From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Giovanni Cabiddu <giovanni.cabiddu@intel.com>,
        Marco Chiappero <marco.chiappero@intel.com>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.4 075/162] crypto: qat - detect PFVF collision after ACK
Date:   Wed, 24 Nov 2021 12:56:18 +0100
Message-Id: <20211124115700.744685132@linuxfoundation.org>
In-Reply-To: <20211124115658.328640564@linuxfoundation.org>
References: <20211124115658.328640564@linuxfoundation.org>
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From: Giovanni Cabiddu <giovanni.cabiddu@intel.com>

[ Upstream commit 9b768e8a3909ac1ab39ed44a3933716da7761a6f ]

Detect a PFVF collision between the local and the remote function by
checking if the message on the PFVF CSR has been overwritten.
This is done after the remote function confirms that the message has
been received, by clearing the interrupt bit, or the maximum number of
attempts (ADF_IOV_MSG_ACK_MAX_RETRY) to check the CSR has been exceeded.

Fixes: ed8ccaef52fa ("crypto: qat - Add support for SRIOV")
Signed-off-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Co-developed-by: Marco Chiappero <marco.chiappero@intel.com>
Signed-off-by: Marco Chiappero <marco.chiappero@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/crypto/qat/qat_common/adf_pf2vf_msg.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/crypto/qat/qat_common/adf_pf2vf_msg.c b/drivers/crypto/qat/qat_common/adf_pf2vf_msg.c
index 711706819b05d..7e45c21a61657 100644
--- a/drivers/crypto/qat/qat_common/adf_pf2vf_msg.c
+++ b/drivers/crypto/qat/qat_common/adf_pf2vf_msg.c
@@ -218,6 +218,13 @@ static int __adf_iov_putmsg(struct adf_accel_dev *accel_dev, u32 msg, u8 vf_nr)
 		val = ADF_CSR_RD(pmisc_bar_addr, pf2vf_offset);
 	} while ((val & int_bit) && (count++ < ADF_IOV_MSG_ACK_MAX_RETRY));
 
+	if (val != msg) {
+		dev_dbg(&GET_DEV(accel_dev),
+			"Collision - PFVF CSR overwritten by remote function\n");
+		ret = -EIO;
+		goto out;
+	}
+
 	if (val & int_bit) {
 		dev_dbg(&GET_DEV(accel_dev), "ACK not received from remote\n");
 		val &= ~int_bit;
-- 
2.33.0