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Subject: Re: [PATCH v11 08/13] vfio/pci: Add framework for custom interrupt
 indices
To:     Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>,
        "eric.auger.pro@gmail.com" <eric.auger.pro@gmail.com>,
        "iommu@lists.linux-foundation.org" <iommu@lists.linux-foundation.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
        "kvmarm@lists.cs.columbia.edu" <kvmarm@lists.cs.columbia.edu>,
        "will@kernel.org" <will@kernel.org>,
        "joro@8bytes.org" <joro@8bytes.org>,
        "maz@kernel.org" <maz@kernel.org>,
        "robin.murphy@arm.com" <robin.murphy@arm.com>,
        "alex.williamson@redhat.com" <alex.williamson@redhat.com>
Cc:     "jean-philippe@linaro.org" <jean-philippe@linaro.org>,
        "zhangfei.gao@linaro.org" <zhangfei.gao@linaro.org>,
        "zhangfei.gao@gmail.com" <zhangfei.gao@gmail.com>,
        "vivek.gautam@arm.com" <vivek.gautam@arm.com>,
        "jacob.jun.pan@linux.intel.com" <jacob.jun.pan@linux.intel.com>,
        "yi.l.liu@intel.com" <yi.l.liu@intel.com>,
        "tn@semihalf.com" <tn@semihalf.com>,
        "nicoleotsuka@gmail.com" <nicoleotsuka@gmail.com>,
        yuzenghui <yuzenghui@huawei.com>,
        qubingbing <qubingbing@hisilicon.com>,
        Linuxarm <linuxarm@huawei.com>
References: <20201116110030.32335-1-eric.auger@redhat.com>
 <20201116110030.32335-9-eric.auger@redhat.com>
 <d938eaf119c441359b1c30fe1b7c58ef@huawei.com>
From:   Auger Eric <eric.auger@redhat.com>
Message-ID: <84492a63-4369-d7c7-87d4-f0a94f6ba070@redhat.com>
Date:   Tue, 24 Nov 2020 09:35:50 +0100
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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
>