Commit 1c380f94 authored by Avi Kivity's avatar Avi Kivity
Browse files

pci: honor PCI_COMMAND_MASTER 



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: default avatarAvi Kivity <avi@redhat.com>
parent 817dcc53

hw/pci.c

+11 −2
Original line number Diff line number Diff line
@@ -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()));

        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);

hw/pci.h

+1 −0
Original line number Diff line number Diff line
@@ -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 */