Commit 07412e1f authored by Roman Kisel's avatar Roman Kisel Committed by Wei Liu
Browse files

hyperv: Do not overlap the hvcall IO areas in get_vtl() 

The Top-Level Functional Specification for Hyper-V, Section 3.6 [1, 2],
disallows overlapping of the input and output hypercall areas, and
get_vtl(void) does overlap them.

Use the output hypercall page of the current vCPU for the hypercall.

[1] https://learn.microsoft.com/en-us/virtualization/hyper-v-on-windows/tlfs/hypercall-interface
[2] https://github.com/MicrosoftDocs/Virtualization-Documentation/tree/main/tlfs



Fixes: 8387ce06 ("x86/hyperv: Set Virtual Trust Level in VMBus init message")
Signed-off-by: default avatarRoman Kisel <romank@linux.microsoft.com>
Reviewed-by: default avatarTianyu Lan <tiala@microsoft.com>
Reviewed-by: default avatarEaswar Hariharan <eahariha@linux.microsoft.com>
Link: https://lore.kernel.org/r/20250108222138.1623703-5-romank@linux.microsoft.com


Signed-off-by: default avatarWei Liu <wei.liu@kernel.org>
Message-ID: <20250108222138.1623703-5-romank@linux.microsoft.com>
parent 9263abc7

arch/x86/hyperv/hv_init.c

+1 −1
Original line number Diff line number Diff line
@@ -422,7 +422,7 @@ static u8 __init get_vtl(void) 


	local_irq_save(flags);

	input = *this_cpu_ptr(hyperv_pcpu_input_arg);

	output = (struct hv_output_get_vp_registers *)input;

	output = *this_cpu_ptr(hyperv_pcpu_output_arg);



	memset(input, 0, struct_size(input, names, 1));

	input->partition_id = HV_PARTITION_ID_SELF;