On Wed, Oct 10, 2012 at 12:32 AM, Avi Kivity <a...@redhat.com> wrote:
> Currently we ignore PCI_COMMAND_MASTER completely: DMA succeeds even when
> the bit is clear.
>
> Honor PCI_COMMAND_MASTER by inserting a memory region into the device's
> bus master address space, and tying its enable status to PCI_COMMAND_MASTER.
>
> Tested using
>
> setpci -s 03 COMMAND=3
>
> while a ping was running on a NIC in slot 3. The kernel (Linux) detected
> the stall and recovered after the command
>
> setpci -s 03 COMMAND=7
>
> was issued.
>
> Signed-off-by: Avi Kivity <a...@redhat.com>
> ---
> hw/pci.c | 13 +++++++++++--
> hw/pci.h | 1 +
> 2 files changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/hw/pci.c b/hw/pci.c
> index 8e8e030..7adf61b 100644
> --- a/hw/pci.c
> +++ b/hw/pci.c
> @@ -782,7 +782,11 @@ static PCIDevice *do_pci_register_device(PCIDevice
> *pci_dev, PCIBus *bus,
> /* FIXME: Make dma_context_fn use MemoryRegions instead, so this
> path is
> * taken unconditionally */
> /* FIXME: inherit memory region from bus creator */
> - address_space_init(&pci_dev->bus_master_as, get_system_memory());
> + memory_region_init_alias(&pci_dev->bus_master_enable_region, "bus
> master",
> + get_system_memory(), 0,
> + memory_region_size(get_system_memory()));
Could we achieve that hiding special mr from some address space? I
think one approach is to limit the iommu's lookup table, but that is
the guest's willing. The other one is use dummy-mr to overlap some
piece of region of system_memory.
This method will require changing the render sequence of alias mr.
diff --git a/memory.c b/memory.c
index 2f68d67..cf67c66 100644
--- a/memory.c
+++ b/memory.c
@@ -499,6 +499,11 @@ static void render_memory_region(FlatView *view,
clip = addrrange_intersection(tmp, clip);
+ /* Render subregions in priority order. */
+ QTAILQ_FOREACH(subregion, &mr->subregions, subregions_link) {
+ render_memory_region(view, subregion, base, clip, readonly);
+ }
+
if (mr->alias) {
int128_subfrom(&base, int128_make64(mr->alias->addr));
int128_subfrom(&base, int128_make64(mr->alias_offset));
@@ -506,11 +511,6 @@ static void render_memory_region(FlatView *view,
return;
}
- /* Render subregions in priority order. */
- QTAILQ_FOREACH(subregion, &mr->subregions, subregions_link) {
- render_memory_region(view, subregion, base, clip, readonly);
- }
-
Regards,
pingfan
> + memory_region_set_enabled(&pci_dev->bus_master_enable_region, false);
> + address_space_init(&pci_dev->bus_master_as,
> &pci_dev->bus_master_enable_region);
> pci_dev->dma = g_new(DMAContext, 1);
> dma_context_init(pci_dev->dma, &pci_dev->bus_master_as, NULL, NULL,
> NULL);
> }
> @@ -841,6 +845,7 @@ static void do_pci_unregister_device(PCIDevice *pci_dev)
>
> if (!pci_dev->bus->dma_context_fn) {
> address_space_destroy(&pci_dev->bus_master_as);
> + memory_region_destroy(&pci_dev->bus_master_enable_region);
> g_free(pci_dev->dma);
> pci_dev->dma = NULL;
> }
> @@ -1065,8 +1070,12 @@ void pci_default_write_config(PCIDevice *d, uint32_t
> addr, uint32_t val, int l)
> range_covers_byte(addr, l, PCI_COMMAND))
> pci_update_mappings(d);
>
> - if (range_covers_byte(addr, l, PCI_COMMAND))
> + if (range_covers_byte(addr, l, PCI_COMMAND)) {
> pci_update_irq_disabled(d, was_irq_disabled);
> + memory_region_set_enabled(&d->bus_master_enable_region,
> + pci_get_word(d->config + PCI_COMMAND)
> + & PCI_COMMAND_MASTER);
> + }
>
> msi_write_config(d, addr, val, l);
> msix_write_config(d, addr, val, l);
> diff --git a/hw/pci.h b/hw/pci.h
> index 3192d81..a65e490 100644
> --- a/hw/pci.h
> +++ b/hw/pci.h
> @@ -212,6 +212,7 @@ struct PCIDevice {
> char name[64];
> PCIIORegion io_regions[PCI_NUM_REGIONS];
> AddressSpace bus_master_as;
> + MemoryRegion bus_master_enable_region;
> DMAContext *dma;
>
> /* do not access the following fields */
> --
> 1.7.12
>
