[Qemu-devel] Re: [PATCH v3] Do not try loading option ROM for hotplug PCI device in pc-0.11 compat mode
On 08/30/2010 03:16 AM, jes.soren...@redhat.com wrote:
From: Jes Sorensenjes.soren...@redhat.com
pc-0.11 and older uses fw_cfg to provide option ROMs. As fw_cfg is setup
at init time, it is not possible to load an option ROM for a hotplug
device when running in compat mode.
v2: Alex Williamson pointed out that one can get to qdev directly from
pci_dev, so no need to pass it down.
v3: Braces
What's the specific bug? The devices themselves have a check for
hotplug which inhibits rom addition during hotplug so either there's a
device missing this check or if we're going to go this route, we ought
to remove those checks in the other devices.
Regards,
Anthony Liguori
Signed-off-by: Jes Sorensenjes.soren...@redhat.com
---
hw/pci.c |9 +++--
1 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/hw/pci.c b/hw/pci.c
index a98d6f3..a20f796 100644
--- a/hw/pci.c
+++ b/hw/pci.c
@@ -1810,11 +1810,16 @@ static int pci_add_option_rom(PCIDevice *pdev)
return 0;
if (!pdev-rom_bar) {
+int class;
/*
* Load rom via fw_cfg instead of creating a rom bar,
- * for 0.11 compatibility.
+ * for 0.11 compatibility. fw_cfg is initialized at boot, so
+ * we cannot do hotplug load of option roms.
*/
-int class = pci_get_word(pdev-config + PCI_CLASS_DEVICE);
+if (pdev-qdev.hotplugged) {
+return 0;
+}
+class = pci_get_word(pdev-config + PCI_CLASS_DEVICE);
if (class == 0x0300) {
rom_add_vga(pdev-romfile);
} else {
[Qemu-devel] Re: [PATCH v3] Do not try loading option ROM for hotplug PCI device in pc-0.11 compat mode
On 08/30/10 15:00, Anthony Liguori wrote: On 08/30/2010 03:16 AM, jes.soren...@redhat.com wrote: From: Jes Sorensenjes.soren...@redhat.com pc-0.11 and older uses fw_cfg to provide option ROMs. As fw_cfg is setup at init time, it is not possible to load an option ROM for a hotplug device when running in compat mode. v2: Alex Williamson pointed out that one can get to qdev directly from pci_dev, so no need to pass it down. v3: Braces What's the specific bug? The devices themselves have a check for hotplug which inhibits rom addition during hotplug so either there's a device missing this check or if we're going to go this route, we ought to remove those checks in the other devices. If you run in -M pc-0.11 or older option ROMs are provided via fw_cfg, which means QEMU is unable to load it after boot time if you try to hot-plug a new network device via the monitor. Instead it decides to exit with an error. My patch makes QEMU not try to load the option ROM in this case, which IMHO is a reasonable workaround. It means you can't PXE from the hot-plugged device, but at least QEMU doesn't exit out on you. Cheers, Jes
Re: [Qemu-devel] Re: [PATCH v3] Do not try loading option ROM for hotplug PCI device in pc-0.11 compat mode
Anthony Liguori anth...@codemonkey.ws writes: On 08/30/2010 03:16 AM, jes.soren...@redhat.com wrote: From: Jes Sorensenjes.soren...@redhat.com pc-0.11 and older uses fw_cfg to provide option ROMs. As fw_cfg is setup at init time, it is not possible to load an option ROM for a hotplug device when running in compat mode. v2: Alex Williamson pointed out that one can get to qdev directly from pci_dev, so no need to pass it down. v3: Braces What's the specific bug? The devices themselves have a check for hotplug which inhibits rom addition during hotplug so either there's a device missing this check or if we're going to go this route, we ought to remove those checks in the other devices. Quoting my reply to v1[*]: Example: $ qemu -M pc-0.11 -S -monitor stdio QEMU 0.12.50 monitor - type 'help' for more information (qemu) device_add e1000 qemu: hardware error: ROM images must be loaded at startup [...] Aborted (core dumped) The fix silently omits the option ROM when we can't load it. Works for me. [*] http://lists.nongnu.org/archive/html/qemu-devel/2010-07/msg01397.html
[Qemu-devel] Re: [PATCH v3] Do not try loading option ROM for hotplug PCI device in pc-0.11 compat mode
On 08/30/10 15:45, Anthony Liguori wrote: On 08/30/2010 08:11 AM, Jes Sorensen wrote: On 08/30/10 15:00, Anthony Liguori wrote: On 08/30/2010 03:16 AM, jes.soren...@redhat.com wrote: From: Jes Sorensenjes.soren...@redhat.com pc-0.11 and older uses fw_cfg to provide option ROMs. As fw_cfg is setup at init time, it is not possible to load an option ROM for a hotplug device when running in compat mode. v2: Alex Williamson pointed out that one can get to qdev directly from pci_dev, so no need to pass it down. v3: Braces What's the specific bug? The devices themselves have a check for hotplug which inhibits rom addition during hotplug so either there's a device missing this check or if we're going to go this route, we ought to remove those checks in the other devices. If you run in -M pc-0.11 or older option ROMs are provided via fw_cfg, which means QEMU is unable to load it after boot time if you try to hot-plug a new network device via the monitor. Instead it decides to exit with an error. Which network device? Take a look at ne2k.c's rom loading. It's got logic for rom loading with hotplug but e1000 and rtl8139 don't. Maybe it's because ne2k also supports an ISA mode? I think I just forgot to convert ne2k over to using .romfile instead. Just skipping fw_cfg-based rom loading looks sane to me. After all it is just for pc-0.11 compatibility. And it is even bug compatible: hot-plug nic + reboot + pxe-boot from the hot-plugged nic didn't work in 0.11 too ;) cheers, Gerd
[Qemu-devel] Re: [PATCH v3] Do not try loading option ROM for hotplug PCI device in pc-0.11 compat mode
On 08/30/2010 08:11 AM, Jes Sorensen wrote: On 08/30/10 15:00, Anthony Liguori wrote: On 08/30/2010 03:16 AM, jes.soren...@redhat.com wrote: From: Jes Sorensenjes.soren...@redhat.com pc-0.11 and older uses fw_cfg to provide option ROMs. As fw_cfg is setup at init time, it is not possible to load an option ROM for a hotplug device when running in compat mode. v2: Alex Williamson pointed out that one can get to qdev directly from pci_dev, so no need to pass it down. v3: Braces What's the specific bug? The devices themselves have a check for hotplug which inhibits rom addition during hotplug so either there's a device missing this check or if we're going to go this route, we ought to remove those checks in the other devices. If you run in -M pc-0.11 or older option ROMs are provided via fw_cfg, which means QEMU is unable to load it after boot time if you try to hot-plug a new network device via the monitor. Instead it decides to exit with an error. Which network device? Take a look at ne2k.c's rom loading. It's got logic for rom loading with hotplug but e1000 and rtl8139 don't. Maybe it's because ne2k also supports an ISA mode? Gerd, what was your intention here? Regards, Anthony Liguori My patch makes QEMU not try to load the option ROM in this case, which IMHO is a reasonable workaround. It means you can't PXE from the hot-plugged device, but at least QEMU doesn't exit out on you. Cheers, Jes
[Qemu-devel] Re: [PATCH v3] Do not try loading option ROM for hotplug PCI device in pc-0.11 compat mode
On 08/30/10 15:45, Anthony Liguori wrote: On 08/30/2010 08:11 AM, Jes Sorensen wrote: If you run in -M pc-0.11 or older option ROMs are provided via fw_cfg, which means QEMU is unable to load it after boot time if you try to hot-plug a new network device via the monitor. Instead it decides to exit with an error. Which network device? Take a look at ne2k.c's rom loading. It's got logic for rom loading with hotplug but e1000 and rtl8139 don't. Maybe it's because ne2k also supports an ISA mode? It happens with virtio-net as well which is where I saw it first. However, it's really only an issue in compat mode since with 0.12 onwards we can load option ROMs on the fly. Cheers, Jes
