[SLOF] [PATCH slof v3 4/4] virtio: Enable IOMMU
Michael Roth
mdroth at linux.vnet.ibm.com
Sat Nov 23 01:42:05 AEDT 2019
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
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
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