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[80.187.67.108]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-5c42bc8907asm3682402a12.85.2024.09.17.03.07.56 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 17 Sep 2024 03:07:58 -0700 (PDT) Message-ID: Date: Tue, 17 Sep 2024 12:07:53 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 1/5] vhost-user: Add VIRTIO Shared Memory map request To: Albert Esteve , qemu-devel@nongnu.org Cc: =?UTF-8?Q?Alex_Benn=C3=A9e?= , slp@redhat.com, hi@alyssa.is, mst@redhat.com, jasowang@redhat.com, stefanha@redhat.com, Stefano Garzarella , stevensd@chromium.org References: <20240912145335.129447-1-aesteve@redhat.com> <20240912145335.129447-2-aesteve@redhat.com> From: David Hildenbrand Content-Language: en-US Autocrypt: addr=david@redhat.com; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZgEEwEIAEICGwMGCwkIBwMCBhUIAgkKCwQW AgMBAh4BAheAAhkBFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAl8Ox4kFCRKpKXgACgkQTd4Q 9wD/g1oHcA//a6Tj7SBNjFNM1iNhWUo1lxAja0lpSodSnB2g4FCZ4R61SBR4l/psBL73xktp rDHrx4aSpwkRP6Epu6mLvhlfjmkRG4OynJ5HG1gfv7RJJfnUdUM1z5kdS8JBrOhMJS2c/gPf wv1TGRq2XdMPnfY2o0CxRqpcLkx4vBODvJGl2mQyJF/gPepdDfcT8/PY9BJ7FL6Hrq1gnAo4 3Iv9qV0JiT2wmZciNyYQhmA1V6dyTRiQ4YAc31zOo2IM+xisPzeSHgw3ONY/XhYvfZ9r7W1l pNQdc2G+o4Di9NPFHQQhDw3YTRR1opJaTlRDzxYxzU6ZnUUBghxt9cwUWTpfCktkMZiPSDGd KgQBjnweV2jw9UOTxjb4LXqDjmSNkjDdQUOU69jGMUXgihvo4zhYcMX8F5gWdRtMR7DzW/YE BgVcyxNkMIXoY1aYj6npHYiNQesQlqjU6azjbH70/SXKM5tNRplgW8TNprMDuntdvV9wNkFs 9TyM02V5aWxFfI42+aivc4KEw69SE9KXwC7FSf5wXzuTot97N9Phj/Z3+jx443jo2NR34XgF 89cct7wJMjOF7bBefo0fPPZQuIma0Zym71cP61OP/i11ahNye6HGKfxGCOcs5wW9kRQEk8P9 M/k2wt3mt/fCQnuP/mWutNPt95w9wSsUyATLmtNrwccz63XOwU0EVcufkQEQAOfX3n0g0fZz Bgm/S2zF/kxQKCEKP8ID+Vz8sy2GpDvveBq4H2Y34XWsT1zLJdvqPI4af4ZSMxuerWjXbVWb T6d4odQIG0fKx4F8NccDqbgHeZRNajXeeJ3R7gAzvWvQNLz4piHrO/B4tf8svmRBL0ZB5P5A 2uhdwLU3NZuK22zpNn4is87BPWF8HhY0L5fafgDMOqnf4guJVJPYNPhUFzXUbPqOKOkL8ojk CXxkOFHAbjstSK5Ca3fKquY3rdX3DNo+EL7FvAiw1mUtS+5GeYE+RMnDCsVFm/C7kY8c2d0G NWkB9pJM5+mnIoFNxy7YBcldYATVeOHoY4LyaUWNnAvFYWp08dHWfZo9WCiJMuTfgtH9tc75 7QanMVdPt6fDK8UUXIBLQ2TWr/sQKE9xtFuEmoQGlE1l6bGaDnnMLcYu+Asp3kDT0w4zYGsx 5r6XQVRH4+5N6eHZiaeYtFOujp5n+pjBaQK7wUUjDilPQ5QMzIuCL4YjVoylWiBNknvQWBXS lQCWmavOT9sttGQXdPCC5ynI+1ymZC1ORZKANLnRAb0NH/UCzcsstw2TAkFnMEbo9Zu9w7Kv AxBQXWeXhJI9XQssfrf4Gusdqx8nPEpfOqCtbbwJMATbHyqLt7/oz/5deGuwxgb65pWIzufa N7eop7uh+6bezi+rugUI+w6DABEBAAHCwXwEGAEIACYCGwwWIQQb2cqtc1xMOkYN/MpN3hD3 AP+DWgUCXw7HsgUJEqkpoQAKCRBN3hD3AP+DWrrpD/4qS3dyVRxDcDHIlmguXjC1Q5tZTwNB boaBTPHSy/Nksu0eY7x6HfQJ3xajVH32Ms6t1trDQmPx2iP5+7iDsb7OKAb5eOS8h+BEBDeq 3ecsQDv0fFJOA9ag5O3LLNk+3x3q7e0uo06XMaY7UHS341ozXUUI7wC7iKfoUTv03iO9El5f XpNMx/YrIMduZ2+nd9Di7o5+KIwlb2mAB9sTNHdMrXesX8eBL6T9b+MZJk+mZuPxKNVfEQMQ a5SxUEADIPQTPNvBewdeI80yeOCrN+Zzwy/Mrx9EPeu59Y5vSJOx/z6OUImD/GhX7Xvkt3kq Er5KTrJz3++B6SH9pum9PuoE/k+nntJkNMmQpR4MCBaV/J9gIOPGodDKnjdng+mXliF3Ptu6 3oxc2RCyGzTlxyMwuc2U5Q7KtUNTdDe8T0uE+9b8BLMVQDDfJjqY0VVqSUwImzTDLX9S4g/8 kC4HRcclk8hpyhY2jKGluZO0awwTIMgVEzmTyBphDg/Gx7dZU1Xf8HFuE+UZ5UDHDTnwgv7E th6RC9+WrhDNspZ9fJjKWRbveQgUFCpe1sa77LAw+XFrKmBHXp9ZVIe90RMe2tRL06BGiRZr jPrnvUsUUsjRoRNJjKKA/REq+sAnhkNPPZ/NNMjaZ5b8Tovi8C0tmxiCHaQYqj7G2rgnT0kt WNyWQQ== Organization: Red Hat In-Reply-To: <20240912145335.129447-2-aesteve@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=170.10.129.124; envelope-from=david@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 12.09.24 16:53, Albert Esteve wrote: > Add SHMEM_MAP/UNMAP requests to vhost-user to > handle VIRTIO Shared Memory mappings. > > This request allows backends to dynamically map > fds into a VIRTIO Shared Memory Region indentified > by its `shmid`. Then, the fd memory is advertised > to the driver as a base addres + offset, so it > can be read/written (depending on the mmap flags > requested) while its valid. > > The backend can munmap the memory range > in a given VIRTIO Shared Memory Region (again, > identified by its `shmid`), to free it. Upon > receiving this message, the front-end must > mmap the regions with PROT_NONE to reserve > the virtual memory space. > > The device model needs to create MemoryRegion > instances for the VIRTIO Shared Memory Regions > and add them to the `VirtIODevice` instance. > > Signed-off-by: Albert Esteve > --- > hw/virtio/vhost-user.c | 122 ++++++++++++++++++++++ > hw/virtio/virtio.c | 13 +++ > include/hw/virtio/virtio.h | 5 + > subprojects/libvhost-user/libvhost-user.c | 60 +++++++++++ > subprojects/libvhost-user/libvhost-user.h | 52 +++++++++ > 5 files changed, 252 insertions(+) > > diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c > index 00561daa06..338cc942ec 100644 > --- a/hw/virtio/vhost-user.c > +++ b/hw/virtio/vhost-user.c > @@ -115,6 +115,8 @@ typedef enum VhostUserBackendRequest { > VHOST_USER_BACKEND_SHARED_OBJECT_ADD = 6, > VHOST_USER_BACKEND_SHARED_OBJECT_REMOVE = 7, > VHOST_USER_BACKEND_SHARED_OBJECT_LOOKUP = 8, > + VHOST_USER_BACKEND_SHMEM_MAP = 9, > + VHOST_USER_BACKEND_SHMEM_UNMAP = 10, > VHOST_USER_BACKEND_MAX > } VhostUserBackendRequest; > > @@ -192,6 +194,24 @@ typedef struct VhostUserShared { > unsigned char uuid[16]; > } VhostUserShared; > > +/* For the flags field of VhostUserMMap */ > +#define VHOST_USER_FLAG_MAP_R (1u << 0) > +#define VHOST_USER_FLAG_MAP_W (1u << 1) > + > +typedef struct { > + /* VIRTIO Shared Memory Region ID */ > + uint8_t shmid; > + uint8_t padding[7]; > + /* File offset */ > + uint64_t fd_offset; > + /* Offset within the VIRTIO Shared Memory Region */ > + uint64_t shm_offset; > + /* Size of the mapping */ > + uint64_t len; > + /* Flags for the mmap operation, from VHOST_USER_FLAG_* */ > + uint64_t flags; > +} VhostUserMMap; > + > typedef struct { > VhostUserRequest request; > > @@ -224,6 +244,7 @@ typedef union { > VhostUserInflight inflight; > VhostUserShared object; > VhostUserTransferDeviceState transfer_state; > + VhostUserMMap mmap; > } VhostUserPayload; > > typedef struct VhostUserMsg { > @@ -1749,6 +1770,100 @@ vhost_user_backend_handle_shared_object_lookup(struct vhost_user *u, > return 0; > } > > +static int > +vhost_user_backend_handle_shmem_map(struct vhost_dev *dev, > + VhostUserMMap *vu_mmap, > + int fd) > +{ > + void *addr = 0; > + MemoryRegion *mr = NULL; > + > + if (fd < 0) { > + error_report("Bad fd for map"); > + return -EBADF; > + } > + > + if (!dev->vdev->shmem_list || > + dev->vdev->n_shmem_regions <= vu_mmap->shmid) { > + error_report("Device only has %d VIRTIO Shared Memory Regions. " > + "Requested ID: %d", > + dev->vdev->n_shmem_regions, vu_mmap->shmid); > + return -EFAULT; > + } > + > + mr = &dev->vdev->shmem_list[vu_mmap->shmid]; > + > + if (!mr) { > + error_report("VIRTIO Shared Memory Region at " > + "ID %d unitialized", vu_mmap->shmid); > + return -EFAULT; > + } > + > + if ((vu_mmap->shm_offset + vu_mmap->len) < vu_mmap->len || > + (vu_mmap->shm_offset + vu_mmap->len) > mr->size) { > + error_report("Bad offset/len for mmap %" PRIx64 "+%" PRIx64, > + vu_mmap->shm_offset, vu_mmap->len); > + return -EFAULT; > + } > + > + void *shmem_ptr = memory_region_get_ram_ptr(mr); > + > + addr = mmap(shmem_ptr + vu_mmap->shm_offset, vu_mmap->len, > + ((vu_mmap->flags & VHOST_USER_FLAG_MAP_R) ? PROT_READ : 0) | > + ((vu_mmap->flags & VHOST_USER_FLAG_MAP_W) ? PROT_WRITE : 0), > + MAP_SHARED | MAP_FIXED, fd, vu_mmap->fd_offset); > + I'm sorry, but that looks completely wrong. You cannot just take some RAM memory region/ RAMBlock that has properly set flags/fd/whatssoever and map whatever you want in there. Likely you would need a distinct RAMBlock/RAM memory region per mmap(), and would end up mmaping implicitly via qemu_ram_mmap(). Then, your shared region would simply be an empty container into which you map these RAM memory regions. -- Cheers, David / dhildenb