAZiIYQHDgqbK/5UNZqK3D9ip zkpodPsr9IRpJsP8+m7lpIkLK36YOVs/ZXv6pOlB4cE1AA== X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 Content-Transfer-Encoding: 8bit From: Greg Kroah-Hartman Description =========== In the Linux kernel, the following vulnerability has been resolved: KVM: SVM: Disable AVIC IPI virtualization on Hygon Family 18h (erratum #1235) Hygon Family 18h CPUs are derived from AMD Family 17h (Zen1) silicon and share the same erratum #1235: hardware may read a stale IsRunning=1 bit during ICR write emulation and silently fail to generate an AVIC_IPI_FAILURE_TARGET_NOT_RUNNING VM-Exit on the sending vCPU. The absence of the VM-Exit causes KVM to miss the required wakeup of blocking target vCPUs, leading to hung vCPUs and unbounded delays in guest execution. Extend the existing AMD Family 17h erratum #1235 workaround to also cover Hygon Family 18h. With IPI virtualization disabled, KVM never sets IsRunning=1 in the Physical ID table, so every non-self IPI generates a VM-Exit and is correctly emulated. The Linux kernel CVE team has assigned CVE-2026-64172 to this issue. Affected and fixed versions =========================== Issue introduced in 6.17 with commit 8de4a1c8164e5b2e40d1df764840a31de983f40b and fixed in 6.18.34 with commit 94ade38f317ea086a181db0e6b69c574b3b70a5e Issue introduced in 6.17 with commit 8de4a1c8164e5b2e40d1df764840a31de983f40b and fixed in 7.0.11 with commit 9560e6fee887a9594a89fa265b5b9c79b1591803 Issue introduced in 6.17 with commit 8de4a1c8164e5b2e40d1df764840a31de983f40b and fixed in 7.1 with commit 9a12fa5213cfc391e0eed63902d3be98f0913765 Please see https://www.kernel.org for a full list of currently supported kernel versions by the kernel community. Unaffected versions might change over time as fixes are backported to older supported kernel versions. The official CVE entry at https://cve.org/CVERecord/?id=CVE-2026-64172 will be updated if fixes are backported, please check that for the most up to date information about this issue. Affected files ============== The file(s) affected by this issue are: arch/x86/kvm/svm/avic.c Mitigation ========== The Linux kernel CVE team recommends that you update to the latest stable kernel version for this, and many other bugfixes. Individual changes are never tested alone, but rather are part of a larger kernel release. Cherry-picking individual commits is not recommended or supported by the Linux kernel community at all. If however, updating to the latest release is impossible, the individual changes to resolve this issue can be found at these commits: https://git.kernel.org/stable/c/94ade38f317ea086a181db0e6b69c574b3b70a5e https://git.kernel.org/stable/c/9560e6fee887a9594a89fa265b5b9c79b1591803 https://git.kernel.org/stable/c/9a12fa5213cfc391e0eed63902d3be98f0913765