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[Qemu-devel] Re: [PATCH] PCI: Bus number from the bridge, not the device
From: |
Michael S. Tsirkin |
Subject: |
[Qemu-devel] Re: [PATCH] PCI: Bus number from the bridge, not the device |
Date: |
Mon, 8 Nov 2010 13:22:27 +0200 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Mon, Oct 04, 2010 at 03:53:11PM -0600, Alex Williamson wrote:
> pcibus_dev_print() was erroneously retrieving the device bus
> number from the secondary bus number offset of the device
> instead of the bridge above the device. This ends of landing
> in the 2nd byte of the 3rd BAR for devices, which thankfully
> is usually zero. pcibus_get_dev_path() copied this code,
> inheriting the same bug. pcibus_get_dev_path() is used for
> ramblock naming, so changing it can effect migration. However,
> I've only seen this byte be non-zero for an assigned device,
> which can't migrate anyway, so hopefully we won't run into
> any issues.
>
> Signed-off-by: Alex Williamson <address@hidden>
Good catch. Applied.
I don't really see why do we put the dev path
in the bus object: why not let device supply its name?
And I think this will affect nested bridges. However they are currently
broken anyway: we really must convert to topological names as bus number
is guest-assigned - they don't have to be unique, even.
What does fixing this involve? Just changing pcibus_get_dev_path?
> ---
>
> hw/pci.c | 5 ++---
> 1 files changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/hw/pci.c b/hw/pci.c
> index 6d0934d..15416dd 100644
> --- a/hw/pci.c
> +++ b/hw/pci.c
> @@ -1940,8 +1940,7 @@ static void pcibus_dev_print(Monitor *mon, DeviceState
> *dev, int indent)
>
> monitor_printf(mon, "%*sclass %s, addr %02x:%02x.%x, "
> "pci id %04x:%04x (sub %04x:%04x)\n",
> - indent, "", ctxt,
> - d->config[PCI_SECONDARY_BUS],
> + indent, "", ctxt, pci_bus_num(d->bus),
> PCI_SLOT(d->devfn), PCI_FUNC(d->devfn),
> pci_get_word(d->config + PCI_VENDOR_ID),
> pci_get_word(d->config + PCI_DEVICE_ID),
> @@ -1965,7 +1964,7 @@ static char *pcibus_get_dev_path(DeviceState *dev)
> char path[16];
>
> snprintf(path, sizeof(path), "%04x:%02x:%02x.%x",
> - pci_find_domain(d->bus), d->config[PCI_SECONDARY_BUS],
> + pci_find_domain(d->bus), pci_bus_num(d->bus),
> PCI_SLOT(d->devfn), PCI_FUNC(d->devfn));
>
> return strdup(path);
>
- [Qemu-devel] Re: [PATCH] PCI: Bus number from the bridge, not the device,
Michael S. Tsirkin <=
- [Qemu-devel] Re: [PATCH] PCI: Bus number from the bridge, not the device, Alex Williamson, 2010/11/08
- [Qemu-devel] Re: [PATCH] PCI: Bus number from the bridge, not the device, Michael S. Tsirkin, 2010/11/08
- [Qemu-devel] Re: [PATCH] PCI: Bus number from the bridge, not the device, Gleb Natapov, 2010/11/08
- [Qemu-devel] Re: [PATCH] PCI: Bus number from the bridge, not the device, Michael S. Tsirkin, 2010/11/08
- [Qemu-devel] Re: [PATCH] PCI: Bus number from the bridge, not the device, Gleb Natapov, 2010/11/08
- Re: [Qemu-devel] Re: [PATCH] PCI: Bus number from the bridge, not the device, Isaku Yamahata, 2010/11/08
- Re: [Qemu-devel] Re: [PATCH] PCI: Bus number from the bridge, not the device, Michael S. Tsirkin, 2010/11/09
- Re: [Qemu-devel] Re: [PATCH] PCI: Bus number from the bridge, not the device, Markus Armbruster, 2010/11/19