Hi Michael,
On 7/31/19 9:25 PM, Michael S. Tsirkin wrote:
> On Tue, Jul 30, 2019 at 11:20:44PM +0000, Tian, Kevin wrote:
>>> From: Michael S. Tsirkin [mailto:m...@redhat.com]
>>> Sent: Wednesday, July 31, 2019 3:38 AM
>>>
>>> On Tue, Jul 30, 2019 at 07:21:33PM +0200, Eric Auger wrote:
>>>> We introduce a new msi_bypass field which indicates whether
>>>> the IOAPIC MSI window [0xFEE00000 - 0xFEEFFFFF] must be exposed
>>
>> it's not good to call it IOAPIC MSI window. any write to this range, either
>> from IOAPIC or PCI device, is interpreted by the platform as interrupt
>> request. I'd call it "x86 interrupt address range".
>
> Isn't this APIC_DEFAULT_ADDRESS? I'm not sure guests can't change it
> even though I'm not sure qemu supports changing it.
That's indeed matching:
#define APIC_DEFAULT_ADDRESS 0xfee00000
#define APIC_SPACE_SIZE 0x100000
>
> And if so I'd say integrating IOAPIC defaults into the device itself is
> inelegant.
I agree.
How about having guest supply the range through config
> space? It's a small change that won't be too late for Linux.
Isn't it a property of the platform instead. I mean isn't it the job of
the machine model to set this. The guest driver is arch agnostic if I am
not wrong.
>
>>>> as a reserved region. By default the field is set to true at
>>>> instantiation time. Later on we will introduce a property at
>>>> virtio pci proxy level to turn it off.
>>>>
>>>> Signed-off-by: Eric Auger <eric.au...@redhat.com>
>>>>
>>>> ---
>>>>
>>>> v8 -> v9:
>>>> - pass IOAPIC_RANGE_END to virtio_iommu_register_resv_region
>>>> - take into account the change in the struct virtio_iommu_probe_resv_mem
>>>> definition
>>>> - We just introduce the field here. A property will be introduced later on
>>>> at pci proxy level.
>>>> ---
>>>> hw/virtio/virtio-iommu.c | 36 ++++++++++++++++++++++++++++++++
>>>> include/hw/virtio/virtio-iommu.h | 1 +
>>>> 2 files changed, 37 insertions(+)
>>>>
>>>> diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c
>>>> index 66be9a4627..74038288b0 100644
>>>> --- a/hw/virtio/virtio-iommu.c
>>>> +++ b/hw/virtio/virtio-iommu.c
>>>> @@ -39,6 +39,9 @@
>>>> #define VIOMMU_DEFAULT_QUEUE_SIZE 256
>>>> #define VIOMMU_PROBE_SIZE 512
>>>>
>>>> +#define IOAPIC_RANGE_START (0xfee00000)
>>>> +#define IOAPIC_RANGE_END (0xfeefffff)
>>>> +
>>>> #define SUPPORTED_PROBE_PROPERTIES (\
>>>> 1 << VIRTIO_IOMMU_PROBE_T_RESV_MEM)
>>>>
>>>
>>> Sorry where are these numbers coming from?
>>
>> this is architecturally defined in x86 SDM.
>>
>>> Does this really work on all platforms?
>>
>> x86 only.
>
> But you seem to add this code for all platforms:
>
> @@ -6,6 +6,11 @@ config VIRTIO_RNG
> default y
> depends on VIRTIO
>
> +config VIRTIO_IOMMU
> + bool
> + default y
> + depends on VIRTIO
> +
Actually it was supposed to be integrated with ARM first and then with x86.
Thanks
Eric
>
>
>>> With all guests?
>>
>> yes.
>>
>>>
>>>> @@ -100,6 +103,30 @@ static void
>>> virtio_iommu_detach_endpoint_from_domain(viommu_endpoint *ep)
>>>> ep->domain = NULL;
>>>> }
>>>>
>>>> +static void virtio_iommu_register_resv_region(viommu_endpoint *ep,
>>>> + uint8_t subtype,
>>>> + uint64_t start, uint64_t
>>>> end)
>>>> +{
>>>> + viommu_interval *interval;
>>>> + struct virtio_iommu_probe_resv_mem *resv_reg_prop;
>>>> + size_t prop_size = sizeof(struct virtio_iommu_probe_resv_mem);
>>>> + size_t value_size = prop_size -
>>>> + sizeof(struct virtio_iommu_probe_property);
>>>> +
>>>> + interval = g_malloc0(sizeof(*interval));
>>>> + interval->low = start;
>>>> + interval->high = end;
>>>> +
>>>> + resv_reg_prop = g_malloc0(prop_size);
>>>> + resv_reg_prop->head.type = VIRTIO_IOMMU_PROBE_T_RESV_MEM;
>>>> + resv_reg_prop->head.length = cpu_to_le64(value_size);
>>>> + resv_reg_prop->subtype = cpu_to_le64(subtype);
>>>> + resv_reg_prop->start = cpu_to_le64(start);
>>>> + resv_reg_prop->end = cpu_to_le64(end);
>>>> +
>>>> + g_tree_insert(ep->reserved_regions, interval, resv_reg_prop);
>>>> +}
>>>> +
>>>> static viommu_endpoint *virtio_iommu_get_endpoint(VirtIOIOMMU *s,
>>>> uint32_t ep_id)
>>>> {
>>>> @@ -117,6 +144,12 @@ static viommu_endpoint
>>> *virtio_iommu_get_endpoint(VirtIOIOMMU *s,
>>>> ep->reserved_regions =
>>> g_tree_new_full((GCompareDataFunc)interval_cmp,
>>>> NULL, (GDestroyNotify)g_free,
>>>> (GDestroyNotify)g_free);
>>>> + if (s->msi_bypass) {
>>>> + virtio_iommu_register_resv_region(ep,
>>> VIRTIO_IOMMU_RESV_MEM_T_MSI,
>>>> + IOAPIC_RANGE_START,
>>>> + IOAPIC_RANGE_END);
>>>> + }
>>>> +
>>>> return ep;
>>>> }
>>>>
>>>> @@ -822,6 +855,9 @@ static void virtio_iommu_set_status(VirtIODevice
>>> *vdev, uint8_t status)
>>>>
>>>> static void virtio_iommu_instance_init(Object *obj)
>>>> {
>>>> + VirtIOIOMMU *s = VIRTIO_IOMMU(obj);
>>>> +
>>>> + s->msi_bypass = true;
>>>> }
>>>>
>>>> static const VMStateDescription vmstate_virtio_iommu = {
>>>> diff --git a/include/hw/virtio/virtio-iommu.h b/include/hw/virtio/virtio-
>>> iommu.h
>>>> index f55f48d304..56c8b4e57f 100644
>>>> --- a/include/hw/virtio/virtio-iommu.h
>>>> +++ b/include/hw/virtio/virtio-iommu.h
>>>> @@ -59,6 +59,7 @@ typedef struct VirtIOIOMMU {
>>>> GTree *domains;
>>>> QemuMutex mutex;
>>>> GTree *endpoints;
>>>> + bool msi_bypass;
>>>> } VirtIOIOMMU;
>>>>
>>>> #endif
>>>> --
>>>> 2.20.1
