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Re: [Qemu-devel] Re: [PATCH] PCI: Bus number from the bridge, not the de
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] Re: [PATCH] PCI: Bus number from the bridge, not the device |
Date: |
Tue, 14 Dec 2010 06:46:58 +0200 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Mon, Dec 13, 2010 at 01:04:23PM -0700, Alex Williamson wrote:
> On Mon, 2010-11-08 at 13:22 +0200, Michael S. Tsirkin wrote:
> > 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.
>
> Um... submitted vs applied:
>
> PCI: Bus number from the bridge, not the device
>
> @@ -6,20 +8,28 @@
> 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,
> + is usually zero.
> +
> + Note: 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.
>
> + This patch does not touch pcibus_get_dev_path, as
> + bus number is guest assigned for nested buses,
> + so using it for migration is broken anyway.
> + Fix it properly later.
> +
> Signed-off-by: Alex Williamson <address@hidden>
> + Signed-off-by: Michael S. Tsirkin <address@hidden>
>
> diff --git a/hw/pci.c b/hw/pci.c
> -index 6d0934d..15416dd 100644
> +index 962886e..8f6fcf8 100644
> --- a/hw/pci.c
> +++ b/hw/pci.c
> -@@ -1940,8 +1940,7 @@ static void pcibus_dev_print(Monitor *mon, DeviceState
> *dev, int indent)
> +@@ -1806,8 +1806,7 @@ 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",
> @@ -29,14 +39,3 @@
> 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);
> -
> -
>
> So the chunk that fixed the part that I was actually interested in got
> dropped even though the existing code is clearly wrong. Yes, we still
> have issues with nested bridges (not that we have many of those), but
> until the "Fix it properly later" part comes along, can we please
> include the obvious bug fix? Thanks,
>
> Alex
We can stick 0 in there - would that help? I would much rather not
create a version where we put the bus number there.
--
MST
- Re: [Qemu-devel] Re: [PATCH] PCI: Bus number from the bridge, not the device, Alex Williamson, 2010/12/13
- Re: [Qemu-devel] Re: [PATCH] PCI: Bus number from the bridge, not the device,
Michael S. Tsirkin <=
- Re: [Qemu-devel] Re: [PATCH] PCI: Bus number from the bridge, not the device, Alex Williamson, 2010/12/13
- Re: [Qemu-devel] Re: [PATCH] PCI: Bus number from the bridge, not the device, Michael S. Tsirkin, 2010/12/13
- Re: [Qemu-devel] Re: [PATCH] PCI: Bus number from the bridge, not the device, Alex Williamson, 2010/12/14
- Re: [Qemu-devel] Re: [PATCH] PCI: Bus number from the bridge, not the device, Michael S. Tsirkin, 2010/12/14
- Re: [Qemu-devel] Re: [PATCH] PCI: Bus number from the bridge, not the device, Alex Williamson, 2010/12/14
- Re: [Qemu-devel] Re: [PATCH] PCI: Bus number from the bridge, not the device, Michael S. Tsirkin, 2010/12/15
- Re: [Qemu-devel] Re: [PATCH] PCI: Bus number from the bridge, not the device, Alex Williamson, 2010/12/15
- Re: [Qemu-devel] Re: [PATCH] PCI: Bus number from the bridge, not the device, Isaku Yamahata, 2010/12/16
- Re: [Qemu-devel] Re: [PATCH] PCI: Bus number from the bridge, not the device, Michael S. Tsirkin, 2010/12/16
- Re: [Qemu-devel] Re: [PATCH] PCI: Bus number from the bridge, not the device, Isaku Yamahata, 2010/12/21