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Message-ID: <CAG8rG2yAAQ62wyO6fyTo71+0VmS_PvP_BWWg=srvmtiJsvrg2Q@mail.gmail.com>
Date: Mon, 24 Nov 2014 16:53:13 +0100
From: Antonios Motakis <a.motakis@...tualopensystems.com>
To: Eric Auger <eric.auger@...aro.org>
Cc: kvm-arm <kvmarm@...ts.cs.columbia.edu>,
Linux IOMMU <iommu@...ts.linux-foundation.org>,
Alex Williamson <alex.williamson@...hat.com>,
Will Deacon <will.deacon@....com>,
VirtualOpenSystems Technical Team <tech@...tualopensystems.com>,
Christoffer Dall <christoffer.dall@...aro.org>,
Kim Phillips <kim.phillips@...escale.com>,
Marc Zyngier <marc.zyngier@....com>,
"open list:VFIO DRIVER <kvm@...r.kernel.org>, open list"
<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v9 07/19] vfio/platform: return info for device memory
mapped IO regions
On Thu, Nov 20, 2014 at 3:11 PM, Antonios Motakis
<a.motakis@...tualopensystems.com> wrote:
> On Wed, Nov 12, 2014 at 11:58 AM, Eric Auger <eric.auger@...aro.org> wrote:
>> On 10/27/2014 07:07 PM, Antonios Motakis wrote:
>>> This patch enables the IOCTLs VFIO_DEVICE_GET_REGION_INFO ioctl call,
>>> which allows the user to learn about the available MMIO resources of
>>> a device.
>>>
>>> Signed-off-by: Antonios Motakis <a.motakis@...tualopensystems.com>
>>> ---
>>> drivers/vfio/platform/vfio_platform_common.c | 110 +++++++++++++++++++++++++-
>>> drivers/vfio/platform/vfio_platform_private.h | 22 ++++++
>>> 2 files changed, 128 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
>>> index cb20526..82de752 100644
>>> --- a/drivers/vfio/platform/vfio_platform_common.c
>>> +++ b/drivers/vfio/platform/vfio_platform_common.c
>>> @@ -27,17 +27,97 @@
>>>
>>> #include "vfio_platform_private.h"
>>>
>>> +static DEFINE_MUTEX(driver_lock);
>>> +
>>> +static int vfio_platform_regions_init(struct vfio_platform_device *vdev)
>>> +{
>>> + int cnt = 0, i;
>>> +
>>> + while (vdev->get_resource(vdev, cnt))
>>> + cnt++;
>>> +
>>> + vdev->regions = kcalloc(cnt, sizeof(struct vfio_platform_region),
>>> + GFP_KERNEL);
>>> + if (!vdev->regions)
>>> + return -ENOMEM;
>>> +
>>> + for (i = 0; i < cnt; i++) {
>>> + struct resource *res =
>>> + vdev->get_resource(vdev, i);
>>> +
>>> + if (!res)
>>> + goto err;
>>> +
>>> + vdev->regions[i].addr = res->start;
>>> + vdev->regions[i].size = resource_size(res);
>>> + vdev->regions[i].flags = 0;
>>> +
>>> + switch (resource_type(res)) {
>>> + case IORESOURCE_MEM:
>>> + vdev->regions[i].type = VFIO_PLATFORM_REGION_TYPE_MMIO;
>>> + break;
>>> + case IORESOURCE_IO:
>>> + vdev->regions[i].type = VFIO_PLATFORM_REGION_TYPE_PIO;
>>> + break;
>>> + default:
>>> + goto err;
>>> + }
>>> + }
>>> +
>>> + vdev->num_regions = cnt;
>>> +
>>> + return 0;
>>> +err:
>> Isn't it safer to reset vdev->num_regions here?
>> I think in a next patch you will iounmap the num_regions in
>> vfio_platform_regions_cleanup.
Actually, num_regions is only set just before the successful return,
so it seems there is no need to reset it.
>
> Agreed!
>
>> -- Eric
>>> + kfree(vdev->regions);
>>> + return -EINVAL;
>>> +}
>>> +
>>> +static void vfio_platform_regions_cleanup(struct vfio_platform_device *vdev)
>>> +{
>>> + vdev->num_regions = 0;
>>> + kfree(vdev->regions);
>>> +}
>>> +
>>> static void vfio_platform_release(void *device_data)
>>> {
>>> + struct vfio_platform_device *vdev = device_data;
>>> +
>>> + mutex_lock(&driver_lock);
>>> +
>>> + if (!(--vdev->refcnt)) {
>>> + vfio_platform_regions_cleanup(vdev);
>>> + }
>>> +
>>> + mutex_unlock(&driver_lock);
>>> +
>>> module_put(THIS_MODULE);
>>> }
>>>
>>> static int vfio_platform_open(void *device_data)
>>> {
>>> + struct vfio_platform_device *vdev = device_data;
>>> + int ret;
>>> +
>>> if (!try_module_get(THIS_MODULE))
>>> return -ENODEV;
>>>
>>> + mutex_lock(&driver_lock);
>>> +
>>> + if (!vdev->refcnt) {
>>> + ret = vfio_platform_regions_init(vdev);
>>> + if (ret)
>>> + goto err_reg;
>>> + }
>>> +
>>> + vdev->refcnt++;
>>> +
>>> + mutex_unlock(&driver_lock);
>>> return 0;
>>> +
>>> +err_reg:
>>> + mutex_unlock(&driver_lock);
>>> + module_put(THIS_MODULE);
>>> + return ret;
>>> }
>>>
>>> static long vfio_platform_ioctl(void *device_data,
>>> @@ -58,15 +138,33 @@ static long vfio_platform_ioctl(void *device_data,
>>> return -EINVAL;
>>>
>>> info.flags = vdev->flags;
>>> - info.num_regions = 0;
>>> + info.num_regions = vdev->num_regions;
>>> info.num_irqs = 0;
>>>
>>> return copy_to_user((void __user *)arg, &info, minsz);
>>>
>>> - } else if (cmd == VFIO_DEVICE_GET_REGION_INFO)
>>> - return -EINVAL;
>>> + } else if (cmd == VFIO_DEVICE_GET_REGION_INFO) {
>>> + struct vfio_region_info info;
>>> +
>>> + minsz = offsetofend(struct vfio_region_info, offset);
>>> +
>>> + if (copy_from_user(&info, (void __user *)arg, minsz))
>>> + return -EFAULT;
>>>
>>> - else if (cmd == VFIO_DEVICE_GET_IRQ_INFO)
>>> + if (info.argsz < minsz)
>>> + return -EINVAL;
>>> +
>>> + if (info.index >= vdev->num_regions)
>>> + return -EINVAL;
>>> +
>>> + /* map offset to the physical address */
>>> + info.offset = VFIO_PLATFORM_INDEX_TO_OFFSET(info.index);
>>> + info.size = vdev->regions[info.index].size;
>>> + info.flags = vdev->regions[info.index].flags;
>>> +
>>> + return copy_to_user((void __user *)arg, &info, minsz);
>>> +
>>> + } else if (cmd == VFIO_DEVICE_GET_IRQ_INFO)
>>> return -EINVAL;
>>>
>>> else if (cmd == VFIO_DEVICE_SET_IRQS)
>>> @@ -134,10 +232,14 @@ struct vfio_platform_device *vfio_platform_remove_common(struct device *dev)
>>> {
>>> struct vfio_platform_device *vdev;
>>>
>>> + mutex_lock(&driver_lock);
>>> +
>>> vdev = vfio_del_group_dev(dev);
>>> if (vdev)
>>> iommu_group_put(dev->iommu_group);
>>>
>>> + mutex_unlock(&driver_lock);
>>> +
>>> return vdev;
>>> }
>>> EXPORT_SYMBOL_GPL(vfio_platform_remove_common);
>>> diff --git a/drivers/vfio/platform/vfio_platform_private.h b/drivers/vfio/platform/vfio_platform_private.h
>>> index 062b92d..b24729f 100644
>>> --- a/drivers/vfio/platform/vfio_platform_private.h
>>> +++ b/drivers/vfio/platform/vfio_platform_private.h
>>> @@ -15,7 +15,29 @@
>>> #ifndef VFIO_PLATFORM_PRIVATE_H
>>> #define VFIO_PLATFORM_PRIVATE_H
>>>
>>> +#define VFIO_PLATFORM_OFFSET_SHIFT 40
>>> +#define VFIO_PLATFORM_OFFSET_MASK (((u64)(1) << VFIO_PLATFORM_OFFSET_SHIFT) - 1)
>>> +
>>> +#define VFIO_PLATFORM_OFFSET_TO_INDEX(off) \
>>> + (off >> VFIO_PLATFORM_OFFSET_SHIFT)
>>> +
>>> +#define VFIO_PLATFORM_INDEX_TO_OFFSET(index) \
>>> + ((u64)(index) << VFIO_PLATFORM_OFFSET_SHIFT)
>>> +
>>> +struct vfio_platform_region {
>>> + u64 addr;
>>> + resource_size_t size;
>>> + u32 flags;
>>> + u32 type;
>>> +#define VFIO_PLATFORM_REGION_TYPE_MMIO 1
>>> +#define VFIO_PLATFORM_REGION_TYPE_PIO 2
>>> +};
>>> +
>>> struct vfio_platform_device {
>>> + struct vfio_platform_region *regions;
>>> + u32 num_regions;
>>> + int refcnt;
>>> +
>>> /*
>>> * These fields should be filled by the bus specific binder
>>> */
>>>
>>
--
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