linux/arch/x86/hyperv
Praveen Kumar e5d9b714fe x86/hyperv: fix root partition faults when writing to VP assist page MSR
For root partition the VP assist pages are pre-determined by the
hypervisor. The root kernel is not allowed to change them to
different locations. And thus, we are getting below stack as in
current implementation root is trying to perform write to specific
MSR.

    [ 2.778197] unchecked MSR access error: WRMSR to 0x40000073 (tried to write 0x0000000145ac5001) at rIP: 0xffffffff810c1084 (native_write_msr+0x4/0x30)
    [ 2.784867] Call Trace:
    [ 2.791507] hv_cpu_init+0xf1/0x1c0
    [ 2.798144] ? hyperv_report_panic+0xd0/0xd0
    [ 2.804806] cpuhp_invoke_callback+0x11a/0x440
    [ 2.811465] ? hv_resume+0x90/0x90
    [ 2.818137] cpuhp_issue_call+0x126/0x130
    [ 2.824782] __cpuhp_setup_state_cpuslocked+0x102/0x2b0
    [ 2.831427] ? hyperv_report_panic+0xd0/0xd0
    [ 2.838075] ? hyperv_report_panic+0xd0/0xd0
    [ 2.844723] ? hv_resume+0x90/0x90
    [ 2.851375] __cpuhp_setup_state+0x3d/0x90
    [ 2.858030] hyperv_init+0x14e/0x410
    [ 2.864689] ? enable_IR_x2apic+0x190/0x1a0
    [ 2.871349] apic_intr_mode_init+0x8b/0x100
    [ 2.878017] x86_late_time_init+0x20/0x30
    [ 2.884675] start_kernel+0x459/0x4fb
    [ 2.891329] secondary_startup_64_no_verify+0xb0/0xbb

Since the hypervisor already provides the VP assist pages for root
partition, we need to memremap the memory from hypervisor for root
kernel to use. The mapping is done in hv_cpu_init during bringup and is
unmapped in hv_cpu_die during teardown.

Signed-off-by: Praveen Kumar <kumarpraveen@linux.microsoft.com>
Reviewed-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Link: https://lore.kernel.org/r/20210731120519.17154-1-kumarpraveen@linux.microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-08-04 11:56:53 +00:00
..
hv_apic.c drivers: hv: Create a consistent pattern for checking Hyper-V hypercall status 2021-04-21 09:49:19 +00:00
hv_init.c x86/hyperv: fix root partition faults when writing to VP assist page MSR 2021-08-04 11:56:53 +00:00
hv_proc.c drivers: hv: Create a consistent pattern for checking Hyper-V hypercall status 2021-04-21 09:49:19 +00:00
hv_spinlock.c x86/hyperv: Fix unused variable 'msr_val' warning in hv_qlock_wait 2021-03-24 11:31:04 +00:00
irqdomain.c drivers: hv: Create a consistent pattern for checking Hyper-V hypercall status 2021-04-21 09:49:19 +00:00
Makefile x86/hyperv: implement an MSI domain for root partition 2021-02-11 08:47:07 +00:00
mmu.c The x86 MM changes in this cycle were: 2021-04-29 11:41:43 -07:00
nested.c drivers: hv: Create a consistent pattern for checking Hyper-V hypercall status 2021-04-21 09:49:19 +00:00