kernel.git/drivers/hv/hv.c, branch linux-4.5.y

drivers/hv: correct tsc page sequence invalid value

2015-12-15T03:15:05Z

Hypervisor Top Level Functional Specification v3/4 says that TSC page sequence value = -1(0xFFFFFFFF) is used to indicate that TSC page no longer reliable source of reference timer. Unfortunately, we found that Windows Hyper-V guest side implementation uses sequence value = 0 to indicate that Tsc page no longer valid. This is clearly visible inside Windows 2012R2 ntoskrnl.exe HvlGetReferenceTime() function dissassembly: HvlGetReferenceTime proc near xchg ax, ax loc_1401C3132: mov rax, cs:HvlpReferenceTscPage mov r9d, [rax] test r9d, r9d jz short loc_1401C3176 rdtsc mov rcx, cs:HvlpReferenceTscPage shl rdx, 20h or rdx, rax mov rax, [rcx+8] mov rcx, cs:HvlpReferenceTscPage mov r8, [rcx+10h] mul rdx mov rax, cs:HvlpReferenceTscPage add rdx, r8 mov ecx, [rax] cmp ecx, r9d jnz short loc_1401C3132 jmp short loc_1401C3184 loc_1401C3176: mov ecx, 40000020h rdmsr shl rdx, 20h or rdx, rax loc_1401C3184: mov rax, rdx retn HvlGetReferenceTime endp This patch aligns Tsc page invalid sequence value with Windows Hyper-V guest implementation which is more compatible with both Hyper-V hypervisor and KVM hypervisor. Signed-off-by: Andrey Smetanin Signed-off-by: Denis V. Lunev CC: "K. Y. Srinivasan" CC: Haiyang Zhang CC: Vitaly Kuznetsov Signed-off-by: Denis V. Lunev Signed-off-by: K. Y. Srinivasan Signed-off-by: Greg Kroah-Hartman

drivers:hv: Export the API to invoke a hypercall on Hyper-V

2015-12-15T03:12:21Z

This patch exposes the function that hv_vmbus.ko uses to make hypercalls. This is necessary for retargeting an interrupt when it is given a new affinity. Since we are exporting this API, rename the API as it will be visible outside the hv.c file. Signed-off-by: Jake Oshins Signed-off-by: K. Y. Srinivasan Signed-off-by: Greg Kroah-Hartman

Drivers: hv: vmbus: fix build warning

2015-12-14T21:34:50Z

We were getting build warning about unused variable "tsc_msr" and "va_tsc" while building for i386 allmodconfig. Signed-off-by: Sudip Mukherjee Signed-off-by: Greg Kroah-Hartman

Drivers: hv: vmbus: Implement a clocksource based on the TSC page

2015-08-05T18:44:29Z

The current Hyper-V clock source is based on the per-partition reference counter and this counter is being accessed via s synthetic MSR - HV_X64_MSR_TIME_REF_COUNT. Hyper-V has a more efficient way of computing the per-partition reference counter value that does not involve reading a synthetic MSR. We implement a time source based on this mechanism. Tested-by: Vivek Yadav Signed-off-by: K. Y. Srinivasan Signed-off-by: Greg Kroah-Hartman

drivers/hv: Migrate to new 'set-state' interface

2015-08-05T18:44:29Z

Migrate hv driver to the new 'set-state' interface provided by clockevents core, the earlier 'set-mode' interface is marked obsolete now. This also enables us to implement callbacks for new states of clockevent devices, for example: ONESHOT_STOPPED. Cc: "K. Y. Srinivasan" Cc: Haiyang Zhang Cc: devel@linuxdriverproject.org Signed-off-by: Viresh Kumar Signed-off-by: K. Y. Srinivasan Signed-off-by: Greg Kroah-Hartman

Drivers: hv: vmbus: Improve the CPU affiliation for channels

2015-08-05T18:41:31Z

The current code tracks the assigned CPUs within a NUMA node in the context of the primary channel. So, if we have a VM with a single NUMA node with 8 VCPUs, we may end up unevenly distributing the channel load. Fix the issue by tracking affiliations globally. Signed-off-by: K. Y. Srinivasan Signed-off-by: Greg Kroah-Hartman

Drivers: hv: don't do hypercalls when hypercall_page is NULL

2015-08-05T05:25:29Z

At the very late stage of kexec a driver (which are not being unloaded) can try to post a message or signal an event. This will crash the kernel as we already did hv_cleanup() and the hypercall page is NULL. Move all common (between 32 and 64 bit code) declarations to the beginning of the do_hypercall() function. Unfortunately we have to write the !hypercall_page check twice to not mix declarations and code. Signed-off-by: Vitaly Kuznetsov Signed-off-by: K. Y. Srinivasan Signed-off-by: Greg Kroah-Hartman

Drivers: hv: vmbus: remove hv_synic_free_cpu() call from hv_synic_cleanup()

2015-08-05T05:25:28Z

We already have hv_synic_free() which frees all per-cpu pages for all CPUs, let's remove the hv_synic_free_cpu() call from hv_synic_cleanup() so it will be possible to do separate cleanup (writing to MSRs) and final freeing. This is going to be used to assist kexec. Signed-off-by: Vitaly Kuznetsov Signed-off-by: K. Y. Srinivasan Signed-off-by: Greg Kroah-Hartman

Drivers: hv: vmbus: Teardown clockevent devices on module unload

2015-03-02T03:30:07Z

Newly introduced clockevent devices made it impossible to unload hv_vmbus module as clockevents_config_and_register() takes additional reverence to the module. To make it possible again we do the following: - avoid setting dev->owner for clockevent devices; - implement hv_synic_clockevents_cleanup() doing clockevents_unbind_device(); - call it from vmbus_exit(). In theory hv_synic_clockevents_cleanup() can be merged with hv_synic_cleanup(), however, we call hv_synic_cleanup() from smp_call_function_single() and this doesn't work for clockevents_unbind_device() as it does such call on its own. I opted for a separate function. Signed-off-by: Vitaly Kuznetsov Signed-off-by: K. Y. Srinivasan Signed-off-by: Greg Kroah-Hartman

drivers: hv: vmbus: Teardown synthetic interrupt controllers on module unload

2015-03-02T03:29:05Z

SynIC has to be switched off when we unload the module, otherwise registered memory pages can get corrupted after (as Hyper-V host still writes there) and we see the following crashes for random processes: [ 89.116774] BUG: Bad page map in process sh pte:4989c716 pmd:36f81067 [ 89.159454] addr:0000000000437000 vm_flags:00000875 anon_vma: (null) mapping:ffff88007bba55a0 index:37 [ 89.226146] vma->vm_ops->fault: filemap_fault+0x0/0x410 [ 89.257776] vma->vm_file->f_op->mmap: generic_file_mmap+0x0/0x60 [ 89.297570] CPU: 0 PID: 215 Comm: sh Tainted: G B 3.19.0-rc5_bug923184+ #488 [ 89.353738] Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS 090006 05/23/2012 [ 89.409138] 0000000000000000 000000004e083d7b ffff880036e9fa18 ffffffff81a68d31 [ 89.468724] 0000000000000000 0000000000437000 ffff880036e9fa68 ffffffff811a1e3a [ 89.519233] 000000004989c716 0000000000000037 ffffea0001edc340 0000000000437000 [ 89.575751] Call Trace: [ 89.591060] [] dump_stack+0x45/0x57 [ 89.625164] [] print_bad_pte+0x1aa/0x250 [ 89.667234] [] vm_normal_page+0x55/0xa0 [ 89.703818] [] unmap_page_range+0x425/0x8a0 [ 89.737982] [] unmap_single_vma+0x81/0xf0 [ 89.780385] [] ? lru_deactivate_fn+0x190/0x190 [ 89.820130] [] unmap_vmas+0x51/0xa0 [ 89.860168] [] exit_mmap+0xac/0x1a0 [ 89.890588] [] mmput+0x63/0x100 [ 89.919205] [] flush_old_exec+0x3f8/0x8b0 [ 89.962135] [] load_elf_binary+0x32b/0x1260 [ 89.998581] [] ? get_user_pages+0x52/0x60 hv_synic_cleanup() function exists but noone calls it now. Do the following: - call hv_synic_cleanup() on each cpu from vmbus_exit(); - write global disable bit through MSR; - use hv_synic_free_cpu() to avoid memory leask and code duplication. Signed-off-by: Vitaly Kuznetsov Signed-off-by: K. Y. Srinivasan Signed-off-by: Greg Kroah-Hartman