Re: [PATCH v11 08/13] vfio/pci: Add framework for custom interrupt indices

Auger Eric
2020-11-24T08:36:34Z

Hi Shameer, Qubingbing
On 11/23/20 1:51 PM, Shameerali Kolothum Thodi wrote:
> Hi Eric,
>
>> -----Original Message-----
>> From: Eric Auger [mailto:eric.auger@redhat.com]
>> Sent: 16 November 2020 11:00
>> To: eric.auger.pro@gmail.com; eric.auger@redhat.com;
>> iommu@lists.linux-foundation.org; linux-kernel@vger.kernel.org;
>> kvm@vger.kernel.org; kvmarm@lists.cs.columbia.edu; will@kernel.org;
>> joro@8bytes.org; maz@kernel.org; robin.murphy@arm.com;
>> alex.williamson@redhat.com
>> Cc: jean-philippe@linaro.org; zhangfei.gao@linaro.org;
>> zhangfei.gao@gmail.com; vivek.gautam@arm.com; Shameerali Kolothum
>> Thodi <shameerali.kolothum.thodi@huawei.com>;
>> jacob.jun.pan@linux.intel.com; yi.l.liu@intel.com; tn@semihalf.com;
>> nicoleotsuka@gmail.com; yuzenghui <yuzenghui@huawei.com>
>> Subject: [PATCH v11 08/13] vfio/pci: Add framework for custom interrupt
>> indices
>>
>> Implement IRQ capability chain infrastructure. All interrupt
>> indexes beyond VFIO_PCI_NUM_IRQS are handled as extended
>> interrupts. They are registered with a specific type/subtype
>> and supported flags.
>>
>> Signed-off-by: Eric Auger <eric.auger@redhat.com>
>> ---
>> drivers/vfio/pci/vfio_pci.c | 99 +++++++++++++++++++++++------
>> drivers/vfio/pci/vfio_pci_intrs.c | 62 ++++++++++++++++++
>> drivers/vfio/pci/vfio_pci_private.h | 14 ++++
>> 3 files changed, 157 insertions(+), 18 deletions(-)
>>
>> diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
>> index 2a6cc1a87323..93e03a4a5f32 100644
>> --- a/drivers/vfio/pci/vfio_pci.c
>> +++ b/drivers/vfio/pci/vfio_pci.c
>> @@ -608,6 +608,14 @@ static void vfio_pci_disable(struct vfio_pci_device
>> *vdev)
>>
>> WARN_ON(iommu_unregister_device_fault_handler(&vdev->pdev->dev));
>>
>> + for (i = 0; i < vdev->num_ext_irqs; i++)
>> + vfio_pci_set_irqs_ioctl(vdev, VFIO_IRQ_SET_DATA_NONE |
>> + VFIO_IRQ_SET_ACTION_TRIGGER,
>> + VFIO_PCI_NUM_IRQS + i, 0, 0, NULL);
>> + vdev->num_ext_irqs = 0;
>> + kfree(vdev->ext_irqs);
>> + vdev->ext_irqs = NULL;
>> +
>> /* Device closed, don't need mutex here */
>> list_for_each_entry_safe(ioeventfd, ioeventfd_tmp,
>> &vdev->ioeventfds_list, next) {
>> @@ -823,6 +831,9 @@ static int vfio_pci_get_irq_count(struct vfio_pci_device
>> *vdev, int irq_type)
>> return 1;
>> } else if (irq_type == VFIO_PCI_REQ_IRQ_INDEX) {
>> return 1;
>> + } else if (irq_type >= VFIO_PCI_NUM_IRQS &&
>> + irq_type < VFIO_PCI_NUM_IRQS + vdev->num_ext_irqs) {
>> + return 1;
>> }
>>
>> return 0;
>> @@ -1008,7 +1019,7 @@ static long vfio_pci_ioctl(void *device_data,
>> info.flags |= VFIO_DEVICE_FLAGS_RESET;
>>
>> info.num_regions = VFIO_PCI_NUM_REGIONS + vdev->num_regions;
>> - info.num_irqs = VFIO_PCI_NUM_IRQS;
>> + info.num_irqs = VFIO_PCI_NUM_IRQS + vdev->num_ext_irqs;
>>
>> if (IS_ENABLED(CONFIG_VFIO_PCI_ZDEV)) {
>> int ret = vfio_pci_info_zdev_add_caps(vdev, &caps);
>> @@ -1187,36 +1198,87 @@ static long vfio_pci_ioctl(void *device_data,
>>
>> } else if (cmd == VFIO_DEVICE_GET_IRQ_INFO) {
>> struct vfio_irq_info info;
>> + struct vfio_info_cap caps = { .buf = NULL, .size = 0 };
>> + unsigned long capsz;
>>
>> minsz = offsetofend(struct vfio_irq_info, count);
>>
>> + /* For backward compatibility, cannot require this */
>> + capsz = offsetofend(struct vfio_irq_info, cap_offset);
>> +
>> if (copy_from_user(&info, (void __user *)arg, minsz))
>> return -EFAULT;
>>
>> - if (info.argsz < minsz || info.index >= VFIO_PCI_NUM_IRQS)
>> + if (info.argsz < minsz ||
>> + info.index >= VFIO_PCI_NUM_IRQS + vdev->num_ext_irqs)
>> return -EINVAL;
>>
>> - switch (info.index) {
>> - case VFIO_PCI_INTX_IRQ_INDEX ... VFIO_PCI_MSIX_IRQ_INDEX:
>> - case VFIO_PCI_REQ_IRQ_INDEX:
>> - break;
>> - case VFIO_PCI_ERR_IRQ_INDEX:
>> - if (pci_is_pcie(vdev->pdev))
>> - break;
>> - fallthrough;
>> - default:
>> - return -EINVAL;
>> - }
>> + if (info.argsz >= capsz)
>> + minsz = capsz;
>>
>> info.flags = VFIO_IRQ_INFO_EVENTFD;
>>
>> - info.count = vfio_pci_get_irq_count(vdev, info.index);
>> -
>> - if (info.index == VFIO_PCI_INTX_IRQ_INDEX)
>> + switch (info.index) {
>> + case VFIO_PCI_INTX_IRQ_INDEX:
>> info.flags |= (VFIO_IRQ_INFO_MASKABLE |
>> VFIO_IRQ_INFO_AUTOMASKED);
>> - else
>> + break;
>> + case VFIO_PCI_MSI_IRQ_INDEX ... VFIO_PCI_MSIX_IRQ_INDEX:
>> + case VFIO_PCI_REQ_IRQ_INDEX:
>> info.flags |= VFIO_IRQ_INFO_NORESIZE;
>> + break;
>> + case VFIO_PCI_ERR_IRQ_INDEX:
>> + info.flags |= VFIO_IRQ_INFO_NORESIZE;
>> + if (!pci_is_pcie(vdev->pdev))
>> + return -EINVAL;
>> + break;
>> + default:
>> + {
>> + struct vfio_irq_info_cap_type cap_type = {
>> + .header.id = VFIO_IRQ_INFO_CAP_TYPE,
>> + .header.version = 1 };
>> + int ret, i;
>> +
>> + if (info.index >= VFIO_PCI_NUM_IRQS +
>> + vdev->num_ext_irqs)
>> + return -EINVAL;
>> + info.index = array_index_nospec(info.index,
>> + VFIO_PCI_NUM_IRQS +
>> + vdev->num_ext_irqs);
>> + i = info.index - VFIO_PCI_NUM_IRQS;
>> +
>> + info.flags = vdev->ext_irqs[i].flags;
>> + cap_type.type = vdev->ext_irqs[i].type;
>> + cap_type.subtype = vdev->ext_irqs[i].subtype;
>> +
>> + ret = vfio_info_add_capability(&caps,
>> + &cap_type.header,
>> + sizeof(cap_type));
>> + if (ret)
>> + return ret;
>> + }
>> + }
>> +
>> + info.count = vfio_pci_get_irq_count(vdev, info.index);
>> +
>> + if (caps.size) {
>> + info.flags |= VFIO_IRQ_INFO_FLAG_CAPS;
>> + if (info.argsz < sizeof(info) + caps.size) {
>> + info.argsz = sizeof(info) + caps.size;
>> + info.cap_offset = 0;
>> + } else {
>> + vfio_info_cap_shift(&caps, sizeof(info));
>> + if (copy_to_user((void __user *)arg +
>> + sizeof(info), caps.buf,
>> + caps.size)) {
>> + kfree(caps.buf);
>> + return -EFAULT;
>> + }
>> + info.cap_offset = sizeof(info);
>> + }
>> +
>> + kfree(caps.buf);
>> + }
>>
>> return copy_to_user((void __user *)arg, &info, minsz) ?
>> -EFAULT : 0;
>> @@ -1235,7 +1297,8 @@ static long vfio_pci_ioctl(void *device_data,
>> max = vfio_pci_get_irq_count(vdev, hdr.index);
>>
>> ret = vfio_set_irqs_validate_and_prepare(&hdr, max,
>> - VFIO_PCI_NUM_IRQS, &data_size);
>> + VFIO_PCI_NUM_IRQS + vdev->num_ext_irqs,
>> + &data_size);
>> if (ret)
>> return ret;
>>
>> diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c
>> index 869dce5f134d..1e785a5f5fb2 100644
>> --- a/drivers/vfio/pci/vfio_pci_intrs.c
>> +++ b/drivers/vfio/pci/vfio_pci_intrs.c
>> @@ -19,6 +19,7 @@
>> #include <linux/vfio.h>
>> #include <linux/wait.h>
>> #include <linux/slab.h>
>> +#include <linux/nospec.h>
>>
>> #include "vfio_pci_private.h"
>>
>> @@ -635,6 +636,24 @@ static int vfio_pci_set_req_trigger(struct
>> vfio_pci_device *vdev,
>> count, flags, data);
>> }
>>
>> +static int vfio_pci_set_ext_irq_trigger(struct vfio_pci_device *vdev,
>> + unsigned int index, unsigned int start,
>> + unsigned int count, uint32_t flags,
>> + void *data)
>> +{
>> + int i;
>> +
>> + if (start != 0 || count > 1)
>> + return -EINVAL;
>
> It looks like we need to add ! vdev->num_ext_irqs check above
> as the vdev->ext_irqs is allocated for "nested" case only.
>
> Thanks to qubingbing for reporting the below crash,
>
> [ 5034.902114] Unable to handle kernel paging request at virtual address ffffffffffffff98
> [ 5034.927645] Mem abort info:
> ...
> [ 5035.088409] pc : vfio_pci_set_ctx_trigger_single+0x2c/0x108 [vfio_pci]
> [ 5035.102140] lr : vfio_pci_set_ext_irq_trigger+0x84/0xa0 [vfio_pci]
> ...
> [ 5035.289655] Call trace:
> [ 5035.294796] vfio_pci_set_ctx_trigger_single+0x2c/0x108 [vfio_pci]
> [ 5035.307795] vfio_pci_set_ext_irq_trigger+0x84/0xa0 [vfio_pci]
> [ 5035.320062] vfio_pci_set_irqs_ioctl+0xf0/0x120 [vfio_pci]
> [ 5035.331601] vfio_pci_disable+0x60/0x4e0 [vfio_pci]
> [ 5035.341859] vfio_pci_release+0x74/0xb0 [vfio_pci]
>
> This is observed when the Guest is launched without vsmmu and then "poweroff".
>
> estuary:/home/vsmmu$ ./qemu-system-aarch64_vsmmu5.20 \
>> -machine virt,gic-version=3 \
>> -cpu host \
>> -smp 1 \
>> -m 1024 \
>> -kernel Image_vsmmu \
>> -initrd rootfs_vsmmu.cpio.gz \
>> -device vfio-pci,host=7d:01.0,id=net0 \
>> -net none \
>> -nographic -D -d -enable-kvm \
>> -append "rdinit=init console=ttyAMA0 ealycon=pl0ll,0x90000000"
>
> estuary:/$ poweroff
>
> Could you please take a look.
Sure I will.

Thanks

Eric
>
> Thanks,
> Shameer
>
>
>> + index = array_index_nospec(index,
>> + VFIO_PCI_NUM_IRQS + vdev->num_ext_irqs);
>> + i = index - VFIO_PCI_NUM_IRQS;
>> +
>> + return vfio_pci_set_ctx_trigger_single(&vdev->ext_irqs[i].trigger,
>> + count, flags, data);
>> +}
>> +
>> int vfio_pci_set_irqs_ioctl(struct vfio_pci_device *vdev, uint32_t flags,
>> unsigned index, unsigned start, unsigned count,
>> void *data)
>> @@ -684,6 +703,13 @@ int vfio_pci_set_irqs_ioctl(struct vfio_pci_device
>> *vdev, uint32_t flags,
>> break;
>> }
>> break;
>> + default:
>> + switch (flags & VFIO_IRQ_SET_ACTION_TYPE_MASK) {
>> + case VFIO_IRQ_SET_ACTION_TRIGGER:
>> + func = vfio_pci_set_ext_irq_trigger;
>> + break;
>> + }
>> + break;
>> }
>>
>> if (!func)
>> @@ -691,3 +717,39 @@ int vfio_pci_set_irqs_ioctl(struct vfio_pci_device
>> *vdev, uint32_t flags,
>>
>> return func(vdev, index, start, count, flags, data);
>> }
>> +
>> +int vfio_pci_get_ext_irq_index(struct vfio_pci_device *vdev,
>> + unsigned int type, unsigned int subtype)
>> +{
>> + int i;
>> +
>> + for (i = 0; i < vdev->num_ext_irqs; i++) {
>> + if (vdev->ext_irqs[i].type == type &&
>> + vdev->ext_irqs[i].subtype == subtype) {
>> + return i;
>> + }
>> + }
>> + return -EINVAL;
>> +}
>> +
>> +int vfio_pci_register_irq(struct vfio_pci_device *vdev,
>> + unsigned int type, unsigned int subtype,
>> + u32 flags)
>> +{
>> + struct vfio_ext_irq *ext_irqs;
>> +
>> + ext_irqs = krealloc(vdev->ext_irqs,
>> + (vdev->num_ext_irqs + 1) * sizeof(*ext_irqs),
>> + GFP_KERNEL);
>> + if (!ext_irqs)
>> + return -ENOMEM;
>> +
>> + vdev->ext_irqs = ext_irqs;
>> +
>> + vdev->ext_irqs[vdev->num_ext_irqs].type = type;
>> + vdev->ext_irqs[vdev->num_ext_irqs].subtype = subtype;
>> + vdev->ext_irqs[vdev->num_ext_irqs].flags = flags;
>> + vdev->ext_irqs[vdev->num_ext_irqs].trigger = NULL;
>> + vdev->num_ext_irqs++;
>> + return 0;
>> +}
>> diff --git a/drivers/vfio/pci/vfio_pci_private.h
>> b/drivers/vfio/pci/vfio_pci_private.h
>> index 1d9b0f648133..e180b5435c8f 100644
>> --- a/drivers/vfio/pci/vfio_pci_private.h
>> +++ b/drivers/vfio/pci/vfio_pci_private.h
>> @@ -77,6 +77,13 @@ struct vfio_pci_region {
>> u32 flags;
>> };
>>
>> +struct vfio_ext_irq {
>> + u32 type;
>> + u32 subtype;
>> + u32 flags;
>> + struct eventfd_ctx *trigger;
>> +};
>> +
>> struct vfio_pci_dummy_resource {
>> struct resource resource;
>> int index;
>> @@ -111,6 +118,8 @@ struct vfio_pci_device {
>> struct vfio_pci_irq_ctx *ctx;
>> int num_ctx;
>> int irq_type;
>> + struct vfio_ext_irq *ext_irqs;
>> + int num_ext_irqs;
>> int num_regions;
>> struct vfio_pci_region *region;
>> u8 msi_qmax;
>> @@ -154,6 +163,11 @@ struct vfio_pci_device {
>>
>> extern void vfio_pci_intx_mask(struct vfio_pci_device *vdev);
>> extern void vfio_pci_intx_unmask(struct vfio_pci_device *vdev);
>> +extern int vfio_pci_register_irq(struct vfio_pci_device *vdev,
>> + unsigned int type, unsigned int subtype,
>> + u32 flags);
>> +extern int vfio_pci_get_ext_irq_index(struct vfio_pci_device *vdev,
>> + unsigned int type, unsigned int subtype);
>>
>> extern int vfio_pci_set_irqs_ioctl(struct vfio_pci_device *vdev,
>> uint32_t flags, unsigned index,
>> --
>> 2.21.3
>