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From: Jason Wang <jasowang@redhat.com>
To: Eugenio Perez Martin <eperezma@redhat.com>, Peter Xu <peterx@redhat.com>
Cc: Peter Maydell <peter.maydell@linaro.org>,
	Yan Zhao <yan.y.zhao@intel.com>,
	Juan Quintela <quintela@redhat.com>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	qemu-devel@nongnu.org, Eric Auger <eric.auger@redhat.com>,
	Avi Kivity <avi@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [RFC v3 1/1] memory: Skip bad range assertion if notifier supports arbitrary masks
Date: Wed, 19 Aug 2020 15:15:26 +0800	[thread overview]
Message-ID: <eb26c5d7-465a-34ed-3f8f-bad11eda5bee@redhat.com> (raw)
In-Reply-To: <CAJaqyWe+KgnVegtprpRmVvXo7kFVFDL_erK_5Nyp4K=gTUcN=Q@mail.gmail.com>


On 2020/8/18 下午10:24, Eugenio Perez Martin wrote:
> On Wed, Aug 12, 2020 at 10:49 AM Eugenio Perez Martin
> <eperezma@redhat.com>  wrote:
>> On Wed, Aug 12, 2020 at 4:24 AM Jason Wang<jasowang@redhat.com>  wrote:
>>> On 2020/8/12 上午1:55, Eugenio Pérez wrote:
>>>> Signed-off-by: Eugenio Pérez<eperezma@redhat.com>
>>>> ---
>>>>    hw/virtio/vhost.c     |  2 +-
>>>>    include/exec/memory.h |  2 ++
>>>>    softmmu/memory.c      | 10 ++++++++--
>>>>    3 files changed, 11 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
>>>> index 1a1384e7a6..e74ad9e09b 100644
>>>> --- a/hw/virtio/vhost.c
>>>> +++ b/hw/virtio/vhost.c
>>>> @@ -729,7 +729,7 @@ static void vhost_iommu_region_add(MemoryListener *listener,
>>>>        iommu_idx = memory_region_iommu_attrs_to_index(iommu_mr,
>>>>                                                       MEMTXATTRS_UNSPECIFIED);
>>>>        iommu_notifier_init(&iommu->n, vhost_iommu_unmap_notify,
>>>> -                        IOMMU_NOTIFIER_UNMAP,
>>>> +                        IOMMU_NOTIFIER_UNMAP | IOMMU_NOTIFIER_IOTLB,
>>> I think we can safely drop IOMMU_NOTIFIER_UNMAP here since device IOTLB
>>> is sufficient.
>>>
>>> Btw, IOMMU_NOTIFIER_IOTLB is kind of confusing, maybe something like
>>> IOMMU_NOTIFIER_DEVIOTLB.
>>>
>> Got it, will change.
>>
>>>>                            section->offset_within_region,
>>>>                            int128_get64(end),
>>>>                            iommu_idx);
>>>> diff --git a/include/exec/memory.h b/include/exec/memory.h
>>>> index 307e527835..4d94c1e984 100644
>>>> --- a/include/exec/memory.h
>>>> +++ b/include/exec/memory.h
>>>> @@ -87,6 +87,8 @@ typedef enum {
>>>>        IOMMU_NOTIFIER_UNMAP = 0x1,
>>>>        /* Notify entry changes (newly created entries) */
>>>>        IOMMU_NOTIFIER_MAP = 0x2,
>>>> +    /* Notify changes on IOTLB entries */
>>>> +    IOMMU_NOTIFIER_IOTLB = 0x04,
>>>>    } IOMMUNotifierFlag;
>>>>
>>>>    #define IOMMU_NOTIFIER_ALL (IOMMU_NOTIFIER_MAP | IOMMU_NOTIFIER_UNMAP)
>>>> diff --git a/softmmu/memory.c b/softmmu/memory.c
>>>> index af25987518..e2c5f6d0e7 100644
>>>> --- a/softmmu/memory.c
>>>> +++ b/softmmu/memory.c
>>>> @@ -1895,6 +1895,7 @@ void memory_region_notify_one(IOMMUNotifier *notifier,
>>> (we probably need a better name of this function, at least something
>>> like "memory_region_iommu_notify_one").
>>>
>> Ok will change.
>>
>>>>    {
>>>>        IOMMUNotifierFlag request_flags;
>>>>        hwaddr entry_end = entry->iova + entry->addr_mask;
>>>> +    IOMMUTLBEntry tmp = *entry;
>>>>
>>>>        /*
>>>>         * Skip the notification if the notification does not overlap
>>>> @@ -1904,7 +1905,12 @@ void memory_region_notify_one(IOMMUNotifier *notifier,
>>>>            return;
>>>>        }
>>>>
>>>> -    assert(entry->iova >= notifier->start && entry_end <= notifier->end);
>>>> +    if (notifier->notifier_flags & IOMMU_NOTIFIER_IOTLB) {
>>>> +        tmp.iova = MAX(tmp.iova, notifier->start);
>>>> +        tmp.addr_mask = MIN(entry_end, notifier->end) - tmp.iova;
>>> Any reason for doing such re-calculation here, a comment would be helpful.
>>>
>> It was proposed by Peter, but I understand as limiting the
>> address+range we pass to the notifier. Although vhost seems to support
>> it as long as it contains (notifier->start, notifier->end) in range, a
>> future notifier might not.


Yes, actually, I feel confused after reading the codes. Is 
notifier->start IOVA or GPA?

In vfio.c, we did:

         iommu_notifier_init(&giommu->n, vfio_iommu_map_notify,
                             IOMMU_NOTIFIER_ALL,
                             section->offset_within_region,
                             int128_get64(llend),
                             iommu_idx);

So it looks to me the start and end are GPA, but the assertion above 
check it against IOVA which seems to be wrong ....

Thanks


>>
>> It could be done as iommu_entry_crop(IOMMUTLBEntry *entry, const
>> IOMMUNotifier *notifier) though.



  reply	other threads:[~2020-08-19  7:16 UTC|newest]

Thread overview: 68+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-26  6:41 [RFC v2 0/1] memory: Delete assertion in memory_region_unregister_iommu_notifier Eugenio Pérez
2020-06-26  6:41 ` [RFC v2 1/1] " Eugenio Pérez
2020-06-26 21:29   ` Peter Xu
2020-06-27  7:26     ` Yan Zhao
2020-06-27 12:57       ` Peter Xu
2020-06-28  1:36         ` Yan Zhao
2020-06-28  7:03     ` Jason Wang
2020-06-28 14:47       ` Peter Xu
2020-06-29  5:51         ` Jason Wang
2020-06-29 13:34           ` Peter Xu
2020-06-30  2:41             ` Jason Wang
2020-06-30  8:29               ` Jason Wang
2020-06-30  9:21                 ` Michael S. Tsirkin
2020-06-30  9:23                   ` Jason Wang
2020-06-30 15:20                     ` Peter Xu
2020-07-01  8:11                       ` Jason Wang
2020-07-01 12:16                         ` Peter Xu
2020-07-01 12:30                           ` Jason Wang
2020-07-01 12:41                             ` Peter Xu
2020-07-02  3:00                               ` Jason Wang
2020-06-30 15:39               ` Peter Xu
2020-07-01  8:09                 ` Jason Wang
2020-07-02  3:01                   ` Jason Wang
2020-07-02 15:45                     ` Peter Xu
2020-07-03  7:24                       ` Jason Wang
2020-07-03 13:03                         ` Peter Xu
2020-07-07  8:03                           ` Jason Wang
2020-07-07 19:54                             ` Peter Xu
2020-07-08  5:42                               ` Jason Wang
2020-07-08 14:16                                 ` Peter Xu
2020-07-09  5:58                                   ` Jason Wang
2020-07-09 14:10                                     ` Peter Xu
2020-07-10  6:34                                       ` Jason Wang
2020-07-10 13:30                                         ` Peter Xu
2020-07-13  4:04                                           ` Jason Wang
2020-07-16  1:00                                             ` Peter Xu
2020-07-16  2:54                                               ` Jason Wang
2020-07-17 14:18                                                 ` Peter Xu
2020-07-20  4:02                                                   ` Jason Wang
2020-07-20 13:03                                                     ` Peter Xu
2020-07-21  6:20                                                       ` Jason Wang
2020-07-21 15:10                                                         ` Peter Xu
2020-08-03 16:00                         ` Eugenio Pérez
2020-08-04 20:30                           ` Peter Xu
2020-08-05  5:45                             ` Jason Wang
2020-08-11 17:01     ` Eugenio Perez Martin
2020-08-11 17:10       ` Eugenio Perez Martin
2020-06-29 15:05 ` [RFC v2 0/1] " Paolo Bonzini
2020-07-03  7:39   ` Eugenio Perez Martin
2020-07-03 10:10     ` Paolo Bonzini
2020-08-11 17:55 ` [RFC v3 " Eugenio Pérez
2020-08-11 17:55   ` [RFC v3 1/1] memory: Skip bad range assertion if notifier supports arbitrary masks Eugenio Pérez
2020-08-12  2:24     ` Jason Wang
2020-08-12  8:49       ` Eugenio Perez Martin
2020-08-18 14:24         ` Eugenio Perez Martin
2020-08-19  7:15           ` Jason Wang [this message]
2020-08-19  8:22             ` Eugenio Perez Martin
2020-08-19  9:36               ` Jason Wang
2020-08-19 15:50             ` Peter Xu
2020-08-20  2:28               ` Jason Wang
2020-08-21 14:12                 ` Peter Xu
2020-09-01  3:05                   ` Jason Wang
2020-09-01 19:35                     ` Peter Xu
2020-09-02  5:13                       ` Jason Wang
2020-08-11 18:10   ` [RFC v3 0/1] memory: Delete assertion in memory_region_unregister_iommu_notifier Eugenio Perez Martin
2020-08-11 19:27     ` Peter Xu
2020-08-12 14:33       ` Eugenio Perez Martin
2020-08-12 21:12         ` Peter Xu

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