[PATCH v4 0/5] VIRTIO-IOMMU probe request support and MSI bypass on ARM

[PATCH v4 0/5] VIRTIO-IOMMU probe request support and MSI bypass on ARM

[Eric Auger]

By default the virtio-iommu translates MSI transactions. This
behavior is inherited from ARM SMMU. However the virt machine
code knows where the MSI doorbells are, so we can easily
declare those regions as VIRTIO_IOMMU_RESV_MEM_T_MSI. With that
setting the guest iommu subsystem will not need to map MSIs.
This setup will simplify the VFIO integration.

In this series, the ITS or GICV2M doorbells are declared as
HW MSI regions to be bypassed by the VIRTIO-IOMMU.

This also paves the way to the x86 integration where the MSI
region, [0xFEE00000,0xFEEFFFFF], will be exposed by the q35
machine.  However this will be handled in a separate series
when not-DT support gets resolved.

Best Regards

Eric

This series can be found at:
https://github.com/eauger/qemu/tree/v5.0.0-virtio-iommu-msi-bypass-v4

History:

v3 -> v4:
- collected Jean and markus's R-bs
- tool into account all Markus' comments in [1/5] (except removal of
  goto)
- use ':' as delimitor instead of commas
- add example in 4/5 commit message as suggested by Markus

v2 -> v3:
- Introduce VIRT_MSI_CTRL_NONE in VirtMSIControllerType
- do not fill the remainder of the probe buffer

v1 -> v2:
- check which MSI controller is in use and advertise the
  corresponding MSI doorbell
- managed for both ITS and GICv2M
- various fixes spotted by Peter and Jean-Philippe, see
  individual logs

v1: Most of those patches were respinned from
  [PATCH for-5.0 v11 00/20] VIRTIO-IOMMU device
  except the last one which is new


Eric Auger (5):
  qdev: Introduce DEFINE_PROP_RESERVED_REGION
  virtio-iommu: Implement RESV_MEM probe request
  virtio-iommu: Handle reserved regions in the translation process
  virtio-iommu-pci: Add array of Interval properties
  hw/arm/virt: Let the virtio-iommu bypass MSIs

 include/exec/memory.h            |   6 ++
 include/hw/arm/virt.h            |   7 ++
 include/hw/qdev-properties.h     |   3 +
 include/hw/virtio/virtio-iommu.h |   2 +
 include/qemu/typedefs.h          |   1 +
 hw/arm/virt.c                    |  18 +++++
 hw/core/qdev-properties.c        |  89 +++++++++++++++++++++++++
 hw/virtio/virtio-iommu-pci.c     |   3 +
 hw/virtio/virtio-iommu.c         | 110 +++++++++++++++++++++++++++++--
 hw/virtio/trace-events           |   1 +
 10 files changed, 236 insertions(+), 4 deletions(-)

-- 
2.20.1

[PATCH v4 1/5] qdev: Introduce DEFINE_PROP_RESERVED_REGION

[Eric Auger]

Introduce a new property defining a reserved region:
<low address>:<high address>:<type>.

This will be used to encode reserved IOVA regions.

For instance, in virtio-iommu use case, reserved IOVA regions
will be passed by the machine code to the virtio-iommu-pci
device (an array of those). The type of the reserved region
will match the virtio_iommu_probe_resv_mem subtype value:
- VIRTIO_IOMMU_RESV_MEM_T_RESERVED (0)
- VIRTIO_IOMMU_RESV_MEM_T_MSI (1)

on PC/Q35 machine, this will be used to inform the
virtio-iommu-pci device it should bypass the MSI region.
The reserved region will be: 0xfee00000:0xfeefffff:1.

On ARM, we can declare the ITS MSI doorbell as an MSI
region to prevent MSIs from being mapped on guest side.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>

---

v3 -> v4:
- use ':' instead of commas as separators.
- rearrange error messages
- check snprintf returned value
- dared to keep Markus' R-b despite those changes
---
 include/exec/memory.h        |  6 +++
 include/hw/qdev-properties.h |  3 ++
 include/qemu/typedefs.h      |  1 +
 hw/core/qdev-properties.c    | 89 ++++++++++++++++++++++++++++++++++++
 4 files changed, 99 insertions(+)

diff --git a/include/exec/memory.h b/include/exec/memory.h
index 7207025bd4..d7a53b96cc 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -51,6 +51,12 @@ extern bool global_dirty_log;
 
 typedef struct MemoryRegionOps MemoryRegionOps;
 
+struct ReservedRegion {
+    hwaddr low;
+    hwaddr high;
+    unsigned int type;
+};
+
 typedef struct IOMMUTLBEntry IOMMUTLBEntry;
 
 /* See address_space_translate: bit 0 is read, bit 1 is write.  */
diff --git a/include/hw/qdev-properties.h b/include/hw/qdev-properties.h
index 5252bb6b1a..95d0e7201d 100644
--- a/include/hw/qdev-properties.h
+++ b/include/hw/qdev-properties.h
@@ -19,6 +19,7 @@ extern const PropertyInfo qdev_prop_string;
 extern const PropertyInfo qdev_prop_chr;
 extern const PropertyInfo qdev_prop_tpm;
 extern const PropertyInfo qdev_prop_macaddr;
+extern const PropertyInfo qdev_prop_reserved_region;
 extern const PropertyInfo qdev_prop_on_off_auto;
 extern const PropertyInfo qdev_prop_multifd_compression;
 extern const PropertyInfo qdev_prop_losttickpolicy;
@@ -184,6 +185,8 @@ extern const PropertyInfo qdev_prop_pcie_link_width;
     DEFINE_PROP(_n, _s, _f, qdev_prop_drive_iothread, BlockBackend *)
 #define DEFINE_PROP_MACADDR(_n, _s, _f)         \
     DEFINE_PROP(_n, _s, _f, qdev_prop_macaddr, MACAddr)
+#define DEFINE_PROP_RESERVED_REGION(_n, _s, _f)         \
+    DEFINE_PROP(_n, _s, _f, qdev_prop_reserved_region, ReservedRegion)
 #define DEFINE_PROP_ON_OFF_AUTO(_n, _s, _f, _d) \
     DEFINE_PROP_SIGNED(_n, _s, _f, _d, qdev_prop_on_off_auto, OnOffAuto)
 #define DEFINE_PROP_MULTIFD_COMPRESSION(_n, _s, _f, _d) \
diff --git a/include/qemu/typedefs.h b/include/qemu/typedefs.h
index ce4a78b687..15f5047bf1 100644
--- a/include/qemu/typedefs.h
+++ b/include/qemu/typedefs.h
@@ -58,6 +58,7 @@ typedef struct ISABus ISABus;
 typedef struct ISADevice ISADevice;
 typedef struct IsaDma IsaDma;
 typedef struct MACAddr MACAddr;
+typedef struct ReservedRegion ReservedRegion;
 typedef struct MachineClass MachineClass;
 typedef struct MachineState MachineState;
 typedef struct MemoryListener MemoryListener;
diff --git a/hw/core/qdev-properties.c b/hw/core/qdev-properties.c
index ead35d7ffd..193d0d95f9 100644
--- a/hw/core/qdev-properties.c
+++ b/hw/core/qdev-properties.c
@@ -15,6 +15,7 @@
 #include "chardev/char.h"
 #include "qemu/uuid.h"
 #include "qemu/units.h"
+#include "qemu/cutils.h"
 
 void qdev_prop_set_after_realize(DeviceState *dev, const char *name,
                                   Error **errp)
@@ -578,6 +579,94 @@ const PropertyInfo qdev_prop_macaddr = {
     .set   = set_mac,
 };
 
+/* --- Reserved Region --- */
+
+/*
+ * accepted syntax version:
+ *   <low address>:<high address>:<type>
+ *   where low/high addresses are uint64_t in hexadecimal
+ *   and type is an unsigned integer in decimal
+ */
+static void get_reserved_region(Object *obj, Visitor *v, const char *name,
+                                void *opaque, Error **errp)
+{
+    DeviceState *dev = DEVICE(obj);
+    Property *prop = opaque;
+    ReservedRegion *rr = qdev_get_prop_ptr(dev, prop);
+    char buffer[64];
+    char *p = buffer;
+    int rc;
+
+    rc = snprintf(buffer, sizeof(buffer), "0x%"PRIx64":0x%"PRIx64":%u",
+                  rr->low, rr->high, rr->type);
+    assert(rc < sizeof(buffer));
+
+    visit_type_str(v, name, &p, errp);
+}
+
+static void set_reserved_region(Object *obj, Visitor *v, const char *name,
+                                void *opaque, Error **errp)
+{
+    DeviceState *dev = DEVICE(obj);
+    Property *prop = opaque;
+    ReservedRegion *rr = qdev_get_prop_ptr(dev, prop);
+    Error *local_err = NULL;
+    const char *endptr;
+    char *str;
+    int ret;
+
+    if (dev->realized) {
+        qdev_prop_set_after_realize(dev, name, errp);
+        return;
+    }
+
+    visit_type_str(v, name, &str, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        return;
+    }
+
+    ret = qemu_strtou64(str, &endptr, 16, &rr->low);
+    if (ret) {
+        error_setg(errp, "start address of '%s'"
+                   " must be a hexadecimal integer", name);
+        goto out;
+    }
+    if (*endptr != ':') {
+        goto separator_error;
+    }
+
+    ret = qemu_strtou64(endptr + 1, &endptr, 16, &rr->high);
+    if (ret) {
+        error_setg(errp, "end address of '%s'"
+                   " must be a hexadecimal integer", name);
+        goto out;
+    }
+    if (*endptr != ':') {
+        goto separator_error;
+    }
+
+    ret = qemu_strtoui(endptr + 1, &endptr, 10, &rr->type);
+    if (ret) {
+        error_setg(errp, "type of '%s'"
+                   " must be an unsigned integer in decimal", name);
+    }
+    goto out;
+
+separator_error:
+    error_setg(errp, "reserved region fields must be separated with ':'");
+out:
+    g_free(str);
+    return;
+}
+
+const PropertyInfo qdev_prop_reserved_region = {
+    .name  = "reserved_region",
+    .description = "Reserved Region, example: 0xFEE00000:0xFEEFFFFF:0",
+    .get   = get_reserved_region,
+    .set   = set_reserved_region,
+};
+
 /* --- on/off/auto --- */
 
 const PropertyInfo qdev_prop_on_off_auto = {
-- 
2.20.1

[PATCH v4 2/5] virtio-iommu: Implement RESV_MEM probe request

[Eric Auger]

This patch implements the PROBE request. At the moment,
only THE RESV_MEM property is handled. The first goal is
to report iommu wide reserved regions such as the MSI regions
set by the machine code. On x86 this will be the IOAPIC MSI
region, [0xFEE00000 - 0xFEEFFFFF], on ARM this may be the ITS
doorbell.

In the future we may introduce per device reserved regions.
This will be useful when protecting host assigned devices
which may expose their own reserved regions

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Jean-Philippe Brucker <jean-philippe@linaro.org>

---

v3 -> v4:
- removed any reference to the NONE property that does not
  exist anymore.

v2 -> v3:
- on probe, do not fill the reminder of the buffer with zeroes
  as the buffer was already zero initialized (Bharat)

v1 -> v2:
- move the unlock back to the same place
- remove the push label and factorize the code after the out label
- fix a bunch of cpu_to_leX according to the latest spec revision
- do not remove sizeof(last) from free space
- check the ep exists
---
 include/hw/virtio/virtio-iommu.h |  2 +
 hw/virtio/virtio-iommu.c         | 90 ++++++++++++++++++++++++++++++--
 hw/virtio/trace-events           |  1 +
 3 files changed, 89 insertions(+), 4 deletions(-)

diff --git a/include/hw/virtio/virtio-iommu.h b/include/hw/virtio/virtio-iommu.h
index e653004d7c..49eb105cd8 100644
--- a/include/hw/virtio/virtio-iommu.h
+++ b/include/hw/virtio/virtio-iommu.h
@@ -53,6 +53,8 @@ typedef struct VirtIOIOMMU {
     GHashTable *as_by_busptr;
     IOMMUPciBus *iommu_pcibus_by_bus_num[PCI_BUS_MAX];
     PCIBus *primary_bus;
+    ReservedRegion *reserved_regions;
+    uint32_t nb_reserved_regions;
     GTree *domains;
     QemuMutex mutex;
     GTree *endpoints;
diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c
index 483883ec1d..5e72fd53a1 100644
--- a/hw/virtio/virtio-iommu.c
+++ b/hw/virtio/virtio-iommu.c
@@ -38,6 +38,7 @@
 
 /* Max size */
 #define VIOMMU_DEFAULT_QUEUE_SIZE 256
+#define VIOMMU_PROBE_SIZE 512
 
 typedef struct VirtIOIOMMUDomain {
     uint32_t id;
@@ -378,6 +379,61 @@ static int virtio_iommu_unmap(VirtIOIOMMU *s,
     return ret;
 }
 
+static ssize_t virtio_iommu_fill_resv_mem_prop(VirtIOIOMMU *s, uint32_t ep,
+                                               uint8_t *buf, size_t free)
+{
+    struct virtio_iommu_probe_resv_mem prop = {};
+    size_t size = sizeof(prop), length = size - sizeof(prop.head), total;
+    int i;
+
+    total = size * s->nb_reserved_regions;
+
+    if (total > free) {
+        return -ENOSPC;
+    }
+
+    for (i = 0; i < s->nb_reserved_regions; i++) {
+        prop.head.type = cpu_to_le16(VIRTIO_IOMMU_PROBE_T_RESV_MEM);
+        prop.head.length = cpu_to_le16(length);
+        prop.subtype = s->reserved_regions[i].type;
+        prop.start = cpu_to_le64(s->reserved_regions[i].low);
+        prop.end = cpu_to_le64(s->reserved_regions[i].high);
+
+        memcpy(buf, &prop, size);
+
+        trace_virtio_iommu_fill_resv_property(ep, prop.subtype,
+                                              prop.start, prop.end);
+        buf += size;
+    }
+    return total;
+}
+
+/**
+ * virtio_iommu_probe - Fill the probe request buffer with
+ * the properties the device is able to return
+ */
+static int virtio_iommu_probe(VirtIOIOMMU *s,
+                              struct virtio_iommu_req_probe *req,
+                              uint8_t *buf)
+{
+    uint32_t ep_id = le32_to_cpu(req->endpoint);
+    size_t free = VIOMMU_PROBE_SIZE;
+    ssize_t count;
+
+    if (!virtio_iommu_mr(s, ep_id)) {
+        return VIRTIO_IOMMU_S_NOENT;
+    }
+
+    count = virtio_iommu_fill_resv_mem_prop(s, ep_id, buf, free);
+    if (count < 0) {
+        return VIRTIO_IOMMU_S_INVAL;
+    }
+    buf += count;
+    free -= count;
+
+    return VIRTIO_IOMMU_S_OK;
+}
+
 static int virtio_iommu_iov_to_req(struct iovec *iov,
                                    unsigned int iov_cnt,
                                    void *req, size_t req_sz)
@@ -407,15 +463,27 @@ virtio_iommu_handle_req(detach)
 virtio_iommu_handle_req(map)
 virtio_iommu_handle_req(unmap)
 
+static int virtio_iommu_handle_probe(VirtIOIOMMU *s,
+                                     struct iovec *iov,
+                                     unsigned int iov_cnt,
+                                     uint8_t *buf)
+{
+    struct virtio_iommu_req_probe req;
+    int ret = virtio_iommu_iov_to_req(iov, iov_cnt, &req, sizeof(req));
+
+    return ret ? ret : virtio_iommu_probe(s, &req, buf);
+}
+
 static void virtio_iommu_handle_command(VirtIODevice *vdev, VirtQueue *vq)
 {
     VirtIOIOMMU *s = VIRTIO_IOMMU(vdev);
     struct virtio_iommu_req_head head;
     struct virtio_iommu_req_tail tail = {};
+    size_t output_size = sizeof(tail), sz;
     VirtQueueElement *elem;
     unsigned int iov_cnt;
     struct iovec *iov;
-    size_t sz;
+    void *buf = NULL;
 
     for (;;) {
         elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
@@ -452,6 +520,17 @@ static void virtio_iommu_handle_command(VirtIODevice *vdev, VirtQueue *vq)
         case VIRTIO_IOMMU_T_UNMAP:
             tail.status = virtio_iommu_handle_unmap(s, iov, iov_cnt);
             break;
+        case VIRTIO_IOMMU_T_PROBE:
+        {
+            struct virtio_iommu_req_tail *ptail;
+
+            output_size = s->config.probe_size + sizeof(tail);
+            buf = g_malloc0(output_size);
+
+            ptail = (struct virtio_iommu_req_tail *)
+                        (buf + s->config.probe_size);
+            ptail->status = virtio_iommu_handle_probe(s, iov, iov_cnt, buf);
+        }
         default:
             tail.status = VIRTIO_IOMMU_S_UNSUPP;
         }
@@ -459,12 +538,13 @@ static void virtio_iommu_handle_command(VirtIODevice *vdev, VirtQueue *vq)
 
 out:
         sz = iov_from_buf(elem->in_sg, elem->in_num, 0,
-                          &tail, sizeof(tail));
-        assert(sz == sizeof(tail));
+                          buf ? buf : &tail, output_size);
+        assert(sz == output_size);
 
-        virtqueue_push(vq, elem, sizeof(tail));
+        virtqueue_push(vq, elem, sz);
         virtio_notify(vdev, vq);
         g_free(elem);
+        g_free(buf);
     }
 }
 
@@ -667,6 +747,7 @@ static void virtio_iommu_device_realize(DeviceState *dev, Error **errp)
     s->config.page_size_mask = TARGET_PAGE_MASK;
     s->config.input_range.end = -1UL;
     s->config.domain_range.end = 32;
+    s->config.probe_size = VIOMMU_PROBE_SIZE;
 
     virtio_add_feature(&s->features, VIRTIO_RING_F_EVENT_IDX);
     virtio_add_feature(&s->features, VIRTIO_RING_F_INDIRECT_DESC);
@@ -676,6 +757,7 @@ static void virtio_iommu_device_realize(DeviceState *dev, Error **errp)
     virtio_add_feature(&s->features, VIRTIO_IOMMU_F_MAP_UNMAP);
     virtio_add_feature(&s->features, VIRTIO_IOMMU_F_BYPASS);
     virtio_add_feature(&s->features, VIRTIO_IOMMU_F_MMIO);
+    virtio_add_feature(&s->features, VIRTIO_IOMMU_F_PROBE);
 
     qemu_mutex_init(&s->mutex);
 
diff --git a/hw/virtio/trace-events b/hw/virtio/trace-events
index 6427a0047d..23109f69bb 100644
--- a/hw/virtio/trace-events
+++ b/hw/virtio/trace-events
@@ -74,3 +74,4 @@ virtio_iommu_get_domain(uint32_t domain_id) "Alloc domain=%d"
 virtio_iommu_put_domain(uint32_t domain_id) "Free domain=%d"
 virtio_iommu_translate_out(uint64_t virt_addr, uint64_t phys_addr, uint32_t sid) "0x%"PRIx64" -> 0x%"PRIx64 " for sid=%d"
 virtio_iommu_report_fault(uint8_t reason, uint32_t flags, uint32_t endpoint, uint64_t addr) "FAULT reason=%d flags=%d endpoint=%d address =0x%"PRIx64
+virtio_iommu_fill_resv_property(uint32_t devid, uint8_t subtype, uint64_t start, uint64_t end) "dev= %d, type=%d start=0x%"PRIx64" end=0x%"PRIx64
-- 
2.20.1

[PATCH v4 3/5] virtio-iommu: Handle reserved regions in the translation process

[Eric Auger]

When translating an address we need to check if it belongs to
a reserved virtual address range. If it does, there are 2 cases:

- it belongs to a RESERVED region: the guest should neither use
  this address in a MAP not instruct the end-point to DMA on
  them. We report an error

- It belongs to an MSI region: we bypass the translation.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Jean-Philippe Brucker <jean-philippe@linaro.org>

---

v1 -> v2:
- use addr when testing addr belongs to the reserved region
  and use a block local variable
---
 hw/virtio/virtio-iommu.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c
index 5e72fd53a1..4a50e24d21 100644
--- a/hw/virtio/virtio-iommu.c
+++ b/hw/virtio/virtio-iommu.c
@@ -603,6 +603,7 @@ static IOMMUTLBEntry virtio_iommu_translate(IOMMUMemoryRegion *mr, hwaddr addr,
     uint32_t sid, flags;
     bool bypass_allowed;
     bool found;
+    int i;
 
     interval.low = addr;
     interval.high = addr + 1;
@@ -636,6 +637,25 @@ static IOMMUTLBEntry virtio_iommu_translate(IOMMUMemoryRegion *mr, hwaddr addr,
         goto unlock;
     }
 
+    for (i = 0; i < s->nb_reserved_regions; i++) {
+        ReservedRegion *reg = &s->reserved_regions[i];
+
+        if (addr >= reg->low && addr <= reg->high) {
+            switch (reg->type) {
+            case VIRTIO_IOMMU_RESV_MEM_T_MSI:
+                entry.perm = flag;
+                break;
+            case VIRTIO_IOMMU_RESV_MEM_T_RESERVED:
+            default:
+                virtio_iommu_report_fault(s, VIRTIO_IOMMU_FAULT_R_MAPPING,
+                                          VIRTIO_IOMMU_FAULT_F_ADDRESS,
+                                          sid, addr);
+                break;
+            }
+            goto unlock;
+        }
+    }
+
     if (!ep->domain) {
         if (!bypass_allowed) {
             error_report_once("%s %02x:%02x.%01x not attached to any domain",
-- 
2.20.1

[PATCH v4 4/5] virtio-iommu-pci: Add array of Interval properties

[Eric Auger]

The machine may need to pass reserved regions to the
virtio-iommu-pci device (such as the MSI window on x86
or the MSI doorbells on ARM).

So let's add an array of Interval properties.

Note: if some reserved regions are already set by the
machine code - which should be the case in general -,
the length of the property array is already set and
prevents the end-user from modifying them. For example,
attempting to use:

-device virtio-iommu-pci,\
 len-reserved-regions=1,reserved-regions[0]=0xfee00000:0xfeefffff:1

would result in the following error message:

-device virtio-iommu-pci,len-reserved-regions=1,len-reserved-regions=1,
 reserved-regions[0]=0xfee00000:0xfeefffff:1: array size property
 len-reserved-regions may not be set more than once

Otherwise, for example, adding two reserved regions is achieved
using the following options:

-device virtio-iommu-pci,addr=0xa,len-reserved-regions=2,\
 reserved-regions[0]=0xfee00000:0xfeefffff:1,\
 reserved-regions[1]=0x1000000:100ffff:1

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Jean-Philippe Brucker <jean-philippe@linaro.org>

---

v3 -> v4:
- added examples in the commit message as suggested by Markus
- added Jean's R-b
---
 hw/virtio/virtio-iommu-pci.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/hw/virtio/virtio-iommu-pci.c b/hw/virtio/virtio-iommu-pci.c
index 632533abaf..d0746fa93c 100644
--- a/hw/virtio/virtio-iommu-pci.c
+++ b/hw/virtio/virtio-iommu-pci.c
@@ -33,6 +33,9 @@ struct VirtIOIOMMUPCI {
 
 static Property virtio_iommu_pci_properties[] = {
     DEFINE_PROP_UINT32("class", VirtIOPCIProxy, class_code, 0),
+    DEFINE_PROP_ARRAY("reserved-regions", VirtIOIOMMUPCI,
+                      vdev.nb_reserved_regions, vdev.reserved_regions,
+                      qdev_prop_reserved_region, ReservedRegion),
     DEFINE_PROP_END_OF_LIST(),
 };
 
-- 
2.20.1

[PATCH v4 5/5] hw/arm/virt: Let the virtio-iommu bypass MSIs

[Eric Auger]

At the moment the virtio-iommu translates MSI transactions.
This behavior is inherited from ARM SMMU. The virt machine
code knows where the guest MSI doorbells are so we can easily
declare those regions as VIRTIO_IOMMU_RESV_MEM_T_MSI. With that
setting the guest will not map MSIs through the IOMMU and those
transactions will be simply bypassed.

Depending on which MSI controller is in use (ITS or GICV2M),
we declare either:
- the ITS interrupt translation space (ITS_base + 0x10000),
  containing the GITS_TRANSLATOR or
- The GICV2M single frame, containing the MSI_SETSP_NS register.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Jean-Philippe Brucker <jean-philippe@linaro.org>

---
v3 -> v4:
- use ':' as separators

v2 -> v3:
- Add a new value to VirtMSIControllerType

v1 -> v2:
- Test which MSI controller is instantiated
- If GICV2M is in use, declare its doorbell as an MSI doorbell too
---
 include/hw/arm/virt.h |  7 +++++++
 hw/arm/virt.c         | 18 ++++++++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/include/hw/arm/virt.h b/include/hw/arm/virt.h
index 31878ddc72..a18b6b397b 100644
--- a/include/hw/arm/virt.h
+++ b/include/hw/arm/virt.h
@@ -96,6 +96,12 @@ typedef enum VirtIOMMUType {
     VIRT_IOMMU_VIRTIO,
 } VirtIOMMUType;
 
+typedef enum VirtMSIControllerType {
+    VIRT_MSI_CTRL_NONE,
+    VIRT_MSI_CTRL_GICV2M,
+    VIRT_MSI_CTRL_ITS,
+} VirtMSIControllerType;
+
 typedef enum VirtGICType {
     VIRT_GIC_VERSION_MAX,
     VIRT_GIC_VERSION_HOST,
@@ -136,6 +142,7 @@ typedef struct {
     OnOffAuto acpi;
     VirtGICType gic_version;
     VirtIOMMUType iommu;
+    VirtMSIControllerType msi_controller;
     uint16_t virtio_iommu_bdf;
     struct arm_boot_info bootinfo;
     MemMapEntry *memmap;
diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index caceb1e4a0..75cf31fcba 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -602,6 +602,7 @@ static void create_its(VirtMachineState *vms)
     sysbus_mmio_map(SYS_BUS_DEVICE(dev), 0, vms->memmap[VIRT_GIC_ITS].base);
 
     fdt_add_its_gic_node(vms);
+    vms->msi_controller = VIRT_MSI_CTRL_ITS;
 }
 
 static void create_v2m(VirtMachineState *vms)
@@ -622,6 +623,7 @@ static void create_v2m(VirtMachineState *vms)
     }
 
     fdt_add_v2m_gic_node(vms);
+    vms->msi_controller = VIRT_MSI_CTRL_GICV2M;
 }
 
 static void create_gic(VirtMachineState *vms)
@@ -2149,8 +2151,24 @@ out:
 static void virt_machine_device_pre_plug_cb(HotplugHandler *hotplug_dev,
                                             DeviceState *dev, Error **errp)
 {
+    VirtMachineState *vms = VIRT_MACHINE(hotplug_dev);
+
     if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
         virt_memory_pre_plug(hotplug_dev, dev, errp);
+    } else if (object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_IOMMU_PCI)) {
+        /* we declare a VIRTIO_IOMMU_RESV_MEM_T_MSI region */
+
+        if (vms->msi_controller == VIRT_MSI_CTRL_ITS) {
+            /* GITS_TRANSLATER page */
+            qdev_prop_set_uint32(dev, "len-reserved-regions", 1);
+            qdev_prop_set_string(dev, "reserved-regions[0]",
+                                 "0x8090000:0x809FFFF:1");
+        } else if (vms->msi_controller == VIRT_MSI_CTRL_GICV2M) {
+            /* MSI_SETSPI_NS page */
+            qdev_prop_set_uint32(dev, "len-reserved-regions", 1);
+            qdev_prop_set_string(dev, "reserved-regions[0]",
+                                 "0x8020000:0x8020FFF:1");
+        }
     }
 }
 
-- 
2.20.1

Re: [PATCH v4 1/5] qdev: Introduce DEFINE_PROP_RESERVED_REGION

[Markus Armbruster]

Eric Auger <eric.auger@redhat.com> writes:

> Introduce a new property defining a reserved region:
> <low address>:<high address>:<type>.
>
> This will be used to encode reserved IOVA regions.
>
> For instance, in virtio-iommu use case, reserved IOVA regions
> will be passed by the machine code to the virtio-iommu-pci
> device (an array of those). The type of the reserved region
> will match the virtio_iommu_probe_resv_mem subtype value:
> - VIRTIO_IOMMU_RESV_MEM_T_RESERVED (0)
> - VIRTIO_IOMMU_RESV_MEM_T_MSI (1)
>
> on PC/Q35 machine, this will be used to inform the
> virtio-iommu-pci device it should bypass the MSI region.
> The reserved region will be: 0xfee00000:0xfeefffff:1.
>
> On ARM, we can declare the ITS MSI doorbell as an MSI
> region to prevent MSIs from being mapped on guest side.
>
> Signed-off-by: Eric Auger <eric.auger@redhat.com>
> Reviewed-by: Markus Armbruster <armbru@redhat.com>
>
> ---
>
> v3 -> v4:
> - use ':' instead of commas as separators.
> - rearrange error messages
> - check snprintf returned value
> - dared to keep Markus' R-b despite those changes
> ---
>  include/exec/memory.h        |  6 +++
>  include/hw/qdev-properties.h |  3 ++
>  include/qemu/typedefs.h      |  1 +
>  hw/core/qdev-properties.c    | 89 ++++++++++++++++++++++++++++++++++++
>  4 files changed, 99 insertions(+)
>
> diff --git a/include/exec/memory.h b/include/exec/memory.h
> index 7207025bd4..d7a53b96cc 100644
> --- a/include/exec/memory.h
> +++ b/include/exec/memory.h
> @@ -51,6 +51,12 @@ extern bool global_dirty_log;
>  
>  typedef struct MemoryRegionOps MemoryRegionOps;
>  
> +struct ReservedRegion {
> +    hwaddr low;
> +    hwaddr high;
> +    unsigned int type;

Suggest to s/unsigned int/unsigned/.

> +};
> +
>  typedef struct IOMMUTLBEntry IOMMUTLBEntry;
>  
>  /* See address_space_translate: bit 0 is read, bit 1 is write.  */
> diff --git a/include/hw/qdev-properties.h b/include/hw/qdev-properties.h
> index 5252bb6b1a..95d0e7201d 100644
> --- a/include/hw/qdev-properties.h
> +++ b/include/hw/qdev-properties.h
> @@ -19,6 +19,7 @@ extern const PropertyInfo qdev_prop_string;
>  extern const PropertyInfo qdev_prop_chr;
>  extern const PropertyInfo qdev_prop_tpm;
>  extern const PropertyInfo qdev_prop_macaddr;
> +extern const PropertyInfo qdev_prop_reserved_region;
>  extern const PropertyInfo qdev_prop_on_off_auto;
>  extern const PropertyInfo qdev_prop_multifd_compression;
>  extern const PropertyInfo qdev_prop_losttickpolicy;
> @@ -184,6 +185,8 @@ extern const PropertyInfo qdev_prop_pcie_link_width;
>      DEFINE_PROP(_n, _s, _f, qdev_prop_drive_iothread, BlockBackend *)
>  #define DEFINE_PROP_MACADDR(_n, _s, _f)         \
>      DEFINE_PROP(_n, _s, _f, qdev_prop_macaddr, MACAddr)
> +#define DEFINE_PROP_RESERVED_REGION(_n, _s, _f)         \
> +    DEFINE_PROP(_n, _s, _f, qdev_prop_reserved_region, ReservedRegion)
>  #define DEFINE_PROP_ON_OFF_AUTO(_n, _s, _f, _d) \
>      DEFINE_PROP_SIGNED(_n, _s, _f, _d, qdev_prop_on_off_auto, OnOffAuto)
>  #define DEFINE_PROP_MULTIFD_COMPRESSION(_n, _s, _f, _d) \
> diff --git a/include/qemu/typedefs.h b/include/qemu/typedefs.h
> index ce4a78b687..15f5047bf1 100644
> --- a/include/qemu/typedefs.h
> +++ b/include/qemu/typedefs.h
> @@ -58,6 +58,7 @@ typedef struct ISABus ISABus;
>  typedef struct ISADevice ISADevice;
>  typedef struct IsaDma IsaDma;
>  typedef struct MACAddr MACAddr;
> +typedef struct ReservedRegion ReservedRegion;
>  typedef struct MachineClass MachineClass;
>  typedef struct MachineState MachineState;
>  typedef struct MemoryListener MemoryListener;
> diff --git a/hw/core/qdev-properties.c b/hw/core/qdev-properties.c
> index ead35d7ffd..193d0d95f9 100644
> --- a/hw/core/qdev-properties.c
> +++ b/hw/core/qdev-properties.c
> @@ -15,6 +15,7 @@
>  #include "chardev/char.h"
>  #include "qemu/uuid.h"
>  #include "qemu/units.h"
> +#include "qemu/cutils.h"
>  
>  void qdev_prop_set_after_realize(DeviceState *dev, const char *name,
>                                    Error **errp)
> @@ -578,6 +579,94 @@ const PropertyInfo qdev_prop_macaddr = {
>      .set   = set_mac,
>  };
>  
> +/* --- Reserved Region --- */
> +
> +/*
> + * accepted syntax version:

"version" feels redundant.  Suggest to capitalize "Accepted".

> + *   <low address>:<high address>:<type>
> + *   where low/high addresses are uint64_t in hexadecimal
> + *   and type is an unsigned integer in decimal
> + */
> +static void get_reserved_region(Object *obj, Visitor *v, const char *name,
> +                                void *opaque, Error **errp)
> +{
> +    DeviceState *dev = DEVICE(obj);
> +    Property *prop = opaque;
> +    ReservedRegion *rr = qdev_get_prop_ptr(dev, prop);
> +    char buffer[64];
> +    char *p = buffer;
> +    int rc;
> +
> +    rc = snprintf(buffer, sizeof(buffer), "0x%"PRIx64":0x%"PRIx64":%u",
> +                  rr->low, rr->high, rr->type);
> +    assert(rc < sizeof(buffer));
> +
> +    visit_type_str(v, name, &p, errp);
> +}
> +
> +static void set_reserved_region(Object *obj, Visitor *v, const char *name,
> +                                void *opaque, Error **errp)
> +{
> +    DeviceState *dev = DEVICE(obj);
> +    Property *prop = opaque;
> +    ReservedRegion *rr = qdev_get_prop_ptr(dev, prop);
> +    Error *local_err = NULL;
> +    const char *endptr;
> +    char *str;
> +    int ret;
> +
> +    if (dev->realized) {
> +        qdev_prop_set_after_realize(dev, name, errp);
> +        return;
> +    }
> +
> +    visit_type_str(v, name, &str, &local_err);
> +    if (local_err) {
> +        error_propagate(errp, local_err);
> +        return;
> +    }
> +
> +    ret = qemu_strtou64(str, &endptr, 16, &rr->low);
> +    if (ret) {
> +        error_setg(errp, "start address of '%s'"
> +                   " must be a hexadecimal integer", name);
> +        goto out;
> +    }
> +    if (*endptr != ':') {
> +        goto separator_error;
> +    }
> +
> +    ret = qemu_strtou64(endptr + 1, &endptr, 16, &rr->high);
> +    if (ret) {
> +        error_setg(errp, "end address of '%s'"
> +                   " must be a hexadecimal integer", name);
> +        goto out;
> +    }
> +    if (*endptr != ':') {
> +        goto separator_error;
> +    }
> +
> +    ret = qemu_strtoui(endptr + 1, &endptr, 10, &rr->type);
> +    if (ret) {
> +        error_setg(errp, "type of '%s'"
> +                   " must be an unsigned integer in decimal", name);

Suggest "must be a non-negative decimal integer".

Whatever uses the property needs a range check.  I can't see that the
patches that follow.  What am I missing?

> +    }
> +    goto out;
> +
> +separator_error:
> +    error_setg(errp, "reserved region fields must be separated with ':'");
> +out:
> +    g_free(str);
> +    return;
> +}
> +
> +const PropertyInfo qdev_prop_reserved_region = {
> +    .name  = "reserved_region",
> +    .description = "Reserved Region, example: 0xFEE00000:0xFEEFFFFF:0",
> +    .get   = get_reserved_region,
> +    .set   = set_reserved_region,
> +};
> +
>  /* --- on/off/auto --- */
>  
>  const PropertyInfo qdev_prop_on_off_auto = {

R-by for this patch stands.

Re: [PATCH v4 1/5] qdev: Introduce DEFINE_PROP_RESERVED_REGION

[Auger Eric]

Hi Markus,

On 6/23/20 5:13 PM, Markus Armbruster wrote:
> Eric Auger <eric.auger@redhat.com> writes:
> 
>> Introduce a new property defining a reserved region:
>> <low address>:<high address>:<type>.
>>
>> This will be used to encode reserved IOVA regions.
>>
>> For instance, in virtio-iommu use case, reserved IOVA regions
>> will be passed by the machine code to the virtio-iommu-pci
>> device (an array of those). The type of the reserved region
>> will match the virtio_iommu_probe_resv_mem subtype value:
>> - VIRTIO_IOMMU_RESV_MEM_T_RESERVED (0)
>> - VIRTIO_IOMMU_RESV_MEM_T_MSI (1)
>>
>> on PC/Q35 machine, this will be used to inform the
>> virtio-iommu-pci device it should bypass the MSI region.
>> The reserved region will be: 0xfee00000:0xfeefffff:1.
>>
>> On ARM, we can declare the ITS MSI doorbell as an MSI
>> region to prevent MSIs from being mapped on guest side.
>>
>> Signed-off-by: Eric Auger <eric.auger@redhat.com>
>> Reviewed-by: Markus Armbruster <armbru@redhat.com>
>>
>> ---
>>
>> v3 -> v4:
>> - use ':' instead of commas as separators.
>> - rearrange error messages
>> - check snprintf returned value
>> - dared to keep Markus' R-b despite those changes
>> ---
>>  include/exec/memory.h        |  6 +++
>>  include/hw/qdev-properties.h |  3 ++
>>  include/qemu/typedefs.h      |  1 +
>>  hw/core/qdev-properties.c    | 89 ++++++++++++++++++++++++++++++++++++
>>  4 files changed, 99 insertions(+)
>>
>> diff --git a/include/exec/memory.h b/include/exec/memory.h
>> index 7207025bd4..d7a53b96cc 100644
>> --- a/include/exec/memory.h
>> +++ b/include/exec/memory.h
>> @@ -51,6 +51,12 @@ extern bool global_dirty_log;
>>  
>>  typedef struct MemoryRegionOps MemoryRegionOps;
>>  
>> +struct ReservedRegion {
>> +    hwaddr low;
>> +    hwaddr high;
>> +    unsigned int type;
> 
> Suggest to s/unsigned int/unsigned/.
> 
>> +};
>> +
>>  typedef struct IOMMUTLBEntry IOMMUTLBEntry;
>>  
>>  /* See address_space_translate: bit 0 is read, bit 1 is write.  */
>> diff --git a/include/hw/qdev-properties.h b/include/hw/qdev-properties.h
>> index 5252bb6b1a..95d0e7201d 100644
>> --- a/include/hw/qdev-properties.h
>> +++ b/include/hw/qdev-properties.h
>> @@ -19,6 +19,7 @@ extern const PropertyInfo qdev_prop_string;
>>  extern const PropertyInfo qdev_prop_chr;
>>  extern const PropertyInfo qdev_prop_tpm;
>>  extern const PropertyInfo qdev_prop_macaddr;
>> +extern const PropertyInfo qdev_prop_reserved_region;
>>  extern const PropertyInfo qdev_prop_on_off_auto;
>>  extern const PropertyInfo qdev_prop_multifd_compression;
>>  extern const PropertyInfo qdev_prop_losttickpolicy;
>> @@ -184,6 +185,8 @@ extern const PropertyInfo qdev_prop_pcie_link_width;
>>      DEFINE_PROP(_n, _s, _f, qdev_prop_drive_iothread, BlockBackend *)
>>  #define DEFINE_PROP_MACADDR(_n, _s, _f)         \
>>      DEFINE_PROP(_n, _s, _f, qdev_prop_macaddr, MACAddr)
>> +#define DEFINE_PROP_RESERVED_REGION(_n, _s, _f)         \
>> +    DEFINE_PROP(_n, _s, _f, qdev_prop_reserved_region, ReservedRegion)
>>  #define DEFINE_PROP_ON_OFF_AUTO(_n, _s, _f, _d) \
>>      DEFINE_PROP_SIGNED(_n, _s, _f, _d, qdev_prop_on_off_auto, OnOffAuto)
>>  #define DEFINE_PROP_MULTIFD_COMPRESSION(_n, _s, _f, _d) \
>> diff --git a/include/qemu/typedefs.h b/include/qemu/typedefs.h
>> index ce4a78b687..15f5047bf1 100644
>> --- a/include/qemu/typedefs.h
>> +++ b/include/qemu/typedefs.h
>> @@ -58,6 +58,7 @@ typedef struct ISABus ISABus;
>>  typedef struct ISADevice ISADevice;
>>  typedef struct IsaDma IsaDma;
>>  typedef struct MACAddr MACAddr;
>> +typedef struct ReservedRegion ReservedRegion;
>>  typedef struct MachineClass MachineClass;
>>  typedef struct MachineState MachineState;
>>  typedef struct MemoryListener MemoryListener;
>> diff --git a/hw/core/qdev-properties.c b/hw/core/qdev-properties.c
>> index ead35d7ffd..193d0d95f9 100644
>> --- a/hw/core/qdev-properties.c
>> +++ b/hw/core/qdev-properties.c
>> @@ -15,6 +15,7 @@
>>  #include "chardev/char.h"
>>  #include "qemu/uuid.h"
>>  #include "qemu/units.h"
>> +#include "qemu/cutils.h"
>>  
>>  void qdev_prop_set_after_realize(DeviceState *dev, const char *name,
>>                                    Error **errp)
>> @@ -578,6 +579,94 @@ const PropertyInfo qdev_prop_macaddr = {
>>      .set   = set_mac,
>>  };
>>  
>> +/* --- Reserved Region --- */
>> +
>> +/*
>> + * accepted syntax version:
> 
> "version" feels redundant.  Suggest to capitalize "Accepted".
> 
>> + *   <low address>:<high address>:<type>
>> + *   where low/high addresses are uint64_t in hexadecimal
>> + *   and type is an unsigned integer in decimal
>> + */
>> +static void get_reserved_region(Object *obj, Visitor *v, const char *name,
>> +                                void *opaque, Error **errp)
>> +{
>> +    DeviceState *dev = DEVICE(obj);
>> +    Property *prop = opaque;
>> +    ReservedRegion *rr = qdev_get_prop_ptr(dev, prop);
>> +    char buffer[64];
>> +    char *p = buffer;
>> +    int rc;
>> +
>> +    rc = snprintf(buffer, sizeof(buffer), "0x%"PRIx64":0x%"PRIx64":%u",
>> +                  rr->low, rr->high, rr->type);
>> +    assert(rc < sizeof(buffer));
>> +
>> +    visit_type_str(v, name, &p, errp);
>> +}
>> +
>> +static void set_reserved_region(Object *obj, Visitor *v, const char *name,
>> +                                void *opaque, Error **errp)
>> +{
>> +    DeviceState *dev = DEVICE(obj);
>> +    Property *prop = opaque;
>> +    ReservedRegion *rr = qdev_get_prop_ptr(dev, prop);
>> +    Error *local_err = NULL;
>> +    const char *endptr;
>> +    char *str;
>> +    int ret;
>> +
>> +    if (dev->realized) {
>> +        qdev_prop_set_after_realize(dev, name, errp);
>> +        return;
>> +    }
>> +
>> +    visit_type_str(v, name, &str, &local_err);
>> +    if (local_err) {
>> +        error_propagate(errp, local_err);
>> +        return;
>> +    }
>> +
>> +    ret = qemu_strtou64(str, &endptr, 16, &rr->low);
>> +    if (ret) {
>> +        error_setg(errp, "start address of '%s'"
>> +                   " must be a hexadecimal integer", name);
>> +        goto out;
>> +    }
>> +    if (*endptr != ':') {
>> +        goto separator_error;
>> +    }
>> +
>> +    ret = qemu_strtou64(endptr + 1, &endptr, 16, &rr->high);
>> +    if (ret) {
>> +        error_setg(errp, "end address of '%s'"
>> +                   " must be a hexadecimal integer", name);
>> +        goto out;
>> +    }
>> +    if (*endptr != ':') {
>> +        goto separator_error;
>> +    }
>> +
>> +    ret = qemu_strtoui(endptr + 1, &endptr, 10, &rr->type);
>> +    if (ret) {
>> +        error_setg(errp, "type of '%s'"
>> +                   " must be an unsigned integer in decimal", name);
> 
> Suggest "must be a non-negative decimal integer".
> 
> Whatever uses the property needs a range check.  I can't see that the
> patches that follow.  What am I missing?
Do you mean, you would expect the virtio-iommu-pci device to abort in
case a wrong VIRTIO reserved region type has been registered?
Effectively I could do that.

For the time being, unexpected types are considered as RESERVED type.
Also reserved regions are set by the machinesa nd we don't expect users
to set them directly so I thought it was sufficient.

Thanks

Eric
> 
>> +    }
>> +    goto out;
>> +
>> +separator_error:
>> +    error_setg(errp, "reserved region fields must be separated with ':'");
>> +out:
>> +    g_free(str);
>> +    return;
>> +}
>> +
>> +const PropertyInfo qdev_prop_reserved_region = {
>> +    .name  = "reserved_region",
>> +    .description = "Reserved Region, example: 0xFEE00000:0xFEEFFFFF:0",
>> +    .get   = get_reserved_region,
>> +    .set   = set_reserved_region,
>> +};
>> +
>>  /* --- on/off/auto --- */
>>  
>>  const PropertyInfo qdev_prop_on_off_auto = {
> 
> R-by for this patch stands.
> 

Re: [PATCH v4 1/5] qdev: Introduce DEFINE_PROP_RESERVED_REGION

[Markus Armbruster]

Auger Eric <eric.auger@redhat.com> writes:

> Hi Markus,
>
> On 6/23/20 5:13 PM, Markus Armbruster wrote:
>> Eric Auger <eric.auger@redhat.com> writes:
>> 
>>> Introduce a new property defining a reserved region:
>>> <low address>:<high address>:<type>.
>>>
>>> This will be used to encode reserved IOVA regions.
>>>
>>> For instance, in virtio-iommu use case, reserved IOVA regions
>>> will be passed by the machine code to the virtio-iommu-pci
>>> device (an array of those). The type of the reserved region
>>> will match the virtio_iommu_probe_resv_mem subtype value:
>>> - VIRTIO_IOMMU_RESV_MEM_T_RESERVED (0)
>>> - VIRTIO_IOMMU_RESV_MEM_T_MSI (1)
>>>
>>> on PC/Q35 machine, this will be used to inform the
>>> virtio-iommu-pci device it should bypass the MSI region.
>>> The reserved region will be: 0xfee00000:0xfeefffff:1.
>>>
>>> On ARM, we can declare the ITS MSI doorbell as an MSI
>>> region to prevent MSIs from being mapped on guest side.
>>>
>>> Signed-off-by: Eric Auger <eric.auger@redhat.com>
>>> Reviewed-by: Markus Armbruster <armbru@redhat.com>
>>>
>>> ---
>>>
>>> v3 -> v4:
>>> - use ':' instead of commas as separators.
>>> - rearrange error messages
>>> - check snprintf returned value
>>> - dared to keep Markus' R-b despite those changes
>>> ---
>>>  include/exec/memory.h        |  6 +++
>>>  include/hw/qdev-properties.h |  3 ++
>>>  include/qemu/typedefs.h      |  1 +
>>>  hw/core/qdev-properties.c    | 89 ++++++++++++++++++++++++++++++++++++
>>>  4 files changed, 99 insertions(+)
>>>
>>> diff --git a/include/exec/memory.h b/include/exec/memory.h
>>> index 7207025bd4..d7a53b96cc 100644
>>> --- a/include/exec/memory.h
>>> +++ b/include/exec/memory.h
>>> @@ -51,6 +51,12 @@ extern bool global_dirty_log;
>>>  
>>>  typedef struct MemoryRegionOps MemoryRegionOps;
>>>  
>>> +struct ReservedRegion {
>>> +    hwaddr low;
>>> +    hwaddr high;
>>> +    unsigned int type;
>> 
>> Suggest to s/unsigned int/unsigned/.
>> 
>>> +};
>>> +
>>>  typedef struct IOMMUTLBEntry IOMMUTLBEntry;
>>>  
>>>  /* See address_space_translate: bit 0 is read, bit 1 is write.  */
>>> diff --git a/include/hw/qdev-properties.h b/include/hw/qdev-properties.h
>>> index 5252bb6b1a..95d0e7201d 100644
>>> --- a/include/hw/qdev-properties.h
>>> +++ b/include/hw/qdev-properties.h
>>> @@ -19,6 +19,7 @@ extern const PropertyInfo qdev_prop_string;
>>>  extern const PropertyInfo qdev_prop_chr;
>>>  extern const PropertyInfo qdev_prop_tpm;
>>>  extern const PropertyInfo qdev_prop_macaddr;
>>> +extern const PropertyInfo qdev_prop_reserved_region;
>>>  extern const PropertyInfo qdev_prop_on_off_auto;
>>>  extern const PropertyInfo qdev_prop_multifd_compression;
>>>  extern const PropertyInfo qdev_prop_losttickpolicy;
>>> @@ -184,6 +185,8 @@ extern const PropertyInfo qdev_prop_pcie_link_width;
>>>      DEFINE_PROP(_n, _s, _f, qdev_prop_drive_iothread, BlockBackend *)
>>>  #define DEFINE_PROP_MACADDR(_n, _s, _f)         \
>>>      DEFINE_PROP(_n, _s, _f, qdev_prop_macaddr, MACAddr)
>>> +#define DEFINE_PROP_RESERVED_REGION(_n, _s, _f)         \
>>> +    DEFINE_PROP(_n, _s, _f, qdev_prop_reserved_region, ReservedRegion)
>>>  #define DEFINE_PROP_ON_OFF_AUTO(_n, _s, _f, _d) \
>>>      DEFINE_PROP_SIGNED(_n, _s, _f, _d, qdev_prop_on_off_auto, OnOffAuto)
>>>  #define DEFINE_PROP_MULTIFD_COMPRESSION(_n, _s, _f, _d) \
>>> diff --git a/include/qemu/typedefs.h b/include/qemu/typedefs.h
>>> index ce4a78b687..15f5047bf1 100644
>>> --- a/include/qemu/typedefs.h
>>> +++ b/include/qemu/typedefs.h
>>> @@ -58,6 +58,7 @@ typedef struct ISABus ISABus;
>>>  typedef struct ISADevice ISADevice;
>>>  typedef struct IsaDma IsaDma;
>>>  typedef struct MACAddr MACAddr;
>>> +typedef struct ReservedRegion ReservedRegion;
>>>  typedef struct MachineClass MachineClass;
>>>  typedef struct MachineState MachineState;
>>>  typedef struct MemoryListener MemoryListener;
>>> diff --git a/hw/core/qdev-properties.c b/hw/core/qdev-properties.c
>>> index ead35d7ffd..193d0d95f9 100644
>>> --- a/hw/core/qdev-properties.c
>>> +++ b/hw/core/qdev-properties.c
>>> @@ -15,6 +15,7 @@
>>>  #include "chardev/char.h"
>>>  #include "qemu/uuid.h"
>>>  #include "qemu/units.h"
>>> +#include "qemu/cutils.h"
>>>  
>>>  void qdev_prop_set_after_realize(DeviceState *dev, const char *name,
>>>                                    Error **errp)
>>> @@ -578,6 +579,94 @@ const PropertyInfo qdev_prop_macaddr = {
>>>      .set   = set_mac,
>>>  };
>>>  
>>> +/* --- Reserved Region --- */
>>> +
>>> +/*
>>> + * accepted syntax version:
>> 
>> "version" feels redundant.  Suggest to capitalize "Accepted".
>> 
>>> + *   <low address>:<high address>:<type>
>>> + *   where low/high addresses are uint64_t in hexadecimal
>>> + *   and type is an unsigned integer in decimal
>>> + */
>>> +static void get_reserved_region(Object *obj, Visitor *v, const char *name,
>>> +                                void *opaque, Error **errp)
>>> +{
>>> +    DeviceState *dev = DEVICE(obj);
>>> +    Property *prop = opaque;
>>> +    ReservedRegion *rr = qdev_get_prop_ptr(dev, prop);
>>> +    char buffer[64];
>>> +    char *p = buffer;
>>> +    int rc;
>>> +
>>> +    rc = snprintf(buffer, sizeof(buffer), "0x%"PRIx64":0x%"PRIx64":%u",
>>> +                  rr->low, rr->high, rr->type);
>>> +    assert(rc < sizeof(buffer));
>>> +
>>> +    visit_type_str(v, name, &p, errp);
>>> +}
>>> +
>>> +static void set_reserved_region(Object *obj, Visitor *v, const char *name,
>>> +                                void *opaque, Error **errp)
>>> +{
>>> +    DeviceState *dev = DEVICE(obj);
>>> +    Property *prop = opaque;
>>> +    ReservedRegion *rr = qdev_get_prop_ptr(dev, prop);
>>> +    Error *local_err = NULL;
>>> +    const char *endptr;
>>> +    char *str;
>>> +    int ret;
>>> +
>>> +    if (dev->realized) {
>>> +        qdev_prop_set_after_realize(dev, name, errp);
>>> +        return;
>>> +    }
>>> +
>>> +    visit_type_str(v, name, &str, &local_err);
>>> +    if (local_err) {
>>> +        error_propagate(errp, local_err);
>>> +        return;
>>> +    }
>>> +
>>> +    ret = qemu_strtou64(str, &endptr, 16, &rr->low);
>>> +    if (ret) {
>>> +        error_setg(errp, "start address of '%s'"
>>> +                   " must be a hexadecimal integer", name);
>>> +        goto out;
>>> +    }
>>> +    if (*endptr != ':') {
>>> +        goto separator_error;
>>> +    }
>>> +
>>> +    ret = qemu_strtou64(endptr + 1, &endptr, 16, &rr->high);
>>> +    if (ret) {
>>> +        error_setg(errp, "end address of '%s'"
>>> +                   " must be a hexadecimal integer", name);
>>> +        goto out;
>>> +    }
>>> +    if (*endptr != ':') {
>>> +        goto separator_error;
>>> +    }
>>> +
>>> +    ret = qemu_strtoui(endptr + 1, &endptr, 10, &rr->type);
>>> +    if (ret) {
>>> +        error_setg(errp, "type of '%s'"
>>> +                   " must be an unsigned integer in decimal", name);
>> 
>> Suggest "must be a non-negative decimal integer".
>> 
>> Whatever uses the property needs a range check.  I can't see that the
>> patches that follow.  What am I missing?
> Do you mean, you would expect the virtio-iommu-pci device to abort in
> case a wrong VIRTIO reserved region type has been registered?

Knowing nothing about reserved region types, I (naively?) assume that a
finite set of types are encoded as small integers.  Any other integers
are then meaningless, and should be rejected.

> Effectively I could do that.
>
> For the time being, unexpected types are considered as RESERVED type.
> Also reserved regions are set by the machinesa nd we don't expect users
> to set them directly so I thought it was sufficient.

One, rejecting invalid values is useful even when they're set
programmatically, because it can catch programming errors.

Two, expecting users to only do what you expect is walking on rather
thin ice ;)

Re: [PATCH v4 1/5] qdev: Introduce DEFINE_PROP_RESERVED_REGION

[Auger Eric]

Hi Markus,

On 6/24/20 10:10 AM, Markus Armbruster wrote:
> Auger Eric <eric.auger@redhat.com> writes:
> 
>> Hi Markus,
>>
>> On 6/23/20 5:13 PM, Markus Armbruster wrote:
>>> Eric Auger <eric.auger@redhat.com> writes:
>>>
>>>> Introduce a new property defining a reserved region:
>>>> <low address>:<high address>:<type>.
>>>>
>>>> This will be used to encode reserved IOVA regions.
>>>>
>>>> For instance, in virtio-iommu use case, reserved IOVA regions
>>>> will be passed by the machine code to the virtio-iommu-pci
>>>> device (an array of those). The type of the reserved region
>>>> will match the virtio_iommu_probe_resv_mem subtype value:
>>>> - VIRTIO_IOMMU_RESV_MEM_T_RESERVED (0)
>>>> - VIRTIO_IOMMU_RESV_MEM_T_MSI (1)
>>>>
>>>> on PC/Q35 machine, this will be used to inform the
>>>> virtio-iommu-pci device it should bypass the MSI region.
>>>> The reserved region will be: 0xfee00000:0xfeefffff:1.
>>>>
>>>> On ARM, we can declare the ITS MSI doorbell as an MSI
>>>> region to prevent MSIs from being mapped on guest side.
>>>>
>>>> Signed-off-by: Eric Auger <eric.auger@redhat.com>
>>>> Reviewed-by: Markus Armbruster <armbru@redhat.com>
>>>>
>>>> ---
>>>>
>>>> v3 -> v4:
>>>> - use ':' instead of commas as separators.
>>>> - rearrange error messages
>>>> - check snprintf returned value
>>>> - dared to keep Markus' R-b despite those changes
>>>> ---
>>>>  include/exec/memory.h        |  6 +++
>>>>  include/hw/qdev-properties.h |  3 ++
>>>>  include/qemu/typedefs.h      |  1 +
>>>>  hw/core/qdev-properties.c    | 89 ++++++++++++++++++++++++++++++++++++
>>>>  4 files changed, 99 insertions(+)
>>>>
>>>> diff --git a/include/exec/memory.h b/include/exec/memory.h
>>>> index 7207025bd4..d7a53b96cc 100644
>>>> --- a/include/exec/memory.h
>>>> +++ b/include/exec/memory.h
>>>> @@ -51,6 +51,12 @@ extern bool global_dirty_log;
>>>>  
>>>>  typedef struct MemoryRegionOps MemoryRegionOps;
>>>>  
>>>> +struct ReservedRegion {
>>>> +    hwaddr low;
>>>> +    hwaddr high;
>>>> +    unsigned int type;
>>>
>>> Suggest to s/unsigned int/unsigned/.
>>>
>>>> +};
>>>> +
>>>>  typedef struct IOMMUTLBEntry IOMMUTLBEntry;
>>>>  
>>>>  /* See address_space_translate: bit 0 is read, bit 1 is write.  */
>>>> diff --git a/include/hw/qdev-properties.h b/include/hw/qdev-properties.h
>>>> index 5252bb6b1a..95d0e7201d 100644
>>>> --- a/include/hw/qdev-properties.h
>>>> +++ b/include/hw/qdev-properties.h
>>>> @@ -19,6 +19,7 @@ extern const PropertyInfo qdev_prop_string;
>>>>  extern const PropertyInfo qdev_prop_chr;
>>>>  extern const PropertyInfo qdev_prop_tpm;
>>>>  extern const PropertyInfo qdev_prop_macaddr;
>>>> +extern const PropertyInfo qdev_prop_reserved_region;
>>>>  extern const PropertyInfo qdev_prop_on_off_auto;
>>>>  extern const PropertyInfo qdev_prop_multifd_compression;
>>>>  extern const PropertyInfo qdev_prop_losttickpolicy;
>>>> @@ -184,6 +185,8 @@ extern const PropertyInfo qdev_prop_pcie_link_width;
>>>>      DEFINE_PROP(_n, _s, _f, qdev_prop_drive_iothread, BlockBackend *)
>>>>  #define DEFINE_PROP_MACADDR(_n, _s, _f)         \
>>>>      DEFINE_PROP(_n, _s, _f, qdev_prop_macaddr, MACAddr)
>>>> +#define DEFINE_PROP_RESERVED_REGION(_n, _s, _f)         \
>>>> +    DEFINE_PROP(_n, _s, _f, qdev_prop_reserved_region, ReservedRegion)
>>>>  #define DEFINE_PROP_ON_OFF_AUTO(_n, _s, _f, _d) \
>>>>      DEFINE_PROP_SIGNED(_n, _s, _f, _d, qdev_prop_on_off_auto, OnOffAuto)
>>>>  #define DEFINE_PROP_MULTIFD_COMPRESSION(_n, _s, _f, _d) \
>>>> diff --git a/include/qemu/typedefs.h b/include/qemu/typedefs.h
>>>> index ce4a78b687..15f5047bf1 100644
>>>> --- a/include/qemu/typedefs.h
>>>> +++ b/include/qemu/typedefs.h
>>>> @@ -58,6 +58,7 @@ typedef struct ISABus ISABus;
>>>>  typedef struct ISADevice ISADevice;
>>>>  typedef struct IsaDma IsaDma;
>>>>  typedef struct MACAddr MACAddr;
>>>> +typedef struct ReservedRegion ReservedRegion;
>>>>  typedef struct MachineClass MachineClass;
>>>>  typedef struct MachineState MachineState;
>>>>  typedef struct MemoryListener MemoryListener;
>>>> diff --git a/hw/core/qdev-properties.c b/hw/core/qdev-properties.c
>>>> index ead35d7ffd..193d0d95f9 100644
>>>> --- a/hw/core/qdev-properties.c
>>>> +++ b/hw/core/qdev-properties.c
>>>> @@ -15,6 +15,7 @@
>>>>  #include "chardev/char.h"
>>>>  #include "qemu/uuid.h"
>>>>  #include "qemu/units.h"
>>>> +#include "qemu/cutils.h"
>>>>  
>>>>  void qdev_prop_set_after_realize(DeviceState *dev, const char *name,
>>>>                                    Error **errp)
>>>> @@ -578,6 +579,94 @@ const PropertyInfo qdev_prop_macaddr = {
>>>>      .set   = set_mac,
>>>>  };
>>>>  
>>>> +/* --- Reserved Region --- */
>>>> +
>>>> +/*
>>>> + * accepted syntax version:
>>>
>>> "version" feels redundant.  Suggest to capitalize "Accepted".
>>>
>>>> + *   <low address>:<high address>:<type>
>>>> + *   where low/high addresses are uint64_t in hexadecimal
>>>> + *   and type is an unsigned integer in decimal
>>>> + */
>>>> +static void get_reserved_region(Object *obj, Visitor *v, const char *name,
>>>> +                                void *opaque, Error **errp)
>>>> +{
>>>> +    DeviceState *dev = DEVICE(obj);
>>>> +    Property *prop = opaque;
>>>> +    ReservedRegion *rr = qdev_get_prop_ptr(dev, prop);
>>>> +    char buffer[64];
>>>> +    char *p = buffer;
>>>> +    int rc;
>>>> +
>>>> +    rc = snprintf(buffer, sizeof(buffer), "0x%"PRIx64":0x%"PRIx64":%u",
>>>> +                  rr->low, rr->high, rr->type);
>>>> +    assert(rc < sizeof(buffer));
>>>> +
>>>> +    visit_type_str(v, name, &p, errp);
>>>> +}
>>>> +
>>>> +static void set_reserved_region(Object *obj, Visitor *v, const char *name,
>>>> +                                void *opaque, Error **errp)
>>>> +{
>>>> +    DeviceState *dev = DEVICE(obj);
>>>> +    Property *prop = opaque;
>>>> +    ReservedRegion *rr = qdev_get_prop_ptr(dev, prop);
>>>> +    Error *local_err = NULL;
>>>> +    const char *endptr;
>>>> +    char *str;
>>>> +    int ret;
>>>> +
>>>> +    if (dev->realized) {
>>>> +        qdev_prop_set_after_realize(dev, name, errp);
>>>> +        return;
>>>> +    }
>>>> +
>>>> +    visit_type_str(v, name, &str, &local_err);
>>>> +    if (local_err) {
>>>> +        error_propagate(errp, local_err);
>>>> +        return;
>>>> +    }
>>>> +
>>>> +    ret = qemu_strtou64(str, &endptr, 16, &rr->low);
>>>> +    if (ret) {
>>>> +        error_setg(errp, "start address of '%s'"
>>>> +                   " must be a hexadecimal integer", name);
>>>> +        goto out;
>>>> +    }
>>>> +    if (*endptr != ':') {
>>>> +        goto separator_error;
>>>> +    }
>>>> +
>>>> +    ret = qemu_strtou64(endptr + 1, &endptr, 16, &rr->high);
>>>> +    if (ret) {
>>>> +        error_setg(errp, "end address of '%s'"
>>>> +                   " must be a hexadecimal integer", name);
>>>> +        goto out;
>>>> +    }
>>>> +    if (*endptr != ':') {
>>>> +        goto separator_error;
>>>> +    }
>>>> +
>>>> +    ret = qemu_strtoui(endptr + 1, &endptr, 10, &rr->type);
>>>> +    if (ret) {
>>>> +        error_setg(errp, "type of '%s'"
>>>> +                   " must be an unsigned integer in decimal", name);
>>>
>>> Suggest "must be a non-negative decimal integer".
>>>
>>> Whatever uses the property needs a range check.  I can't see that the
>>> patches that follow.  What am I missing?
>> Do you mean, you would expect the virtio-iommu-pci device to abort in
>> case a wrong VIRTIO reserved region type has been registered?
> 
> Knowing nothing about reserved region types, I (naively?) assume that a
> finite set of types are encoded as small integers.  Any other integers
> are then meaningless, and should be rejected.
you're right.
> 
>> Effectively I could do that.
>>
>> For the time being, unexpected types are considered as RESERVED type.
>> Also reserved regions are set by the machinesa nd we don't expect users
>> to set them directly so I thought it was sufficient.
> 
> One, rejecting invalid values is useful even when they're set
> programmatically, because it can catch programming errors.
> 
> Two, expecting users to only do what you expect is walking on rather
> thin ice ;)
Agreed, I will add an assert()

Thanks!

Eric
>