user/sven/linux.git/include/linux/hyperv.h, branch v6.1.87

Drivers: hv: vmbus: Calculate ring buffer size for more efficient use of memory

2024-04-03T13:19:40Z

commit b8209544296edbd1af186e2ea9c648642c37b18c upstream. The VMBUS_RING_SIZE macro adds space for a ring buffer header to the requested ring buffer size. The header size is always 1 page, and so its size varies based on the PAGE_SIZE for which the kernel is built. If the requested ring buffer size is a large power-of-2 size and the header size is small, the resulting size is inefficient in its use of memory. For example, a 512 Kbyte ring buffer with a 4 Kbyte page size results in a 516 Kbyte allocation, which is rounded to up 1 Mbyte by the memory allocator, and wastes 508 Kbytes of memory. In such situations, the exact size of the ring buffer isn't that important, and it's OK to allocate the 4 Kbyte header at the beginning of the 512 Kbytes, leaving the ring buffer itself with just 508 Kbytes. The memory allocation can be 512 Kbytes instead of 1 Mbyte and nothing is wasted. Update VMBUS_RING_SIZE to implement this approach for "large" ring buffer sizes. "Large" is somewhat arbitrarily defined as 8 times the size of the ring buffer header (which is of size PAGE_SIZE). For example, for 4 Kbyte PAGE_SIZE, ring buffers of 32 Kbytes and larger use the first 4 Kbytes as the ring buffer header. For 64 Kbyte PAGE_SIZE, ring buffers of 512 Kbytes and larger use the first 64 Kbytes as the ring buffer header. In both cases, smaller sizes add space for the header so the ring size isn't reduced too much by using part of the space for the header. For example, with a 64 Kbyte page size, we don't want a 128 Kbyte ring buffer to be reduced to 64 Kbytes by allocating half of the space for the header. In such a case, the memory allocation is less efficient, but it's the best that can be done. While the new algorithm slightly changes the amount of space allocated for ring buffers by drivers that use VMBUS_RING_SIZE, the devices aren't known to be sensitive to small changes in ring buffer size, so there shouldn't be any effect. Fixes: c1135c7fd0e9 ("Drivers: hv: vmbus: Introduce types of GPADL") Fixes: 6941f67ad37d ("hv_netvsc: Calculate correct ring size when PAGE_SIZE is not 4 Kbytes") Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218502 Cc: stable@vger.kernel.org Signed-off-by: Michael Kelley Reviewed-by: Saurabh Sengar Reviewed-by: Dexuan Cui Tested-by: Souradeep Chakrabarti Link: https://lore.kernel.org/r/20240229004533.313662-1-mhklinux@outlook.com Signed-off-by: Wei Liu Message-ID: <20240229004533.313662-1-mhklinux@outlook.com> Signed-off-by: Greg Kroah-Hartman

video: hyperv_fb: Avoid taking busy spinlock on panic path

2022-12-31T12:32:56Z

[ Upstream commit 1d044ca035dc22df0d3b39e56f2881071d9118bd ] The Hyper-V framebuffer code registers a panic notifier in order to try updating its fbdev if the kernel crashed. The notifier callback is straightforward, but it calls the vmbus_sendpacket() routine eventually, and such function takes a spinlock for the ring buffer operations. Panic path runs in atomic context, with local interrupts and preemption disabled, and all secondary CPUs shutdown. That said, taking a spinlock might cause a lockup if a secondary CPU was disabled with such lock taken. Fix it here by checking if the ring buffer spinlock is busy on Hyper-V framebuffer panic notifier; if so, bail-out avoiding the potential lockup scenario. Cc: Andrea Parri (Microsoft) Cc: Dexuan Cui Cc: Haiyang Zhang Cc: "K. Y. Srinivasan" Cc: Michael Kelley Cc: Stephen Hemminger Cc: Tianyu Lan Cc: Wei Liu Tested-by: Fabio A M Martins Signed-off-by: Guilherme G. Piccoli Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20220819221731.480795-10-gpiccoli@igalia.com Signed-off-by: Wei Liu Signed-off-by: Sasha Levin

Merge tag 'driver-core-5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

2022-06-03T18:48:47Z

Pull driver core updates from Greg KH: "Here is the set of driver core changes for 5.19-rc1. Lots of tiny driver core changes and cleanups happened this cycle, but the two major things are: - firmware_loader reorganization and additions including the ability to have XZ compressed firmware images and the ability for userspace to initiate the firmware load when it needs to, instead of being always initiated by the kernel. FPGA devices specifically want this ability to have their firmware changed over the lifetime of the system boot, and this allows them to work without having to come up with yet-another-custom-uapi interface for loading firmware for them. - physical location support added to sysfs so that devices that know this information, can tell userspace where they are located in a common way. Some ACPI devices already support this today, and more bus types should support this in the future. Smaller changes include: - driver_override api cleanups and fixes - error path cleanups and fixes - get_abi script fixes - deferred probe timeout changes. It's that last change that I'm the most worried about. It has been reported to cause boot problems for a number of systems, and I have a tested patch series that resolves this issue. But I didn't get it merged into my tree before 5.18-final came out, so it has not gotten any linux-next testing. I'll send the fixup patches (there are 2) as a follow-on series to this pull request. All have been tested in linux-next for weeks, with no reported issues other than the above-mentioned boot time-outs" * tag 'driver-core-5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (55 commits) driver core: fix deadlock in __device_attach kernfs: Separate kernfs_pr_cont_buf and rename_lock. topology: Remove unused cpu_cluster_mask() driver core: Extend deferred probe timeout on driver registration MAINTAINERS: add Russ Weight as a firmware loader maintainer driver: base: fix UAF when driver_attach failed test_firmware: fix end of loop test in upload_read_show() driver core: location: Add "back" as a possible output for panel driver core: location: Free struct acpi_pld_info *pld driver core: Add "*" wildcard support to driver_async_probe cmdline param driver core: location: Check for allocations failure arch_topology: Trace the update thermal pressure kernfs: Rename kernfs_put_open_node to kernfs_unlink_open_file. export: fix string handling of namespace in EXPORT_SYMBOL_NS rpmsg: use local 'dev' variable rpmsg: Fix calling device_lock() on non-initialized device firmware_loader: describe 'module' parameter of firmware_upload_register() firmware_loader: Move definitions from sysfs_upload.h to sysfs.h firmware_loader: Fix configs for sysfs split selftests: firmware: Add firmware upload selftests ...

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: Refactor the ring-buffer iterator functions

2022-04-28T15:01:15Z

With no users of hv_pkt_iter_next_raw() and no "external" users of hv_pkt_iter_first_raw(), the iterator functions can be refactored and simplified to remove some indirection/code. Signed-off-by: Andrea Parri (Microsoft) Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20220428145107.7878-6-parri.andrea@gmail.com Signed-off-by: Wei Liu

Drivers: hv: vmbus: Accept hv_sock offers in isolated guests

2022-04-28T15:01:14Z

So that isolated guests can communicate with the host via hv_sock channels. Signed-off-by: Andrea Parri (Microsoft) Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20220428145107.7878-5-parri.andrea@gmail.com Signed-off-by: Wei Liu

hv_sock: Add validation for untrusted Hyper-V values

2022-04-28T15:01:14Z

For additional robustness in the face of Hyper-V errors or malicious behavior, validate all values that originate from packets that Hyper-V has sent to the guest in the host-to-guest ring buffer. Ensure that invalid values cannot cause data being copied out of the bounds of the source buffer in hvs_stream_dequeue(). Signed-off-by: Andrea Parri (Microsoft) Reviewed-by: Michael Kelley Reviewed-by: Stefano Garzarella Link: https://lore.kernel.org/r/20220428145107.7878-4-parri.andrea@gmail.com Signed-off-by: Wei Liu

Drivers: hv: vmbus: Introduce {lock,unlock}_requestor()

2022-04-25T15:51:13Z

To abtract the lock and unlock operations on the requestor spin lock. The helpers will come in handy in hv_pci. No functional change. Suggested-by: Michael Kelley Signed-off-by: Andrea Parri (Microsoft) Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20220419122325.10078-6-parri.andrea@gmail.com Signed-off-by: Wei Liu

Drivers: hv: vmbus: Introduce vmbus_request_addr_match()

2022-04-25T15:51:12Z

The function can be used to retrieve and clear/remove a transation ID from a channel requestor, provided the memory address corresponding to the ID equals a specified address. The function, and its 'lockless' variant __vmbus_request_addr_match(), will be used by hv_pci. Refactor vmbus_request_addr() to reuse the 'newly' introduced code. No functional change. Suggested-by: Michael Kelley Signed-off-by: Andrea Parri (Microsoft) Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20220419122325.10078-5-parri.andrea@gmail.com Signed-off-by: Wei Liu

Drivers: hv: vmbus: Introduce vmbus_sendpacket_getid()

2022-04-25T15:51:12Z

The function can be used to send a VMbus packet and retrieve the corresponding transaction ID. It will be used by hv_pci. No functional change. Suggested-by: Michael Kelley Signed-off-by: Andrea Parri (Microsoft) Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20220419122325.10078-4-parri.andrea@gmail.com Signed-off-by: Wei Liu