kernel.git/drivers/hv/connection.c, branch linux-6.1.y

Drivers: hv: Allocate interrupt and monitor pages aligned to system page boundary

2025-07-06T08:57:58Z

[ Upstream commit 09eea7ad0b8e973dcf5ed49902838e5d68177f8e ] There are use cases that interrupt and monitor pages are mapped to user-mode through UIO, so they need to be system page aligned. Some Hyper-V allocation APIs introduced earlier broke those requirements. Fix this by using page allocation functions directly for interrupt and monitor pages. Cc: stable@vger.kernel.org Fixes: ca48739e59df ("Drivers: hv: vmbus: Move Hyper-V page allocator to arch neutral code") Signed-off-by: Long Li Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/1746492997-4599-2-git-send-email-longli@linuxonhyperv.com Signed-off-by: Wei Liu Message-ID: <1746492997-4599-2-git-send-email-longli@linuxonhyperv.com> Signed-off-by: Sasha Levin

Drivers: hv: vmbus: Leak pages if set_memory_encrypted() fails

2025-07-06T08:57:58Z

[ Upstream commit 03f5a999adba062456c8c818a683beb1b498983a ] 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. VMBus code could free decrypted pages if set_memory_encrypted()/decrypted() fails. Leak the pages if this happens. 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/20240311161558.1310-2-mhklinux@outlook.com Signed-off-by: Wei Liu Message-ID: <20240311161558.1310-2-mhklinux@outlook.com> Stable-dep-of: 09eea7ad0b8e ("Drivers: hv: Allocate interrupt and monitor pages aligned to system page boundary") Signed-off-by: Sasha Levin

Drivers: hv: Change hv_free_hyperv_page() to take void * argument

2025-07-06T08:57:58Z

[ Upstream commit a6fe043880820981f6e4918240f967ea79bb063e ] Currently hv_free_hyperv_page() takes an unsigned long argument, which is inconsistent with the void * return value from the corresponding hv_alloc_hyperv_page() function and variants. This creates unnecessary extra casting. Change the hv_free_hyperv_page() argument type to void *. Also remove redundant casts from invocations of hv_alloc_hyperv_page() and variants. Signed-off-by: Kameron Carr Reviewed-by: Nuno Das Neves Reviewed-by: Dexuan Cui Link: https://lore.kernel.org/r/1687558189-19734-1-git-send-email-kameroncarr@linux.microsoft.com Signed-off-by: Wei Liu Stable-dep-of: 09eea7ad0b8e ("Drivers: hv: Allocate interrupt and monitor pages aligned to system page boundary") Signed-off-by: Sasha Levin

Drivers: hv: vmbus: Remove second mapping of VMBus monitor pages

2025-07-06T08:57:58Z

[ Upstream commit a5ddb74588213c31ce993a8e9a09d1ffdc11a142 ] 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 VMBus monitor pages. Because set_memory_decrypted() and set_memory_encrypted() are no-ops in normal VMs, it's not even necessary to test for being in a Confidential VM (a.k.a., "Isolation VM"). Signed-off-by: Michael Kelley Reviewed-by: Tianyu Lan Link: https://lore.kernel.org/r/1679838727-87310-9-git-send-email-mikelley@microsoft.com Signed-off-by: Wei Liu Stable-dep-of: 09eea7ad0b8e ("Drivers: hv: Allocate interrupt and monitor pages aligned to system page boundary") Signed-off-by: Sasha Levin

Drivers: vmbus: Check for channel allocation before looking up relids

2023-04-13T14:55:18Z

[ Upstream commit 1eb65c8687316c65140b48fad27133d583178e15 ] relid2channel() assumes vmbus channel array to be allocated when called. However, in cases such as kdump/kexec, not all relids will be reset by the host. When the second kernel boots and if the guest receives a vmbus interrupt during vmbus driver initialization before vmbus_connect() is called, before it finishes, or if it fails, the vmbus interrupt service routine is called which in turn calls relid2channel() and can cause a null pointer dereference. Print a warning and error out in relid2channel() for a channel id that's invalid in the second kernel. Fixes: 8b6a877c060e ("Drivers: hv: vmbus: Replace the per-CPU channel lists with a global array of channels") Signed-off-by: Mohammed Gamal Reviewed-by: Dexuan Cui Link: https://lore.kernel.org/r/20230217204411.212709-1-mgamal@redhat.com Signed-off-by: Wei Liu Signed-off-by: Sasha Levin

Drivers: hv: vmbus: Optimize vmbus_on_event

2022-09-23T09:27:17Z

In the vmbus_on_event loop, 2 jiffies timer will not serve the purpose if callback_fn takes longer. For effective use move this check inside of callback functions where needed. Out of all the VMbus drivers using vmbus_on_event, only storvsc has a high packet volume, thus add this limit only in storvsc callback for now. There is no apparent benefit of loop itself because this tasklet will be scheduled anyway again if there are packets left in ring buffer. This patch removes this unnecessary loop as well. Signed-off-by: Saurabh Sengar Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/1658741848-4210-1-git-send-email-ssengar@linux.microsoft.com Signed-off-by: Wei Liu

Drivers: hv: vm_bus: Handle vmbus rescind calls after vmbus is suspended

2022-07-11T18:53:42Z

Add a flag to indicate that the vmbus is suspended so we should ignore any offer message. Add a new work_queue for rescind msg, so we could drain it along with other offer work_queues upon suspension. It was observed that in some hibernation related scenario testing, after vmbus_bus_suspend() we get rescind offer message for the vmbus. This would lead to processing of a rescind message for a channel that has already been suspended. Signed-off-by: Shradha Gupta Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20220711041147.GA5569@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net Signed-off-by: Wei Liu

Drivers: hv: vmbus: Remove support for Hyper-V 2008 and Hyper-V 2008R2/Win7

2022-05-11T17:49:49Z

The VMbus driver has special case code for running on the first released versions of Hyper-V: 2008 and 2008 R2/Windows 7. These versions are now out of support (except for extended security updates) and lack the performance features needed for effective production usage of Linux guests. Simplify the code by removing the negotiation of the VMbus protocol versions required for these releases of Hyper-V, and by removing the special case code for handling these VMbus protocol versions. Signed-off-by: Michael Kelley Reviewed-by: Andrea Parri (Microsoft) Link: https://lore.kernel.org/r/1651509391-2058-2-git-send-email-mikelley@microsoft.com Signed-off-by: Wei Liu

Drivers: hv: vmbus: Add SNP support for VMbus channel initiate message

2021-10-28T11:22:55Z

The monitor pages in the CHANNELMSG_INITIATE_CONTACT msg are shared with host in Isolation VM and so it's necessary to use hvcall to set them visible to host. In Isolation VM with AMD SEV SNP, the access address should be in the extra space which is above shared gpa boundary. So remap these pages into the extra address(pa + shared_gpa_boundary). Introduce monitor_pages_original[] in the struct vmbus_connection to store monitor page virtual address returned by hv_alloc_hyperv_ zeroed_page() and free monitor page via monitor_pages_original in the vmbus_disconnect(). The monitor_pages[] is to used to access monitor page and it is initialized to be equal with monitor_pages_ original. The monitor_pages[] will be overridden in the isolation VM with va of extra address. Introduce monitor_pages_pa[] to store monitor pages' physical address and use it to populate pa in the initiate msg. Reviewed-by: Michael Kelley Signed-off-by: Tianyu Lan Link: https://lore.kernel.org/r/20211025122116.264793-9-ltykernel@gmail.com Signed-off-by: Wei Liu

x86/hyperv: Add ghcb hvcall support for SNP VM

2021-10-28T11:22:49Z

hyperv provides ghcb hvcall to handle VMBus HVCALL_SIGNAL_EVENT and HVCALL_POST_MESSAGE msg in SNP Isolation VM. Add such support. Reviewed-by: Michael Kelley Signed-off-by: Tianyu Lan Link: https://lore.kernel.org/r/20211025122116.264793-8-ltykernel@gmail.com Signed-off-by: Wei Liu