kernel/git/stable/linux.git/drivers/hv, branch linux-6.0.y

video: hyperv_fb: Avoid taking busy spinlock on panic path

2022-12-31T12:26:40+00:00

[ 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

Drivers: hv: vmbus: fix possible memory leak in vmbus_device_register()

2022-12-02T16:43:06+00:00

[ Upstream commit 25c94b051592c010abe92c85b0485f1faedc83f3 ] If device_register() returns error in vmbus_device_register(), the name allocated by dev_set_name() must be freed. As comment of device_register() says, it should use put_device() to give up the reference in the error path. So fix this by calling put_device(), then the name can be freed in kobject_cleanup(). Fixes: 09d50ff8a233 ("Staging: hv: make the Hyper-V virtual bus code build") Signed-off-by: Yang Yingliang Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20221119081135.1564691-3-yangyingliang@huawei.com Signed-off-by: Wei Liu Signed-off-by: Sasha Levin

Drivers: hv: vmbus: fix double free in the error path of vmbus_add_channel_work()

2022-12-02T16:43:05+00:00

[ Upstream commit f92a4b50f0bd7fd52391dc4bb9a309085d278f91 ] In the error path of vmbus_device_register(), device_unregister() is called, which calls vmbus_device_release(). The latter frees the struct hv_device that was passed in to vmbus_device_register(). So remove the kfree() in vmbus_add_channel_work() to avoid a double free. Fixes: c2e5df616e1a ("vmbus: add per-channel sysfs info") Suggested-by: Michael Kelley Signed-off-by: Yang Yingliang Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20221119081135.1564691-2-yangyingliang@huawei.com Signed-off-by: Wei Liu Signed-off-by: Sasha Levin

Drivers: hv: Never allocate anything besides framebuffer from framebuffer memory region

2022-09-05T17:02:15+00:00

Passed through PCI device sometimes misbehave on Gen1 VMs when Hyper-V DRM driver is also loaded. Looking at IOMEM assignment, we can see e.g. $ cat /proc/iomem ... f8000000-fffbffff : PCI Bus 0000:00 f8000000-fbffffff : 0000:00:08.0 f8000000-f8001fff : bb8c4f33-2ba2-4808-9f7f-02f3b4da22fe ... fe0000000-fffffffff : PCI Bus 0000:00 fe0000000-fe07fffff : bb8c4f33-2ba2-4808-9f7f-02f3b4da22fe fe0000000-fe07fffff : 2ba2:00:02.0 fe0000000-fe07fffff : mlx4_core the interesting part is the 'f8000000' region as it is actually the VM's framebuffer: $ lspci -v ... 0000:00:08.0 VGA compatible controller: Microsoft Corporation Hyper-V virtual VGA (prog-if 00 [VGA controller]) Flags: bus master, fast devsel, latency 0, IRQ 11 Memory at f8000000 (32-bit, non-prefetchable) [size=64M] ... hv_vmbus: registering driver hyperv_drm hyperv_drm 5620e0c7-8062-4dce-aeb7-520c7ef76171: [drm] Synthvid Version major 3, minor 5 hyperv_drm 0000:00:08.0: vgaarb: deactivate vga console hyperv_drm 0000:00:08.0: BAR 0: can't reserve [mem 0xf8000000-0xfbffffff] hyperv_drm 5620e0c7-8062-4dce-aeb7-520c7ef76171: [drm] Cannot request framebuffer, boot fb still active? Note: "Cannot request framebuffer" is not a fatal error in hyperv_setup_gen1() as the code assumes there's some other framebuffer device there but we actually have some other PCI device (mlx4 in this case) config space there! The problem appears to be that vmbus_allocate_mmio() can use dedicated framebuffer region to serve any MMIO request from any device. The semantics one might assume of a parameter named "fb_overlap_ok" aren't implemented because !fb_overlap_ok essentially has no effect. The existing semantics are really "prefer_fb_overlap". This patch implements the expected and needed semantics, which is to not allocate from the frame buffer space when !fb_overlap_ok. Note, Gen2 VMs are usually unaffected by the issue because framebuffer region is already taken by EFI fb (in case kernel supports it) but Gen1 VMs may have this region unclaimed by the time Hyper-V PCI pass-through driver tries allocating MMIO space if Hyper-V DRM/FB drivers load after it. Devices can be brought up in any sequence so let's resolve the issue by always ignoring 'fb_mmio' region for non-FB requests, even if the region is unclaimed. Reviewed-by: Michael Kelley Signed-off-by: Vitaly Kuznetsov Link: https://lore.kernel.org/r/20220827130345.1320254-4-vkuznets@redhat.com Signed-off-by: Wei Liu

Drivers: hv: Always reserve framebuffer region for Gen1 VMs

2022-09-05T17:02:15+00:00

vmbus_reserve_fb() tries reserving framebuffer region iff 'screen_info.lfb_base' is set. Gen2 VMs seem to have it set by EFI and/or by the kernel EFI FB driver (or, in some edge cases like kexec, the address where the buffer was moved, see https://lore.kernel.org/all/20201014092429.1415040-1-kasong@redhat.com/) but on Gen1 VM it depends on bootloader behavior. With grub, it depends on 'gfxpayload=' setting but in some cases it is observed to be zero. That being said, relying on 'screen_info.lfb_base' to reserve framebuffer region is risky. For Gen1 VMs, it should always be possible to get the address from the dedicated PCI device instead. Check for legacy PCI video device presence and reserve the whole region for framebuffer on Gen1 VMs. Reviewed-by: Michael Kelley Signed-off-by: Vitaly Kuznetsov Link: https://lore.kernel.org/r/20220827130345.1320254-3-vkuznets@redhat.com Signed-off-by: Wei Liu

Drivers: hv: remove duplicate word in a comment

2022-09-05T16:28:40+00:00

Signed-off-by: Shaomin Deng Link: https://lore.kernel.org/r/20220904154808.26022-1-dengshaomin@cdjrlc.com Signed-off-by: Wei Liu

Drivers: hv: Create debugfs file with hyper-v balloon usage information

2022-07-18T11:19:02+00:00

Allow the guest to know how much it is ballooned by the host. It is useful when debugging out of memory conditions. When host gets back memory from the guest it is accounted as used memory in the guest but the guest have no way to know how much it is actually ballooned. Expose current state, flags and max possible memory to the guest. While at it - fix a 10+ years old typo. Signed-off-by: Alexander Atanasov Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20220711181825.52318-1-alexander.atanasov@virtuozzo.com Signed-off-by: Wei Liu

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

2022-07-11T18:53:42+00:00

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: Release cpu lock in error case

2022-06-10T08:41:28+00:00

In case of invalid sub channel, release cpu lock before returning. Fixes: a949e86c0d780 ("Drivers: hv: vmbus: Resolve race between init_vp_index() and CPU hotplug") Signed-off-by: Saurabh Sengar Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/1654794996-13244-1-git-send-email-ssengar@linux.microsoft.com Signed-off-by: Wei Liu

Drivers: hv: Fix syntax errors in comments

2022-06-08T12:26:28+00:00

Delete the redundant word 'in'. Signed-off-by: Xiang wangx Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20220605085524.11289-1-wangxiang@cdjrlc.com Signed-off-by: Wei Liu