Commit e4024630 authored by Laurent Vivier's avatar Laurent Vivier Committed by Michael S. Tsirkin
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pci: allow 0 address for PCI IO/MEM regions 



Some kernels program a 0 address for io regions. PCI 3.0 spec
section 6.2.5.1 doesn't seem to disallow this.

based on patch by Michael Roth <mdroth@linux.vnet.ibm.com>

Add pci_allow_0_addr in MachineClass to conditionally
allow addr 0 for pseries, as this can break other architectures.

This patch allows to hotplug PCI card in pseries machine, as the first
added card BAR0 is always set to 0 address.

This as a temporary hack, waiting to fix PCI memory priorities for more
machine types...

Signed-off-by: default avatarLaurent Vivier <lvivier@redhat.com>
Reviewed-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent c8d163bc

hw/pci/pci.c

+9 −3
Original line number Diff line number Diff line
@@ -38,6 +38,7 @@ 
#include "hw/pci/msix.h"

#include "exec/address-spaces.h"

#include "hw/hotplug.h"

#include "hw/boards.h"



//#define DEBUG_PCI

#ifdef DEBUG_PCI
@@ -1065,6 +1066,10 @@ static pcibus_t pci_bar_address(PCIDevice *d, 
    pcibus_t new_addr, last_addr;

    int bar = pci_bar(d, reg);

    uint16_t cmd = pci_get_word(d->config + PCI_COMMAND);

    Object *machine = qdev_get_machine();

    ObjectClass *oc = object_get_class(machine);

    MachineClass *mc = MACHINE_CLASS(oc);

    bool allow_0_address = mc->pci_allow_0_address;



    if (type & PCI_BASE_ADDRESS_SPACE_IO) {

        if (!(cmd & PCI_COMMAND_IO)) {
@@ -1075,7 +1080,8 @@ static pcibus_t pci_bar_address(PCIDevice *d, 
        /* Check if 32 bit BAR wraps around explicitly.

         * TODO: make priorities correct and remove this work around.

         */

        if (last_addr <= new_addr || new_addr == 0 || last_addr >= UINT32_MAX) {

        if (last_addr <= new_addr || last_addr >= UINT32_MAX ||

            (!allow_0_address && new_addr == 0)) {

            return PCI_BAR_UNMAPPED;

        }

        return new_addr;
@@ -1099,8 +1105,8 @@ static pcibus_t pci_bar_address(PCIDevice *d, 
    /* XXX: as we cannot support really dynamic

       mappings, we handle specific values as invalid

       mappings. */

    if (last_addr <= new_addr || new_addr == 0 ||

        last_addr == PCI_BAR_UNMAPPED) {

    if (last_addr <= new_addr || last_addr == PCI_BAR_UNMAPPED ||

        (!allow_0_address && new_addr == 0)) {

        return PCI_BAR_UNMAPPED;

    }

hw/ppc/spapr.c

+1 −0
Original line number Diff line number Diff line
@@ -1835,6 +1835,7 @@ static void spapr_machine_class_init(ObjectClass *oc, void *data) 
    mc->default_ram_size = 512 * M_BYTE;

    mc->kvm_type = spapr_kvm_type;

    mc->has_dynamic_sysbus = true;

    mc->pci_allow_0_address = true;



    fwc->get_dev_path = spapr_get_fw_dev_path;

    nc->nmi_monitor_handler = spapr_nmi;

include/hw/boards.h

+2 −1
Original line number Diff line number Diff line
@@ -100,7 +100,8 @@ struct MachineClass { 
        no_cdrom:1,

        no_sdcard:1,

        has_dynamic_sysbus:1,

        no_tco:1;

        no_tco:1,

        pci_allow_0_address:1;

    int is_default;

    const char *default_machine_opts;

    const char *default_boot_order;