From 9b768e8a3909ac1ab39ed44a3933716da7761a6f Mon Sep 17 00:00:00 2001
From: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Date: Tue, 28 Sep 2021 12:44:29 +0100
Subject: [PATCH] crypto: qat - detect PFVF collision after ACK
Git-commit: 9b768e8a3909ac1ab39ed44a3933716da7761a6f
References: git-fixes
Patch-mainline: v5.16-rc1

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: Oliver Neukum <oneukum@suse.com>
---
 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 976b9ab7617c..789a4135e28c 100644
--- a/drivers/crypto/qat/qat_common/adf_pf2vf_msg.c
+++ b/drivers/crypto/qat/qat_common/adf_pf2vf_msg.c
@@ -156,6 +156,13 @@ 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;
-- 
2.26.2