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 5EEE535AC03; Fri, 4 Sep 2026 06:05:39 +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=1788501940; cv=none; b=r0zWLJab4EmFYUzu64l73i41Xt00rEWuZmAbHAw5bLczX3FVpbuK/9ZJqpsCusMjj9FcF42+aQ5VKrMBWJkhE4O+uISsQYsceFy4qjdGk0+HS51lS3CoZXA1VGHLCmJs36vXWEE/amXGLrQDzW5G22byK5xRphhk21RUSbexUwI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788501940; c=relaxed/simple; bh=/py6J0KeFkVVCkEbqCbm2ukZvQa351aXsTjwfI1L0bA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=HFvRRu6C5G0xMuoJpKYpD8lyIOTPHCwaAtG3n5L9IJYdlwntHdgrkM4lPdyY39SR5QPBhLF5vbVZDfmmqSbFmajs1RcnBljjX0v4JH3/C7W/IZZ7OHZi8+VYfyzVGyK1y63RI+Wx+AceYsJw9D7rSdYvh0T+9o+y7uvJFh4jOSE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=fsof4M57; 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="fsof4M57" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AFBA71F00A3D; Fri, 4 Sep 2026 06:05:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788501939; bh=CLNnOjihf3Wxp0K/aqJGXaYapo3i7mRmsOMUcjlvGUc=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=fsof4M57ksXSAkt52/ap086drVbeq3NQ2YcIaiIRQBD+gVbXGIMrdw1kHZXCeXMZI QtnoT/jPuVBKS8p06liSf76Ll/wN1d9etSBLuClyGVXmeSVNkpAbt0ApFlVWQRT+aA pExLo7E5kJx/G+r2+5tIyCSH6EMDC44WuCaU0QXY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Borys Tsyrulnikov , "Kiryl Shutsemau (Meta)" , Dave Hansen , Binbin Wu Subject: [PATCH 6.12 032/403] x86/tdx: Fix zero-extension for 32-bit port I/O Date: Fri, 4 Sep 2026 06:57:15 +0200 Message-ID: <20260904045735.544739033@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260904045734.806166532@linuxfoundation.org> References: <20260904045734.806166532@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-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kiryl Shutsemau (Meta) commit 941370fc93cc3474e26811f4d3b062903eefe2cf upstream. According to x86 architecture rules, 32-bit operations zero-extend the result to 64 bits. The current implementation of handle_in() only masks the lower 32 bits, which preserves the upper 32 bits of RAX when a 32-bit port IN instruction is emulated. Use insn_assign_reg() to write the result back into RAX with proper partial-register-write semantics: 1- and 2-byte forms leave the upper bits untouched, the 4-byte form zero-extends to the full register. Fixes: 03149948832a ("x86/tdx: Port I/O: Add runtime hypercalls") Reported-by: Borys Tsyrulnikov Signed-off-by: Kiryl Shutsemau (Meta) Signed-off-by: Dave Hansen Reviewed-by: Binbin Wu Link: https://lore.kernel.org/all/CAKw_Dz96rfSQc6Rn+9QBcUFHhmkK+9zu+P=bxowfZwxrATCBRg@mail.gmail.com/ Cc:stable@vger.kernel.org Link: https://patch.msgid.link/20260713133753.223947-4-kirill@shutemov.name Signed-off-by: Greg Kroah-Hartman --- arch/x86/coco/tdx/tdx.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) --- a/arch/x86/coco/tdx/tdx.c +++ b/arch/x86/coco/tdx/tdx.c @@ -606,8 +606,8 @@ static bool handle_in(struct pt_regs *re .r13 = PORT_READ, .r14 = port, }; - u64 mask = GENMASK(BITS_PER_BYTE * size - 1, 0); bool success; + u64 val; /* * Emulate the I/O read via hypercall. More info about ABI can be found @@ -615,11 +615,9 @@ static bool handle_in(struct pt_regs *re * "TDG.VP.VMCALL". */ success = !__tdx_hypercall(&args); + val = success ? args.r11 : 0; - /* Update part of the register affected by the emulated instruction */ - regs->ax &= ~mask; - if (success) - regs->ax |= args.r11 & mask; + insn_assign_reg(®s->ax, val, size); return success; }