From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 DA7F7332EAF; Mon, 29 Dec 2025 16:30:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767025859; cv=none; b=fhRVDO+klIkREW1rThiagbckYmLy1iWWlN81nRs9DVD2nZ0WxifgYWy2nOwpbRbawXBXwR1kblRTAK4NHdzu44jM3opl+W0n8n9VGnCm9A6N7Kwupb0MXvQRWrc9HdCqPcbZ4g5l0RX3zSL5ZYjJZVd8hFthDSNFULrvW2NBt2Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767025859; c=relaxed/simple; bh=9yWTxMBMPRFnan4JmKrHp/v8JKwlt27P37WYX3KwEo8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=btHN3Pu5YLIX6YsnFxI2bFF1mnz+sTvuxf37E/dNRX4+JLxFOISJL52tY0O+cKJCrS7gczb8sgCSwE0XTaLsPI4NmRU9tzWSdrP7LPU8a2SmA2r9lQMfqq/bDmUyljNv5aKHg+jGU30L4IxRb6/IMnHNtQZw9SemFMFl2VBZGxU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=srISrcZP; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="srISrcZP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 65BF5C19421; Mon, 29 Dec 2025 16:30:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1767025859; bh=9yWTxMBMPRFnan4JmKrHp/v8JKwlt27P37WYX3KwEo8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=srISrcZPyy+IB+Duq4PUAoWpMDVO4OHfdNifTRaqPfpZSSrHo9K7Z5GbZHoazKk+I Ps4GOdjijzLyJIVf7oy4d6Po7mMQZyc4OftmV0cr3h1xRbO8xemZnC0/rj8rY8L2nv OXHFc1+RSHqWnOn8cPXUYiObv9nqkfBREB/JpGj0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Matteo Rizzo , Yosry Ahmed , Sean Christopherson Subject: [PATCH 6.18 345/430] KVM: nSVM: Propagate SVM_EXIT_CR0_SEL_WRITE correctly for LMSW emulation Date: Mon, 29 Dec 2025 17:12:27 +0100 Message-ID: <20251229160737.024525269@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20251229160724.139406961@linuxfoundation.org> References: <20251229160724.139406961@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Yosry Ahmed commit 5674a76db0213f9db1e4d08e847ff649b46889c0 upstream. When emulating L2 instructions, svm_check_intercept() checks whether a write to CR0 should trigger a synthesized #VMEXIT with SVM_EXIT_CR0_SEL_WRITE. For MOV-to-CR0, SVM_EXIT_CR0_SEL_WRITE is only triggered if any bit other than CR0.MP and CR0.TS is updated. However, according to the APM (24593—Rev. 3.42—March 2024, Table 15-7): The LMSW instruction treats the selective CR0-write intercept as a non-selective intercept (i.e., it intercepts regardless of the value being written). Skip checking the changed bits for x86_intercept_lmsw and always inject SVM_EXIT_CR0_SEL_WRITE. Fixes: cfec82cb7d31 ("KVM: SVM: Add intercept check for emulated cr accesses") Cc: stable@vger.kernel.org Reported-by: Matteo Rizzo Signed-off-by: Yosry Ahmed Link: https://patch.msgid.link/20251024192918.3191141-3-yosry.ahmed@linux.dev Signed-off-by: Sean Christopherson Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/svm/svm.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -4553,20 +4553,20 @@ static int svm_check_intercept(struct kv if (info->intercept == x86_intercept_clts) break; - cr0 = vcpu->arch.cr0 & ~SVM_CR0_SELECTIVE_MASK; - val = info->src_val & ~SVM_CR0_SELECTIVE_MASK; - + /* LMSW always triggers INTERCEPT_SELECTIVE_CR0 */ if (info->intercept == x86_intercept_lmsw) { - cr0 &= 0xfUL; - val &= 0xfUL; - /* lmsw can't clear PE - catch this here */ - if (cr0 & X86_CR0_PE) - val |= X86_CR0_PE; + icpt_info.exit_code = SVM_EXIT_CR0_SEL_WRITE; + break; } + /* + * MOV-to-CR0 only triggers INTERCEPT_SELECTIVE_CR0 if any bit + * other than SVM_CR0_SELECTIVE_MASK is changed. + */ + cr0 = vcpu->arch.cr0 & ~SVM_CR0_SELECTIVE_MASK; + val = info->src_val & ~SVM_CR0_SELECTIVE_MASK; if (cr0 ^ val) icpt_info.exit_code = SVM_EXIT_CR0_SEL_WRITE; - break; } case SVM_EXIT_READ_DR0: