kernel/linux.git/drivers/net/hyperv/netvsc.c, branch v6.6.150

hv_netvsc: use kmap_local_page in netvsc_copy_to_send_buf

2026-06-19T11:39:42+00:00

[ Upstream commit 004e9ecfe6c5384f9e0b2f6f6389d42ec22789af ] netvsc_copy_to_send_buf() copies page buffer entries into the VMBus send buffer using phys_to_virt() on the entry PFN. Entries for the RNDIS header and the skb linear data come from kmalloc'd memory and are always in the kernel direct map, but entries for skb fragments reference page cache or user pages, which on 32-bit x86 with CONFIG_HIGHMEM=y can live above the LOWMEM boundary. For such a page phys_to_virt() returns an address outside the direct map and the subsequent memcpy() faults on the transmit softirq path, which is fatal. Map the pages with kmap_local_page() instead, handling two properties of the page buffer entries: - pb[i].pfn is a Hyper-V PFN at HV_HYP_PAGE_SIZE (4K) granularity, not a native PFN. Reconstruct the physical address first and derive the native page from it, so the mapping stays correct where PAGE_SIZE > HV_HYP_PAGE_SIZE (e.g. arm64 with 64K pages). - Since commit 41a6328b2c55 ("hv_netvsc: Preserve contiguous PFN grouping in the page buffer array"), an entry describes a full physically contiguous fragment and pb[i].len can exceed PAGE_SIZE, while kmap_local_page() maps a single page. Copy page by page, splitting at native page boundaries. The copy path only handles packets smaller than the send section size (6144 bytes by default); larger packets take the cp_partial path where only the RNDIS header is copied. So entries here are bounded by the section size and a copy is split at most once on 4K-page systems. On !CONFIG_HIGHMEM configs kmap_local_page() folds to page_address() and no mapping work is added. Fixes: c25aaf814a63 ("hyperv: Enable sendbuf mechanism on the send path") Cc: stable@vger.kernel.org Signed-off-by: Anton Leontev Link: https://patch.msgid.link/20260604165938.32033-1-leontyevantony@gmail.com Signed-off-by: Paolo Abeni [ adapted `phys_to_page(paddr)` to `pfn_to_page(PHYS_PFN(paddr))` ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

hv_netvsc: Remove rmsg_pgcnt

2025-05-22T12:12:21+00:00

commit 5bbc644bbf4e97a05bc0cb052189004588ff8a09 upstream. init_page_array() now always creates a single page buffer array entry for the rndis message, even if the rndis message crosses a page boundary. As such, the number of page buffer array entries used for the rndis message must no longer be tracked -- it is always just 1. Remove the rmsg_pgcnt field and use "1" where the value is needed. Cc: # 6.1.x Signed-off-by: Michael Kelley Link: https://patch.msgid.link/20250513000604.1396-5-mhklinux@outlook.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

hv_netvsc: Use vmbus_sendpacket_mpb_desc() to send VMBus messages

2025-05-22T12:12:20+00:00

commit 4f98616b855cb0e3b5917918bb07b44728eb96ea upstream. netvsc currently uses vmbus_sendpacket_pagebuffer() to send VMBus messages. This function creates a series of GPA ranges, each of which contains a single PFN. However, if the rndis header in the VMBus message crosses a page boundary, the netvsc protocol with the host requires that both PFNs for the rndis header must be in a single "GPA range" data structure, which isn't possible with vmbus_sendpacket_pagebuffer(). As the first step in fixing this, add a new function netvsc_build_mpb_array() to build a VMBus message with multiple GPA ranges, each of which may contain multiple PFNs. Use vmbus_sendpacket_mpb_desc() to send this VMBus message to the host. There's no functional change since higher levels of netvsc don't maintain or propagate knowledge of contiguous PFNs. Based on its input, netvsc_build_mpb_array() still produces a separate GPA range for each PFN and the behavior is the same as with vmbus_sendpacket_pagebuffer(). But the groundwork is laid for a subsequent patch to provide the necessary grouping. Cc: # 6.1.x Signed-off-by: Michael Kelley Link: https://patch.msgid.link/20250513000604.1396-3-mhklinux@outlook.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

hv_netvsc: Don't free decrypted memory

2024-05-17T10:02:17+00:00

[ Upstream commit bbf9ac34677b57506a13682b31a2a718934c0e31 ] In CoCo VMs it is possible for the untrusted host to cause set_memory_encrypted() or set_memory_decrypted() to fail such that an error is returned and the resulting memory is shared. Callers need to take care to handle these errors to avoid returning decrypted (shared) memory to the page allocator, which could lead to functional or security issues. The netvsc driver could free decrypted/shared pages if set_memory_decrypted() fails. Check the decrypted field in the gpadl to decide whether to free the memory. Signed-off-by: Rick Edgecombe Signed-off-by: Michael Kelley Reviewed-by: Kuppuswamy Sathyanarayanan Acked-by: Kirill A. Shutemov Link: https://lore.kernel.org/r/20240311161558.1310-4-mhklinux@outlook.com Signed-off-by: Wei Liu Message-ID: <20240311161558.1310-4-mhklinux@outlook.com> Signed-off-by: Sasha Levin

hv_netvsc: Fix race condition between netvsc_probe and netvsc_remove

2024-02-23T08:25:08+00:00

commit e0526ec5360a48ad3ab2e26e802b0532302a7e11 upstream. In commit ac5047671758 ("hv_netvsc: Disable NAPI before closing the VMBus channel"), napi_disable was getting called for all channels, including all subchannels without confirming if they are enabled or not. This caused hv_netvsc getting hung at napi_disable, when netvsc_probe() has finished running but nvdev->subchan_work has not started yet. netvsc_subchan_work() -> rndis_set_subchannel() has not created the sub-channels and because of that netvsc_sc_open() is not running. netvsc_remove() calls cancel_work_sync(&nvdev->subchan_work), for which netvsc_subchan_work did not run. netif_napi_add() sets the bit NAPI_STATE_SCHED because it ensures NAPI cannot be scheduled. Then netvsc_sc_open() -> napi_enable will clear the NAPIF_STATE_SCHED bit, so it can be scheduled. napi_disable() does the opposite. Now during netvsc_device_remove(), when napi_disable is called for those subchannels, napi_disable gets stuck on infinite msleep. This fix addresses this problem by ensuring that napi_disable() is not getting called for non-enabled NAPI struct. But netif_napi_del() is still necessary for these non-enabled NAPI struct for cleanup purpose. Call trace: [ 654.559417] task:modprobe state:D stack: 0 pid: 2321 ppid: 1091 flags:0x00004002 [ 654.568030] Call Trace: [ 654.571221] [ 654.573790] __schedule+0x2d6/0x960 [ 654.577733] schedule+0x69/0xf0 [ 654.581214] schedule_timeout+0x87/0x140 [ 654.585463] ? __bpf_trace_tick_stop+0x20/0x20 [ 654.590291] msleep+0x2d/0x40 [ 654.593625] napi_disable+0x2b/0x80 [ 654.597437] netvsc_device_remove+0x8a/0x1f0 [hv_netvsc] [ 654.603935] rndis_filter_device_remove+0x194/0x1c0 [hv_netvsc] [ 654.611101] ? do_wait_intr+0xb0/0xb0 [ 654.615753] netvsc_remove+0x7c/0x120 [hv_netvsc] [ 654.621675] vmbus_remove+0x27/0x40 [hv_vmbus] Cc: stable@vger.kernel.org Fixes: ac5047671758 ("hv_netvsc: Disable NAPI before closing the VMBus channel") Signed-off-by: Souradeep Chakrabarti Reviewed-by: Dexuan Cui Reviewed-by: Haiyang Zhang Reviewed-by: Simon Horman Link: https://lore.kernel.org/r/1706686551-28510-1-git-send-email-schakrabarti@linux.microsoft.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

hv_netvsc: Remove second mapping of send and recv buffers

2023-04-17T19:19:04+00:00

With changes to how Hyper-V guest VMs flip memory between private (encrypted) and shared (decrypted), creating a second kernel virtual mapping for shared memory is no longer necessary. Everything needed for the transition to shared is handled by set_memory_decrypted(). As such, remove the code to create and manage the second mapping for the pre-allocated send and recv buffers. This mapping is the last user of hv_map_memory()/hv_unmap_memory(), so delete these functions as well. Finally, hv_map_memory() is the last user of vmap_pfn() in Hyper-V guest code, so remove the Kconfig selection of VMAP_PFN. Signed-off-by: Michael Kelley Reviewed-by: Tianyu Lan Link: https://lore.kernel.org/r/1679838727-87310-11-git-send-email-mikelley@microsoft.com Signed-off-by: Wei Liu

hv_netvsc: Check status in SEND_RNDIS_PKT completion message

2023-02-14T12:56:56+00:00

Completion responses to SEND_RNDIS_PKT messages are currently processed regardless of the status in the response, so that resources associated with the request are freed. While this is appropriate, code bugs that cause sending a malformed message, or errors on the Hyper-V host, go undetected. Fix this by checking the status and outputting a rate-limited message if there is an error. Signed-off-by: Michael Kelley Reviewed-by: Haiyang Zhang Link: https://lore.kernel.org/r/1676264881-48928-1-git-send-email-mikelley@microsoft.com Signed-off-by: Paolo Abeni

hv_netvsc: Allocate memory in netvsc_dma_map() with GFP_ATOMIC

2023-02-08T04:39:26+00:00

Memory allocations in the network transmit path must use GFP_ATOMIC so they won't sleep. Reported-by: Paolo Abeni Link: https://lore.kernel.org/lkml/8a4d08f94d3e6fe8b6da68440eaa89a088ad84f9.camel@redhat.com/ Fixes: 846da38de0e8 ("net: netvsc: Add Isolation VM support for netvsc driver") Cc: stable@vger.kernel.org Signed-off-by: Michael Kelley Link: https://lore.kernel.org/r/1675714317-48577-1-git-send-email-mikelley@microsoft.com Signed-off-by: Jakub Kicinski

hv_netvsc: Fix missed pagebuf entries in netvsc_dma_map/unmap()

2023-02-02T08:15:30+00:00

netvsc_dma_map() and netvsc_dma_unmap() currently check the cp_partial flag and adjust the page_count so that pagebuf entries for the RNDIS portion of the message are skipped when it has already been copied into a send buffer. But this adjustment has already been made by code in netvsc_send(). The duplicate adjustment causes some pagebuf entries to not be mapped. In a normal VM, this doesn't break anything because the mapping doesn’t change the PFN. But in a Confidential VM, dma_map_single() does bounce buffering and provides a different PFN. Failing to do the mapping causes the wrong PFN to be passed to Hyper-V, and various errors ensue. Fix this by removing the duplicate adjustment in netvsc_dma_map() and netvsc_dma_unmap(). Fixes: 846da38de0e8 ("net: netvsc: Add Isolation VM support for netvsc driver") Cc: stable@vger.kernel.org Signed-off-by: Michael Kelley Reviewed-by: Haiyang Zhang Link: https://lore.kernel.org/r/1675135986-254490-1-git-send-email-mikelley@microsoft.com Signed-off-by: Paolo Abeni

hv_netvsc: Fix race between VF offering and VF association message from host

2022-10-07T07:43:58+00:00

During vm boot, there might be possibility that vf registration call comes before the vf association from host to vm. And this might break netvsc vf path, To prevent the same block vf registration until vf bind message comes from host. Cc: stable@vger.kernel.org Fixes: 00d7ddba11436 ("hv_netvsc: pair VF based on serial number") Reviewed-by: Haiyang Zhang Signed-off-by: Gaurav Kohli Signed-off-by: David S. Miller