[PATCH v2 0/4] vdpa_sim_blk: add support for flush, discard, and write-zeroes

[PATCH v2 0/4] vdpa_sim_blk: add support for flush, discard, and write-zeroes

[Stefano Garzarella]

The first 2 patches are in preparation and generalize parts later used
by the following patches that add handling of flush, discard, and
write-zeroes requests.

v2:
- rebased on https://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git
- used dev_dbg() to print errors [Jason]
- moved sector to be 0 checking to another patch and generalized for
  other requests
- modified vdpasim_blk_check_range() to be used also with discard and
  write-zeroes
- added discard and write-zeroes requests handling

v1: https://lore.kernel.org/virtualization/20220428151242.213824-1-sgarzare@redhat.com/

Tree available here:
https://gitlab.com/sgarzarella/linux.git vdpa-sim-blk-flush-discard-wz

Thanks,
Stefano

Stefano Garzarella (4):
  vdpa_sim_blk: check if sector is 0 for commands other than read or
    write
  vdpa_sim_blk: make vdpasim_blk_check_range usable by other requests
  vdpa_sim_blk: add support for VIRTIO_BLK_T_FLUSH
  vdpa_sim_blk: add support for discard and write-zeroes

 drivers/vdpa/vdpa_sim/vdpa_sim_blk.c | 127 +++++++++++++++++++++++----
 1 file changed, 111 insertions(+), 16 deletions(-)

-- 
2.37.1

[PATCH v2 0/4] vdpa_sim_blk: add support for flush, discard, and write-zeroes

[Stefano Garzarella]

The first 2 patches are in preparation and generalize parts later used
by the following patches that add handling of flush, discard, and
write-zeroes requests.

v2:
- rebased on https://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git
- used dev_dbg() to print errors [Jason]
- moved sector to be 0 checking to another patch and generalized for
  other requests
- modified vdpasim_blk_check_range() to be used also with discard and
  write-zeroes
- added discard and write-zeroes requests handling

v1: https://lore.kernel.org/virtualization/20220428151242.213824-1-sgarzare@redhat.com/

Tree available here:
https://gitlab.com/sgarzarella/linux.git vdpa-sim-blk-flush-discard-wz

Thanks,
Stefano

Stefano Garzarella (4):
  vdpa_sim_blk: check if sector is 0 for commands other than read or
    write
  vdpa_sim_blk: make vdpasim_blk_check_range usable by other requests
  vdpa_sim_blk: add support for VIRTIO_BLK_T_FLUSH
  vdpa_sim_blk: add support for discard and write-zeroes

 drivers/vdpa/vdpa_sim/vdpa_sim_blk.c | 127 +++++++++++++++++++++++----
 1 file changed, 111 insertions(+), 16 deletions(-)

-- 
2.37.1

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[PATCH v2 1/4] vdpa_sim_blk: check if sector is 0 for commands other than read or write

[Stefano Garzarella]

VIRTIO spec states: "The sector number indicates the offset
(multiplied by 512) where the read or write is to occur. This field is
unused and set to 0 for commands other than read or write."

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
---
 drivers/vdpa/vdpa_sim/vdpa_sim_blk.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
index ba253f8bce32..69c9f4f36f9a 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
@@ -112,6 +112,15 @@ static bool vdpasim_blk_handle_req(struct vdpasim *vdpasim,
 	offset = sector << SECTOR_SHIFT;
 	status = VIRTIO_BLK_S_OK;
 
+	if (type != VIRTIO_BLK_T_IN && type != VIRTIO_BLK_T_OUT &&
+	    sector != 0) {
+		dev_dbg(&vdpasim->vdpa.dev,
+			"sector must be 0 for %u request - sector: 0x%llx\n",
+			type, sector);
+		status = VIRTIO_BLK_S_IOERR;
+		goto err_status;
+	}
+
 	switch (type) {
 	case VIRTIO_BLK_T_IN:
 		if (!vdpasim_blk_check_range(sector, to_push)) {
@@ -178,6 +187,7 @@ static bool vdpasim_blk_handle_req(struct vdpasim *vdpasim,
 		break;
 	}
 
+err_status:
 	/* If some operations fail, we need to skip the remaining bytes
 	 * to put the status in the last byte
 	 */
-- 
2.37.1

[PATCH v2 1/4] vdpa_sim_blk: check if sector is 0 for commands other than read or write

[Stefano Garzarella]

VIRTIO spec states: "The sector number indicates the offset
(multiplied by 512) where the read or write is to occur. This field is
unused and set to 0 for commands other than read or write."

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
---
 drivers/vdpa/vdpa_sim/vdpa_sim_blk.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
index ba253f8bce32..69c9f4f36f9a 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
@@ -112,6 +112,15 @@ static bool vdpasim_blk_handle_req(struct vdpasim *vdpasim,
 	offset = sector << SECTOR_SHIFT;
 	status = VIRTIO_BLK_S_OK;
 
+	if (type != VIRTIO_BLK_T_IN && type != VIRTIO_BLK_T_OUT &&
+	    sector != 0) {
+		dev_dbg(&vdpasim->vdpa.dev,
+			"sector must be 0 for %u request - sector: 0x%llx\n",
+			type, sector);
+		status = VIRTIO_BLK_S_IOERR;
+		goto err_status;
+	}
+
 	switch (type) {
 	case VIRTIO_BLK_T_IN:
 		if (!vdpasim_blk_check_range(sector, to_push)) {
@@ -178,6 +187,7 @@ static bool vdpasim_blk_handle_req(struct vdpasim *vdpasim,
 		break;
 	}
 
+err_status:
 	/* If some operations fail, we need to skip the remaining bytes
 	 * to put the status in the last byte
 	 */
-- 
2.37.1

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[PATCH v2 2/4] vdpa_sim_blk: make vdpasim_blk_check_range usable by other requests

[Stefano Garzarella]

Next patches will add handling of other requests, where will be
useful to reuse vdpasim_blk_check_range().
So let's make it more generic by adding the `max_sectors` parameter,
since different requests allow different numbers of maximum sectors.

Let's also print the messages directly in vdpasim_blk_check_range()
to avoid duplicate prints.

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
---
 drivers/vdpa/vdpa_sim/vdpa_sim_blk.c | 38 +++++++++++++++++-----------
 1 file changed, 23 insertions(+), 15 deletions(-)

diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
index 69c9f4f36f9a..24dd9cae6450 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
@@ -42,18 +42,28 @@
 
 static char vdpasim_blk_id[VIRTIO_BLK_ID_BYTES] = "vdpa_blk_sim";
 
-static bool vdpasim_blk_check_range(u64 start_sector, size_t range_size)
+static bool vdpasim_blk_check_range(struct vdpasim *vdpasim, u64 start_sector,
+				    u64 num_sectors, u64 max_sectors)
 {
-	u64 range_sectors = range_size >> SECTOR_SHIFT;
-
-	if (range_size > VDPASIM_BLK_SIZE_MAX * VDPASIM_BLK_SEG_MAX)
-		return false;
+	if (start_sector > VDPASIM_BLK_CAPACITY) {
+		dev_dbg(&vdpasim->vdpa.dev,
+			"starting sector exceeds the capacity - start: 0x%llx capacity: 0x%x\n",
+			start_sector, VDPASIM_BLK_CAPACITY);
+	}
 
-	if (start_sector > VDPASIM_BLK_CAPACITY)
+	if (num_sectors > max_sectors) {
+		dev_dbg(&vdpasim->vdpa.dev,
+			"number of sectors exceeds the max allowed in a request - num: 0x%llx max: 0x%llx\n",
+			num_sectors, max_sectors);
 		return false;
+	}
 
-	if (range_sectors > VDPASIM_BLK_CAPACITY - start_sector)
+	if (num_sectors > VDPASIM_BLK_CAPACITY - start_sector) {
+		dev_dbg(&vdpasim->vdpa.dev,
+			"request exceeds the capacity - start: 0x%llx num: 0x%llx capacity: 0x%x\n",
+			start_sector, num_sectors, VDPASIM_BLK_CAPACITY);
 		return false;
+	}
 
 	return true;
 }
@@ -123,10 +133,9 @@ static bool vdpasim_blk_handle_req(struct vdpasim *vdpasim,
 
 	switch (type) {
 	case VIRTIO_BLK_T_IN:
-		if (!vdpasim_blk_check_range(sector, to_push)) {
-			dev_dbg(&vdpasim->vdpa.dev,
-				"reading over the capacity - offset: 0x%llx len: 0x%zx\n",
-				offset, to_push);
+		if (!vdpasim_blk_check_range(vdpasim, sector,
+					     to_push >> SECTOR_SHIFT,
+					     VDPASIM_BLK_SIZE_MAX * VDPASIM_BLK_SEG_MAX)) {
 			status = VIRTIO_BLK_S_IOERR;
 			break;
 		}
@@ -146,10 +155,9 @@ static bool vdpasim_blk_handle_req(struct vdpasim *vdpasim,
 		break;
 
 	case VIRTIO_BLK_T_OUT:
-		if (!vdpasim_blk_check_range(sector, to_pull)) {
-			dev_dbg(&vdpasim->vdpa.dev,
-				"writing over the capacity - offset: 0x%llx len: 0x%zx\n",
-				offset, to_pull);
+		if (!vdpasim_blk_check_range(vdpasim, sector,
+					     to_pull >> SECTOR_SHIFT,
+					     VDPASIM_BLK_SIZE_MAX * VDPASIM_BLK_SEG_MAX)) {
 			status = VIRTIO_BLK_S_IOERR;
 			break;
 		}
-- 
2.37.1

[PATCH v2 2/4] vdpa_sim_blk: make vdpasim_blk_check_range usable by other requests

[Stefano Garzarella]

Next patches will add handling of other requests, where will be
useful to reuse vdpasim_blk_check_range().
So let's make it more generic by adding the `max_sectors` parameter,
since different requests allow different numbers of maximum sectors.

Let's also print the messages directly in vdpasim_blk_check_range()
to avoid duplicate prints.

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
---
 drivers/vdpa/vdpa_sim/vdpa_sim_blk.c | 38 +++++++++++++++++-----------
 1 file changed, 23 insertions(+), 15 deletions(-)

diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
index 69c9f4f36f9a..24dd9cae6450 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
@@ -42,18 +42,28 @@
 
 static char vdpasim_blk_id[VIRTIO_BLK_ID_BYTES] = "vdpa_blk_sim";
 
-static bool vdpasim_blk_check_range(u64 start_sector, size_t range_size)
+static bool vdpasim_blk_check_range(struct vdpasim *vdpasim, u64 start_sector,
+				    u64 num_sectors, u64 max_sectors)
 {
-	u64 range_sectors = range_size >> SECTOR_SHIFT;
-
-	if (range_size > VDPASIM_BLK_SIZE_MAX * VDPASIM_BLK_SEG_MAX)
-		return false;
+	if (start_sector > VDPASIM_BLK_CAPACITY) {
+		dev_dbg(&vdpasim->vdpa.dev,
+			"starting sector exceeds the capacity - start: 0x%llx capacity: 0x%x\n",
+			start_sector, VDPASIM_BLK_CAPACITY);
+	}
 
-	if (start_sector > VDPASIM_BLK_CAPACITY)
+	if (num_sectors > max_sectors) {
+		dev_dbg(&vdpasim->vdpa.dev,
+			"number of sectors exceeds the max allowed in a request - num: 0x%llx max: 0x%llx\n",
+			num_sectors, max_sectors);
 		return false;
+	}
 
-	if (range_sectors > VDPASIM_BLK_CAPACITY - start_sector)
+	if (num_sectors > VDPASIM_BLK_CAPACITY - start_sector) {
+		dev_dbg(&vdpasim->vdpa.dev,
+			"request exceeds the capacity - start: 0x%llx num: 0x%llx capacity: 0x%x\n",
+			start_sector, num_sectors, VDPASIM_BLK_CAPACITY);
 		return false;
+	}
 
 	return true;
 }
@@ -123,10 +133,9 @@ static bool vdpasim_blk_handle_req(struct vdpasim *vdpasim,
 
 	switch (type) {
 	case VIRTIO_BLK_T_IN:
-		if (!vdpasim_blk_check_range(sector, to_push)) {
-			dev_dbg(&vdpasim->vdpa.dev,
-				"reading over the capacity - offset: 0x%llx len: 0x%zx\n",
-				offset, to_push);
+		if (!vdpasim_blk_check_range(vdpasim, sector,
+					     to_push >> SECTOR_SHIFT,
+					     VDPASIM_BLK_SIZE_MAX * VDPASIM_BLK_SEG_MAX)) {
 			status = VIRTIO_BLK_S_IOERR;
 			break;
 		}
@@ -146,10 +155,9 @@ static bool vdpasim_blk_handle_req(struct vdpasim *vdpasim,
 		break;
 
 	case VIRTIO_BLK_T_OUT:
-		if (!vdpasim_blk_check_range(sector, to_pull)) {
-			dev_dbg(&vdpasim->vdpa.dev,
-				"writing over the capacity - offset: 0x%llx len: 0x%zx\n",
-				offset, to_pull);
+		if (!vdpasim_blk_check_range(vdpasim, sector,
+					     to_pull >> SECTOR_SHIFT,
+					     VDPASIM_BLK_SIZE_MAX * VDPASIM_BLK_SEG_MAX)) {
 			status = VIRTIO_BLK_S_IOERR;
 			break;
 		}
-- 
2.37.1

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[PATCH v2 3/4] vdpa_sim_blk: add support for VIRTIO_BLK_T_FLUSH

[Stefano Garzarella]

The simulator behaves like a ramdisk, so we don't have to do
anything when a VIRTIO_BLK_T_FLUSH request is received, but it
could be useful to test driver behavior.

Let's expose the VIRTIO_BLK_F_FLUSH feature to inform the driver
that we support the flush command.

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
---
 drivers/vdpa/vdpa_sim/vdpa_sim_blk.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
index 24dd9cae6450..1f18f336cf0c 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
@@ -25,6 +25,7 @@
 #define DRV_LICENSE  "GPL v2"
 
 #define VDPASIM_BLK_FEATURES	(VDPASIM_FEATURES | \
+				 (1ULL << VIRTIO_BLK_F_FLUSH)    | \
 				 (1ULL << VIRTIO_BLK_F_SIZE_MAX) | \
 				 (1ULL << VIRTIO_BLK_F_SEG_MAX)  | \
 				 (1ULL << VIRTIO_BLK_F_BLK_SIZE) | \
@@ -188,6 +189,10 @@ static bool vdpasim_blk_handle_req(struct vdpasim *vdpasim,
 		pushed += bytes;
 		break;
 
+	case VIRTIO_BLK_T_FLUSH:
+		/* nothing to do */
+		break;
+
 	default:
 		dev_dbg(&vdpasim->vdpa.dev,
 			"Unsupported request type %d\n", type);
-- 
2.37.1

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[PATCH v2 3/4] vdpa_sim_blk: add support for VIRTIO_BLK_T_FLUSH

[Stefano Garzarella]

The simulator behaves like a ramdisk, so we don't have to do
anything when a VIRTIO_BLK_T_FLUSH request is received, but it
could be useful to test driver behavior.

Let's expose the VIRTIO_BLK_F_FLUSH feature to inform the driver
that we support the flush command.

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
---
 drivers/vdpa/vdpa_sim/vdpa_sim_blk.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
index 24dd9cae6450..1f18f336cf0c 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
@@ -25,6 +25,7 @@
 #define DRV_LICENSE  "GPL v2"
 
 #define VDPASIM_BLK_FEATURES	(VDPASIM_FEATURES | \
+				 (1ULL << VIRTIO_BLK_F_FLUSH)    | \
 				 (1ULL << VIRTIO_BLK_F_SIZE_MAX) | \
 				 (1ULL << VIRTIO_BLK_F_SEG_MAX)  | \
 				 (1ULL << VIRTIO_BLK_F_BLK_SIZE) | \
@@ -188,6 +189,10 @@ static bool vdpasim_blk_handle_req(struct vdpasim *vdpasim,
 		pushed += bytes;
 		break;
 
+	case VIRTIO_BLK_T_FLUSH:
+		/* nothing to do */
+		break;
+
 	default:
 		dev_dbg(&vdpasim->vdpa.dev,
 			"Unsupported request type %d\n", type);
-- 
2.37.1

[PATCH v2 4/4] vdpa_sim_blk: add support for discard and write-zeroes

[Stefano Garzarella]

Expose VIRTIO_BLK_F_DISCARD and VIRTIO_BLK_F_WRITE_ZEROES features
to the drivers and handle VIRTIO_BLK_T_DISCARD and
VIRTIO_BLK_T_WRITE_ZEROES requests checking ranges and flags.

The simulator behaves like a ramdisk, so for VIRTIO_BLK_F_DISCARD
does nothing, while for VIRTIO_BLK_T_WRITE_ZEROES sets to 0 the
specified region.

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
---
 drivers/vdpa/vdpa_sim/vdpa_sim_blk.c | 74 +++++++++++++++++++++++++++-
 1 file changed, 73 insertions(+), 1 deletion(-)

diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
index 1f18f336cf0c..db85df1d5073 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
@@ -30,11 +30,14 @@
 				 (1ULL << VIRTIO_BLK_F_SEG_MAX)  | \
 				 (1ULL << VIRTIO_BLK_F_BLK_SIZE) | \
 				 (1ULL << VIRTIO_BLK_F_TOPOLOGY) | \
-				 (1ULL << VIRTIO_BLK_F_MQ))
+				 (1ULL << VIRTIO_BLK_F_MQ)       | \
+				 (1ULL << VIRTIO_BLK_F_DISCARD)  | \
+				 (1ULL << VIRTIO_BLK_F_WRITE_ZEROES))
 
 #define VDPASIM_BLK_CAPACITY	0x40000
 #define VDPASIM_BLK_SIZE_MAX	0x1000
 #define VDPASIM_BLK_SEG_MAX	32
+#define VDPASIM_BLK_DWZ_MAX_SECTORS UINT_MAX
 
 /* 1 virtqueue, 1 address space, 1 virtqueue group */
 #define VDPASIM_BLK_VQ_NUM	1
@@ -193,6 +196,64 @@ static bool vdpasim_blk_handle_req(struct vdpasim *vdpasim,
 		/* nothing to do */
 		break;
 
+	case VIRTIO_BLK_T_DISCARD:
+	case VIRTIO_BLK_T_WRITE_ZEROES:
+		struct virtio_blk_discard_write_zeroes range;
+		u32 num_sectors, flags;
+
+		if (to_pull != sizeof(range)) {
+			dev_dbg(&vdpasim->vdpa.dev,
+				"discard/write_zeroes header len: 0x%zx [expected: 0x%zx]\n",
+				to_pull, sizeof(range));
+			status = VIRTIO_BLK_S_IOERR;
+			break;
+		}
+
+		bytes = vringh_iov_pull_iotlb(&vq->vring, &vq->out_iov, &range,
+					      to_pull);
+		if (bytes < 0) {
+			dev_dbg(&vdpasim->vdpa.dev,
+				"vringh_iov_pull_iotlb() error: %zd offset: 0x%llx len: 0x%zx\n",
+				bytes, offset, to_pull);
+			status = VIRTIO_BLK_S_IOERR;
+			break;
+		}
+
+		sector = vdpasim64_to_cpu(vdpasim, range.sector);
+		offset = sector << SECTOR_SHIFT;
+		num_sectors = vdpasim32_to_cpu(vdpasim, range.num_sectors);
+		flags = vdpasim32_to_cpu(vdpasim, range.flags);
+
+		if (type == VIRTIO_BLK_T_DISCARD && flags != 0) {
+			dev_dbg(&vdpasim->vdpa.dev,
+				"discard unexpected flags set - flags: 0x%x\n",
+				flags);
+			status = VIRTIO_BLK_S_UNSUPP;
+			break;
+		}
+
+		if (type == VIRTIO_BLK_T_WRITE_ZEROES &&
+		    flags & ~VIRTIO_BLK_WRITE_ZEROES_FLAG_UNMAP) {
+			dev_dbg(&vdpasim->vdpa.dev,
+				"write_zeroes unexpected flags set - flags: 0x%x\n",
+				flags);
+			status = VIRTIO_BLK_S_UNSUPP;
+			break;
+		}
+
+		if (!vdpasim_blk_check_range(vdpasim, sector, num_sectors,
+					     VDPASIM_BLK_DWZ_MAX_SECTORS)) {
+			status = VIRTIO_BLK_S_IOERR;
+			break;
+		}
+
+		if (type == VIRTIO_BLK_T_WRITE_ZEROES) {
+			memset(vdpasim->buffer + offset, 0,
+			       num_sectors << SECTOR_SHIFT);
+		}
+
+		break;
+
 	default:
 		dev_dbg(&vdpasim->vdpa.dev,
 			"Unsupported request type %d\n", type);
@@ -281,6 +342,17 @@ static void vdpasim_blk_get_config(struct vdpasim *vdpasim, void *config)
 	blk_config->min_io_size = cpu_to_vdpasim16(vdpasim, 1);
 	blk_config->opt_io_size = cpu_to_vdpasim32(vdpasim, 1);
 	blk_config->blk_size = cpu_to_vdpasim32(vdpasim, SECTOR_SIZE);
+	/* VIRTIO_BLK_F_DISCARD */
+	blk_config->discard_sector_alignment =
+		cpu_to_vdpasim32(vdpasim, SECTOR_SIZE);
+	blk_config->max_discard_sectors =
+		cpu_to_vdpasim32(vdpasim, VDPASIM_BLK_DWZ_MAX_SECTORS);
+	blk_config->max_discard_seg = cpu_to_vdpasim32(vdpasim, 1);
+	/* VIRTIO_BLK_F_WRITE_ZEROES */
+	blk_config->max_write_zeroes_sectors =
+		cpu_to_vdpasim32(vdpasim, VDPASIM_BLK_DWZ_MAX_SECTORS);
+	blk_config->max_write_zeroes_seg = cpu_to_vdpasim32(vdpasim, 1);
+
 }
 
 static void vdpasim_blk_mgmtdev_release(struct device *dev)
-- 
2.37.1

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[PATCH v2 4/4] vdpa_sim_blk: add support for discard and write-zeroes

[Stefano Garzarella]

Expose VIRTIO_BLK_F_DISCARD and VIRTIO_BLK_F_WRITE_ZEROES features
to the drivers and handle VIRTIO_BLK_T_DISCARD and
VIRTIO_BLK_T_WRITE_ZEROES requests checking ranges and flags.

The simulator behaves like a ramdisk, so for VIRTIO_BLK_F_DISCARD
does nothing, while for VIRTIO_BLK_T_WRITE_ZEROES sets to 0 the
specified region.

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
---
 drivers/vdpa/vdpa_sim/vdpa_sim_blk.c | 74 +++++++++++++++++++++++++++-
 1 file changed, 73 insertions(+), 1 deletion(-)

diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
index 1f18f336cf0c..db85df1d5073 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
@@ -30,11 +30,14 @@
 				 (1ULL << VIRTIO_BLK_F_SEG_MAX)  | \
 				 (1ULL << VIRTIO_BLK_F_BLK_SIZE) | \
 				 (1ULL << VIRTIO_BLK_F_TOPOLOGY) | \
-				 (1ULL << VIRTIO_BLK_F_MQ))
+				 (1ULL << VIRTIO_BLK_F_MQ)       | \
+				 (1ULL << VIRTIO_BLK_F_DISCARD)  | \
+				 (1ULL << VIRTIO_BLK_F_WRITE_ZEROES))
 
 #define VDPASIM_BLK_CAPACITY	0x40000
 #define VDPASIM_BLK_SIZE_MAX	0x1000
 #define VDPASIM_BLK_SEG_MAX	32
+#define VDPASIM_BLK_DWZ_MAX_SECTORS UINT_MAX
 
 /* 1 virtqueue, 1 address space, 1 virtqueue group */
 #define VDPASIM_BLK_VQ_NUM	1
@@ -193,6 +196,64 @@ static bool vdpasim_blk_handle_req(struct vdpasim *vdpasim,
 		/* nothing to do */
 		break;
 
+	case VIRTIO_BLK_T_DISCARD:
+	case VIRTIO_BLK_T_WRITE_ZEROES:
+		struct virtio_blk_discard_write_zeroes range;
+		u32 num_sectors, flags;
+
+		if (to_pull != sizeof(range)) {
+			dev_dbg(&vdpasim->vdpa.dev,
+				"discard/write_zeroes header len: 0x%zx [expected: 0x%zx]\n",
+				to_pull, sizeof(range));
+			status = VIRTIO_BLK_S_IOERR;
+			break;
+		}
+
+		bytes = vringh_iov_pull_iotlb(&vq->vring, &vq->out_iov, &range,
+					      to_pull);
+		if (bytes < 0) {
+			dev_dbg(&vdpasim->vdpa.dev,
+				"vringh_iov_pull_iotlb() error: %zd offset: 0x%llx len: 0x%zx\n",
+				bytes, offset, to_pull);
+			status = VIRTIO_BLK_S_IOERR;
+			break;
+		}
+
+		sector = vdpasim64_to_cpu(vdpasim, range.sector);
+		offset = sector << SECTOR_SHIFT;
+		num_sectors = vdpasim32_to_cpu(vdpasim, range.num_sectors);
+		flags = vdpasim32_to_cpu(vdpasim, range.flags);
+
+		if (type == VIRTIO_BLK_T_DISCARD && flags != 0) {
+			dev_dbg(&vdpasim->vdpa.dev,
+				"discard unexpected flags set - flags: 0x%x\n",
+				flags);
+			status = VIRTIO_BLK_S_UNSUPP;
+			break;
+		}
+
+		if (type == VIRTIO_BLK_T_WRITE_ZEROES &&
+		    flags & ~VIRTIO_BLK_WRITE_ZEROES_FLAG_UNMAP) {
+			dev_dbg(&vdpasim->vdpa.dev,
+				"write_zeroes unexpected flags set - flags: 0x%x\n",
+				flags);
+			status = VIRTIO_BLK_S_UNSUPP;
+			break;
+		}
+
+		if (!vdpasim_blk_check_range(vdpasim, sector, num_sectors,
+					     VDPASIM_BLK_DWZ_MAX_SECTORS)) {
+			status = VIRTIO_BLK_S_IOERR;
+			break;
+		}
+
+		if (type == VIRTIO_BLK_T_WRITE_ZEROES) {
+			memset(vdpasim->buffer + offset, 0,
+			       num_sectors << SECTOR_SHIFT);
+		}
+
+		break;
+
 	default:
 		dev_dbg(&vdpasim->vdpa.dev,
 			"Unsupported request type %d\n", type);
@@ -281,6 +342,17 @@ static void vdpasim_blk_get_config(struct vdpasim *vdpasim, void *config)
 	blk_config->min_io_size = cpu_to_vdpasim16(vdpasim, 1);
 	blk_config->opt_io_size = cpu_to_vdpasim32(vdpasim, 1);
 	blk_config->blk_size = cpu_to_vdpasim32(vdpasim, SECTOR_SIZE);
+	/* VIRTIO_BLK_F_DISCARD */
+	blk_config->discard_sector_alignment =
+		cpu_to_vdpasim32(vdpasim, SECTOR_SIZE);
+	blk_config->max_discard_sectors =
+		cpu_to_vdpasim32(vdpasim, VDPASIM_BLK_DWZ_MAX_SECTORS);
+	blk_config->max_discard_seg = cpu_to_vdpasim32(vdpasim, 1);
+	/* VIRTIO_BLK_F_WRITE_ZEROES */
+	blk_config->max_write_zeroes_sectors =
+		cpu_to_vdpasim32(vdpasim, VDPASIM_BLK_DWZ_MAX_SECTORS);
+	blk_config->max_write_zeroes_seg = cpu_to_vdpasim32(vdpasim, 1);
+
 }
 
 static void vdpasim_blk_mgmtdev_release(struct device *dev)
-- 
2.37.1