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Re: [PATCH v2 3/3] vdpa: Check for iova range at mappings changes
From: |
Eugenio Perez Martin |
Subject: |
Re: [PATCH v2 3/3] vdpa: Check for iova range at mappings changes |
Date: |
Tue, 12 Oct 2021 08:27:52 +0200 |
On Tue, Oct 12, 2021 at 5:50 AM Jason Wang <jasowang@redhat.com> wrote:
>
> On Tue, Oct 5, 2021 at 9:49 PM Eugenio Pérez <eperezma@redhat.com> wrote:
> >
> > Check vdpa device range before updating memory regions so we don't add
> > any outside of it, and report the invalid change if any.
> >
> > Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
> > ---
> > include/hw/virtio/vhost-vdpa.h | 2 +
> > hw/virtio/vhost-vdpa.c | 68 ++++++++++++++++++++++++++--------
> > hw/virtio/trace-events | 1 +
> > 3 files changed, 55 insertions(+), 16 deletions(-)
> >
> > diff --git a/include/hw/virtio/vhost-vdpa.h b/include/hw/virtio/vhost-vdpa.h
> > index a8963da2d9..c288cf7ecb 100644
> > --- a/include/hw/virtio/vhost-vdpa.h
> > +++ b/include/hw/virtio/vhost-vdpa.h
> > @@ -13,6 +13,7 @@
> > #define HW_VIRTIO_VHOST_VDPA_H
> >
> > #include "hw/virtio/virtio.h"
> > +#include "standard-headers/linux/vhost_types.h"
> >
> > typedef struct VhostVDPAHostNotifier {
> > MemoryRegion mr;
> > @@ -24,6 +25,7 @@ typedef struct vhost_vdpa {
> > uint32_t msg_type;
> > bool iotlb_batch_begin_sent;
> > MemoryListener listener;
> > + struct vhost_vdpa_iova_range iova_range;
> > struct vhost_dev *dev;
> > VhostVDPAHostNotifier notifier[VIRTIO_QUEUE_MAX];
> > } VhostVDPA;
> > diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
> > index be7c63b4ba..6654287050 100644
> > --- a/hw/virtio/vhost-vdpa.c
> > +++ b/hw/virtio/vhost-vdpa.c
> > @@ -37,20 +37,34 @@ static Int128 vhost_vdpa_section_end(const
> > MemoryRegionSection *section)
> > return llend;
> > }
> >
> > -static bool vhost_vdpa_listener_skipped_section(MemoryRegionSection
> > *section)
> > -{
> > - return (!memory_region_is_ram(section->mr) &&
> > - !memory_region_is_iommu(section->mr)) ||
> > - memory_region_is_protected(section->mr) ||
> > - /* vhost-vDPA doesn't allow MMIO to be mapped */
> > - memory_region_is_ram_device(section->mr) ||
> > - /*
> > - * Sizing an enabled 64-bit BAR can cause spurious mappings to
> > - * addresses in the upper part of the 64-bit address space.
> > These
> > - * are never accessed by the CPU and beyond the address width of
> > - * some IOMMU hardware. TODO: VDPA should tell us the IOMMU
> > width.
> > - */
> > - section->offset_within_address_space & (1ULL << 63);
> > +static bool vhost_vdpa_listener_skipped_section(MemoryRegionSection
> > *section,
> > + uint64_t iova_min,
> > + uint64_t iova_max)
> > +{
> > + Int128 llend;
> > +
> > + if ((!memory_region_is_ram(section->mr) &&
> > + !memory_region_is_iommu(section->mr)) ||
> > + memory_region_is_protected(section->mr) ||
> > + /* vhost-vDPA doesn't allow MMIO to be mapped */
> > + memory_region_is_ram_device(section->mr)) {
> > + return true;
> > + }
> > +
> > + if (section->offset_within_address_space < iova_min) {
> > + error_report("RAM section out of device range (min=%lu, addr=%lu)",
> > + iova_min, section->offset_within_address_space);
> > + return true;
> > + }
> > +
> > + llend = vhost_vdpa_section_end(section);
> > + if (int128_gt(llend, int128_make64(iova_max))) {
> > + error_report("RAM section out of device range (max=%lu, end
> > addr=%lu)",
> > + iova_max, int128_get64(llend));
> > + return true;
> > + }
> > +
> > + return false;
> > }
> >
> > static int vhost_vdpa_dma_map(struct vhost_vdpa *v, hwaddr iova, hwaddr
> > size,
> > @@ -162,7 +176,8 @@ static void
> > vhost_vdpa_listener_region_add(MemoryListener *listener,
> > void *vaddr;
> > int ret;
> >
> > - if (vhost_vdpa_listener_skipped_section(section)) {
> > + if (vhost_vdpa_listener_skipped_section(section, v->iova_range.first,
> > + v->iova_range.last)) {
> > return;
> > }
> >
> > @@ -220,7 +235,8 @@ static void
> > vhost_vdpa_listener_region_del(MemoryListener *listener,
> > Int128 llend, llsize;
> > int ret;
> >
> > - if (vhost_vdpa_listener_skipped_section(section)) {
> > + if (vhost_vdpa_listener_skipped_section(section, v->iova_range.first,
> > + v->iova_range.last)) {
> > return;
> > }
> >
> > @@ -288,9 +304,24 @@ static void vhost_vdpa_add_status(struct vhost_dev
> > *dev, uint8_t status)
> > vhost_vdpa_call(dev, VHOST_VDPA_SET_STATUS, &s);
> > }
> >
> > +static int vhost_vdpa_get_iova_range(struct vhost_vdpa *v)
> > +{
> > + int ret;
> > +
> > + ret = vhost_vdpa_call(v->dev, VHOST_VDPA_GET_IOVA_RANGE,
> > &v->iova_range);
> > + if (ret != 0) {
> > + return ret;
> > + }
>
> I think we need a fallback for the kernel that does not support
> VHOST_VDPA_GET_IOVA_RANGE?
>
I'm fine with giving a default, but only "old" kernels will not have
the syscall. Future kernels will return success and [0, ULLONG_MAX]
range, won't it?
Taking that into account, what is the good default value? Before this
commit the valid range was [0, 2^63). Although that seems too wide for
every iommu, I would go with that one. The kernel considers fine [0,
ULLONG_MAX] in case the device and iommu domain does not support
them...
Thanks!
> Thanks
>
> > +
> > + trace_vhost_vdpa_get_iova_range(v->dev, v->iova_range.first,
> > + v->iova_range.last);
> > + return ret;
> > +}
> > +
> > static int vhost_vdpa_init(struct vhost_dev *dev, void *opaque, Error
> > **errp)
> > {
> > struct vhost_vdpa *v;
> > + int r;
> > assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_VDPA);
> > trace_vhost_vdpa_init(dev, opaque);
> >
> > @@ -300,6 +331,11 @@ static int vhost_vdpa_init(struct vhost_dev *dev, void
> > *opaque, Error **errp)
> > v->listener = vhost_vdpa_memory_listener;
> > v->msg_type = VHOST_IOTLB_MSG_V2;
> >
> > + r = vhost_vdpa_get_iova_range(v);
> > + if (unlikely(!r)) {
> > + return r;
> > + }
> > +
> > vhost_vdpa_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE |
> > VIRTIO_CONFIG_S_DRIVER);
> >
> > diff --git a/hw/virtio/trace-events b/hw/virtio/trace-events
> > index 8ed19e9d0c..650e521e35 100644
> > --- a/hw/virtio/trace-events
> > +++ b/hw/virtio/trace-events
> > @@ -52,6 +52,7 @@ vhost_vdpa_set_vring_call(void *dev, unsigned int index,
> > int fd) "dev: %p index:
> > vhost_vdpa_get_features(void *dev, uint64_t features) "dev: %p features:
> > 0x%"PRIx64
> > vhost_vdpa_set_owner(void *dev) "dev: %p"
> > vhost_vdpa_vq_get_addr(void *dev, void *vq, uint64_t desc_user_addr,
> > uint64_t avail_user_addr, uint64_t used_user_addr) "dev: %p vq: %p
> > desc_user_addr: 0x%"PRIx64" avail_user_addr: 0x%"PRIx64" used_user_addr:
> > 0x%"PRIx64
> > +vhost_vdpa_get_iova_range(void *dev, uint64_t first, uint64_t last) "dev:
> > %p first: 0x%"PRIx64" last: 0x%"PRIx64
> >
> > # virtio.c
> > virtqueue_alloc_element(void *elem, size_t sz, unsigned in_num, unsigned
> > out_num) "elem %p size %zd in_num %u out_num %u"
> > --
> > 2.27.0
> >
>