[PATCH v5 0/4] VIRTIO-IOMMU: Introduce an aw-bits option

[PATCH v5 0/4] VIRTIO-IOMMU: Introduce an aw-bits option

[Eric Auger]

In [1] and [2] we attempted to fix a case where a VFIO-PCI device
protected with a virtio-iommu is assigned to an x86 guest. On x86
the physical IOMMU may have an address width (gaw) of 39 or 48 bits
whereas the virtio-iommu exposes a 64b input address space by default.
Hence the guest may try to use the full 64b space and DMA MAP
failures may be encountered. To work around this issue we endeavoured
to pass usable host IOVA regions (excluding the out of range space) from
VFIO to the virtio-iommu device so that the virtio-iommu driver can
query those latter during the probe request and let the guest iommu
kernel subsystem carve them out.

However if there are several devices in the same iommu group,
only the reserved regions of the first one are taken into
account by the iommu subsystem of the guest. This generally
works on baremetal because devices are not going to
expose different reserved regions. However in our case, this
may prevent from taking into account the host iommu geometry.

So the simplest solution to this problem looks to introduce an
input address width option, aw-bits, which matches what is
done on the intel-iommu. By default, from now on it is set
to 39 bits with pc_q35 and 48 with arm virt. This replaces the
previous default value of 64b. So we need to introduce a compat
for machines older than 9.0 to behave similarly. We use
hw_compat_8_2 to acheive that goal.

Outstanding series [2] remains useful to let resv regions beeing
communicated on time before the probe request.

[1] [PATCH v4 00/12] VIRTIO-IOMMU/VFIO: Don't assume 64b IOVA space
    https://lore.kernel.org/all/20231019134651.842175-1-eric.auger@redhat.com/
    - This is merged -

[2] [RFC 0/7] VIRTIO-IOMMU/VFIO: Fix host iommu geometry handling for hotplugged devices
    https://lore.kernel.org/all/20240117080414.316890-1-eric.auger@redhat.com/
    - This is pending for review on the ML -

This series can be found at:
https://github.com/eauger/qemu/tree/virtio-iommu-aw-bits-v5

History:
v4 -> v5:
- small change in the aw-bits options description  [Cédric]

v3 -> v4:
- remove dependency on
  [PATCH v2] virtio-iommu: Use qemu_real_host_page_mask as default page_size_mask
- Fix qtest error [Michael]
- add doc entry in qemu-options.hx

v2 -> v3:
- Collected Zhenzhong and Cédric's R-b + Yanghang's T-b
- use &error_abort instead of NULL error handle
  on object_property_get_uint() call (Cédric)
- use VTD_HOST_AW_39BIT (Cédric)

v1 -> v2
- Limit aw to 48b on ARM
- Check aw is within [32,64]
- Use hw_compat_8_2


Eric Auger (4):
  virtio-iommu: Add an option to define the input range width
  virtio-iommu: Trace domain range limits as unsigned int
  hw: Set virtio-iommu aw-bits default value on pc_q35 and arm virt
  qemu-options.hx: Add an entry for virtio-iommu-pci and document
    aw-bits

 include/hw/virtio/virtio-iommu.h | 1 +
 hw/arm/virt.c                    | 6 ++++++
 hw/core/machine.c                | 5 ++++-
 hw/i386/pc.c                     | 6 ++++++
 hw/virtio/virtio-iommu.c         | 7 ++++++-
 tests/qtest/virtio-iommu-test.c  | 2 +-
 hw/virtio/trace-events           | 2 +-
 qemu-options.hx                  | 8 ++++++++
 8 files changed, 33 insertions(+), 4 deletions(-)

-- 
2.41.0

[PATCH v5 1/4] virtio-iommu: Add an option to define the input range width

[Eric Auger]

aw-bits is a new option that allows to set the bit width of
the input address range. This value will be used as a default for
the device config input_range.end. By default it is set to 64 bits
which is the current value.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>

---

v1 -> v2:
- Check the aw-bits value is within [32,64]
---
 include/hw/virtio/virtio-iommu.h | 1 +
 hw/virtio/virtio-iommu.c         | 7 ++++++-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/include/hw/virtio/virtio-iommu.h b/include/hw/virtio/virtio-iommu.h
index 781ebaea8f..5fbe4677c2 100644
--- a/include/hw/virtio/virtio-iommu.h
+++ b/include/hw/virtio/virtio-iommu.h
@@ -66,6 +66,7 @@ struct VirtIOIOMMU {
     bool boot_bypass;
     Notifier machine_done;
     bool granule_frozen;
+    uint8_t aw_bits;
 };
 
 #endif
diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c
index 86623d55a5..8b541de850 100644
--- a/hw/virtio/virtio-iommu.c
+++ b/hw/virtio/virtio-iommu.c
@@ -1314,7 +1314,11 @@ static void virtio_iommu_device_realize(DeviceState *dev, Error **errp)
      */
     s->config.bypass = s->boot_bypass;
     s->config.page_size_mask = qemu_target_page_mask();
-    s->config.input_range.end = UINT64_MAX;
+    if (s->aw_bits < 32 || s->aw_bits > 64) {
+        error_setg(errp, "aw-bits must be within [32,64]");
+    }
+    s->config.input_range.end =
+        s->aw_bits == 64 ? UINT64_MAX : BIT_ULL(s->aw_bits) - 1;
     s->config.domain_range.end = UINT32_MAX;
     s->config.probe_size = VIOMMU_PROBE_SIZE;
 
@@ -1522,6 +1526,7 @@ static Property virtio_iommu_properties[] = {
     DEFINE_PROP_LINK("primary-bus", VirtIOIOMMU, primary_bus,
                      TYPE_PCI_BUS, PCIBus *),
     DEFINE_PROP_BOOL("boot-bypass", VirtIOIOMMU, boot_bypass, true),
+    DEFINE_PROP_UINT8("aw-bits", VirtIOIOMMU, aw_bits, 64),
     DEFINE_PROP_END_OF_LIST(),
 };
 
-- 
2.41.0

[PATCH v5 2/4] virtio-iommu: Trace domain range limits as unsigned int

[Eric Auger]

Use %u format to trace domain_range limits.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
---
 hw/virtio/trace-events | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/virtio/trace-events b/hw/virtio/trace-events
index 77905d1994..2350849fbd 100644
--- a/hw/virtio/trace-events
+++ b/hw/virtio/trace-events
@@ -111,7 +111,7 @@ virtio_iommu_device_reset(void) "reset!"
 virtio_iommu_system_reset(void) "system reset!"
 virtio_iommu_get_features(uint64_t features) "device supports features=0x%"PRIx64
 virtio_iommu_device_status(uint8_t status) "driver status = %d"
-virtio_iommu_get_config(uint64_t page_size_mask, uint64_t start, uint64_t end, uint32_t domain_start, uint32_t domain_end, uint32_t probe_size, uint8_t bypass) "page_size_mask=0x%"PRIx64" input range start=0x%"PRIx64" input range end=0x%"PRIx64" domain range start=%d domain range end=%d probe_size=0x%x bypass=0x%x"
+virtio_iommu_get_config(uint64_t page_size_mask, uint64_t start, uint64_t end, uint32_t domain_start, uint32_t domain_end, uint32_t probe_size, uint8_t bypass) "page_size_mask=0x%"PRIx64" input range start=0x%"PRIx64" input range end=0x%"PRIx64" domain range start=%u domain range end=%u probe_size=0x%x bypass=0x%x"
 virtio_iommu_set_config(uint8_t bypass) "bypass=0x%x"
 virtio_iommu_attach(uint32_t domain_id, uint32_t ep_id) "domain=%d endpoint=%d"
 virtio_iommu_detach(uint32_t domain_id, uint32_t ep_id) "domain=%d endpoint=%d"
-- 
2.41.0

[PATCH v5 3/4] hw: Set virtio-iommu aw-bits default value on pc_q35 and arm virt

[Eric Auger]

Currently the default input range can extend to 64 bits. On x86,
when the virtio-iommu protects vfio devices, the physical iommu
may support only 39 bits. Let's set the default to 39, as done
for the intel-iommu. On ARM we set 48b as a default (matching
SMMUv3 SMMU_IDR5.VAX == 0).

We use hw_compat_8_2 to handle the compatibility for machines
before 9.0 which used to have a virtio-iommu default input range
of 64 bits.

Of course if aw-bits is set from the command line, the default
is overriden.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Tested-by: Yanghang Liu<yanghliu@redhat.com>

---

v3 -> v4:
- update the qos test to relax the check on the max input IOVA

v2 -> v3:
- collected Zhenzhong's R-b
- use &error_abort instead of NULL error handle
  on object_property_get_uint() call (Cédric)
- use VTD_HOST_AW_39BIT (Cédric)

v1 -> v2:
- set aw-bits to 48b on ARM
- use hw_compat_8_2 to handle the compat for older machines
  which used 64b as a default
---
 hw/arm/virt.c                   | 6 ++++++
 hw/core/machine.c               | 5 ++++-
 hw/i386/pc.c                    | 6 ++++++
 hw/virtio/virtio-iommu.c        | 2 +-
 tests/qtest/virtio-iommu-test.c | 2 +-
 5 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index 368c2a415a..0994f2a560 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -2716,10 +2716,16 @@ static void virt_machine_device_pre_plug_cb(HotplugHandler *hotplug_dev,
     } else if (object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_MD_PCI)) {
         virtio_md_pci_pre_plug(VIRTIO_MD_PCI(dev), MACHINE(hotplug_dev), errp);
     } else if (object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_IOMMU_PCI)) {
+        uint8_t aw_bits = object_property_get_uint(OBJECT(dev),
+                                                   "aw-bits", &error_abort);
         hwaddr db_start = 0, db_end = 0;
         QList *reserved_regions;
         char *resv_prop_str;
 
+        if (!aw_bits) {
+            qdev_prop_set_uint8(dev, "aw-bits", 48);
+        }
+
         if (vms->iommu != VIRT_IOMMU_NONE) {
             error_setg(errp, "virt machine does not support multiple IOMMUs");
             return;
diff --git a/hw/core/machine.c b/hw/core/machine.c
index fb5afdcae4..70ac96954c 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -30,9 +30,12 @@
 #include "exec/confidential-guest-support.h"
 #include "hw/virtio/virtio-pci.h"
 #include "hw/virtio/virtio-net.h"
+#include "hw/virtio/virtio-iommu.h"
 #include "audio/audio.h"
 
-GlobalProperty hw_compat_8_2[] = {};
+GlobalProperty hw_compat_8_2[] = {
+    { TYPE_VIRTIO_IOMMU_PCI, "aw-bits", "64" },
+};
 const size_t hw_compat_8_2_len = G_N_ELEMENTS(hw_compat_8_2);
 
 GlobalProperty hw_compat_8_1[] = {
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 196827531a..ee2d379c90 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -1456,6 +1456,8 @@ static void pc_machine_device_pre_plug_cb(HotplugHandler *hotplug_dev,
     } else if (object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_MD_PCI)) {
         virtio_md_pci_pre_plug(VIRTIO_MD_PCI(dev), MACHINE(hotplug_dev), errp);
     } else if (object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_IOMMU_PCI)) {
+        uint8_t aw_bits = object_property_get_uint(OBJECT(dev),
+                                                   "aw-bits", &error_abort);
         /* Declare the APIC range as the reserved MSI region */
         char *resv_prop_str = g_strdup_printf("0xfee00000:0xfeefffff:%d",
                                               VIRTIO_IOMMU_RESV_MEM_T_MSI);
@@ -1464,6 +1466,10 @@ static void pc_machine_device_pre_plug_cb(HotplugHandler *hotplug_dev,
         qlist_append_str(reserved_regions, resv_prop_str);
         qdev_prop_set_array(dev, "reserved-regions", reserved_regions);
 
+        if (!aw_bits) {
+            qdev_prop_set_uint8(dev, "aw-bits", VTD_HOST_AW_39BIT);
+        }
+
         g_free(resv_prop_str);
     }
 
diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c
index 8b541de850..2ec5ef3cd1 100644
--- a/hw/virtio/virtio-iommu.c
+++ b/hw/virtio/virtio-iommu.c
@@ -1526,7 +1526,7 @@ static Property virtio_iommu_properties[] = {
     DEFINE_PROP_LINK("primary-bus", VirtIOIOMMU, primary_bus,
                      TYPE_PCI_BUS, PCIBus *),
     DEFINE_PROP_BOOL("boot-bypass", VirtIOIOMMU, boot_bypass, true),
-    DEFINE_PROP_UINT8("aw-bits", VirtIOIOMMU, aw_bits, 64),
+    DEFINE_PROP_UINT8("aw-bits", VirtIOIOMMU, aw_bits, 0),
     DEFINE_PROP_END_OF_LIST(),
 };
 
diff --git a/tests/qtest/virtio-iommu-test.c b/tests/qtest/virtio-iommu-test.c
index 068e7a9e6c..0f36381acb 100644
--- a/tests/qtest/virtio-iommu-test.c
+++ b/tests/qtest/virtio-iommu-test.c
@@ -34,7 +34,7 @@ static void pci_config(void *obj, void *data, QGuestAllocator *t_alloc)
     uint8_t bypass = qvirtio_config_readb(dev, 36);
 
     g_assert_cmpint(input_range_start, ==, 0);
-    g_assert_cmphex(input_range_end, ==, UINT64_MAX);
+    g_assert_cmphex(input_range_end, >=, 32);
     g_assert_cmpint(domain_range_start, ==, 0);
     g_assert_cmpint(domain_range_end, ==, UINT32_MAX);
     g_assert_cmpint(bypass, ==, 1);
-- 
2.41.0

Re: [PATCH v5 3/4] hw: Set virtio-iommu aw-bits default value on pc_q35 and arm virt

[Cédric Le Goater]

Hello Eric,

On 2/15/24 09:42, Eric Auger wrote:
> Currently the default input range can extend to 64 bits. On x86,
> when the virtio-iommu protects vfio devices, the physical iommu
> may support only 39 bits. Let's set the default to 39, as done
> for the intel-iommu. On ARM we set 48b as a default (matching
> SMMUv3 SMMU_IDR5.VAX == 0).
> 
> We use hw_compat_8_2 to handle the compatibility for machines
> before 9.0 which used to have a virtio-iommu default input range
> of 64 bits.
> 
> Of course if aw-bits is set from the command line, the default
> is overriden.
> 
> Signed-off-by: Eric Auger <eric.auger@redhat.com>
> Reviewed-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
> Tested-by: Yanghang Liu<yanghliu@redhat.com>

We need a property fixup for pseries also:

$ build/ppc64-softmmu/qemu-system-ppc64 -M pseries  -device virtio-iommu-pci,addr=04.0
qemu-system-ppc64: -device virtio-iommu-pci,addr=04.0: aw-bits must be within [32,64]


Thanks,

C.



> ---
> 
> v3 -> v4:
> - update the qos test to relax the check on the max input IOVA
> 
> v2 -> v3:
> - collected Zhenzhong's R-b
> - use &error_abort instead of NULL error handle
>    on object_property_get_uint() call (Cédric)
> - use VTD_HOST_AW_39BIT (Cédric)
> 
> v1 -> v2:
> - set aw-bits to 48b on ARM
> - use hw_compat_8_2 to handle the compat for older machines
>    which used 64b as a default
> ---
>   hw/arm/virt.c                   | 6 ++++++
>   hw/core/machine.c               | 5 ++++-
>   hw/i386/pc.c                    | 6 ++++++
>   hw/virtio/virtio-iommu.c        | 2 +-
>   tests/qtest/virtio-iommu-test.c | 2 +-
>   5 files changed, 18 insertions(+), 3 deletions(-)
> 
> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index 368c2a415a..0994f2a560 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -2716,10 +2716,16 @@ static void virt_machine_device_pre_plug_cb(HotplugHandler *hotplug_dev,
>       } else if (object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_MD_PCI)) {
>           virtio_md_pci_pre_plug(VIRTIO_MD_PCI(dev), MACHINE(hotplug_dev), errp);
>       } else if (object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_IOMMU_PCI)) {
> +        uint8_t aw_bits = object_property_get_uint(OBJECT(dev),
> +                                                   "aw-bits", &error_abort);
>           hwaddr db_start = 0, db_end = 0;
>           QList *reserved_regions;
>           char *resv_prop_str;
>   
> +        if (!aw_bits) {
> +            qdev_prop_set_uint8(dev, "aw-bits", 48);
> +        }
> +
>           if (vms->iommu != VIRT_IOMMU_NONE) {
>               error_setg(errp, "virt machine does not support multiple IOMMUs");
>               return;
> diff --git a/hw/core/machine.c b/hw/core/machine.c
> index fb5afdcae4..70ac96954c 100644
> --- a/hw/core/machine.c
> +++ b/hw/core/machine.c
> @@ -30,9 +30,12 @@
>   #include "exec/confidential-guest-support.h"
>   #include "hw/virtio/virtio-pci.h"
>   #include "hw/virtio/virtio-net.h"
> +#include "hw/virtio/virtio-iommu.h"
>   #include "audio/audio.h"
>   
> -GlobalProperty hw_compat_8_2[] = {};
> +GlobalProperty hw_compat_8_2[] = {
> +    { TYPE_VIRTIO_IOMMU_PCI, "aw-bits", "64" },
> +};
>   const size_t hw_compat_8_2_len = G_N_ELEMENTS(hw_compat_8_2);
>   
>   GlobalProperty hw_compat_8_1[] = {
> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> index 196827531a..ee2d379c90 100644
> --- a/hw/i386/pc.c
> +++ b/hw/i386/pc.c
> @@ -1456,6 +1456,8 @@ static void pc_machine_device_pre_plug_cb(HotplugHandler *hotplug_dev,
>       } else if (object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_MD_PCI)) {
>           virtio_md_pci_pre_plug(VIRTIO_MD_PCI(dev), MACHINE(hotplug_dev), errp);
>       } else if (object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_IOMMU_PCI)) {
> +        uint8_t aw_bits = object_property_get_uint(OBJECT(dev),
> +                                                   "aw-bits", &error_abort);
>           /* Declare the APIC range as the reserved MSI region */
>           char *resv_prop_str = g_strdup_printf("0xfee00000:0xfeefffff:%d",
>                                                 VIRTIO_IOMMU_RESV_MEM_T_MSI);
> @@ -1464,6 +1466,10 @@ static void pc_machine_device_pre_plug_cb(HotplugHandler *hotplug_dev,
>           qlist_append_str(reserved_regions, resv_prop_str);
>           qdev_prop_set_array(dev, "reserved-regions", reserved_regions);
>   
> +        if (!aw_bits) {
> +            qdev_prop_set_uint8(dev, "aw-bits", VTD_HOST_AW_39BIT);
> +        }
> +
>           g_free(resv_prop_str);
>       }
>   
> diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c
> index 8b541de850..2ec5ef3cd1 100644
> --- a/hw/virtio/virtio-iommu.c
> +++ b/hw/virtio/virtio-iommu.c
> @@ -1526,7 +1526,7 @@ static Property virtio_iommu_properties[] = {
>       DEFINE_PROP_LINK("primary-bus", VirtIOIOMMU, primary_bus,
>                        TYPE_PCI_BUS, PCIBus *),
>       DEFINE_PROP_BOOL("boot-bypass", VirtIOIOMMU, boot_bypass, true),
> -    DEFINE_PROP_UINT8("aw-bits", VirtIOIOMMU, aw_bits, 64),
> +    DEFINE_PROP_UINT8("aw-bits", VirtIOIOMMU, aw_bits, 0),
>       DEFINE_PROP_END_OF_LIST(),
>   };
>   
> diff --git a/tests/qtest/virtio-iommu-test.c b/tests/qtest/virtio-iommu-test.c
> index 068e7a9e6c..0f36381acb 100644
> --- a/tests/qtest/virtio-iommu-test.c
> +++ b/tests/qtest/virtio-iommu-test.c
> @@ -34,7 +34,7 @@ static void pci_config(void *obj, void *data, QGuestAllocator *t_alloc)
>       uint8_t bypass = qvirtio_config_readb(dev, 36);
>   
>       g_assert_cmpint(input_range_start, ==, 0);
> -    g_assert_cmphex(input_range_end, ==, UINT64_MAX);
> +    g_assert_cmphex(input_range_end, >=, 32);
>       g_assert_cmpint(domain_range_start, ==, 0);
>       g_assert_cmpint(domain_range_end, ==, UINT32_MAX);
>       g_assert_cmpint(bypass, ==, 1);

Re: [PATCH v5 3/4] hw: Set virtio-iommu aw-bits default value on pc_q35 and arm virt

[Eric Auger]

Hi Cédric,

On 2/27/24 18:17, Cédric Le Goater wrote:
> Hello Eric,
>
> On 2/15/24 09:42, Eric Auger wrote:
>> Currently the default input range can extend to 64 bits. On x86,
>> when the virtio-iommu protects vfio devices, the physical iommu
>> may support only 39 bits. Let's set the default to 39, as done
>> for the intel-iommu. On ARM we set 48b as a default (matching
>> SMMUv3 SMMU_IDR5.VAX == 0).
>>
>> We use hw_compat_8_2 to handle the compatibility for machines
>> before 9.0 which used to have a virtio-iommu default input range
>> of 64 bits.
>>
>> Of course if aw-bits is set from the command line, the default
>> is overriden.
>>
>> Signed-off-by: Eric Auger <eric.auger@redhat.com>
>> Reviewed-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
>> Tested-by: Yanghang Liu<yanghliu@redhat.com>
>
> We need a property fixup for pseries also:
>
> $ build/ppc64-softmmu/qemu-system-ppc64 -M pseries  -device
> virtio-iommu-pci,addr=04.0
> qemu-system-ppc64: -device virtio-iommu-pci,addr=04.0: aw-bits must be
> within [32,64]

as stated in the doc (now! see [PATCH v5 4/4] qemu-options.hx: Add an
entry for virtio-iommu-pci and document aw-bits) , the virtio-iommu-pci
device only is supported in q35 and arm virt.

If you want to support virtio-iommu on other machines, you need to take
care of this aw-bits settings and also of the exposed reserved regions.

Thanks

Eric
>
>
> Thanks,
>
> C.
>
>
>
>> ---
>>
>> v3 -> v4:
>> - update the qos test to relax the check on the max input IOVA
>>
>> v2 -> v3:
>> - collected Zhenzhong's R-b
>> - use &error_abort instead of NULL error handle
>>    on object_property_get_uint() call (Cédric)
>> - use VTD_HOST_AW_39BIT (Cédric)
>>
>> v1 -> v2:
>> - set aw-bits to 48b on ARM
>> - use hw_compat_8_2 to handle the compat for older machines
>>    which used 64b as a default
>> ---
>>   hw/arm/virt.c                   | 6 ++++++
>>   hw/core/machine.c               | 5 ++++-
>>   hw/i386/pc.c                    | 6 ++++++
>>   hw/virtio/virtio-iommu.c        | 2 +-
>>   tests/qtest/virtio-iommu-test.c | 2 +-
>>   5 files changed, 18 insertions(+), 3 deletions(-)
>>
>> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
>> index 368c2a415a..0994f2a560 100644
>> --- a/hw/arm/virt.c
>> +++ b/hw/arm/virt.c
>> @@ -2716,10 +2716,16 @@ static void
>> virt_machine_device_pre_plug_cb(HotplugHandler *hotplug_dev,
>>       } else if (object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_MD_PCI)) {
>>           virtio_md_pci_pre_plug(VIRTIO_MD_PCI(dev),
>> MACHINE(hotplug_dev), errp);
>>       } else if (object_dynamic_cast(OBJECT(dev),
>> TYPE_VIRTIO_IOMMU_PCI)) {
>> +        uint8_t aw_bits = object_property_get_uint(OBJECT(dev),
>> +                                                   "aw-bits",
>> &error_abort);
>>           hwaddr db_start = 0, db_end = 0;
>>           QList *reserved_regions;
>>           char *resv_prop_str;
>>   +        if (!aw_bits) {
>> +            qdev_prop_set_uint8(dev, "aw-bits", 48);
>> +        }
>> +
>>           if (vms->iommu != VIRT_IOMMU_NONE) {
>>               error_setg(errp, "virt machine does not support
>> multiple IOMMUs");
>>               return;
>> diff --git a/hw/core/machine.c b/hw/core/machine.c
>> index fb5afdcae4..70ac96954c 100644
>> --- a/hw/core/machine.c
>> +++ b/hw/core/machine.c
>> @@ -30,9 +30,12 @@
>>   #include "exec/confidential-guest-support.h"
>>   #include "hw/virtio/virtio-pci.h"
>>   #include "hw/virtio/virtio-net.h"
>> +#include "hw/virtio/virtio-iommu.h"
>>   #include "audio/audio.h"
>>   -GlobalProperty hw_compat_8_2[] = {};
>> +GlobalProperty hw_compat_8_2[] = {
>> +    { TYPE_VIRTIO_IOMMU_PCI, "aw-bits", "64" },
>> +};
>>   const size_t hw_compat_8_2_len = G_N_ELEMENTS(hw_compat_8_2);
>>     GlobalProperty hw_compat_8_1[] = {
>> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
>> index 196827531a..ee2d379c90 100644
>> --- a/hw/i386/pc.c
>> +++ b/hw/i386/pc.c
>> @@ -1456,6 +1456,8 @@ static void
>> pc_machine_device_pre_plug_cb(HotplugHandler *hotplug_dev,
>>       } else if (object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_MD_PCI)) {
>>           virtio_md_pci_pre_plug(VIRTIO_MD_PCI(dev),
>> MACHINE(hotplug_dev), errp);
>>       } else if (object_dynamic_cast(OBJECT(dev),
>> TYPE_VIRTIO_IOMMU_PCI)) {
>> +        uint8_t aw_bits = object_property_get_uint(OBJECT(dev),
>> +                                                   "aw-bits",
>> &error_abort);
>>           /* Declare the APIC range as the reserved MSI region */
>>           char *resv_prop_str =
>> g_strdup_printf("0xfee00000:0xfeefffff:%d",
>>                                                
>> VIRTIO_IOMMU_RESV_MEM_T_MSI);
>> @@ -1464,6 +1466,10 @@ static void
>> pc_machine_device_pre_plug_cb(HotplugHandler *hotplug_dev,
>>           qlist_append_str(reserved_regions, resv_prop_str);
>>           qdev_prop_set_array(dev, "reserved-regions",
>> reserved_regions);
>>   +        if (!aw_bits) {
>> +            qdev_prop_set_uint8(dev, "aw-bits", VTD_HOST_AW_39BIT);
>> +        }
>> +
>>           g_free(resv_prop_str);
>>       }
>>   diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c
>> index 8b541de850..2ec5ef3cd1 100644
>> --- a/hw/virtio/virtio-iommu.c
>> +++ b/hw/virtio/virtio-iommu.c
>> @@ -1526,7 +1526,7 @@ static Property virtio_iommu_properties[] = {
>>       DEFINE_PROP_LINK("primary-bus", VirtIOIOMMU, primary_bus,
>>                        TYPE_PCI_BUS, PCIBus *),
>>       DEFINE_PROP_BOOL("boot-bypass", VirtIOIOMMU, boot_bypass, true),
>> -    DEFINE_PROP_UINT8("aw-bits", VirtIOIOMMU, aw_bits, 64),
>> +    DEFINE_PROP_UINT8("aw-bits", VirtIOIOMMU, aw_bits, 0),
>>       DEFINE_PROP_END_OF_LIST(),
>>   };
>>   diff --git a/tests/qtest/virtio-iommu-test.c
>> b/tests/qtest/virtio-iommu-test.c
>> index 068e7a9e6c..0f36381acb 100644
>> --- a/tests/qtest/virtio-iommu-test.c
>> +++ b/tests/qtest/virtio-iommu-test.c
>> @@ -34,7 +34,7 @@ static void pci_config(void *obj, void *data,
>> QGuestAllocator *t_alloc)
>>       uint8_t bypass = qvirtio_config_readb(dev, 36);
>>         g_assert_cmpint(input_range_start, ==, 0);
>> -    g_assert_cmphex(input_range_end, ==, UINT64_MAX);
>> +    g_assert_cmphex(input_range_end, >=, 32);
>>       g_assert_cmpint(domain_range_start, ==, 0);
>>       g_assert_cmpint(domain_range_end, ==, UINT32_MAX);
>>       g_assert_cmpint(bypass, ==, 1);
>

Re: [PATCH v5 3/4] hw: Set virtio-iommu aw-bits default value on pc_q35 and arm virt

[Eric Auger]

Hi,

On 2/27/24 18:17, Cédric Le Goater wrote:
> Hello Eric,
>
> On 2/15/24 09:42, Eric Auger wrote:
>> Currently the default input range can extend to 64 bits. On x86,
>> when the virtio-iommu protects vfio devices, the physical iommu
>> may support only 39 bits. Let's set the default to 39, as done
>> for the intel-iommu. On ARM we set 48b as a default (matching
>> SMMUv3 SMMU_IDR5.VAX == 0).
>>
>> We use hw_compat_8_2 to handle the compatibility for machines
>> before 9.0 which used to have a virtio-iommu default input range
>> of 64 bits.
>>
>> Of course if aw-bits is set from the command line, the default
>> is overriden.
>>
>> Signed-off-by: Eric Auger <eric.auger@redhat.com>
>> Reviewed-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
>> Tested-by: Yanghang Liu<yanghliu@redhat.com>
>
> We need a property fixup for pseries also:
>
> $ build/ppc64-softmmu/qemu-system-ppc64 -M pseries  -device
> virtio-iommu-pci,addr=04.0
> qemu-system-ppc64: -device virtio-iommu-pci,addr=04.0: aw-bits must be
> within [32,64]
after offline discssion with Cédric, despite the virtio-iommu-pci device
is not supported on ppc64 the
tests/qtest/qos-test attempts to execute the
tests/qtest/virtio-iommu-test.c because the machine has a pci bus. Since
by default the aw-bits is 0 the test fails. I need to rework that.
Thanks! Eric
>
>
> Thanks,
>
> C.
>
>
>
>> ---
>>
>> v3 -> v4:
>> - update the qos test to relax the check on the max input IOVA
>>
>> v2 -> v3:
>> - collected Zhenzhong's R-b
>> - use &error_abort instead of NULL error handle
>>    on object_property_get_uint() call (Cédric)
>> - use VTD_HOST_AW_39BIT (Cédric)
>>
>> v1 -> v2:
>> - set aw-bits to 48b on ARM
>> - use hw_compat_8_2 to handle the compat for older machines
>>    which used 64b as a default
>> ---
>>   hw/arm/virt.c                   | 6 ++++++
>>   hw/core/machine.c               | 5 ++++-
>>   hw/i386/pc.c                    | 6 ++++++
>>   hw/virtio/virtio-iommu.c        | 2 +-
>>   tests/qtest/virtio-iommu-test.c | 2 +-
>>   5 files changed, 18 insertions(+), 3 deletions(-)
>>
>> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
>> index 368c2a415a..0994f2a560 100644
>> --- a/hw/arm/virt.c
>> +++ b/hw/arm/virt.c
>> @@ -2716,10 +2716,16 @@ static void
>> virt_machine_device_pre_plug_cb(HotplugHandler *hotplug_dev,
>>       } else if (object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_MD_PCI)) {
>>           virtio_md_pci_pre_plug(VIRTIO_MD_PCI(dev),
>> MACHINE(hotplug_dev), errp);
>>       } else if (object_dynamic_cast(OBJECT(dev),
>> TYPE_VIRTIO_IOMMU_PCI)) {
>> +        uint8_t aw_bits = object_property_get_uint(OBJECT(dev),
>> +                                                   "aw-bits",
>> &error_abort);
>>           hwaddr db_start = 0, db_end = 0;
>>           QList *reserved_regions;
>>           char *resv_prop_str;
>>   +        if (!aw_bits) {
>> +            qdev_prop_set_uint8(dev, "aw-bits", 48);
>> +        }
>> +
>>           if (vms->iommu != VIRT_IOMMU_NONE) {
>>               error_setg(errp, "virt machine does not support
>> multiple IOMMUs");
>>               return;
>> diff --git a/hw/core/machine.c b/hw/core/machine.c
>> index fb5afdcae4..70ac96954c 100644
>> --- a/hw/core/machine.c
>> +++ b/hw/core/machine.c
>> @@ -30,9 +30,12 @@
>>   #include "exec/confidential-guest-support.h"
>>   #include "hw/virtio/virtio-pci.h"
>>   #include "hw/virtio/virtio-net.h"
>> +#include "hw/virtio/virtio-iommu.h"
>>   #include "audio/audio.h"
>>   -GlobalProperty hw_compat_8_2[] = {};
>> +GlobalProperty hw_compat_8_2[] = {
>> +    { TYPE_VIRTIO_IOMMU_PCI, "aw-bits", "64" },
>> +};
>>   const size_t hw_compat_8_2_len = G_N_ELEMENTS(hw_compat_8_2);
>>     GlobalProperty hw_compat_8_1[] = {
>> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
>> index 196827531a..ee2d379c90 100644
>> --- a/hw/i386/pc.c
>> +++ b/hw/i386/pc.c
>> @@ -1456,6 +1456,8 @@ static void
>> pc_machine_device_pre_plug_cb(HotplugHandler *hotplug_dev,
>>       } else if (object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_MD_PCI)) {
>>           virtio_md_pci_pre_plug(VIRTIO_MD_PCI(dev),
>> MACHINE(hotplug_dev), errp);
>>       } else if (object_dynamic_cast(OBJECT(dev),
>> TYPE_VIRTIO_IOMMU_PCI)) {
>> +        uint8_t aw_bits = object_property_get_uint(OBJECT(dev),
>> +                                                   "aw-bits",
>> &error_abort);
>>           /* Declare the APIC range as the reserved MSI region */
>>           char *resv_prop_str =
>> g_strdup_printf("0xfee00000:0xfeefffff:%d",
>>                                                
>> VIRTIO_IOMMU_RESV_MEM_T_MSI);
>> @@ -1464,6 +1466,10 @@ static void
>> pc_machine_device_pre_plug_cb(HotplugHandler *hotplug_dev,
>>           qlist_append_str(reserved_regions, resv_prop_str);
>>           qdev_prop_set_array(dev, "reserved-regions",
>> reserved_regions);
>>   +        if (!aw_bits) {
>> +            qdev_prop_set_uint8(dev, "aw-bits", VTD_HOST_AW_39BIT);
>> +        }
>> +
>>           g_free(resv_prop_str);
>>       }
>>   diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c
>> index 8b541de850..2ec5ef3cd1 100644
>> --- a/hw/virtio/virtio-iommu.c
>> +++ b/hw/virtio/virtio-iommu.c
>> @@ -1526,7 +1526,7 @@ static Property virtio_iommu_properties[] = {
>>       DEFINE_PROP_LINK("primary-bus", VirtIOIOMMU, primary_bus,
>>                        TYPE_PCI_BUS, PCIBus *),
>>       DEFINE_PROP_BOOL("boot-bypass", VirtIOIOMMU, boot_bypass, true),
>> -    DEFINE_PROP_UINT8("aw-bits", VirtIOIOMMU, aw_bits, 64),
>> +    DEFINE_PROP_UINT8("aw-bits", VirtIOIOMMU, aw_bits, 0),
>>       DEFINE_PROP_END_OF_LIST(),
>>   };
>>   diff --git a/tests/qtest/virtio-iommu-test.c
>> b/tests/qtest/virtio-iommu-test.c
>> index 068e7a9e6c..0f36381acb 100644
>> --- a/tests/qtest/virtio-iommu-test.c
>> +++ b/tests/qtest/virtio-iommu-test.c
>> @@ -34,7 +34,7 @@ static void pci_config(void *obj, void *data,
>> QGuestAllocator *t_alloc)
>>       uint8_t bypass = qvirtio_config_readb(dev, 36);
>>         g_assert_cmpint(input_range_start, ==, 0);
>> -    g_assert_cmphex(input_range_end, ==, UINT64_MAX);
>> +    g_assert_cmphex(input_range_end, >=, 32);
>>       g_assert_cmpint(domain_range_start, ==, 0);
>>       g_assert_cmpint(domain_range_end, ==, UINT32_MAX);
>>       g_assert_cmpint(bypass, ==, 1);
>

Re: [PATCH v5 3/4] hw: Set virtio-iommu aw-bits default value on pc_q35 and arm virt

[Igor Mammedov]

On Thu, 15 Feb 2024 09:42:13 +0100
Eric Auger <eric.auger@redhat.com> wrote:

> Currently the default input range can extend to 64 bits. On x86,
> when the virtio-iommu protects vfio devices, the physical iommu
> may support only 39 bits. Let's set the default to 39, as done
> for the intel-iommu. On ARM we set 48b as a default (matching
> SMMUv3 SMMU_IDR5.VAX == 0).
> 
> We use hw_compat_8_2 to handle the compatibility for machines
> before 9.0 which used to have a virtio-iommu default input range
> of 64 bits.

so we have different defaults per target/machine
while open codding fixup in _pre_plug_ works it's
a bit unexpected place to manage defaults and
avoid adding 0 magic.

How about using compat machinery instead to set
machine dependent defaults:
For example:

pc_i440fx_machine_options(MachineClass *m)
{
...
+    compat_props_add(m->compat_props, pc_compat_defaults,pc_compat_defaults_len);
 }

> Of course if aw-bits is set from the command line, the default
> is overriden.
> 
> Signed-off-by: Eric Auger <eric.auger@redhat.com>
> Reviewed-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
> Tested-by: Yanghang Liu<yanghliu@redhat.com>
> 
> ---
> 
> v3 -> v4:
> - update the qos test to relax the check on the max input IOVA
> 
> v2 -> v3:
> - collected Zhenzhong's R-b
> - use &error_abort instead of NULL error handle
>   on object_property_get_uint() call (Cédric)
> - use VTD_HOST_AW_39BIT (Cédric)
> 
> v1 -> v2:
> - set aw-bits to 48b on ARM
> - use hw_compat_8_2 to handle the compat for older machines
>   which used 64b as a default
> ---
>  hw/arm/virt.c                   | 6 ++++++
>  hw/core/machine.c               | 5 ++++-
>  hw/i386/pc.c                    | 6 ++++++
>  hw/virtio/virtio-iommu.c        | 2 +-
>  tests/qtest/virtio-iommu-test.c | 2 +-
>  5 files changed, 18 insertions(+), 3 deletions(-)
> 
> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index 368c2a415a..0994f2a560 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -2716,10 +2716,16 @@ static void virt_machine_device_pre_plug_cb(HotplugHandler *hotplug_dev,
>      } else if (object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_MD_PCI)) {
>          virtio_md_pci_pre_plug(VIRTIO_MD_PCI(dev), MACHINE(hotplug_dev), errp);
>      } else if (object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_IOMMU_PCI)) {
> +        uint8_t aw_bits = object_property_get_uint(OBJECT(dev),
> +                                                   "aw-bits", &error_abort);
>          hwaddr db_start = 0, db_end = 0;
>          QList *reserved_regions;
>          char *resv_prop_str;
>  
> +        if (!aw_bits) {
> +            qdev_prop_set_uint8(dev, "aw-bits", 48);

s/48/macro name/?

> +        }
>
>
>          if (vms->iommu != VIRT_IOMMU_NONE) {
>              error_setg(errp, "virt machine does not support multiple IOMMUs");
>              return;
> diff --git a/hw/core/machine.c b/hw/core/machine.c
> index fb5afdcae4..70ac96954c 100644
> --- a/hw/core/machine.c
> +++ b/hw/core/machine.c
> @@ -30,9 +30,12 @@
>  #include "exec/confidential-guest-support.h"
>  #include "hw/virtio/virtio-pci.h"
>  #include "hw/virtio/virtio-net.h"
> +#include "hw/virtio/virtio-iommu.h"
>  #include "audio/audio.h"
>  
> -GlobalProperty hw_compat_8_2[] = {};
> +GlobalProperty hw_compat_8_2[] = {
> +    { TYPE_VIRTIO_IOMMU_PCI, "aw-bits", "64" },
> +};
>  const size_t hw_compat_8_2_len = G_N_ELEMENTS(hw_compat_8_2);
>  
>  GlobalProperty hw_compat_8_1[] = {
> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> index 196827531a..ee2d379c90 100644
> --- a/hw/i386/pc.c
> +++ b/hw/i386/pc.c
> @@ -1456,6 +1456,8 @@ static void pc_machine_device_pre_plug_cb(HotplugHandler *hotplug_dev,
>      } else if (object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_MD_PCI)) {
>          virtio_md_pci_pre_plug(VIRTIO_MD_PCI(dev), MACHINE(hotplug_dev), errp);
>      } else if (object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_IOMMU_PCI)) {
> +        uint8_t aw_bits = object_property_get_uint(OBJECT(dev),
> +                                                   "aw-bits", &error_abort);
>          /* Declare the APIC range as the reserved MSI region */
>          char *resv_prop_str = g_strdup_printf("0xfee00000:0xfeefffff:%d",
>                                                VIRTIO_IOMMU_RESV_MEM_T_MSI);
> @@ -1464,6 +1466,10 @@ static void pc_machine_device_pre_plug_cb(HotplugHandler *hotplug_dev,
>          qlist_append_str(reserved_regions, resv_prop_str);
>          qdev_prop_set_array(dev, "reserved-regions", reserved_regions);
>  
> +        if (!aw_bits) {
> +            qdev_prop_set_uint8(dev, "aw-bits", VTD_HOST_AW_39BIT);
> +        }
> +
>          g_free(resv_prop_str);
>      }
>  
> diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c
> index 8b541de850..2ec5ef3cd1 100644
> --- a/hw/virtio/virtio-iommu.c
> +++ b/hw/virtio/virtio-iommu.c
> @@ -1526,7 +1526,7 @@ static Property virtio_iommu_properties[] = {
>      DEFINE_PROP_LINK("primary-bus", VirtIOIOMMU, primary_bus,
>                       TYPE_PCI_BUS, PCIBus *),
>      DEFINE_PROP_BOOL("boot-bypass", VirtIOIOMMU, boot_bypass, true),
> -    DEFINE_PROP_UINT8("aw-bits", VirtIOIOMMU, aw_bits, 64),
> +    DEFINE_PROP_UINT8("aw-bits", VirtIOIOMMU, aw_bits, 0),
I'd set some valid value here (obviously not universal) and skip
default property setting for that machine/target
For example pick x86 one.

>      DEFINE_PROP_END_OF_LIST(),
>  };
>  
> diff --git a/tests/qtest/virtio-iommu-test.c b/tests/qtest/virtio-iommu-test.c
> index 068e7a9e6c..0f36381acb 100644
> --- a/tests/qtest/virtio-iommu-test.c
> +++ b/tests/qtest/virtio-iommu-test.c
> @@ -34,7 +34,7 @@ static void pci_config(void *obj, void *data, QGuestAllocator *t_alloc)
>      uint8_t bypass = qvirtio_config_readb(dev, 36);
>  
>      g_assert_cmpint(input_range_start, ==, 0);
> -    g_assert_cmphex(input_range_end, ==, UINT64_MAX);
> +    g_assert_cmphex(input_range_end, >=, 32);
>      g_assert_cmpint(domain_range_start, ==, 0);
>      g_assert_cmpint(domain_range_end, ==, UINT32_MAX);
>      g_assert_cmpint(bypass, ==, 1);

Re: [PATCH v5 3/4] hw: Set virtio-iommu aw-bits default value on pc_q35 and arm virt

[Eric Auger]

Hi Igor,

On 2/29/24 10:20, Igor Mammedov wrote:
> On Thu, 15 Feb 2024 09:42:13 +0100
> Eric Auger <eric.auger@redhat.com> wrote:
>
>> Currently the default input range can extend to 64 bits. On x86,
>> when the virtio-iommu protects vfio devices, the physical iommu
>> may support only 39 bits. Let's set the default to 39, as done
>> for the intel-iommu. On ARM we set 48b as a default (matching
>> SMMUv3 SMMU_IDR5.VAX == 0).
>>
>> We use hw_compat_8_2 to handle the compatibility for machines
>> before 9.0 which used to have a virtio-iommu default input range
>> of 64 bits.
> so we have different defaults per target/machine
> while open codding fixup in _pre_plug_ works it's
> a bit unexpected place to manage defaults and
> avoid adding 0 magic.
>
> How about using compat machinery instead to set
> machine dependent defaults:
> For example:
>
> pc_i440fx_machine_options(MachineClass *m)
> {
> ...
> +    compat_props_add(m->compat_props, pc_compat_defaults,pc_compat_defaults_len);
>  }
Yes I can go this way.
>
>> Of course if aw-bits is set from the command line, the default
>> is overriden.
>>
>> Signed-off-by: Eric Auger <eric.auger@redhat.com>
>> Reviewed-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
>> Tested-by: Yanghang Liu<yanghliu@redhat.com>
>>
>> ---
>>
>> v3 -> v4:
>> - update the qos test to relax the check on the max input IOVA
>>
>> v2 -> v3:
>> - collected Zhenzhong's R-b
>> - use &error_abort instead of NULL error handle
>>   on object_property_get_uint() call (Cédric)
>> - use VTD_HOST_AW_39BIT (Cédric)
>>
>> v1 -> v2:
>> - set aw-bits to 48b on ARM
>> - use hw_compat_8_2 to handle the compat for older machines
>>   which used 64b as a default
>> ---
>>  hw/arm/virt.c                   | 6 ++++++
>>  hw/core/machine.c               | 5 ++++-
>>  hw/i386/pc.c                    | 6 ++++++
>>  hw/virtio/virtio-iommu.c        | 2 +-
>>  tests/qtest/virtio-iommu-test.c | 2 +-
>>  5 files changed, 18 insertions(+), 3 deletions(-)
>>
>> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
>> index 368c2a415a..0994f2a560 100644
>> --- a/hw/arm/virt.c
>> +++ b/hw/arm/virt.c
>> @@ -2716,10 +2716,16 @@ static void virt_machine_device_pre_plug_cb(HotplugHandler *hotplug_dev,
>>      } else if (object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_MD_PCI)) {
>>          virtio_md_pci_pre_plug(VIRTIO_MD_PCI(dev), MACHINE(hotplug_dev), errp);
>>      } else if (object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_IOMMU_PCI)) {
>> +        uint8_t aw_bits = object_property_get_uint(OBJECT(dev),
>> +                                                   "aw-bits", &error_abort);
>>          hwaddr db_start = 0, db_end = 0;
>>          QList *reserved_regions;
>>          char *resv_prop_str;
>>  
>> +        if (!aw_bits) {
>> +            qdev_prop_set_uint8(dev, "aw-bits", 48);
> s/48/macro name/?
with compats it becomes a string.  So I cannot directly reuse X86_64 VTD
or ARM SMMU macros. I would introduce a dummy VIRTIO_IOMMU string which
does not sound really helpful.
>
>> +        }
>>
>>
>>          if (vms->iommu != VIRT_IOMMU_NONE) {
>>              error_setg(errp, "virt machine does not support multiple IOMMUs");
>>              return;
>> diff --git a/hw/core/machine.c b/hw/core/machine.c
>> index fb5afdcae4..70ac96954c 100644
>> --- a/hw/core/machine.c
>> +++ b/hw/core/machine.c
>> @@ -30,9 +30,12 @@
>>  #include "exec/confidential-guest-support.h"
>>  #include "hw/virtio/virtio-pci.h"
>>  #include "hw/virtio/virtio-net.h"
>> +#include "hw/virtio/virtio-iommu.h"
>>  #include "audio/audio.h"
>>  
>> -GlobalProperty hw_compat_8_2[] = {};
>> +GlobalProperty hw_compat_8_2[] = {
>> +    { TYPE_VIRTIO_IOMMU_PCI, "aw-bits", "64" },
>> +};
>>  const size_t hw_compat_8_2_len = G_N_ELEMENTS(hw_compat_8_2);
>>  
>>  GlobalProperty hw_compat_8_1[] = {
>> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
>> index 196827531a..ee2d379c90 100644
>> --- a/hw/i386/pc.c
>> +++ b/hw/i386/pc.c
>> @@ -1456,6 +1456,8 @@ static void pc_machine_device_pre_plug_cb(HotplugHandler *hotplug_dev,
>>      } else if (object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_MD_PCI)) {
>>          virtio_md_pci_pre_plug(VIRTIO_MD_PCI(dev), MACHINE(hotplug_dev), errp);
>>      } else if (object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_IOMMU_PCI)) {
>> +        uint8_t aw_bits = object_property_get_uint(OBJECT(dev),
>> +                                                   "aw-bits", &error_abort);
>>          /* Declare the APIC range as the reserved MSI region */
>>          char *resv_prop_str = g_strdup_printf("0xfee00000:0xfeefffff:%d",
>>                                                VIRTIO_IOMMU_RESV_MEM_T_MSI);
>> @@ -1464,6 +1466,10 @@ static void pc_machine_device_pre_plug_cb(HotplugHandler *hotplug_dev,
>>          qlist_append_str(reserved_regions, resv_prop_str);
>>          qdev_prop_set_array(dev, "reserved-regions", reserved_regions);
>>  
>> +        if (!aw_bits) {
>> +            qdev_prop_set_uint8(dev, "aw-bits", VTD_HOST_AW_39BIT);
>> +        }
>> +
>>          g_free(resv_prop_str);
>>      }
>>  
>> diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c
>> index 8b541de850..2ec5ef3cd1 100644
>> --- a/hw/virtio/virtio-iommu.c
>> +++ b/hw/virtio/virtio-iommu.c
>> @@ -1526,7 +1526,7 @@ static Property virtio_iommu_properties[] = {
>>      DEFINE_PROP_LINK("primary-bus", VirtIOIOMMU, primary_bus,
>>                       TYPE_PCI_BUS, PCIBus *),
>>      DEFINE_PROP_BOOL("boot-bypass", VirtIOIOMMU, boot_bypass, true),
>> -    DEFINE_PROP_UINT8("aw-bits", VirtIOIOMMU, aw_bits, 64),
>> +    DEFINE_PROP_UINT8("aw-bits", VirtIOIOMMU, aw_bits, 0),
> I'd set some valid value here (obviously not universal) and skip
> default property setting for that machine/target
> For example pick x86 one.
Yes the purpose is to have a non null aw_bits value which makes the
virtio-iommu unusable without proper machine integration and puts the
mess on the libqos tests. 
>
>>      DEFINE_PROP_END_OF_LIST(),
>>  };
>>  
>> diff --git a/tests/qtest/virtio-iommu-test.c b/tests/qtest/virtio-iommu-test.c
>> index 068e7a9e6c..0f36381acb 100644
>> --- a/tests/qtest/virtio-iommu-test.c
>> +++ b/tests/qtest/virtio-iommu-test.c
>> @@ -34,7 +34,7 @@ static void pci_config(void *obj, void *data, QGuestAllocator *t_alloc)
>>      uint8_t bypass = qvirtio_config_readb(dev, 36);
>>  
>>      g_assert_cmpint(input_range_start, ==, 0);
>> -    g_assert_cmphex(input_range_end, ==, UINT64_MAX);
>> +    g_assert_cmphex(input_range_end, >=, 32);
>>      g_assert_cmpint(domain_range_start, ==, 0);
>>      g_assert_cmpint(domain_range_end, ==, UINT32_MAX);
>>      g_assert_cmpint(bypass, ==, 1);
Thank you for the suggestions

Eric

[PATCH v5 4/4] qemu-options.hx: Add an entry for virtio-iommu-pci and document aw-bits

[Eric Auger]

We are missing an entry for the virtio-iommu-pci device. Add the
information on which machine it is currently supported and document
the new aw-bits option.

Signed-off-by: Eric Auger <eric.auger@redhat.com>

---

v4 -> v5
- tweek the aw-bits option description according to Cédric's
  suggestion
---
 qemu-options.hx | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/qemu-options.hx b/qemu-options.hx
index 8547254dbf..a98bc7bd60 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -1172,6 +1172,14 @@ SRST
     Please also refer to the wiki page for general scenarios of VT-d
     emulation in QEMU: https://wiki.qemu.org/Features/VT-d.
 
+``-device virtio-iommu-pci[,option=...]``
+    This is only supported by ``-machine q35`` and ``-machine virt``.
+    It supports below options:
+
+    ``aw-bits=val`` (val between 32 and 64, default depends on machine)
+        This decides the address width of IOVA address space. It defaults
+        to 39 bits on q35 machines and 48 bits on ARM virt machines.
+
 ERST
 
 DEF("name", HAS_ARG, QEMU_OPTION_name,
-- 
2.41.0

Re: [PATCH v5 4/4] qemu-options.hx: Add an entry for virtio-iommu-pci and document aw-bits

[Eric Auger]

On 2/15/24 09:42, Eric Auger wrote:
> We are missing an entry for the virtio-iommu-pci device. Add the
> information on which machine it is currently supported and document
> the new aw-bits option.
>
> Signed-off-by: Eric Auger <eric.auger@redhat.com>
argh forgot to add Cédric R-b collected on v4

Reviewed-by: Cédric Le Goater <clg@redhat.com>

Michael, please apply it when/if you decide to pull it

Eric
>
> ---
>
> v4 -> v5
> - tweek the aw-bits option description according to Cédric's
>   suggestion
> ---
>  qemu-options.hx | 8 ++++++++
>  1 file changed, 8 insertions(+)
>
> diff --git a/qemu-options.hx b/qemu-options.hx
> index 8547254dbf..a98bc7bd60 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -1172,6 +1172,14 @@ SRST
>      Please also refer to the wiki page for general scenarios of VT-d
>      emulation in QEMU: https://wiki.qemu.org/Features/VT-d.
>  
> +``-device virtio-iommu-pci[,option=...]``
> +    This is only supported by ``-machine q35`` and ``-machine virt``.
> +    It supports below options:
> +
> +    ``aw-bits=val`` (val between 32 and 64, default depends on machine)
> +        This decides the address width of IOVA address space. It defaults
> +        to 39 bits on q35 machines and 48 bits on ARM virt machines.
> +
>  ERST
>  
>  DEF("name", HAS_ARG, QEMU_OPTION_name,