linux-kernel - [PATCH v4 16/17] dmaengine: idxd: add new wq state for mdev

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Date:   Fri, 30 Oct 2020 11:52:39 -0700
From:   Dave Jiang <dave.jiang@...el.com>
To:     vkoul@...nel.org, megha.dey@...el.com, maz@...nel.org,
        bhelgaas@...gle.com, tglx@...utronix.de,
        alex.williamson@...hat.com, jacob.jun.pan@...el.com,
        ashok.raj@...el.com, jgg@...lanox.com, yi.l.liu@...el.com,
        baolu.lu@...el.com, kevin.tian@...el.com, sanjay.k.kumar@...el.com,
        tony.luck@...el.com, jing.lin@...el.com, dan.j.williams@...el.com,
        kwankhede@...dia.com, eric.auger@...hat.com, parav@...lanox.com,
        jgg@...lanox.com, rafael@...nel.org, netanelg@...lanox.com,
        shahafs@...lanox.com, yan.y.zhao@...ux.intel.com,
        pbonzini@...hat.com, samuel.ortiz@...el.com, mona.hossain@...el.com
Cc:     dmaengine@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-pci@...r.kernel.org, kvm@...r.kernel.org
Subject: [PATCH v4 16/17] dmaengine: idxd: add new wq state for mdev

When a dedicated wq is enabled as mdev, we must disable the wq on the
device in order to program the pasid to the wq. Introduce a wq state
IDXD_WQ_LOCKED that is software state only in order to prevent the user
from modifying the configuration while mdev wq is in this state. While
in this state, the wq is not in DISABLED state and will prevent any
modifications to the configuration. It is also not in the ENABLED state
and therefore prevents any actions allowed in the ENABLED state.

Signed-off-by: Dave Jiang <dave.jiang@...el.com>
---
 drivers/dma/idxd/idxd.h  |    1 +
 drivers/dma/idxd/mdev.c  |    4 +++-
 drivers/dma/idxd/sysfs.c |    2 ++
 3 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/dma/idxd/idxd.h b/drivers/dma/idxd/idxd.h
index 4e583fdd15d2..03275ad9e849 100644
--- a/drivers/dma/idxd/idxd.h
+++ b/drivers/dma/idxd/idxd.h
@@ -61,6 +61,7 @@ struct idxd_group {
 enum idxd_wq_state {
 	IDXD_WQ_DISABLED = 0,
 	IDXD_WQ_ENABLED,
+	IDXD_WQ_LOCKED,
 };
 
 enum idxd_wq_flag {
diff --git a/drivers/dma/idxd/mdev.c b/drivers/dma/idxd/mdev.c
index 16b56f8f7fc1..3db7717a10c0 100644
--- a/drivers/dma/idxd/mdev.c
+++ b/drivers/dma/idxd/mdev.c
@@ -84,8 +84,10 @@ static void idxd_vdcm_init(struct vdcm_idxd *vidxd)
 
 	vidxd_mmio_init(vidxd);
 
-	if (wq_dedicated(wq) && wq->state == IDXD_WQ_ENABLED)
+	if (wq_dedicated(wq) && wq->state == IDXD_WQ_ENABLED) {
 		idxd_wq_disable(wq, NULL);
+		wq->state = IDXD_WQ_LOCKED;
+	}
 }
 
 static void idxd_vdcm_release(struct mdev_device *mdev)
diff --git a/drivers/dma/idxd/sysfs.c b/drivers/dma/idxd/sysfs.c
index 5b79d9019f2e..3bbbd413980e 100644
--- a/drivers/dma/idxd/sysfs.c
+++ b/drivers/dma/idxd/sysfs.c
@@ -821,6 +821,8 @@ static ssize_t wq_state_show(struct device *dev,
 		return sprintf(buf, "disabled\n");
 	case IDXD_WQ_ENABLED:
 		return sprintf(buf, "enabled\n");
+	case IDXD_WQ_LOCKED:
+		return sprintf(buf, "locked\n");
 	}
 
 	return sprintf(buf, "unknown\n");