[SLOF] [PATCH slof v3 4/4] virtio: Enable IOMMU
Alexey Kardashevskiy
aik at ozlabs.ru
Thu Nov 28 11:15:03 AEDT 2019
On 23/11/2019 01:42, Michael Roth wrote:
> Quoting Alexey Kardashevskiy (2019-11-21 21:14:10)
>>
>>
>> On 22/11/2019 12:49, Alexey Kardashevskiy wrote:
>>>
>>>
>>> On 22/11/2019 11:09, Michael Roth wrote:
>>>> Quoting Alexey Kardashevskiy (2019-11-20 17:58:01)
>>>>> When QEMU is started with iommu_platform=on, the guest driver must accept
>>>>> it or the device will fail.
>>>>>
>>>>> This enables IOMMU support for virtio-net, -scsi, -block, -serial, -9p
>>>>> devices. -serial and -9p are only compile tested though.
>>>>>
>>>>> For virtio-net we map all RX buffers once and TX when xmit() is called
>>>>> and unmap older pages when we are about to reuse the VQ descriptor.
>>>>> As all other devices are synchronous, we unmap IOMMU pages right after
>>>>> completion of a transaction.
>>>>>
>>>>> This depends on QEMU's:
>>>>> https://patchwork.ozlabs.org/patch/1194067/
>>>>>
>>>>> Copied-bits-and-pieces-from: Michael Roth <mdroth at linux.vnet.ibm.com>
>>>>> Signed-off-by: Alexey Kardashevskiy <aik at ozlabs.ru>
>>>>> ---
>>>>> Changes:
>>>>> v2:
>>>>> * added Mike's fs/dma-instance-function.fs
>>>>> * total rework
>>>>> ---
>>>>> board-qemu/slof/Makefile | 1 +
>>>>> lib/libvirtio/virtio.h | 5 ++
>>>>> lib/libvirtio/virtio-9p.c | 4 ++
>>>>> lib/libvirtio/virtio-blk.c | 4 ++
>>>>> lib/libvirtio/virtio-net.c | 5 +-
>>>>> lib/libvirtio/virtio-scsi.c | 5 ++
>>>>> lib/libvirtio/virtio-serial.c | 12 +++--
>>>>> lib/libvirtio/virtio.c | 82 +++++++++++++++++++++++++++++++-
>>>>> board-qemu/slof/OF.fs | 3 ++
>>>>> slof/fs/dma-instance-function.fs | 28 +++++++++++
>>>>> 10 files changed, 143 insertions(+), 6 deletions(-)
>>>>> create mode 100644 slof/fs/dma-instance-function.fs
>>>>>
>>>>> diff --git a/board-qemu/slof/Makefile b/board-qemu/slof/Makefile
>>>>> index 2263e751bde9..d7ed2d7a6f18 100644
>>>>> --- a/board-qemu/slof/Makefile
>>>>> +++ b/board-qemu/slof/Makefile
>>>>> @@ -99,6 +99,7 @@ OF_FFS_FILES = \
>>>>> $(SLOFCMNDIR)/fs/graphics.fs \
>>>>> $(SLOFCMNDIR)/fs/generic-disk.fs \
>>>>> $(SLOFCMNDIR)/fs/dma-function.fs \
>>>>> + $(SLOFCMNDIR)/fs/dma-instance-function.fs \
>>>>> $(SLOFCMNDIR)/fs/pci-device.fs \
>>>>> $(SLOFCMNDIR)/fs/pci-bridge.fs \
>>>>> $(SLOFCMNDIR)/fs/pci-properties.fs \
>>>>> diff --git a/lib/libvirtio/virtio.h b/lib/libvirtio/virtio.h
>>>>> index 4927a97f9f5f..250120b3112b 100644
>>>>> --- a/lib/libvirtio/virtio.h
>>>>> +++ b/lib/libvirtio/virtio.h
>>>>> @@ -29,6 +29,7 @@
>>>>> #define VIRTIO_F_RING_INDIRECT_DESC BIT(28)
>>>>> #define VIRTIO_F_RING_EVENT_IDX BIT(29)
>>>>> #define VIRTIO_F_VERSION_1 BIT(32)
>>>>> +#define VIRTIO_F_IOMMU_PLATFORM BIT(33)
>>>>>
>>>>> #define VIRTIO_TIMEOUT 5000 /* 5 sec timeout */
>>>>>
>>>>> @@ -84,6 +85,8 @@ struct vqs {
>>>>> struct vring_desc *desc;
>>>>> struct vring_avail *avail;
>>>>> struct vring_used *used;
>>>>> + void **desc_gpas; /* to get gpa from desc->addr (which is ioba) */
>>>>> + uint64_t bus_desc;
>>>>> };
>>>>>
>>>>> struct virtio_device {
>>>>> @@ -109,6 +112,8 @@ extern struct vring_used *virtio_get_vring_used(struct virtio_device *dev, int q
>>>>> extern void virtio_fill_desc(struct vqs *vq, int id, uint64_t features,
>>>>> uint64_t addr, uint32_t len,
>>>>> uint16_t flags, uint16_t next);
>>>>> +extern void virtio_free_desc(struct vqs *vq, int id, uint64_t features);
>>>>> +void *virtio_desc_addr(struct virtio_device *vdev, int queue, int id);
>>>>> extern struct vqs *virtio_queue_init_vq(struct virtio_device *dev, unsigned int id);
>>>>> extern void virtio_queue_term_vq(struct virtio_device *dev, struct vqs *vq, unsigned int id);
>>>>>
>>>>> diff --git a/lib/libvirtio/virtio-9p.c b/lib/libvirtio/virtio-9p.c
>>>>> index 426069fe9509..76078612b06e 100644
>>>>> --- a/lib/libvirtio/virtio-9p.c
>>>>> +++ b/lib/libvirtio/virtio-9p.c
>>>>> @@ -129,6 +129,10 @@ static int virtio_9p_transact(void *opaque, uint8_t *tx, int tx_size, uint8_t *r
>>>>> // do something better
>>>>> mb();
>>>>> }
>>>>> +
>>>>> + virtio_free_desc(vq, id, dev->features);
>>>>> + virtio_free_desc(vq, id + 1, dev->features);
>>>>> +
>>>>> if (i == 0) {
>>>>> return -1;
>>>>> }
>>>>> diff --git a/lib/libvirtio/virtio-blk.c b/lib/libvirtio/virtio-blk.c
>>>>> index a0dadbb0d6a8..0363038e559d 100644
>>>>> --- a/lib/libvirtio/virtio-blk.c
>>>>> +++ b/lib/libvirtio/virtio-blk.c
>>>>> @@ -195,6 +195,10 @@ virtioblk_transfer(struct virtio_device *dev, char *buf, uint64_t blocknum,
>>>>> break;
>>>>> }
>>>>>
>>>>> + virtio_free_desc(vq, id, dev->features);
>>>>> + virtio_free_desc(vq, id + 1, dev->features);
>>>>> + virtio_free_desc(vq, id + 2, dev->features);
>>>>> +
>>>>> if (status == 0)
>>>>> return cnt;
>>>>>
>>>>> diff --git a/lib/libvirtio/virtio-net.c b/lib/libvirtio/virtio-net.c
>>>>> index ae67883020ef..5a0d19088527 100644
>>>>> --- a/lib/libvirtio/virtio-net.c
>>>>> +++ b/lib/libvirtio/virtio-net.c
>>>>> @@ -255,6 +255,9 @@ static int virtionet_xmit(struct virtio_net *vnet, char *buf, int len)
>>>>> idx = virtio_modern16_to_cpu(vdev, vq_tx->avail->idx);
>>>>> id = (idx * 2) % vq_tx->size;
>>>>>
>>>>> + virtio_free_desc(vq_tx, id, vdev->features);
>>>>> + virtio_free_desc(vq_tx, id + 1, vdev->features);
>>>>> +
>>>>> /* Set up virtqueue descriptor for header */
>>>>> virtio_fill_desc(vq_tx, id, vdev->features, (uint64_t)nethdr,
>>>>> net_hdr_size, VRING_DESC_F_NEXT, id + 1);
>>>>> @@ -317,7 +320,7 @@ static int virtionet_receive(struct virtio_net *vnet, char *buf, int maxlen)
>>>>> #endif
>>>>>
>>>>> /* Copy data to destination buffer */
>>>>> - memcpy(buf, (void *)virtio_modern64_to_cpu(vdev, vq_rx->desc[id].addr), len);
>>>>> + memcpy(buf, virtio_desc_addr(vdev, VQ_RX, id), len);
>>>>>
>>>>> /* Move indices to next entries */
>>>>> last_rx_idx = last_rx_idx + 1;
>>>>> diff --git a/lib/libvirtio/virtio-scsi.c b/lib/libvirtio/virtio-scsi.c
>>>>> index 251661e8d466..44573d10e24c 100644
>>>>> --- a/lib/libvirtio/virtio-scsi.c
>>>>> +++ b/lib/libvirtio/virtio-scsi.c
>>>>> @@ -81,6 +81,11 @@ int virtioscsi_send(struct virtio_device *dev,
>>>>> break;
>>>>> }
>>>>>
>>>>> + virtio_free_desc(vq, id, dev->features);
>>>>> + virtio_free_desc(vq, id + 1, dev->features);
>>>>> + if (!(buf == NULL || buf_len == 0))
>>>>> + virtio_free_desc(vq, id + 2, dev->features);
>>>>> +
>>>>> return 0;
>>>>> }
>>>>>
>>>>> diff --git a/lib/libvirtio/virtio-serial.c b/lib/libvirtio/virtio-serial.c
>>>>> index 78ab0e25d7db..66fbfe8b6cc6 100644
>>>>> --- a/lib/libvirtio/virtio-serial.c
>>>>> +++ b/lib/libvirtio/virtio-serial.c
>>>>> @@ -108,7 +108,7 @@ void virtio_serial_shutdown(struct virtio_device *dev)
>>>>>
>>>>> int virtio_serial_putchar(struct virtio_device *dev, char c)
>>>>> {
>>>>> - int id;
>>>>> + int id, ret;
>>>>> uint32_t vq_size, time;
>>>>> volatile uint16_t *current_used_idx;
>>>>> uint16_t last_used_idx, avail_idx;
>>>>> @@ -135,17 +135,21 @@ int virtio_serial_putchar(struct virtio_device *dev, char c)
>>>>> virtio_queue_notify(dev, TX_Q);
>>>>>
>>>>> /* Wait for host to consume the descriptor */
>>>>> + ret = 1;
>>>>> time = SLOF_GetTimer() + VIRTIO_TIMEOUT;
>>>>> while (*current_used_idx == last_used_idx) {
>>>>> // do something better
>>>>> mb();
>>>>> if (time < SLOF_GetTimer()) {
>>>>> printf("virtio_serial_putchar failed! \n");
>>>>> - return 0;
>>>>> + ret = 0;
>>>>> + break;
>>>>> }
>>>>> }
>>>>>
>>>>> - return 1;
>>>>> + virtio_free_desc(vq, id, dev->features);
>>>>> +
>>>>> + return ret;
>>>>> }
>>>>>
>>>>> char virtio_serial_getchar(struct virtio_device *dev)
>>>>> @@ -165,7 +169,7 @@ char virtio_serial_getchar(struct virtio_device *dev)
>>>>> % vq_rx->size;
>>>>>
>>>>> /* Copy data to destination buffer */
>>>>> - memcpy(buf, (void *)virtio_modern64_to_cpu(dev, vq_rx->desc[id - 1].addr), RX_ELEM_SIZE);
>>>>> + memcpy(buf, virtio_desc_addr(dev, RX_Q, id - 1), RX_ELEM_SIZE);
>>>>>
>>>>> /* Move indices to next entries */
>>>>> last_rx_idx = last_rx_idx + 1;
>>>>> diff --git a/lib/libvirtio/virtio.c b/lib/libvirtio/virtio.c
>>>>> index fff0c7e54c19..d4db5f656888 100644
>>>>> --- a/lib/libvirtio/virtio.c
>>>>> +++ b/lib/libvirtio/virtio.c
>>>>> @@ -273,6 +273,17 @@ void virtio_fill_desc(struct vqs *vq, int id, uint64_t features,
>>>>> next %= vq->size;
>>>>>
>>>>> if (features & VIRTIO_F_VERSION_1) {
>>>>> + if (features & VIRTIO_F_IOMMU_PLATFORM) {
>>>>> + void *gpa = (void *) addr;
>>>>> +
>>>>> + if (!vq->desc_gpas) {
>>>>> + fprintf(stderr, "IOMMU setup has not been done!\n");
>>>>> + return;
>>>>> + }
>>>>> +
>>>>> + addr = SLOF_dma_map_in(gpa, len, 0);
>>>>> + vq->desc_gpas[id] = gpa;
>>>>> + }
>>>>> desc->addr = cpu_to_le64(addr);
>>>>> desc->len = cpu_to_le32(len);
>>>>> desc->flags = cpu_to_le16(flags);
>>>>> @@ -285,6 +296,32 @@ void virtio_fill_desc(struct vqs *vq, int id, uint64_t features,
>>>>> }
>>>>> }
>>>>>
>>>>> +void virtio_free_desc(struct vqs *vq, int id, uint64_t features)
>>>>> +{
>>>>> + struct vring_desc *desc;
>>>>> +
>>>>> + id %= vq->size;
>>>>> + desc = &vq->desc[id];
>>>>> +
>>>>> + if (features & VIRTIO_F_VERSION_1) {
>>>>> + if (features & VIRTIO_F_IOMMU_PLATFORM) {
>>>>> + SLOF_dma_map_out(le64_to_cpu(desc->addr),
>>>>> + 0, le32_to_cpu(desc->len));
>>>>> + vq->desc_gpas[id] = NULL;
>>>>> + }
>>>>> + }
>>>>> +}
>>>>
>>>> On a 4.18 RHEL8 kernel I was unable to boot from virtio-blk, it complains the
>>>> disk isn't bootable and the H_PUT_TCE traces show:
>>>>
>>>> qemu-system-ppc-19019 [045] .... 786844.067356: kvm_hcall_enter: VCPU 0: hcall=H_PUT_TCE GPR4-7=0x80000000,0x1000,0xe46b003,0xdc73350
>>>> qemu-system-ppc-19019 [045] .... 786844.067358: kvm_hcall_exit: VCPU 0: ret=RESUME_GUEST hcall_rc=H_SUCCESS
>>>> qemu-system-ppc-19019 [045] .... 786844.067361: kvm_hcall_enter: VCPU 0: hcall=H_PUT_TCE GPR4-7=0x80000000,0x2000,0xe46c003,0xdc73350
>>>> qemu-system-ppc-19019 [045] .... 786844.067362: kvm_hcall_exit: VCPU 0: ret=RESUME_GUEST hcall_rc=H_SUCCESS
>>>> qemu-system-ppc-19019 [041] .... 786844.070532: kvm_hcall_enter: VCPU 0: hcall=H_PUT_TCE GPR4-7=0x80000000,0x3000,0xe67b003,0xdc73490
>>>> qemu-system-ppc-19019 [041] .... 786844.070533: kvm_hcall_exit: VCPU 0: ret=RESUME_GUEST hcall_rc=H_SUCCESS
>>>> qemu-system-ppc-19019 [041] .... 786844.070817: kvm_hcall_enter: VCPU 0: hcall=H_PUT_TCE GPR4-7=0x80000000,0x4000,0xe469003,0xdc73490
>>>> qemu-system-ppc-19019 [041] .... 786844.070818: kvm_hcall_exit: VCPU 0: ret=RESUME_GUEST hcall_rc=H_SUCCESS
>>>> qemu-system-ppc-19019 [041] .... 786844.071102: kvm_hcall_enter: VCPU 0: hcall=H_PUT_TCE GPR4-7=0x80000000,0x5000,0xe67a003,0xdc73490
>>>> qemu-system-ppc-19019 [041] .... 786844.071103: kvm_hcall_exit: VCPU 0: ret=RESUME_GUEST hcall_rc=H_SUCCESS
>>>> qemu-system-ppc-19019 [041] .... 786844.071123: kvm_hcall_exit: VCPU 0: ret=RESUME_GUEST hcall_rc=H_SUCCESS
>>>> qemu-system-ppc-19019 [041] .... 786844.073532: kvm_hcall_enter: VCPU 0: hcall=H_PUT_TCE GPR4-7=0x80000000,0x3228,0x0,0xdc73488
>>>> qemu-system-ppc-19019 [041] .... 786844.073534: kvm_hcall_exit: VCPU 0: ret=RESUME_GUEST hcall_rc=H_PARAMETER
>>>>
>>>> If I disable in-kernel TCE acceleration, or use TCG, it seems to work
>>>> fine. If I add the following hack it seems to fix things:
>>>>
>>>> @@ -305,7 +307,8 @@ void virtio_free_desc(struct vqs *vq, int id, uint64_t features)
>>>>
>>>> if (features & VIRTIO_F_VERSION_1) {
>>>> if (features & VIRTIO_F_IOMMU_PLATFORM) {
>>>> - SLOF_dma_map_out(le64_to_cpu(desc->addr),
>>>> + fprintf(stderr, "mapping out desc->addr: %llx\n", le64_to_cpu(desc->addr));
>>>> + SLOF_dma_map_out(le64_to_cpu(desc->addr) & ~(0xfff),
>>>> 0, le32_to_cpu(desc->len));
>>>> vq->desc_gpas[id] = NULL;
>>>> }
>>>>
>>>> I guess the kernel is a bit stricter about unmapping unaligned TCE entries? If
>>>> so, maybe we should align automatically in dma-map-out?
>>>
>>>
>>> I thought I did that as well in 1/4, I'll double check. Hmmm.
>>
>>
>> v2 of these patches did not align (or, trunc, really) in dma-map-out but
>> v3 do, it is "swap dma-trunc swap" in dma-map-out of 1/4. SO I am really
>> confused now.
>
> Yah sorry I think the issue was on my end. I thought:
>
> https://github.com/aik/SLOF/commits/virtio-iommu
My bad, I should have pushed it out since I started pushing them out.
The question now is if we are good to go and I can push these out and
send SLOF blob update so people can actually start testing it? Thanks,
>
> reflected this series, but it does contain an older version of the
> dma-map* patch:
>
> index f136324..be529c9 100644
> --- a/board-qemu/slof/pci-phb.fs
> +++ b/board-qemu/slof/pci-phb.fs
> @@ -146,6 +146,7 @@ setup-puid
> \ grub does not align allocated addresses to the size so when mapping,
> \ we might ask bm-alloc for an extra IOMMU page
> : dma-align ( size virt -- aligned-size ) tce-mask and + tce-ps #aligned ;
> +: dma-trunc ( addr -- addr&~fff) tce-mask not and ;
>
> : dma-map-in ( virt size cachable? -- devaddr )
> phb-debug? IF cr ." dma-map-in called: " .s cr THEN
> @@ -163,7 +164,7 @@ setup-puid
> swap ( size dev-addr virt )
> 2dup tce-mask and or >r \ add page offset to the return value
>
> - tce-mask not and 3 OR \ Trunk virt and add read and write perm
> + dma-trunc 3 OR \ Truncate and add read and write perm
> rot ( virt dev-addr size r: dev-addr )
> 0
> ?DO
> @@ -179,10 +180,10 @@ setup-puid
> : dma-map-out ( virt devaddr size -- )
> phb-debug? IF cr ." dma-map-out called: " .s cr THEN
> (init-dma-window-vars)
> - rot drop ( devaddr size )
> + rot drop ( devaddr size )
> over dma-align
> - 2dup swap tce-mask not and swap bm-handle -rot
> - bm-free
> + swap dma-trunc swap ( devaddr-trunc size-extended )
> + 2dup bm-handle -rot bm-free
> 0
> ?DO
> dup 0 dma-window-liobn -rot
>
>
> I haven't been able to re-test yet since something seems to have gone
> awry with the test system last night, but I assume that's what the issue
> was. Sorry for the confusion.
>
>>
>> It is true that checking differs between qemu's and kvm's h_put_tce
>> handlers, I added this (see below) to my qemu and it still works, can
>> you please try in your tree and capture the spapr_iommu_pci_put traces?
>> Thanks,
>>
>>
>> diff --git a/hw/ppc/spapr_iommu.c b/hw/ppc/spapr_iommu.c
>> index 3d3bcc86496a..feae27bf11fa 100644
>> --- a/hw/ppc/spapr_iommu.c
>> +++ b/hw/ppc/spapr_iommu.c
>> @@ -564,6 +564,9 @@ static target_ulong h_put_tce(PowerPCCPU *cpu,
>> SpaprMachineState *spapr,
>> if (tcet) {
>> hwaddr page_mask = IOMMU_PAGE_MASK(tcet->page_shift);
>>
>> + if (ioba & ~page_mask)
>> + abort();
>> +
>>
>>
>>
>>
>> --
>> Alexey
--
Alexey
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