* [Qemu-devel] [PATCH v5] virtio-pci: enable bus master for old guests
@ 2014-09-11 18:20 Michael S. Tsirkin
2014-09-11 18:42 ` Greg Kurz
2014-09-15 9:48 ` Jason Wang
0 siblings, 2 replies; 6+ messages in thread
From: Michael S. Tsirkin @ 2014-09-11 18:20 UTC (permalink / raw)
To: qemu-devel; +Cc: Jason Wang, Anthony Liguori
commit cc943c36faa192cd4b32af8fe5edb31894017d35
pci: Use bus master address space for delivering MSI/MSI-X messages
breaks virtio-net for rhel6.[56] x86 guests because they don't
enable bus mastering for virtio PCI devices. For the same reason,
rhel6.[56] ppc64 guests cannot boot on a virtio-blk disk anymore.
Old guests forgot to enable bus mastering, enable it automatically on
DRIVER (guests use some devices before DRIVER_OK).
Reported-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
Sorry, v4 was broken - forgot to commit before git format-patch.
Here's the correct version.
Still not tested - will do next week.
Testing reports appreciated meanwhile.
hw/virtio/virtio-pci.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index ddb5da1..a827cd4 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -314,6 +314,16 @@ static void virtio_ioport_write(void *opaque, uint32_t addr, uint32_t val)
msix_unuse_all_vectors(&proxy->pci_dev);
}
+ /* Linux before 2.6.34 drives the device without enabling
+ the PCI device bus master bit. Enable it automatically
+ for the guest. This is a PCI spec violation but so is
+ initiating DMA with bus master bit clear. */
+ if (val == (VIRTIO_CONFIG_S_ACKNOWLEDGE | VIRTIO_CONFIG_S_DRIVER)) {
+ pci_default_write_config(&proxy->pci_dev, PCI_COMMAND,
+ proxy->pci_dev.config[PCI_COMMAND] |
+ PCI_COMMAND_MASTER, 1);
+ }
+
/* Linux before 2.6.34 sets the device as OK without enabling
the PCI device bus master bit. In this case we need to disable
some safety checks. */
--
MST
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [Qemu-devel] [PATCH v5] virtio-pci: enable bus master for old guests
2014-09-11 18:20 [Qemu-devel] [PATCH v5] virtio-pci: enable bus master for old guests Michael S. Tsirkin
@ 2014-09-11 18:42 ` Greg Kurz
2014-09-14 10:44 ` Michael S. Tsirkin
2014-09-15 9:48 ` Jason Wang
1 sibling, 1 reply; 6+ messages in thread
From: Greg Kurz @ 2014-09-11 18:42 UTC (permalink / raw)
To: Michael S. Tsirkin
Cc: Jason Wang, Cedric Le Goater, qemu-devel, Anthony Liguori,
qemu-stable
On Thu, 11 Sep 2014 21:20:03 +0300
"Michael S. Tsirkin" <mst@redhat.com> wrote:
> commit cc943c36faa192cd4b32af8fe5edb31894017d35
> pci: Use bus master address space for delivering MSI/MSI-X messages
> breaks virtio-net for rhel6.[56] x86 guests because they don't
> enable bus mastering for virtio PCI devices. For the same reason,
> rhel6.[56] ppc64 guests cannot boot on a virtio-blk disk anymore.
>
> Old guests forgot to enable bus mastering, enable it automatically on
> DRIVER (guests use some devices before DRIVER_OK).
>
> Reported-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
> Sorry, v4 was broken - forgot to commit before git format-patch.
> Here's the correct version.
> Still not tested - will do next week.
> Testing reports appreciated meanwhile.
>
Nice patch indeed ! :)
Reviewed-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
Tested-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
Cc'ing qemu-stable as Michael said he would queue the initial
bus master patch for 2.1.2.
> hw/virtio/virtio-pci.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> index ddb5da1..a827cd4 100644
> --- a/hw/virtio/virtio-pci.c
> +++ b/hw/virtio/virtio-pci.c
> @@ -314,6 +314,16 @@ static void virtio_ioport_write(void *opaque, uint32_t addr, uint32_t val)
> msix_unuse_all_vectors(&proxy->pci_dev);
> }
>
> + /* Linux before 2.6.34 drives the device without enabling
> + the PCI device bus master bit. Enable it automatically
> + for the guest. This is a PCI spec violation but so is
> + initiating DMA with bus master bit clear. */
> + if (val == (VIRTIO_CONFIG_S_ACKNOWLEDGE | VIRTIO_CONFIG_S_DRIVER)) {
> + pci_default_write_config(&proxy->pci_dev, PCI_COMMAND,
> + proxy->pci_dev.config[PCI_COMMAND] |
> + PCI_COMMAND_MASTER, 1);
> + }
> +
> /* Linux before 2.6.34 sets the device as OK without enabling
> the PCI device bus master bit. In this case we need to disable
> some safety checks. */
--
Gregory Kurz kurzgreg@fr.ibm.com
gkurz@linux.vnet.ibm.com
Software Engineer @ IBM/Meiosys http://www.ibm.com
Tel +33 (0)562 165 496
"Anarchy is about taking complete responsibility for yourself."
Alan Moore.
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [Qemu-devel] [PATCH v5] virtio-pci: enable bus master for old guests
2014-09-11 18:42 ` Greg Kurz
@ 2014-09-14 10:44 ` Michael S. Tsirkin
0 siblings, 0 replies; 6+ messages in thread
From: Michael S. Tsirkin @ 2014-09-14 10:44 UTC (permalink / raw)
To: Greg Kurz
Cc: Jason Wang, Cedric Le Goater, qemu-devel, Anthony Liguori,
qemu-stable
On Thu, Sep 11, 2014 at 08:42:06PM +0200, Greg Kurz wrote:
> On Thu, 11 Sep 2014 21:20:03 +0300
> "Michael S. Tsirkin" <mst@redhat.com> wrote:
>
> > commit cc943c36faa192cd4b32af8fe5edb31894017d35
> > pci: Use bus master address space for delivering MSI/MSI-X messages
> > breaks virtio-net for rhel6.[56] x86 guests because they don't
> > enable bus mastering for virtio PCI devices. For the same reason,
> > rhel6.[56] ppc64 guests cannot boot on a virtio-blk disk anymore.
> >
> > Old guests forgot to enable bus mastering, enable it automatically on
> > DRIVER (guests use some devices before DRIVER_OK).
> >
> > Reported-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > ---
> > Sorry, v4 was broken - forgot to commit before git format-patch.
> > Here's the correct version.
> > Still not tested - will do next week.
> > Testing reports appreciated meanwhile.
> >
>
> Nice patch indeed ! :)
>
> Reviewed-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
> Tested-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
>
> Cc'ing qemu-stable as Michael said he would queue the initial
> bus master patch for 2.1.2.
In my opinion it's best to keep the initial patch off stable.
> > hw/virtio/virtio-pci.c | 10 ++++++++++
> > 1 file changed, 10 insertions(+)
> >
> > diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> > index ddb5da1..a827cd4 100644
> > --- a/hw/virtio/virtio-pci.c
> > +++ b/hw/virtio/virtio-pci.c
> > @@ -314,6 +314,16 @@ static void virtio_ioport_write(void *opaque, uint32_t addr, uint32_t val)
> > msix_unuse_all_vectors(&proxy->pci_dev);
> > }
> >
> > + /* Linux before 2.6.34 drives the device without enabling
> > + the PCI device bus master bit. Enable it automatically
> > + for the guest. This is a PCI spec violation but so is
> > + initiating DMA with bus master bit clear. */
> > + if (val == (VIRTIO_CONFIG_S_ACKNOWLEDGE | VIRTIO_CONFIG_S_DRIVER)) {
> > + pci_default_write_config(&proxy->pci_dev, PCI_COMMAND,
> > + proxy->pci_dev.config[PCI_COMMAND] |
> > + PCI_COMMAND_MASTER, 1);
> > + }
> > +
> > /* Linux before 2.6.34 sets the device as OK without enabling
> > the PCI device bus master bit. In this case we need to disable
> > some safety checks. */
>
>
>
> --
> Gregory Kurz kurzgreg@fr.ibm.com
> gkurz@linux.vnet.ibm.com
> Software Engineer @ IBM/Meiosys http://www.ibm.com
> Tel +33 (0)562 165 496
>
> "Anarchy is about taking complete responsibility for yourself."
> Alan Moore.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [Qemu-devel] [PATCH v5] virtio-pci: enable bus master for old guests
2014-09-11 18:20 [Qemu-devel] [PATCH v5] virtio-pci: enable bus master for old guests Michael S. Tsirkin
2014-09-11 18:42 ` Greg Kurz
@ 2014-09-15 9:48 ` Jason Wang
2014-09-15 9:59 ` Michael S. Tsirkin
1 sibling, 1 reply; 6+ messages in thread
From: Jason Wang @ 2014-09-15 9:48 UTC (permalink / raw)
To: Michael S. Tsirkin, qemu-devel; +Cc: Anthony Liguori
On 09/12/2014 02:20 AM, Michael S. Tsirkin wrote:
> commit cc943c36faa192cd4b32af8fe5edb31894017d35
> pci: Use bus master address space for delivering MSI/MSI-X messages
> breaks virtio-net for rhel6.[56] x86 guests because they don't
> enable bus mastering for virtio PCI devices. For the same reason,
> rhel6.[56] ppc64 guests cannot boot on a virtio-blk disk anymore.
>
> Old guests forgot to enable bus mastering, enable it automatically on
> DRIVER (guests use some devices before DRIVER_OK).
>
> Reported-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
> Sorry, v4 was broken - forgot to commit before git format-patch.
> Here's the correct version.
> Still not tested - will do next week.
> Testing reports appreciated meanwhile.
>
> hw/virtio/virtio-pci.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> index ddb5da1..a827cd4 100644
> --- a/hw/virtio/virtio-pci.c
> +++ b/hw/virtio/virtio-pci.c
> @@ -314,6 +314,16 @@ static void virtio_ioport_write(void *opaque, uint32_t addr, uint32_t val)
> msix_unuse_all_vectors(&proxy->pci_dev);
> }
>
> + /* Linux before 2.6.34 drives the device without enabling
> + the PCI device bus master bit. Enable it automatically
> + for the guest. This is a PCI spec violation but so is
> + initiating DMA with bus master bit clear. */
> + if (val == (VIRTIO_CONFIG_S_ACKNOWLEDGE | VIRTIO_CONFIG_S_DRIVER)) {
> + pci_default_write_config(&proxy->pci_dev, PCI_COMMAND,
> + proxy->pci_dev.config[PCI_COMMAND] |
> + PCI_COMMAND_MASTER, 1);
> + }
> +
> /* Linux before 2.6.34 sets the device as OK without enabling
> the PCI device bus master bit. In this case we need to disable
> some safety checks. */
So with this patch, we can also remove the detecting and handling of
VIRTIO_PCI_FLAG_BUS_MATER_BUG?
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [Qemu-devel] [PATCH v5] virtio-pci: enable bus master for old guests
2014-09-15 9:48 ` Jason Wang
@ 2014-09-15 9:59 ` Michael S. Tsirkin
2014-09-15 10:13 ` Amos Kong
0 siblings, 1 reply; 6+ messages in thread
From: Michael S. Tsirkin @ 2014-09-15 9:59 UTC (permalink / raw)
To: Jason Wang; +Cc: qemu-devel, Anthony Liguori
On Mon, Sep 15, 2014 at 05:48:17PM +0800, Jason Wang wrote:
> On 09/12/2014 02:20 AM, Michael S. Tsirkin wrote:
> > commit cc943c36faa192cd4b32af8fe5edb31894017d35
> > pci: Use bus master address space for delivering MSI/MSI-X messages
> > breaks virtio-net for rhel6.[56] x86 guests because they don't
> > enable bus mastering for virtio PCI devices. For the same reason,
> > rhel6.[56] ppc64 guests cannot boot on a virtio-blk disk anymore.
> >
> > Old guests forgot to enable bus mastering, enable it automatically on
> > DRIVER (guests use some devices before DRIVER_OK).
> >
> > Reported-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > ---
> > Sorry, v4 was broken - forgot to commit before git format-patch.
> > Here's the correct version.
> > Still not tested - will do next week.
> > Testing reports appreciated meanwhile.
> >
> > hw/virtio/virtio-pci.c | 10 ++++++++++
> > 1 file changed, 10 insertions(+)
> >
> > diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> > index ddb5da1..a827cd4 100644
> > --- a/hw/virtio/virtio-pci.c
> > +++ b/hw/virtio/virtio-pci.c
> > @@ -314,6 +314,16 @@ static void virtio_ioport_write(void *opaque, uint32_t addr, uint32_t val)
> > msix_unuse_all_vectors(&proxy->pci_dev);
> > }
> >
> > + /* Linux before 2.6.34 drives the device without enabling
> > + the PCI device bus master bit. Enable it automatically
> > + for the guest. This is a PCI spec violation but so is
> > + initiating DMA with bus master bit clear. */
> > + if (val == (VIRTIO_CONFIG_S_ACKNOWLEDGE | VIRTIO_CONFIG_S_DRIVER)) {
> > + pci_default_write_config(&proxy->pci_dev, PCI_COMMAND,
> > + proxy->pci_dev.config[PCI_COMMAND] |
> > + PCI_COMMAND_MASTER, 1);
> > + }
> > +
> > /* Linux before 2.6.34 sets the device as OK without enabling
> > the PCI device bus master bit. In this case we need to disable
> > some safety checks. */
>
> So with this patch, we can also remove the detecting and handling of
> VIRTIO_PCI_FLAG_BUS_MATER_BUG?
Yes - I sent a follow-up patch to do that.
--
MST
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [Qemu-devel] [PATCH v5] virtio-pci: enable bus master for old guests
2014-09-15 9:59 ` Michael S. Tsirkin
@ 2014-09-15 10:13 ` Amos Kong
0 siblings, 0 replies; 6+ messages in thread
From: Amos Kong @ 2014-09-15 10:13 UTC (permalink / raw)
To: Michael S. Tsirkin; +Cc: Jason Wang, qemu-devel, Anthony Liguori
On Mon, Sep 15, 2014 at 12:59:44PM +0300, Michael S. Tsirkin wrote:
> On Mon, Sep 15, 2014 at 05:48:17PM +0800, Jason Wang wrote:
> > On 09/12/2014 02:20 AM, Michael S. Tsirkin wrote:
> > > commit cc943c36faa192cd4b32af8fe5edb31894017d35
> > > pci: Use bus master address space for delivering MSI/MSI-X messages
> > > breaks virtio-net for rhel6.[56] x86 guests because they don't
> > > enable bus mastering for virtio PCI devices. For the same reason,
> > > rhel6.[56] ppc64 guests cannot boot on a virtio-blk disk anymore.
> > >
> > > Old guests forgot to enable bus mastering, enable it automatically on
> > > DRIVER (guests use some devices before DRIVER_OK).
> > >
> > > Reported-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
> > > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > > ---
> > > Sorry, v4 was broken - forgot to commit before git format-patch.
> > > Here's the correct version.
> > > Still not tested - will do next week.
> > > Testing reports appreciated meanwhile.
> > >
> > > hw/virtio/virtio-pci.c | 10 ++++++++++
> > > 1 file changed, 10 insertions(+)
> > >
> > > diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> > > index ddb5da1..a827cd4 100644
> > > --- a/hw/virtio/virtio-pci.c
> > > +++ b/hw/virtio/virtio-pci.c
> > > @@ -314,6 +314,16 @@ static void virtio_ioport_write(void *opaque, uint32_t addr, uint32_t val)
> > > msix_unuse_all_vectors(&proxy->pci_dev);
> > > }
> > >
> > > + /* Linux before 2.6.34 drives the device without enabling
> > > + the PCI device bus master bit. Enable it automatically
> > > + for the guest. This is a PCI spec violation but so is
> > > + initiating DMA with bus master bit clear. */
> > > + if (val == (VIRTIO_CONFIG_S_ACKNOWLEDGE | VIRTIO_CONFIG_S_DRIVER)) {
> > > + pci_default_write_config(&proxy->pci_dev, PCI_COMMAND,
> > > + proxy->pci_dev.config[PCI_COMMAND] |
> > > + PCI_COMMAND_MASTER, 1);
> > > + }
> > > +
> > > /* Linux before 2.6.34 sets the device as OK without enabling
> > > the PCI device bus master bit. In this case we need to disable
> > > some safety checks. */
> >
> > So with this patch, we can also remove the detecting and handling of
> > VIRTIO_PCI_FLAG_BUS_MATER_BUG?
>
> Yes - I sent a follow-up patch to do that.
I will check if this patch fixed this bug (it seems WIN8r2 doesn't set
BUS_MASTER bit correctly): https://bugzilla.redhat.com/show_bug.cgi?id=1090237
--
Amos.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2014-09-15 10:14 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
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2014-09-11 18:20 [Qemu-devel] [PATCH v5] virtio-pci: enable bus master for old guests Michael S. Tsirkin
2014-09-11 18:42 ` Greg Kurz
2014-09-14 10:44 ` Michael S. Tsirkin
2014-09-15 9:48 ` Jason Wang
2014-09-15 9:59 ` Michael S. Tsirkin
2014-09-15 10:13 ` Amos Kong
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