| Message ID | 1463364819-477-7-git-send-email-okaya@codeaurora.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Sinan, On 05/16/2016 04:13 AM, Sinan Kaya wrote: > The code was allowing platform devices to be used without a supporting > VFIO reset driver. The hardware can be left in some inconsistent state > after a guest machine abort. > > The reset driver will put the hardware back to safe state and disable > interrupts before returning the control back to the host machine. The commit message should describe the new module option. You should also describe this is not just a matter of having a reset function implemented & found somewhere but also a matter of having the reset call to succeed. A reset failure now induce a failure on the first open(). Shouldn't we handle this failure in a separate patch to make this clearer? > > Signed-off-by: Sinan Kaya <okaya@codeaurora.org> > --- > drivers/vfio/platform/vfio_amba.c | 5 +++++ > drivers/vfio/platform/vfio_platform.c | 5 +++++ > drivers/vfio/platform/vfio_platform_common.c | 18 ++++++++++++++---- > drivers/vfio/platform/vfio_platform_private.h | 1 + > 4 files changed, 25 insertions(+), 4 deletions(-) > > diff --git a/drivers/vfio/platform/vfio_amba.c b/drivers/vfio/platform/vfio_amba.c > index a66479b..7585902 100644 > --- a/drivers/vfio/platform/vfio_amba.c > +++ b/drivers/vfio/platform/vfio_amba.c > @@ -23,6 +23,10 @@ > #define DRIVER_AUTHOR "Antonios Motakis <a.motakis@virtualopensystems.com>" > #define DRIVER_DESC "VFIO for AMBA devices - User Level meta-driver" > > +static bool reset_required = true; > +module_param(reset_required, bool, 0644); > +MODULE_PARM_DESC(reset_required, "override reset requirement (default: 1)"); > + > /* probing devices from the AMBA bus */ > > static struct resource *get_amba_resource(struct vfio_platform_device *vdev, > @@ -68,6 +72,7 @@ static int vfio_amba_probe(struct amba_device *adev, const struct amba_id *id) > vdev->get_resource = get_amba_resource; > vdev->get_irq = get_amba_irq; > vdev->parent_module = THIS_MODULE; > + vdev->reset_required = reset_required; > > ret = vfio_platform_probe_common(vdev, &adev->dev); > if (ret) { > diff --git a/drivers/vfio/platform/vfio_platform.c b/drivers/vfio/platform/vfio_platform.c > index b1cc3a7..ef89146 100644 > --- a/drivers/vfio/platform/vfio_platform.c > +++ b/drivers/vfio/platform/vfio_platform.c > @@ -23,6 +23,10 @@ > #define DRIVER_AUTHOR "Antonios Motakis <a.motakis@virtualopensystems.com>" > #define DRIVER_DESC "VFIO for platform devices - User Level meta-driver" > > +static bool reset_required = true; > +module_param(reset_required, bool, 0644); > +MODULE_PARM_DESC(reset_required, "override reset requirement (default: 1)"); > + > /* probing devices from the linux platform bus */ > > static struct resource *get_platform_resource(struct vfio_platform_device *vdev, > @@ -66,6 +70,7 @@ static int vfio_platform_probe(struct platform_device *pdev) > vdev->get_resource = get_platform_resource; > vdev->get_irq = get_platform_irq; > vdev->parent_module = THIS_MODULE; > + vdev->reset_required = reset_required; > > ret = vfio_platform_probe_common(vdev, &pdev->dev); > if (ret) > diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c > index 095d5b7..89fb18f 100644 > --- a/drivers/vfio/platform/vfio_platform_common.c > +++ b/drivers/vfio/platform/vfio_platform_common.c > @@ -121,10 +121,10 @@ static bool vfio_platform_has_reset(struct vfio_platform_device *vdev) > return vdev->of_reset ? true : false; > } > > -static void vfio_platform_get_reset(struct vfio_platform_device *vdev) > +static int vfio_platform_get_reset(struct vfio_platform_device *vdev) > { > if (vdev->acpihid) > - return; > + return vfio_platform_acpi_has_reset(vdev) ? 0 : -EINVAL; -ENOENT instead? > > vdev->of_reset = vfio_platform_lookup_reset(vdev->compat, > &vdev->reset_module); > @@ -133,6 +133,8 @@ static void vfio_platform_get_reset(struct vfio_platform_device *vdev) > vdev->of_reset = vfio_platform_lookup_reset(vdev->compat, > &vdev->reset_module); > } > + > + return vdev->of_reset ? 0 : -EINVAL; same > } > > static void vfio_platform_put_reset(struct vfio_platform_device *vdev) > @@ -263,7 +265,9 @@ static int vfio_platform_open(void *device_data) > if (ret) > goto err_irq; > > - vfio_platform_call_reset(vdev); > + ret = vfio_platform_call_reset(vdev); > + if (ret && vdev->reset_required) > + goto err_irq; what do we do at release time in case the reset fails. You did not change anything. Shouldn't we at least emit a warning to the user if the reset becomes mandated (separate patch as evoked above)? Thanks Eric > } > > vdev->refcnt++; > @@ -669,7 +673,13 @@ int vfio_platform_probe_common(struct vfio_platform_device *vdev, > return ret; > } > > - vfio_platform_get_reset(vdev); > + ret = vfio_platform_get_reset(vdev); > + if (ret && vdev->reset_required) { > + pr_err("vfio: no reset function found for device %s\n", > + vdev->name); > + iommu_group_put(group); > + return ret; > + } > > mutex_init(&vdev->igate); > > diff --git a/drivers/vfio/platform/vfio_platform_private.h b/drivers/vfio/platform/vfio_platform_private.h > index ba9e4f8..68fbc00 100644 > --- a/drivers/vfio/platform/vfio_platform_private.h > +++ b/drivers/vfio/platform/vfio_platform_private.h > @@ -50,6 +50,7 @@ struct vfio_platform_region { > }; > > struct vfio_platform_device { > + bool reset_required; > struct vfio_platform_region *regions; > u32 num_regions; > struct vfio_platform_irq *irqs; >
diff --git a/drivers/vfio/platform/vfio_amba.c b/drivers/vfio/platform/vfio_amba.c index a66479b..7585902 100644 --- a/drivers/vfio/platform/vfio_amba.c +++ b/drivers/vfio/platform/vfio_amba.c @@ -23,6 +23,10 @@ #define DRIVER_AUTHOR "Antonios Motakis <a.motakis@virtualopensystems.com>" #define DRIVER_DESC "VFIO for AMBA devices - User Level meta-driver" +static bool reset_required = true; +module_param(reset_required, bool, 0644); +MODULE_PARM_DESC(reset_required, "override reset requirement (default: 1)"); + /* probing devices from the AMBA bus */ static struct resource *get_amba_resource(struct vfio_platform_device *vdev, @@ -68,6 +72,7 @@ static int vfio_amba_probe(struct amba_device *adev, const struct amba_id *id) vdev->get_resource = get_amba_resource; vdev->get_irq = get_amba_irq; vdev->parent_module = THIS_MODULE; + vdev->reset_required = reset_required; ret = vfio_platform_probe_common(vdev, &adev->dev); if (ret) { diff --git a/drivers/vfio/platform/vfio_platform.c b/drivers/vfio/platform/vfio_platform.c index b1cc3a7..ef89146 100644 --- a/drivers/vfio/platform/vfio_platform.c +++ b/drivers/vfio/platform/vfio_platform.c @@ -23,6 +23,10 @@ #define DRIVER_AUTHOR "Antonios Motakis <a.motakis@virtualopensystems.com>" #define DRIVER_DESC "VFIO for platform devices - User Level meta-driver" +static bool reset_required = true; +module_param(reset_required, bool, 0644); +MODULE_PARM_DESC(reset_required, "override reset requirement (default: 1)"); + /* probing devices from the linux platform bus */ static struct resource *get_platform_resource(struct vfio_platform_device *vdev, @@ -66,6 +70,7 @@ static int vfio_platform_probe(struct platform_device *pdev) vdev->get_resource = get_platform_resource; vdev->get_irq = get_platform_irq; vdev->parent_module = THIS_MODULE; + vdev->reset_required = reset_required; ret = vfio_platform_probe_common(vdev, &pdev->dev); if (ret) diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c index 095d5b7..89fb18f 100644 --- a/drivers/vfio/platform/vfio_platform_common.c +++ b/drivers/vfio/platform/vfio_platform_common.c @@ -121,10 +121,10 @@ static bool vfio_platform_has_reset(struct vfio_platform_device *vdev) return vdev->of_reset ? true : false; } -static void vfio_platform_get_reset(struct vfio_platform_device *vdev) +static int vfio_platform_get_reset(struct vfio_platform_device *vdev) { if (vdev->acpihid) - return; + return vfio_platform_acpi_has_reset(vdev) ? 0 : -EINVAL; vdev->of_reset = vfio_platform_lookup_reset(vdev->compat, &vdev->reset_module); @@ -133,6 +133,8 @@ static void vfio_platform_get_reset(struct vfio_platform_device *vdev) vdev->of_reset = vfio_platform_lookup_reset(vdev->compat, &vdev->reset_module); } + + return vdev->of_reset ? 0 : -EINVAL; } static void vfio_platform_put_reset(struct vfio_platform_device *vdev) @@ -263,7 +265,9 @@ static int vfio_platform_open(void *device_data) if (ret) goto err_irq; - vfio_platform_call_reset(vdev); + ret = vfio_platform_call_reset(vdev); + if (ret && vdev->reset_required) + goto err_irq; } vdev->refcnt++; @@ -669,7 +673,13 @@ int vfio_platform_probe_common(struct vfio_platform_device *vdev, return ret; } - vfio_platform_get_reset(vdev); + ret = vfio_platform_get_reset(vdev); + if (ret && vdev->reset_required) { + pr_err("vfio: no reset function found for device %s\n", + vdev->name); + iommu_group_put(group); + return ret; + } mutex_init(&vdev->igate); diff --git a/drivers/vfio/platform/vfio_platform_private.h b/drivers/vfio/platform/vfio_platform_private.h index ba9e4f8..68fbc00 100644 --- a/drivers/vfio/platform/vfio_platform_private.h +++ b/drivers/vfio/platform/vfio_platform_private.h @@ -50,6 +50,7 @@ struct vfio_platform_region { }; struct vfio_platform_device { + bool reset_required; struct vfio_platform_region *regions; u32 num_regions; struct vfio_platform_irq *irqs;
The code was allowing platform devices to be used without a supporting VFIO reset driver. The hardware can be left in some inconsistent state after a guest machine abort. The reset driver will put the hardware back to safe state and disable interrupts before returning the control back to the host machine. Signed-off-by: Sinan Kaya <okaya@codeaurora.org> --- drivers/vfio/platform/vfio_amba.c | 5 +++++ drivers/vfio/platform/vfio_platform.c | 5 +++++ drivers/vfio/platform/vfio_platform_common.c | 18 ++++++++++++++---- drivers/vfio/platform/vfio_platform_private.h | 1 + 4 files changed, 25 insertions(+), 4 deletions(-)