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Re: [PATCH v5 2/5] virtio-iommu: Implement RESV_MEM probe request
From: |
Auger Eric |
Subject: |
Re: [PATCH v5 2/5] virtio-iommu: Implement RESV_MEM probe request |
Date: |
Fri, 26 Jun 2020 09:41:37 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 |
Hi Markus,
On 6/25/20 9:05 AM, Markus Armbruster wrote:
> Eric Auger <eric.auger@redhat.com> writes:
>
>> 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>
>>
>> ---
>>
>> v4 -> v5:
>> - assert if reserved region type is different from RESERVED or
>> MSI
>>
>> 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 | 92 ++++++++++++++++++++++++++++++--
>> hw/virtio/trace-events | 1 +
>> 3 files changed, 91 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..aabc3e36b1 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 +379,63 @@ 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;
>> + assert(prop.subtype == VIRTIO_IOMMU_RESV_MEM_T_RESERVED ||
>> + prop.subtype == VIRTIO_IOMMU_RESV_MEM_T_MSI);
>
> The assertion makes sense here: we're mapping from the generic
> ReservedRegion type (which is unsigned) to the specific
> virtio_iommu_probe_resv_mem subtype (which is uint8_t, but only these
> two values are valid).
>
> Howver, the assertion should test s->reserved_regions[i].type and go
> before the assignment, to ensure it doesn't truncate!
OK I will do.
>
> Can I trigger the assertion with -device? My try to find the answer
> myself failed:
At the moment the virtio-iommu-pci device only can be instantiated with
machvirt, booting in dt mode.
>
> $ qemu-system-x86_64 -nodefaults -S -display none -device
> virtio-iommu-pci,len-reserved-regions=1,reserved-regions[0]=0xfee00000:0xfeefffff:99
> qemu-system-x86_64: -device
> virtio-iommu-pci,len-reserved-regions=1,reserved-regions[0]=0xfee00000:0xfeefffff:99:
> pc-i440fx-5.1 machine fails to create iommu-map device tree bindings
> Check you machine implements a hotplug handler for the virtio-iommu-pci
> device
> Check the guest is booted without FW or with -no-acpi
>
> By the way: s/Check you machine/Check your machine/.
Thanks
Eric
>
> [...]
>
[PATCH v5 3/5] virtio-iommu: Handle reserved regions in the translation process, Eric Auger, 2020/06/24
Re: [PATCH v5 0/5] VIRTIO-IOMMU probe request support and MSI bypass on ARM, Michael S. Tsirkin, 2020/06/24
Re: [PATCH v5 0/5] VIRTIO-IOMMU probe request support and MSI bypass on ARM, Michael S. Tsirkin, 2020/06/24