Re: [RFCv2 5/7] vhost/scsi: Enable T10 PI IOV -> SGL memory mapping

From: Paolo Bonzini
Date: Mon Mar 17 2014 - 07:03:28 EST


Il 17/03/2014 06:32, Nicholas A. Bellinger ha scritto:
> + if (vq->iov[0].iov_len == sizeof(v_req_pi)) {
> + req = (unsigned char *)&v_req_pi;
> + target = &v_req_pi.lun[1];
> + req_size = sizeof(v_req_pi);
> + hdr_pi = true;
> + } else if (vq->iov[0].iov_len == sizeof(v_req)) {
> + req = (unsigned char *)&v_req;
> + target = &v_req.lun[1];
> + req_size = sizeof(v_req);
> + hdr_pi = false;

The right check here is on the negotiated features.

You need a matching QEMU patch to enable the protection information
feature, like this (untested):

diff --git a/hw/scsi/vhost-scsi.c b/hw/scsi/vhost-scsi.c
index 3983a5b..4c8d5cd 100644
--- a/hw/scsi/vhost-scsi.c
+++ b/hw/scsi/vhost-scsi.c
@@ -154,6 +154,9 @@ static uint32_t vhost_scsi_get_features(VirtIODevice *vdev,
if (!(s->dev.features & (1 << VIRTIO_SCSI_F_HOTPLUG))) {
features &= ~(1 << VIRTIO_SCSI_F_HOTPLUG);
}
+ if (!(s->dev.features & (1 << VIRTIO_SCSI_F_T10_PI))) {
+ features &= ~(1 << VIRTIO_SCSI_F_T10_PI);
+ }

return features;
}
diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
index 6610b3a..4a551e9 100644
--- a/hw/scsi/virtio-scsi.c
+++ b/hw/scsi/virtio-scsi.c
@@ -629,6 +629,9 @@ static void virtio_scsi_device_realize(DeviceState *dev, Error **errp)
return;
}

+ /* Protection information is not supported yet. */
+ dev->guest_features &= ~VIRTIO_SCSI_F_T10_PI;
+
scsi_bus_new(&s->bus, sizeof(s->bus), dev,
&virtio_scsi_scsi_info, vdev->bus_name);

diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index 9010246..8621fbf 100644
--- a/include/hw/i386/pc.h
+++ b/include/hw/i386/pc.h
@@ -267,6 +267,16 @@ int e820_add_entry(uint64_t, uint64_t, uint32_t);
.value = "no",\
},\
{\
+ .driver = "virtio-scsi-pci",\
+ .property = "prot_info",\
+ .value = "off",\
+ },\
+ {\
+ .driver = "vhost-scsi-pci",\
+ .property = "prot_info",\
+ .value = "off",\
+ },\
+ {\
.driver = "PIIX4_PM",\
.property = "acpi-pci-hotplug-with-bridge-support",\
.value = "off",\
diff --git a/include/hw/virtio/virtio-scsi.h b/include/hw/virtio/virtio-scsi.h
index 42b1024..a555f49 100644
--- a/include/hw/virtio/virtio-scsi.h
+++ b/include/hw/virtio/virtio-scsi.h
@@ -34,6 +34,7 @@
#define VIRTIO_SCSI_F_INOUT 0
#define VIRTIO_SCSI_F_HOTPLUG 1
#define VIRTIO_SCSI_F_CHANGE 2
+#define VIRTIO_SCSI_F_T10_PI 3

#define VIRTIO_SCSI_VQ_SIZE 128
#define VIRTIO_SCSI_CDB_SIZE 32
@@ -184,7 +185,9 @@ typedef struct {
DEFINE_PROP_BIT("hotplug", _state, _feature_field, VIRTIO_SCSI_F_HOTPLUG, \
true), \
DEFINE_PROP_BIT("param_change", _state, _feature_field, \
- VIRTIO_SCSI_F_CHANGE, true)
+ VIRTIO_SCSI_F_CHANGE, true) \
+ DEFINE_PROP_BIT("prot_info", _state, _feature_field, \
+ VIRTIO_SCSI_F_T10_PI, true)

void virtio_scsi_common_realize(DeviceState *dev, Error **errp);
void virtio_scsi_common_unrealize(DeviceState *dev, Error **errp);

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