Re: [PATCH v2] vfio/pci: Mask buggy SR-IOV VF INTx support
On Thu, 20 Sep 2018 22:53:04 -0700
Christoph Hellwig wrote:
> > +/*
> > + * Nag about hardware bugs, hopefully to have vendors fix them, but at
> > least
> > + * to collect a list of dependencies for the VF INTx pin quirk below.
> > + */
> > +static const struct pci_device_id known_bogus_vf_intx_pin[] = {
> > + { PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x270c) },
> > + {}
> > +};
>
> What device is this? We don't have the device ID anywhere, so I guess
> it is something match by the class code?
Intel hasn't disclosed the device yet, so we don't know that there's an
existing driver at all for it. Thanks,
Alex
Re: [PATCH v2] vfio/pci: Mask buggy SR-IOV VF INTx support
On Thu, 20 Sep 2018 22:53:04 -0700
Christoph Hellwig wrote:
> > +/*
> > + * Nag about hardware bugs, hopefully to have vendors fix them, but at
> > least
> > + * to collect a list of dependencies for the VF INTx pin quirk below.
> > + */
> > +static const struct pci_device_id known_bogus_vf_intx_pin[] = {
> > + { PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x270c) },
> > + {}
> > +};
>
> What device is this? We don't have the device ID anywhere, so I guess
> it is something match by the class code?
Intel hasn't disclosed the device yet, so we don't know that there's an
existing driver at all for it. Thanks,
Alex
Re: [PATCH v2] vfio/pci: Mask buggy SR-IOV VF INTx support
> +/*
> + * Nag about hardware bugs, hopefully to have vendors fix them, but at least
> + * to collect a list of dependencies for the VF INTx pin quirk below.
> + */
> +static const struct pci_device_id known_bogus_vf_intx_pin[] = {
> + { PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x270c) },
> + {}
> +};
What device is this? We don't have the device ID anywhere, so I guess
it is something match by the class code?
Re: [PATCH v2] vfio/pci: Mask buggy SR-IOV VF INTx support
> +/*
> + * Nag about hardware bugs, hopefully to have vendors fix them, but at least
> + * to collect a list of dependencies for the VF INTx pin quirk below.
> + */
> +static const struct pci_device_id known_bogus_vf_intx_pin[] = {
> + { PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x270c) },
> + {}
> +};
What device is this? We don't have the device ID anywhere, so I guess
it is something match by the class code?
Re: [PATCH v2] vfio/pci: Mask buggy SR-IOV VF INTx support
On Thu, Sep 20, 2018 at 03:56:41PM -0700, Eads, Gage wrote: Thanks Gage. > Hi Alex, > > > > Known devices with this issue: 8086:270c > > > > Signed-off-by: Alex Williamson > > Tested-by: Gage Eads Reviewed-by: Ashok Raj
Re: [PATCH v2] vfio/pci: Mask buggy SR-IOV VF INTx support
On Thu, Sep 20, 2018 at 03:56:41PM -0700, Eads, Gage wrote: Thanks Gage. > Hi Alex, > > > > Known devices with this issue: 8086:270c > > > > Signed-off-by: Alex Williamson > > Tested-by: Gage Eads Reviewed-by: Ashok Raj
RE: [PATCH v2] vfio/pci: Mask buggy SR-IOV VF INTx support
Hi Alex, This patch passes testing with the 0x270c device, and (when I comment out its known_bogus_vf_intx_pin entry) the warning is triggered by QEMU. Thanks, Gage > -Original Message- > From: Alex Williamson [mailto:alex.william...@redhat.com] > Sent: Thursday, September 20, 2018 3:03 PM > To: k...@vger.kernel.org; Raj, Ashok ; Eads, Gage > > Cc: gno...@lxorguk.ukuu.org.uk; linux-kernel@vger.kernel.org > Subject: [PATCH v2] vfio/pci: Mask buggy SR-IOV VF INTx support > > The SR-IOV spec requires that VFs must report zero for the INTx pin register > as > VFs are precluded from INTx support. It's much easier for the host kernel to > understand whether a device is a VF and therefore whether a non-zero pin > register value is bogus than it is to do the same in userspace. Override the > INTx > count for such devices and virtualize the pin register to provide a > consistent view > of the device to the user. > > As this is clearly a spec violation, warn about it to support hardware > validation, > but also provide a known whitelist as it doesn't do much good to continue > complaining if the hardware vendor doesn't plan to fix it. > > Known devices with this issue: 8086:270c > > Signed-off-by: Alex Williamson Tested-by: Gage Eads
RE: [PATCH v2] vfio/pci: Mask buggy SR-IOV VF INTx support
Hi Alex, This patch passes testing with the 0x270c device, and (when I comment out its known_bogus_vf_intx_pin entry) the warning is triggered by QEMU. Thanks, Gage > -Original Message- > From: Alex Williamson [mailto:alex.william...@redhat.com] > Sent: Thursday, September 20, 2018 3:03 PM > To: k...@vger.kernel.org; Raj, Ashok ; Eads, Gage > > Cc: gno...@lxorguk.ukuu.org.uk; linux-kernel@vger.kernel.org > Subject: [PATCH v2] vfio/pci: Mask buggy SR-IOV VF INTx support > > The SR-IOV spec requires that VFs must report zero for the INTx pin register > as > VFs are precluded from INTx support. It's much easier for the host kernel to > understand whether a device is a VF and therefore whether a non-zero pin > register value is bogus than it is to do the same in userspace. Override the > INTx > count for such devices and virtualize the pin register to provide a > consistent view > of the device to the user. > > As this is clearly a spec violation, warn about it to support hardware > validation, > but also provide a known whitelist as it doesn't do much good to continue > complaining if the hardware vendor doesn't plan to fix it. > > Known devices with this issue: 8086:270c > > Signed-off-by: Alex Williamson Tested-by: Gage Eads
[PATCH v2] vfio/pci: Mask buggy SR-IOV VF INTx support
The SR-IOV spec requires that VFs must report zero for the INTx pin
register as VFs are precluded from INTx support. It's much easier for
the host kernel to understand whether a device is a VF and therefore
whether a non-zero pin register value is bogus than it is to do the
same in userspace. Override the INTx count for such devices and
virtualize the pin register to provide a consistent view of the device
to the user.
As this is clearly a spec violation, warn about it to support hardware
validation, but also provide a known whitelist as it doesn't do much
good to continue complaining if the hardware vendor doesn't plan to
fix it.
Known devices with this issue: 8086:270c
Signed-off-by: Alex Williamson
---
v2:
Moved the warning to vfio_config_init(), so it triggers on device open and
no longer depends on the user looking at the number of INTx IRQs available.
Also changed from dev_warn_once() to pci_warn() as this new location seems
sufficiently low frequency to nag repeatedly. Please test. Thanks,
Alex
drivers/vfio/pci/vfio_pci.c|8 ++--
drivers/vfio/pci/vfio_pci_config.c | 27 +++
2 files changed, 33 insertions(+), 2 deletions(-)
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index cddb453a1ba5..50cdedfca9fe 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -434,10 +434,14 @@ static int vfio_pci_get_irq_count(struct vfio_pci_device
*vdev, int irq_type)
{
if (irq_type == VFIO_PCI_INTX_IRQ_INDEX) {
u8 pin;
+
+ if (!IS_ENABLED(CONFIG_VFIO_PCI_INTX) ||
+ vdev->nointx || vdev->pdev->is_virtfn)
+ return 0;
+
pci_read_config_byte(vdev->pdev, PCI_INTERRUPT_PIN, );
- if (IS_ENABLED(CONFIG_VFIO_PCI_INTX) && !vdev->nointx && pin)
- return 1;
+ return pin ? 1 : 0;
} else if (irq_type == VFIO_PCI_MSI_IRQ_INDEX) {
u8 pos;
u16 flags;
diff --git a/drivers/vfio/pci/vfio_pci_config.c
b/drivers/vfio/pci/vfio_pci_config.c
index 62023b4a373b..423ea1f98441 100644
--- a/drivers/vfio/pci/vfio_pci_config.c
+++ b/drivers/vfio/pci/vfio_pci_config.c
@@ -1611,6 +1611,15 @@ static int vfio_ecap_init(struct vfio_pci_device *vdev)
return 0;
}
+/*
+ * Nag about hardware bugs, hopefully to have vendors fix them, but at least
+ * to collect a list of dependencies for the VF INTx pin quirk below.
+ */
+static const struct pci_device_id known_bogus_vf_intx_pin[] = {
+ { PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x270c) },
+ {}
+};
+
/*
* For each device we allocate a pci_config_map that indicates the
* capability occupying each dword and thus the struct perm_bits we
@@ -1676,6 +1685,24 @@ int vfio_config_init(struct vfio_pci_device *vdev)
if (pdev->is_virtfn) {
*(__le16 *)[PCI_VENDOR_ID] = cpu_to_le16(pdev->vendor);
*(__le16 *)[PCI_DEVICE_ID] = cpu_to_le16(pdev->device);
+
+ /*
+* Per SR-IOV spec rev 1.1, 3.4.1.18 the interrupt pin register
+* does not apply to VFs and VFs must implement this register
+* as read-only with value zero. Userspace is not readily able
+* to identify whether a device is a VF and thus that the pin
+* definition on the device is bogus should it violate this
+* requirement. We already virtualize the pin register for
+* other purposes, so we simply need to replace the bogus value
+* and consider VFs when we determine INTx IRQ count.
+*/
+ if (vconfig[PCI_INTERRUPT_PIN] &&
+ !pci_match_id(known_bogus_vf_intx_pin, pdev))
+ pci_warn(pdev,
+"Hardware bug: VF reports bogus INTx pin %d\n",
+vconfig[PCI_INTERRUPT_PIN]);
+
+ vconfig[PCI_INTERRUPT_PIN] = 0; /* Gratuitous for good VFs */
}
if (!IS_ENABLED(CONFIG_VFIO_PCI_INTX) || vdev->nointx)
[PATCH v2] vfio/pci: Mask buggy SR-IOV VF INTx support
The SR-IOV spec requires that VFs must report zero for the INTx pin
register as VFs are precluded from INTx support. It's much easier for
the host kernel to understand whether a device is a VF and therefore
whether a non-zero pin register value is bogus than it is to do the
same in userspace. Override the INTx count for such devices and
virtualize the pin register to provide a consistent view of the device
to the user.
As this is clearly a spec violation, warn about it to support hardware
validation, but also provide a known whitelist as it doesn't do much
good to continue complaining if the hardware vendor doesn't plan to
fix it.
Known devices with this issue: 8086:270c
Signed-off-by: Alex Williamson
---
v2:
Moved the warning to vfio_config_init(), so it triggers on device open and
no longer depends on the user looking at the number of INTx IRQs available.
Also changed from dev_warn_once() to pci_warn() as this new location seems
sufficiently low frequency to nag repeatedly. Please test. Thanks,
Alex
drivers/vfio/pci/vfio_pci.c|8 ++--
drivers/vfio/pci/vfio_pci_config.c | 27 +++
2 files changed, 33 insertions(+), 2 deletions(-)
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index cddb453a1ba5..50cdedfca9fe 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -434,10 +434,14 @@ static int vfio_pci_get_irq_count(struct vfio_pci_device
*vdev, int irq_type)
{
if (irq_type == VFIO_PCI_INTX_IRQ_INDEX) {
u8 pin;
+
+ if (!IS_ENABLED(CONFIG_VFIO_PCI_INTX) ||
+ vdev->nointx || vdev->pdev->is_virtfn)
+ return 0;
+
pci_read_config_byte(vdev->pdev, PCI_INTERRUPT_PIN, );
- if (IS_ENABLED(CONFIG_VFIO_PCI_INTX) && !vdev->nointx && pin)
- return 1;
+ return pin ? 1 : 0;
} else if (irq_type == VFIO_PCI_MSI_IRQ_INDEX) {
u8 pos;
u16 flags;
diff --git a/drivers/vfio/pci/vfio_pci_config.c
b/drivers/vfio/pci/vfio_pci_config.c
index 62023b4a373b..423ea1f98441 100644
--- a/drivers/vfio/pci/vfio_pci_config.c
+++ b/drivers/vfio/pci/vfio_pci_config.c
@@ -1611,6 +1611,15 @@ static int vfio_ecap_init(struct vfio_pci_device *vdev)
return 0;
}
+/*
+ * Nag about hardware bugs, hopefully to have vendors fix them, but at least
+ * to collect a list of dependencies for the VF INTx pin quirk below.
+ */
+static const struct pci_device_id known_bogus_vf_intx_pin[] = {
+ { PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x270c) },
+ {}
+};
+
/*
* For each device we allocate a pci_config_map that indicates the
* capability occupying each dword and thus the struct perm_bits we
@@ -1676,6 +1685,24 @@ int vfio_config_init(struct vfio_pci_device *vdev)
if (pdev->is_virtfn) {
*(__le16 *)[PCI_VENDOR_ID] = cpu_to_le16(pdev->vendor);
*(__le16 *)[PCI_DEVICE_ID] = cpu_to_le16(pdev->device);
+
+ /*
+* Per SR-IOV spec rev 1.1, 3.4.1.18 the interrupt pin register
+* does not apply to VFs and VFs must implement this register
+* as read-only with value zero. Userspace is not readily able
+* to identify whether a device is a VF and thus that the pin
+* definition on the device is bogus should it violate this
+* requirement. We already virtualize the pin register for
+* other purposes, so we simply need to replace the bogus value
+* and consider VFs when we determine INTx IRQ count.
+*/
+ if (vconfig[PCI_INTERRUPT_PIN] &&
+ !pci_match_id(known_bogus_vf_intx_pin, pdev))
+ pci_warn(pdev,
+"Hardware bug: VF reports bogus INTx pin %d\n",
+vconfig[PCI_INTERRUPT_PIN]);
+
+ vconfig[PCI_INTERRUPT_PIN] = 0; /* Gratuitous for good VFs */
}
if (!IS_ENABLED(CONFIG_VFIO_PCI_INTX) || vdev->nointx)
