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 57846171A1 for ; Mon, 22 May 2023 19:21:31 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CC92CC433EF; Mon, 22 May 2023 19:21:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1684783291; bh=Z2i5aSkmJsMunBpgbl3Pdi0FR/dx/JbOtYWynnp15cQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mnjQ74JUcCmdzgi8wyCuk4O9r3NnLnjPqwyhW0KdG+ffHiLnifFbhYIdGNpogsTBB SVhx5vxcBxep0VqUqfqQ1Q1nOLiV9B+vY8pwFRQQbomjxOtEd9f6881WjW1L7tZAat GC1IQwc3YlKjF/gubhxhndl0kBtG1dJqUjEkNCLo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Benjamin Block , Steffen Maier , Heiko Carstens , Alexander Gordeev Subject: [PATCH 5.15 200/203] s390/qdio: fix do_sqbs() inline assembly constraint Date: Mon, 22 May 2023 20:10:24 +0100 Message-Id: <20230522190400.581111691@linuxfoundation.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230522190354.935300867@linuxfoundation.org> References: <20230522190354.935300867@linuxfoundation.org> User-Agent: quilt/0.67 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 From: Heiko Carstens commit 2862a2fdfae875888e3c1c3634e3422e01d98147 upstream. Use "a" constraint instead of "d" constraint to pass the state parameter to the do_sqbs() inline assembly. This prevents that general purpose register zero is used for the state parameter. If the compiler would select general purpose register zero this would be problematic for the used instruction in rsy format: the register used for the state parameter is a base register. If the base register is general purpose register zero the contents of the register are unexpectedly ignored when the instruction is executed. This only applies to z/VM guests using QIOASSIST with dedicated (pass through) QDIO-based devices such as FCP [zfcp driver] as well as real OSA or HiperSockets [qeth driver]. A possible symptom for this case using zfcp is the following repeating kernel message pattern: zfcp : A QDIO problem occurred zfcp : A QDIO problem occurred zfcp : qdio: ZFCP on SC using AI:1 QEBSM:1 PRI:1 TDD:1 SIGA: W zfcp : A QDIO problem occurred zfcp : A QDIO problem occurred Each of the qdio problem message can be accompanied by the following entries for the affected subchannel in /sys/kernel/debug/s390dbf/qdio_error/hex_ascii for zfcp or qeth: ccq: 69.... SQBS ERROR. Reviewed-by: Benjamin Block Cc: Steffen Maier Fixes: 8129ee164267 ("[PATCH] s390: qdio V=V pass-through") Cc: Signed-off-by: Heiko Carstens Signed-off-by: Alexander Gordeev Signed-off-by: Greg Kroah-Hartman --- drivers/s390/cio/qdio.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/s390/cio/qdio.h b/drivers/s390/cio/qdio.h index 5ea6249d8180..641f0dbb65a9 100644 --- a/drivers/s390/cio/qdio.h +++ b/drivers/s390/cio/qdio.h @@ -95,7 +95,7 @@ static inline int do_sqbs(u64 token, unsigned char state, int queue, " lgr 1,%[token]\n" " .insn rsy,0xeb000000008a,%[qs],%[ccq],0(%[state])" : [ccq] "+&d" (_ccq), [qs] "+&d" (_queuestart) - : [state] "d" ((unsigned long)state), [token] "d" (token) + : [state] "a" ((unsigned long)state), [token] "d" (token) : "memory", "cc", "1"); *count = _ccq & 0xff; *start = _queuestart & 0xff; -- 2.40.1