Hi Yi,
On Thu, Sep 10, 2020 at 4:13 PM Liu Yi L <[email protected]> wrote: > > This patch is added as instead of returning a boolean for DOMAIN_ATTR_NESTING, > iommu_domain_get_attr() should return an iommu_nesting_info handle. For > now, return an empty nesting info struct for now as true nesting is not > yet supported by the SMMUs. > > Cc: Will Deacon <[email protected]> > Cc: Robin Murphy <[email protected]> > Cc: Eric Auger <[email protected]> > Cc: Jean-Philippe Brucker <[email protected]> > Suggested-by: Jean-Philippe Brucker <[email protected]> > Signed-off-by: Liu Yi L <[email protected]> > Signed-off-by: Jacob Pan <[email protected]> > Reviewed-by: Eric Auger <[email protected]> > --- > v5 -> v6: > *) add review-by from Eric Auger. > > v4 -> v5: > *) address comments from Eric Auger. > --- > drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 29 > +++++++++++++++++++++++++++-- > drivers/iommu/arm/arm-smmu/arm-smmu.c | 29 > +++++++++++++++++++++++++++-- > 2 files changed, 54 insertions(+), 4 deletions(-) > > diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c > b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c > index 7196207..016e2e5 100644 > --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c > +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c > @@ -3019,6 +3019,32 @@ static struct iommu_group > *arm_smmu_device_group(struct device *dev) > return group; > } > > +static int arm_smmu_domain_nesting_info(struct arm_smmu_domain *smmu_domain, > + void *data) > +{ > + struct iommu_nesting_info *info = (struct iommu_nesting_info *)data; > + unsigned int size; > + > + if (!info || smmu_domain->stage != ARM_SMMU_DOMAIN_NESTED) > + return -ENODEV; > + > + size = sizeof(struct iommu_nesting_info); > + > + /* > + * if provided buffer size is smaller than expected, should > + * return 0 and also the expected buffer size to caller. > + */ > + if (info->argsz < size) { > + info->argsz = size; > + return 0; > + } > + > + /* report an empty iommu_nesting_info for now */ > + memset(info, 0x0, size); > + info->argsz = size; > + return 0; > +} > + > static int arm_smmu_domain_get_attr(struct iommu_domain *domain, > enum iommu_attr attr, void *data) > { > @@ -3028,8 +3054,7 @@ static int arm_smmu_domain_get_attr(struct iommu_domain > *domain, > case IOMMU_DOMAIN_UNMANAGED: > switch (attr) { > case DOMAIN_ATTR_NESTING: > - *(int *)data = (smmu_domain->stage == > ARM_SMMU_DOMAIN_NESTED); > - return 0; > + return arm_smmu_domain_nesting_info(smmu_domain, > data); Thanks for the patch. This would unnecessarily overflow 'data' for any caller that's expecting only an int data. Dump from one such issue that I was seeing when testing this change along with local kvmtool changes is pasted below [1]. I could get around with the issue by adding another (iommu_attr) - DOMAIN_ATTR_NESTING_INFO that returns (iommu_nesting_info). Thanks & regards Vivek [1]-------------- [ 811.756516] vfio-pci 0000:08:00.1: vfio_ecap_init: hiding ecap 0x1b@0x108 [ 811.756516] Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: vfio_pci_open+0x644/0x648 [ 811.756516] CPU: 0 PID: 175 Comm: lkvm-cleanup-ne Not tainted 5.10.0-rc5-00096-gf015061e14cf #43 [ 811.756516] Call trace: [ 811.756516] dump_backtrace+0x0/0x1b0 [ 811.756516] show_stack+0x18/0x68 [ 811.756516] dump_stack+0xd8/0x134 [ 811.756516] panic+0x174/0x33c [ 811.756516] __stack_chk_fail+0x3c/0x40 [ 811.756516] vfio_pci_open+0x644/0x648 [ 811.756516] vfio_group_fops_unl_ioctl+0x4bc/0x648 [ 811.756516] 0x0 [ 811.756516] SMP: stopping secondary CPUs [ 811.756597] Kernel Offset: disabled [ 811.756597] CPU features: 0x0040006,6a00aa38 [ 811.756602] Memory Limit: none [ 811.768497] ---[ end Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: vfio_pci_open+0x644/0x648 ] ------------- _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
