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Re: [Qemu-ppc] [PATCH 11/11] vfio: Add guest side IOMMU support
From: |
David Gibson |
Subject: |
Re: [Qemu-ppc] [PATCH 11/11] vfio: Add guest side IOMMU support |
Date: |
Tue, 14 May 2013 23:57:07 +1000 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Tue, May 14, 2013 at 11:48:47AM +0200, Paolo Bonzini wrote:
> Il 14/05/2013 11:13, David Gibson ha scritto:
> > This patch uses the new IOMMU notifiers to allow VFIO pass through devices
> > to work with guest side IOMMUs, as long as the host-side VFIO iommu has
> > sufficient capability and granularity to match the guest side. This works
> > by tracking all map and unmap operations on the guest IOMMU using the
> > notifiers, and mirroring them into VFIO.
> >
> > There are a number of FIXMEs, and the scheme involves rather more notifier
> > structures than I'd like, but it shuold make for a reasonable proof of
> > concept.
> >
> > Signed-off-by: David Gibson <address@hidden>
> > ---
> > hw/misc/vfio.c | 139
> > ++++++++++++++++++++++++++++++++++++++++++++++++++------
> > 1 file changed, 126 insertions(+), 13 deletions(-)
> >
> > diff --git a/hw/misc/vfio.c b/hw/misc/vfio.c
> > index f4e3792..62a83ca 100644
> > --- a/hw/misc/vfio.c
> > +++ b/hw/misc/vfio.c
> > @@ -133,10 +133,18 @@ typedef struct VFIOContainer {
> > };
> > void (*release)(struct VFIOContainer *);
> > } iommu_data;
> > + QLIST_HEAD(, VFIOGuestIOMMU) guest_iommus;
> > QLIST_HEAD(, VFIOGroup) group_list;
> > QLIST_ENTRY(VFIOContainer) next;
> > } VFIOContainer;
> >
> > +typedef struct VFIOGuestIOMMU {
> > + VFIOContainer *container;
> > + MemoryRegion *iommu;
> > + Notifier n;
> > + QLIST_ENTRY(VFIOGuestIOMMU) list;
> > +} VFIOGuestIOMMU;
> > +
> > /* Cache of MSI-X setup plus extra mmap and memory region for split BAR
> > map */
> > typedef struct VFIOMSIXInfo {
> > uint8_t table_bar;
> > @@ -1940,7 +1948,64 @@ static int vfio_dma_map(VFIOContainer *container,
> > hwaddr iova,
> >
> > static bool vfio_listener_skipped_section(MemoryRegionSection *section)
> > {
> > - return !memory_region_is_ram(section->mr);
> > + return !memory_region_is_ram(section->mr) &&
> > + !memory_region_is_iommu(section->mr);
> > +}
> > +
> > +static void vfio_iommu_map_notify(Notifier *n, void *data)
> > +{
> > + VFIOGuestIOMMU *giommu = container_of(n, VFIOGuestIOMMU, n);
> > + MemoryRegion *iommu = giommu->iommu;
> > + VFIOContainer *container = giommu->container;
> > + IOMMUTLBEntry *iotlb = data;
> > + MemoryRegionSection *mrs;
> > + hwaddr xlat;
> > + hwaddr len = iotlb->addr_mask + 1;
> > + void *vaddr;
> > + int ret;
> > +
> > + DPRINTF("iommu map @ %"HWADDR_PRIx" - %"HWADDR_PRIx"\n",
> > + iotlb->iova, iotlb->iova + iotlb->address_mask);
> > +
> > + /* The IOMMU TLB entry we have just covers translation through
> > + * this IOMMU to its immediate target. We need to translate
> > + * it the rest of the way through to memory. */
> > + mrs = address_space_translate(iommu->iommu_target_as,
> > + iotlb->translated_addr,
> > + &xlat, &len, iotlb->perm[1]);
> > + if (!memory_region_is_ram(mrs->mr)) {
> > + DPRINTF("iommu map to non memory area %"HWADDR_PRIx"\n",
> > + xlat);
> > + return;
> > + }
> > + if (len & iotlb->addr_mask) {
> > + DPRINTF("iommu has granularity incompatible with target AS\n");
> > + return;
> > + }
> > +
> > + vaddr = memory_region_get_ram_ptr(mrs->mr) +
> > + mrs->offset_within_region +
> > + (xlat - mrs->offset_within_address_space);
>
> Are you sure you need this translation? It's done already in
> address_space_translate, so it should be just
>
> vaddr = memory_region_get_ram_ptr(mrs->mr) + xlat;
Ah, yes. I wasn't sure what xlat was relative to (the final address
space, or the final memory region). Looking more carefully at the
similar path in address_space_map(), I see that it's the memory
region. I'll fix that up.
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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- [Qemu-ppc] [PATCH 07/11] vfio: Introduce VFIO address spaces, (continued)
[Qemu-ppc] [PATCH 08/11] vfio: Create VFIOAddressSpace objects as needed, David Gibson, 2013/05/14
[Qemu-ppc] [PATCH 04/11] pci: Use AddressSpace rather than MemoryRegion to represent PCI DMA space, David Gibson, 2013/05/14
[Qemu-ppc] [PATCH 05/11] pci: Introduce helper to retrieve a PCI device's DMA address space, David Gibson, 2013/05/14
[Qemu-ppc] [PATCH 01/11] iommu: Fix compile error in ioapic.c, David Gibson, 2013/05/14
[Qemu-ppc] [PATCH 10/11] memory: Add iommu map/unmap notifiers, David Gibson, 2013/05/14