Commit f285d995 authored by Roman Kisel's avatar Roman Kisel Committed by Wei Liu
Browse files

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

The Top-Level Functional Specification for Hyper-V, Section 3.6 [1, 2],
disallows overlapping of the input and output hypercall areas, and
hv_vtl_apicid_to_vp_id() overlaps 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



Reported-by: default avatarMichael Kelley <mhklinux@outlook.com>
Closes: https://lore.kernel.org/lkml/SN6PR02MB4157B98CD34781CC87A9D921D40D2@SN6PR02MB4157.namprd02.prod.outlook.com/


Signed-off-by: default avatarRoman Kisel <romank@linux.microsoft.com>
Reviewed-by: default avatarEaswar Hariharan <eahariha@linux.microsoft.com>
Reviewed-by: default avatarNuno Das Neves <nunodasneves@linux.microsoft.com>
Link: https://lore.kernel.org/r/20250108222138.1623703-6-romank@linux.microsoft.com


Signed-off-by: default avatarWei Liu <wei.liu@kernel.org>
Message-ID: <20250108222138.1623703-6-romank@linux.microsoft.com>
parent 07412e1f

arch/x86/hyperv/hv_vtl.c

+1 −1
Original line number Diff line number Diff line
@@ -189,7 +189,7 @@ static int hv_vtl_apicid_to_vp_id(u32 apic_id) 
	input->partition_id = HV_PARTITION_ID_SELF;

	input->apic_ids[0] = apic_id;



	output = (u32 *)input;

	output = *this_cpu_ptr(hyperv_pcpu_output_arg);



	control = HV_HYPERCALL_REP_COMP_1 | HVCALL_GET_VP_ID_FROM_APIC_ID;

	status = hv_do_hypercall(control, input, output);