summaryrefslogtreecommitdiff
path: root/include/linux/hyperv.h
AgeCommit message (Collapse)Author
2023-09-04Merge tag 'hyperv-next-signed-20230902' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux Pull hyperv updates from Wei Liu: - Support for SEV-SNP guests on Hyper-V (Tianyu Lan) - Support for TDX guests on Hyper-V (Dexuan Cui) - Use SBRM API in Hyper-V balloon driver (Mitchell Levy) - Avoid dereferencing ACPI root object handle in VMBus driver (Maciej Szmigiero) - A few misecllaneous fixes (Jiapeng Chong, Nathan Chancellor, Saurabh Sengar) * tag 'hyperv-next-signed-20230902' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux: (24 commits) x86/hyperv: Remove duplicate include x86/hyperv: Move the code in ivm.c around to avoid unnecessary ifdef's x86/hyperv: Remove hv_isolation_type_en_snp x86/hyperv: Use TDX GHCI to access some MSRs in a TDX VM with the paravisor Drivers: hv: vmbus: Bring the post_msg_page back for TDX VMs with the paravisor x86/hyperv: Introduce a global variable hyperv_paravisor_present Drivers: hv: vmbus: Support >64 VPs for a fully enlightened TDX/SNP VM x86/hyperv: Fix serial console interrupts for fully enlightened TDX guests Drivers: hv: vmbus: Support fully enlightened TDX guests x86/hyperv: Support hypercalls for fully enlightened TDX guests x86/hyperv: Add hv_isolation_type_tdx() to detect TDX guests x86/hyperv: Fix undefined reference to isolation_type_en_snp without CONFIG_HYPERV x86/hyperv: Add missing 'inline' to hv_snp_boot_ap() stub hv: hyperv.h: Replace one-element array with flexible-array member Drivers: hv: vmbus: Don't dereference ACPI root object handle x86/hyperv: Add hyperv-specific handling for VMMCALL under SEV-ES x86/hyperv: Add smp support for SEV-SNP guest clocksource: hyper-v: Mark hyperv tsc page unencrypted in sev-snp enlightened guest x86/hyperv: Use vmmcall to implement Hyper-V hypercall in sev-snp enlightened guest drivers: hv: Mark percpu hvcall input arg page unencrypted in SEV-SNP enlightened guest ...
2023-08-22hv: hyperv.h: Replace one-element array with flexible-array memberSaurabh Sengar
One-element and zero-length arrays are deprecated. Replace one-element array in struct vmtransfer_page_packet_header with flexible-array member. This change fixes below warning: [ 2.593788] ================================================================================ [ 2.593908] UBSAN: array-index-out-of-bounds in drivers/net/hyperv/netvsc.c:1445:41 [ 2.593989] index 1 is out of range for type 'vmtransfer_page_range [1]' [ 2.594049] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 6.5.0-rc4-next-20230803+ #1 [ 2.594114] Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS Hyper-V UEFI Release v4.1 04/20/2023 [ 2.594121] Call Trace: [ 2.594126] <IRQ> [ 2.594133] dump_stack_lvl+0x4c/0x70 [ 2.594154] dump_stack+0x14/0x20 [ 2.594162] __ubsan_handle_out_of_bounds+0xa6/0xf0 [ 2.594224] netvsc_poll+0xc01/0xc90 [hv_netvsc] [ 2.594258] __napi_poll+0x30/0x1e0 [ 2.594320] net_rx_action+0x194/0x2f0 [ 2.594333] __do_softirq+0xde/0x31e [ 2.594345] __irq_exit_rcu+0x6b/0x90 [ 2.594357] irq_exit_rcu+0x12/0x20 [ 2.594366] sysvec_hyperv_callback+0x84/0x90 [ 2.594376] </IRQ> [ 2.594379] <TASK> [ 2.594383] asm_sysvec_hyperv_callback+0x1f/0x30 [ 2.594394] RIP: 0010:pv_native_safe_halt+0xf/0x20 [ 2.594452] Code: 0b 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 05 35 3f 00 fb f4 <c3> cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 [ 2.594459] RSP: 0018:ffffb841c00d3e88 EFLAGS: 00000256 [ 2.594469] RAX: ffff9d18c326f4a0 RBX: ffff9d18c031df40 RCX: 4000000000000000 [ 2.594475] RDX: 0000000000000001 RSI: 0000000000000082 RDI: 00000000000268dc [ 2.594481] RBP: ffffb841c00d3e90 R08: 00000066a171109b R09: 00000000d33d2600 [ 2.594486] R10: 000000009a41bf00 R11: 0000000000000000 R12: 0000000000000001 [ 2.594491] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 2.594501] ? ct_kernel_exit.constprop.0+0x7d/0x90 [ 2.594513] ? default_idle+0xd/0x20 [ 2.594523] arch_cpu_idle+0xd/0x20 [ 2.594532] default_idle_call+0x30/0xe0 [ 2.594542] do_idle+0x200/0x240 [ 2.594553] ? complete+0x71/0x80 [ 2.594613] cpu_startup_entry+0x24/0x30 [ 2.594624] start_secondary+0x12d/0x160 [ 2.594634] secondary_startup_64_no_verify+0x17e/0x18b [ 2.594649] </TASK> [ 2.594656] ================================================================================ With this change the structure size is reduced by 8 bytes, below is the pahole output. struct vmtransfer_page_packet_header { struct vmpacket_descriptor d; /* 0 16 */ u16 xfer_pageset_id; /* 16 2 */ u8 sender_owns_set; /* 18 1 */ u8 reserved; /* 19 1 */ u32 range_cnt; /* 20 4 */ struct vmtransfer_page_range ranges[]; /* 24 0 */ /* size: 24, cachelines: 1, members: 6 */ /* last cacheline: 24 bytes */ }; The validation code in the netvsc driver is affected by changing the struct size, but the effects have been examined and have been determined to be appropriate. Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Wei Liu <wei.liu@kernel.org> Link: https://lore.kernel.org/r/1692160478-18469-1-git-send-email-ssengar@linux.microsoft.com
2023-08-22x86/hyperv: Set Virtual Trust Level in VMBus init messageTianyu Lan
SEV-SNP guests on Hyper-V can run at multiple Virtual Trust Levels (VTL). During boot, get the VTL at which we're running using the GET_VP_REGISTERs hypercall, and save the value for future use. Then during VMBus initialization, set the VTL with the saved value as required in the VMBus init message. Reviewed-by: Dexuan Cui <decui@microsoft.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Tianyu Lan <tiala@microsoft.com> Signed-off-by: Wei Liu <wei.liu@kernel.org> Link: https://lore.kernel.org/r/20230818102919.1318039-3-ltykernel@gmail.com
2023-08-02Drivers: hv: vmbus: Remove unused extern declaration vmbus_ontimer()YueHaibing
Since commit 30fbee49b071 ("Staging: hv: vmbus: Get rid of the unused function vmbus_ontimer()") this is not used anymore, so can remove it. Signed-off-by: YueHaibing <yuehaibing@huawei.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20230725142108.27280-1-yuehaibing@huawei.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2023-02-24Merge tag 'driver-core-6.3-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core Pull driver core updates from Greg KH: "Here is the large set of driver core changes for 6.3-rc1. There's a lot of changes this development cycle, most of the work falls into two different categories: - fw_devlink fixes and updates. This has gone through numerous review cycles and lots of review and testing by lots of different devices. Hopefully all should be good now, and Saravana will be keeping a watch for any potential regression on odd embedded systems. - driver core changes to work to make struct bus_type able to be moved into read-only memory (i.e. const) The recent work with Rust has pointed out a number of areas in the driver core where we are passing around and working with structures that really do not have to be dynamic at all, and they should be able to be read-only making things safer overall. This is the contuation of that work (started last release with kobject changes) in moving struct bus_type to be constant. We didn't quite make it for this release, but the remaining patches will be finished up for the release after this one, but the groundwork has been laid for this effort. Other than that we have in here: - debugfs memory leak fixes in some subsystems - error path cleanups and fixes for some never-able-to-be-hit codepaths. - cacheinfo rework and fixes - Other tiny fixes, full details are in the shortlog All of these have been in linux-next for a while with no reported problems" [ Geert Uytterhoeven points out that that last sentence isn't true, and that there's a pending report that has a fix that is queued up - Linus ] * tag 'driver-core-6.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (124 commits) debugfs: drop inline constant formatting for ERR_PTR(-ERROR) OPP: fix error checking in opp_migrate_dentry() debugfs: update comment of debugfs_rename() i3c: fix device.h kernel-doc warnings dma-mapping: no need to pass a bus_type into get_arch_dma_ops() driver core: class: move EXPORT_SYMBOL_GPL() lines to the correct place Revert "driver core: add error handling for devtmpfs_create_node()" Revert "devtmpfs: add debug info to handle()" Revert "devtmpfs: remove return value of devtmpfs_delete_node()" driver core: cpu: don't hand-override the uevent bus_type callback. devtmpfs: remove return value of devtmpfs_delete_node() devtmpfs: add debug info to handle() driver core: add error handling for devtmpfs_create_node() driver core: bus: update my copyright notice driver core: bus: add bus_get_dev_root() function driver core: bus: constify bus_unregister() driver core: bus: constify some internal functions driver core: bus: constify bus_get_kset() driver core: bus: constify bus_register/unregister_notifier() driver core: remove private pointer from struct bus_type ...
2023-01-27drivers: hv: move device_to_hv_device to use container_of_const()Greg Kroah-Hartman
The driver core is changing to pass some pointers as const, so move device_to_hv_device() to use container_of_const() to handle this change. device_to_hv_device() now properly keeps the const-ness of the pointer passed into it, while as before it could be lost. Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: Dexuan Cui <decui@microsoft.com> Acked-by: Wei Liu <wei.liu@kernel.org> Acked-by: Hans de Goede <hdegoede@redhat.com> Link: https://lore.kernel.org/r/20230111113018.459199-11-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-17Drivers: hv: Make remove callback of hyperv driver void returnedDawei Li
Since commit fc7a6209d571 ("bus: Make remove callback return void") forces bus_type::remove be void-returned, it doesn't make much sense for any bus based driver implementing remove callbalk to return non-void to its caller. As such, change the remove function for Hyper-V VMBus based drivers to return void. Signed-off-by: Dawei Li <set_pte_at@outlook.com> Link: https://lore.kernel.org/r/TYCP286MB2323A93C55526E4DF239D3ACCAFA9@TYCP286MB2323.JPNP286.PROD.OUTLOOK.COM Signed-off-by: Wei Liu <wei.liu@kernel.org>
2022-11-28hv: fix comment typo in vmbus_channel/low_latencyOlaf Hering
morev vs. more. Signed-off-by: Olaf Hering <olaf@aepfle.de> Link: https://lore.kernel.org/r/20221105115401.21592-1-olaf@aepfle.de Signed-off-by: Wei Liu <wei.liu@kernel.org>
2022-11-28video: hyperv_fb: Avoid taking busy spinlock on panic pathGuilherme G. Piccoli
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) <parri.andrea@gmail.com> Cc: Dexuan Cui <decui@microsoft.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Michael Kelley <mikelley@microsoft.com> Cc: Stephen Hemminger <sthemmin@microsoft.com> Cc: Tianyu Lan <Tianyu.Lan@microsoft.com> Cc: Wei Liu <wei.liu@kernel.org> Tested-by: Fabio A M Martins <fabiomirmar@gmail.com> Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20220819221731.480795-10-gpiccoli@igalia.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2022-06-03Merge tag 'driver-core-5.19-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core 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 ...
2022-05-11Drivers: hv: vmbus: Remove support for Hyper-V 2008 and Hyper-V 2008R2/Win7Michael Kelley
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 <mikelley@microsoft.com> Reviewed-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Link: https://lore.kernel.org/r/1651509391-2058-2-git-send-email-mikelley@microsoft.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2022-04-28Drivers: hv: vmbus: Refactor the ring-buffer iterator functionsAndrea Parri (Microsoft)
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) <parri.andrea@gmail.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20220428145107.7878-6-parri.andrea@gmail.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2022-04-28Drivers: hv: vmbus: Accept hv_sock offers in isolated guestsAndrea Parri (Microsoft)
So that isolated guests can communicate with the host via hv_sock channels. Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20220428145107.7878-5-parri.andrea@gmail.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2022-04-28hv_sock: Add validation for untrusted Hyper-V valuesAndrea Parri (Microsoft)
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) <parri.andrea@gmail.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Link: https://lore.kernel.org/r/20220428145107.7878-4-parri.andrea@gmail.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2022-04-25Drivers: hv: vmbus: Introduce {lock,unlock}_requestor()Andrea Parri (Microsoft)
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 <mikelley@microsoft.com> Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20220419122325.10078-6-parri.andrea@gmail.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2022-04-25Drivers: hv: vmbus: Introduce vmbus_request_addr_match()Andrea Parri (Microsoft)
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 <mikelley@microsoft.com> Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20220419122325.10078-5-parri.andrea@gmail.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2022-04-25Drivers: hv: vmbus: Introduce vmbus_sendpacket_getid()Andrea Parri (Microsoft)
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 <mikelley@microsoft.com> Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20220419122325.10078-4-parri.andrea@gmail.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2022-04-25Drivers: hv: vmbus: Add VMbus IMC device to unsupported listMichael Kelley
Hyper-V may offer an Initial Machine Configuration (IMC) synthetic device to guest VMs. The device may be used by Windows guests to get specialization information, such as the hostname. But the device is not used in Linux and there is no Linux driver, so it is unsupported. Currently, the IMC device GUID is not recognized by the VMbus driver, which results in an "Unknown GUID" error message during boot. Add the GUID to the list of known but unsupported devices so that the error message is not generated. Other than avoiding the error message, there is no change in guest behavior. Signed-off-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/1649818140-100953-1-git-send-email-mikelley@microsoft.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2022-04-22hv: Use driver_set_override() instead of open-codingKrzysztof Kozlowski
Use a helper to set driver_override to the reduce amount of duplicated code. Make the driver_override field const char, because it is not modified by the core and it matches other subsystems. Reviewed-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> Link: https://lore.kernel.org/r/20220419113435.246203-5-krzysztof.kozlowski@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-02-07Drivers: hv: vmbus: Rework use of DMA_BIT_MASK(64)Michael Kelley
Using DMA_BIT_MASK(64) as an initializer for a global variable causes problems with Clang 12.0.1. The compiler doesn't understand that value 64 is excluded from the shift at compile time, resulting in a build error. While this is a compiler problem, avoid the issue by setting up the dma_mask memory as part of struct hv_device, and initialize it using dma_set_mask(). Reported-by: Nathan Chancellor <nathan@kernel.org> Reported-by: Vitaly Chikunov <vt@altlinux.org> Reported-by: Jakub Kicinski <kuba@kernel.org> Fixes: 743b237c3a7b ("scsi: storvsc: Add Isolation VM support for storvsc driver") Signed-off-by: Michael Kelley <mikelley@microsoft.com> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Nathan Chancellor <nathan@kernel.org> Link: https://lore.kernel.org/r/1644176216-12531-1-git-send-email-mikelley@microsoft.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-12-20net: netvsc: Add Isolation VM support for netvsc driverTianyu Lan
In Isolation VM, all shared memory with host needs to mark visible to host via hvcall. vmbus_establish_gpadl() has already done it for netvsc rx/tx ring buffer. The page buffer used by vmbus_sendpacket_ pagebuffer() stills need to be handled. Use DMA API to map/umap these memory during sending/receiving packet and Hyper-V swiotlb bounce buffer dma address will be returned. The swiotlb bounce buffer has been masked to be visible to host during boot up. rx/tx ring buffer is allocated via vzalloc() and they need to be mapped into unencrypted address space(above vTOM) before sharing with host and accessing. Add hv_map/unmap_memory() to map/umap rx /tx ring buffer. Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com> Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20211213071407.314309-6-ltykernel@gmail.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-12-20scsi: storvsc: Add Isolation VM support for storvsc driverTianyu Lan
In Isolation VM, all shared memory with host needs to mark visible to host via hvcall. vmbus_establish_gpadl() has already done it for storvsc rx/tx ring buffer. The page buffer used by vmbus_sendpacket_ mpb_desc() still needs to be handled. Use DMA API(scsi_dma_map/unmap) to map these memory during sending/receiving packet and return swiotlb bounce buffer dma address. In Isolation VM, swiotlb bounce buffer is marked to be visible to host and the swiotlb force mode is enabled. Set device's dma min align mask to HV_HYP_PAGE_SIZE - 1 in order to keep the original data offset in the bounce buffer. Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com> Reviewed-by: Long Li <longli@microsoft.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20211213071407.314309-5-ltykernel@gmail.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-10-28Drivers: hv: vmbus: Remove unused code to check for subchannelsMichael Kelley
The last caller of vmbus_are_subchannels_present() was removed in commit c967590457ca ("scsi: storvsc: Fix a race in sub-channel creation that can cause panic"). Remove this dead code, and the utility function invoke_sc_cb() that it is the only caller of. Signed-off-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/1635191674-34407-1-git-send-email-mikelley@microsoft.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-10-28Drivers: hv: vmbus: Mark vmbus ring buffer visible to host in Isolation VMTianyu Lan
Mark vmbus ring buffer visible with set_memory_decrypted() when establish gpadl handle. Reviewed-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com> Link: https://lore.kernel.org/r/20211025122116.264793-5-ltykernel@gmail.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-07-22hv: hyperv.h: Remove unused inline functionsSonia Sharma
There are some unused inline functions in hyper.h. Remove those unused functions. Signed-off-by: Sonia Sharma <sonia.sharma@microsoft.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/1626903663-23615-1-git-send-email-sosha@linux.microsoft.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-05-14scsi: storvsc: Use blk_mq_unique_tag() to generate requestIDsAndrea Parri (Microsoft)
Use blk_mq_unique_tag() to generate requestIDs for StorVSC, avoiding all issues with allocating enough entries in the VMbus requestor. Suggested-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Acked-by: Martin K. Petersen <martin.petersen@oracle.com> Link: https://lore.kernel.org/r/20210510210841.370472-1-parri.andrea@gmail.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-05-14Drivers: hv: vmbus: Copy packets sent by Hyper-V out of the ring bufferAndres Beltran
Pointers to ring-buffer packets sent by Hyper-V are used within the guest VM. Hyper-V can send packets with erroneous values or modify packet fields after they are processed by the guest. To defend against these scenarios, return a copy of the incoming VMBus packet after validating its length and offset fields in hv_pkt_iter_first(). In this way, the packet can no longer be modified by the host. Signed-off-by: Andres Beltran <lkmlabelt@gmail.com> Co-developed-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20210408161439.341988-1-parri.andrea@gmail.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-04-28Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsiLinus Torvalds
Pull SCSI updates from James Bottomley: "This consists of the usual driver updates (ufs, target, tcmu, smartpqi, lpfc, zfcp, qla2xxx, mpt3sas, pm80xx). The major core change is using a sbitmap instead of an atomic for queue tracking" * tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (412 commits) scsi: target: tcm_fc: Fix a kernel-doc header scsi: target: Shorten ALUA error messages scsi: target: Fix two format specifiers scsi: target: Compare explicitly with SAM_STAT_GOOD scsi: sd: Introduce a new local variable in sd_check_events() scsi: dc395x: Open-code status_byte(u8) calls scsi: 53c700: Open-code status_byte(u8) calls scsi: smartpqi: Remove unused functions scsi: qla4xxx: Remove an unused function scsi: myrs: Remove unused functions scsi: myrb: Remove unused functions scsi: mpt3sas: Fix two kernel-doc headers scsi: fcoe: Suppress a compiler warning scsi: libfc: Fix a format specifier scsi: aacraid: Remove an unused function scsi: core: Introduce enum scsi_disposition scsi: core: Modify the scsi_send_eh_cmnd() return value for the SDEV_BLOCK case scsi: core: Rename scsi_softirq_done() into scsi_complete() scsi: core: Remove an incorrect comment scsi: core: Make the scsi_alloc_sgtables() documentation more accurate ...
2021-04-18Drivers: hv: vmbus: Drivers: hv: vmbus: Introduce ↵Andrea Parri (Microsoft)
CHANNELMSG_MODIFYCHANNEL_RESPONSE Introduce the CHANNELMSG_MODIFYCHANNEL_RESPONSE message type, and code to receive and process such a message. Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20210416143449.16185-3-parri.andrea@gmail.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-04-18Drivers: hv: vmbus: Introduce and negotiate VMBus protocol version 5.3Andrea Parri (Microsoft)
Hyper-V has added VMBus protocol version 5.3. Allow Linux guests to negotiate the new version on version of Hyper-V that support it. Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20210416143449.16185-2-parri.andrea@gmail.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-03-24hv: hyperv.h: a few mundane typo fixesBhaskar Chowdhury
s/sructure/structure/ s/extention/extension/ s/offerred/offered/ s/adversley/adversely/ Signed-off-by: Bhaskar Chowdhury <unixbhaskar@gmail.com> Acked-by: Randy Dunlap <rdunlap@infradead.org> Link: https://lore.kernel.org/r/20210321233108.3885240-1-unixbhaskar@gmail.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-03-17scsi: storvsc: Enable scatterlist entry lengths > 4KbytesMichael Kelley
storvsc currently sets .dma_boundary to limit scatterlist entries to 4 Kbytes, which is less efficient with huge pages that offer large chunks of contiguous physical memory. Improve the algorithm for creating the Hyper-V guest physical address PFN array so that scatterlist entries with lengths > 4Kbytes are handled. As a result, remove the .dma_boundary setting. The improved algorithm also adds support for scatterlist entries with offsets >= 4Kbytes, which is supported by many other SCSI low-level drivers. And it retains support for architectures where possibly PAGE_SIZE != HV_HYP_PAGE_SIZE (such as ARM64). Link: https://lore.kernel.org/r/1614120294-1930-1-git-send-email-mikelley@microsoft.com Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2021-02-15Revert "Drivers: hv: vmbus: Copy packets sent by Hyper-V out of the ring buffer"Wei Liu
This reverts commit a8c3209998afb5c4941b49e35b513cea9050cb4a. It is reported that the said commit caused regression in netvsc. Reported-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-02-11hv: hyperv.h: Replace one-element array with flexible-array in struct ↵Gustavo A. R. Silva
icmsg_negotiate There is a regular need in the kernel to provide a way to declare having a dynamically sized set of trailing elements in a structure. Kernel code should always use “flexible array members”[1] for these cases. The older style of one-element or zero-length arrays should no longer be used[2]. Refactor the code according to the use of a flexible-array member in struct icmsg_negotiate, instead of a one-element array. Also, this helps the ongoing efforts to enable -Warray-bounds and fix the following warnings: drivers/hv/channel_mgmt.c:315:23: warning: array subscript 1 is above array bounds of ‘struct ic_version[1]’ [-Warray-bounds] drivers/hv/channel_mgmt.c:316:23: warning: array subscript 1 is above array bounds of ‘struct ic_version[1]’ [-Warray-bounds] [1] https://en.wikipedia.org/wiki/Flexible_array_member [2] https://www.kernel.org/doc/html/v5.9/process/deprecated.html#zero-length-and-one-element-arrays Link: https://github.com/KSPP/linux/issues/79 Link: https://github.com/KSPP/linux/issues/109 Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20210201174334.GA171933@embeddedor Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-02-11Drivers: hv: vmbus: Restrict vmbus_devices on isolated guestsAndrea Parri (Microsoft)
Only the VSCs or ICs that have been hardened and that are critical for the successful adoption of Confidential VMs should be allowed if the guest is running isolated. This change reduces the footprint of the code that will be exercised by Confidential VMs and hence the exposure to bugs and vulnerabilities. Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20210201144814.2701-3-parri.andrea@gmail.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-02-05Drivers: hv: vmbus: Resolve race condition in vmbus_onoffer_rescind()Andrea Parri (Microsoft)
An erroneous or malicious host could send multiple rescind messages for a same channel. In vmbus_onoffer_rescind(), the guest maps the channel ID to obtain a pointer to the channel object and it eventually releases such object and associated data. The host could time rescind messages and lead to an use-after-free. Add a new flag to the channel structure to make sure that only one instance of vmbus_onoffer_rescind() can get the reference to the channel object. Reported-by: Juan Vazquez <juvazq@microsoft.com> Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20201209070827.29335-6-parri.andrea@gmail.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-02-05hv_utils: Add validation for untrusted Hyper-V valuesAndres Beltran
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 indexing off the end of the icversion_data array in vmbus_prep_negotiate_resp(). Signed-off-by: Andres Beltran <lkmlabelt@gmail.com> Co-developed-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20201109100704.9152-1-parri.andrea@gmail.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-02-05Drivers: hv: vmbus: Copy packets sent by Hyper-V out of the ring bufferAndres Beltran
Pointers to ring-buffer packets sent by Hyper-V are used within the guest VM. Hyper-V can send packets with erroneous values or modify packet fields after they are processed by the guest. To defend against these scenarios, return a copy of the incoming VMBus packet after validating its length and offset fields in hv_pkt_iter_first(). In this way, the packet can no longer be modified by the host. Signed-off-by: Andres Beltran <lkmlabelt@gmail.com> Co-developed-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jakub Kicinski <kuba@kernel.org> Cc: "James E.J. Bottomley" <jejb@linux.ibm.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: netdev@vger.kernel.org Cc: linux-scsi@vger.kernel.org Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20201208045311.10244-1-parri.andrea@gmail.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2020-11-17hv_netvsc: Use vmbus_requestor to generate transaction IDs for VMBus hardeningAndres Beltran
Currently, pointers to guest memory are passed to Hyper-V as transaction IDs in netvsc. In the face of errors or malicious behavior in Hyper-V, netvsc should not expose or trust the transaction IDs returned by Hyper-V to be valid guest memory addresses. Instead, use small integers generated by vmbus_requestor as requests (transaction) IDs. Signed-off-by: Andres Beltran <lkmlabelt@gmail.com> Co-developed-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Acked-by: Jakub Kicinski <kuba@kernel.org> Reviewed-by: Wei Liu <wei.liu@kernel.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jakub Kicinski <kuba@kernel.org> Cc: netdev@vger.kernel.org Link: https://lore.kernel.org/r/20201109100402.8946-4-parri.andrea@gmail.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2020-11-17Drivers: hv: vmbus: Add vmbus_requestor data structure for VMBus hardeningAndres Beltran
Currently, VMbus drivers use pointers into guest memory as request IDs for interactions with Hyper-V. To be more robust in the face of errors or malicious behavior from a compromised Hyper-V, avoid exposing guest memory addresses to Hyper-V. Also avoid Hyper-V giving back a bad request ID that is then treated as the address of a guest data structure with no validation. Instead, encapsulate these memory addresses and provide small integers as request IDs. Signed-off-by: Andres Beltran <lkmlabelt@gmail.com> Co-developed-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Reviewed-by: Wei Liu <wei.liu@kernel.org> Link: https://lore.kernel.org/r/20201109100402.8946-2-parri.andrea@gmail.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2020-09-28hv: hyperv.h: Introduce some hvpfn helper functionsBoqun Feng
When a guest communicate with the hypervisor, it must use HV_HYP_PAGE to calculate PFN, so introduce a few hvpfn helper functions as the counterpart of the page helper functions. This is the preparation for supporting guest whose PAGE_SIZE is not 4k. Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20200916034817.30282-7-boqun.feng@gmail.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2020-09-28Drivers: hv: vmbus: Move virt_to_hvpfn() to hyperv headerBoqun Feng
There will be more places other than vmbus where we need to calculate the Hyper-V page PFN from a virtual address, so move virt_to_hvpfn() to hyperv generic header. Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20200916034817.30282-6-boqun.feng@gmail.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2020-09-28Drivers: hv: vmbus: Introduce types of GPADLBoqun Feng
This patch introduces two types of GPADL: HV_GPADL_{BUFFER, RING}. The types of GPADL are purely the concept in the guest, IOW the hypervisor treat them as the same. The reason of introducing the types for GPADL is to support guests whose page size is not 4k (the page size of Hyper-V hypervisor). In these guests, both the headers and the data parts of the ringbuffers need to be aligned to the PAGE_SIZE, because 1) some of the ringbuffers will be mapped into userspace and 2) we use "double mapping" mechanism to support fast wrap-around, and "double mapping" relies on ringbuffers being page-aligned. However, the Hyper-V hypervisor only uses 4k (HV_HYP_PAGE_SIZE) headers. Our solution to this is that we always make the headers of ringbuffers take one guest page and when GPADL is established between the guest and hypervisor, the only first 4k of header is used. To handle this special case, we need the types of GPADL to differ different guest memory usage for GPADL. Type enum is introduced along with several general interfaces to describe the differences between normal buffer GPADL and ringbuffer GPADL. Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20200916034817.30282-4-boqun.feng@gmail.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2020-06-20Drivers: hv: vmbus: Remove the lock field from the vmbus_channel structAndrea Parri (Microsoft)
The spinlock is (now) *not used to protect test-and-set accesses to attributes of the structure or sc_list operations. There is, AFAICT, a distinct lack of {WRITE,READ}_ONCE()s in the handling of channel->state, but the changes below do not seem to make things "worse". ;-) Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Link: https://lore.kernel.org/r/20200617164642.37393-9-parri.andrea@gmail.com Reviewed-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Wei Liu <wei.liu@kernel.org>
2020-06-19Drivers: hv: vmbus: Remove the numa_node field from the vmbus_channel structAndrea Parri (Microsoft)
The field is read only in numa_node_show() and it is already stored twice (after a call to cpu_to_node()) in target_cpu_store() and init_vp_index(); there is no need to "cache" its value in the channel data structure. Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Link: https://lore.kernel.org/r/20200617164642.37393-3-parri.andrea@gmail.com Reviewed-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Wei Liu <wei.liu@kernel.org>
2020-06-19Drivers: hv: vmbus: Remove the target_vp field from the vmbus_channel structAndrea Parri (Microsoft)
The field is read only in __vmbus_open() and it is already stored twice (after a call to hv_cpu_number_to_vp_number()) in target_cpu_store() and init_vp_index(); there is no need to "cache" its value in the channel data structure. Suggested-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Link: https://lore.kernel.org/r/20200617164642.37393-2-parri.andrea@gmail.com Reviewed-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Wei Liu <wei.liu@kernel.org>
2020-05-23Drivers: hv: vmbus: Resolve more races involving init_vp_index()Andrea Parri (Microsoft)
init_vp_index() uses the (per-node) hv_numa_map[] masks to record the CPUs allocated for channel interrupts at a given time, and distribute the performance-critical channels across the available CPUs: in part., the mask of "candidate" target CPUs in a given NUMA node, for a newly offered channel, is determined by XOR-ing the node's CPU mask and the node's hv_numa_map. This operation/mechanism assumes that no offline CPUs is set in the hv_numa_map mask, an assumption that does not hold since such mask is currently not updated when a channel is removed or assigned to a different CPU. To address the issues described above, this adds hooks in the channel removal path (hv_process_channel_removal()) and in target_cpu_store() in order to clear, resp. to update, the hv_numa_map[] masks as needed. This also adds a (missed) update of the masks in init_vp_index() (cf., e.g., the memory-allocation failure path in this function). Like in the case of init_vp_index(), such hooks require to determine if the given channel is performance critical. init_vp_index() does this by parsing the channel's offer, it can not rely on the device data structure (device_obj) to retrieve such information because the device data structure has not been allocated/linked with the channel by the time that init_vp_index() executes. A similar situation may hold in hv_is_alloced_cpu() (defined below); the adopted approach is to "cache" the device type of the channel, as computed by parsing the channel's offer, in the channel structure itself. Fixes: 7527810573436f ("Drivers: hv: vmbus: Introduce the CHANNELMSG_MODIFYCHANNEL message type") Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20200522171901.204127-3-parri.andrea@gmail.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2020-05-20vmbus: Replace zero-length array with flexible-arrayGustavo A. R. Silva
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] sizeof(flexible-array-member) triggers a warning because flexible array members have incomplete type[1]. There are some instances of code in which the sizeof operator is being incorrectly/erroneously applied to zero-length arrays and the result is zero. Such instances may be hiding some bugs. So, this work (flexible-array member conversions) will also help to get completely rid of those sorts of issues. This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Link: https://lore.kernel.org/r/20200507185323.GA14416@embeddedor Signed-off-by: Wei Liu <wei.liu@kernel.org>
2020-05-20scsi: storvsc: Re-init stor_chns when a channel interrupt is re-assignedAndrea Parri (Microsoft)
For each storvsc_device, storvsc keeps track of the channel target CPUs associated to the device (alloced_cpus) and it uses this information to fill a "cache" (stor_chns) mapping CPU->channel according to a certain heuristic. Update the alloced_cpus mask and the stor_chns array when a channel of the storvsc device is re-assigned to a different CPU. Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Cc: "James E.J. Bottomley" <jejb@linux.ibm.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: <linux-scsi@vger.kernel.org> Link: https://lore.kernel.org/r/20200406001514.19876-12-parri.andrea@gmail.com Reviewed-by; Long Li <longli@microsoft.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> [ wei: fix a small issue reported by kbuild test robot <lkp@intel.com> ] Signed-off-by: Wei Liu <wei.liu@kernel.org>
2020-04-23Drivers: hv: vmbus: Introduce the CHANNELMSG_MODIFYCHANNEL message typeAndrea Parri (Microsoft)
VMBus version 4.1 and later support the CHANNELMSG_MODIFYCHANNEL(22) message type which can be used to request Hyper-V to change the vCPU that a channel will interrupt. Introduce the CHANNELMSG_MODIFYCHANNEL message type, and define the vmbus_send_modifychannel() function to send CHANNELMSG_MODIFYCHANNEL requests to the host via a hypercall. The function is then used to define a sysfs "store" operation, which allows to change the (v)CPU the channel will interrupt by using the sysfs interface. The feature can be used for load balancing or other purposes. One interesting catch here is that Hyper-V can *not* currently ACK CHANNELMSG_MODIFYCHANNEL messages with the promise that (after the ACK is sent) the channel won't send any more interrupts to the "old" CPU. The peculiarity of the CHANNELMSG_MODIFYCHANNEL messages is problematic if the user want to take a CPU offline, since we don't want to take a CPU offline (and, potentially, "lose" channel interrupts on such CPU) if the host is still processing a CHANNELMSG_MODIFYCHANNEL message associated to that CPU. It is worth mentioning, however, that we have been unable to observe the above mentioned "race": in all our tests, CHANNELMSG_MODIFYCHANNEL requests appeared *as if* they were processed synchronously by the host. Suggested-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Link: https://lore.kernel.org/r/20200406001514.19876-11-parri.andrea@gmail.com Reviewed-by: Michael Kelley <mikelley@microsoft.com> [ wei: fix conflict in channel_mgmt.c ] Signed-off-by: Wei Liu <wei.liu@kernel.org>