Re: [PATCH 1/2] hyperv: Fix pointer type for the output of the hypercall in get_vtl(void)

[Roman Kisel]

On 12/18/2024 6:45 PM, Wei Liu wrote:
> On Wed, Dec 18, 2024 at 12:54:20PM -0800, Roman Kisel wrote:
> > Commit bc905fa8b633 ("hyperv: Switch from hyperv-tlfs.h to hyperv/hvhdk.h")
> > changed the type of the output pointer to `struct hv_register_assoc` from
> > `struct hv_get_vp_registers_output`. That leads to an incorrect computation,
> > and leaves the system broken.
> >
> > Use the correct pointer type for the output of the GetVpRegisters hypercall.
> >
> > Fixes: bc905fa8b633 ("hyperv: Switch from hyperv-tlfs.h to hyperv/hvhdk.h")
>
> This commit is not in the mainline kernel yet, so this tag is not
> needed.
Got it, thanks for the explanation!

> It will most likely to be wrong since I will need to rebase the
> hyperv-next branch.
>
> I can fold this patch into the original patch and leave your
> Signed-off-by there.
That would be great and appreciated very much, thank you!

> Thanks,
> Wei.
Thank you,
Roman

> > Signed-off-by: Roman Kisel <romank@xxxxxxxxxxxxxxxxxxx>
> > ---
> >   arch/x86/hyperv/hv_init.c   | 6 +++---
> >   include/hyperv/hvgdk_mini.h | 3 ---
> >   2 files changed, 3 insertions(+), 6 deletions(-)
> >
> > diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
> > index 3cf2a227d666..c7185c6a290b 100644
> > --- a/arch/x86/hyperv/hv_init.c
> > +++ b/arch/x86/hyperv/hv_init.c
> > @@ -416,13 +416,13 @@ static u8 __init get_vtl(void)
> >   {
> >   	u64 control = HV_HYPERCALL_REP_COMP_1 | HVCALL_GET_VP_REGISTERS;
> >   	struct hv_input_get_vp_registers *input;
> > -	struct hv_register_assoc *output;
> > +	struct hv_get_vp_registers_output *output;
> >   	unsigned long flags;
> >   	u64 ret;
> >   
> >   	local_irq_save(flags);
> >   	input = *this_cpu_ptr(hyperv_pcpu_input_arg);
> > -	output = (struct hv_register_assoc *)input;
> > +	output = (struct hv_get_vp_registers_output *)input;
> >   
> >   	memset(input, 0, struct_size(input, names, 1));
> >   	input->partition_id = HV_PARTITION_ID_SELF;
> > @@ -432,7 +432,7 @@ static u8 __init get_vtl(void)
> >   
> >   	ret = hv_do_hypercall(control, input, output);
> >   	if (hv_result_success(ret)) {
> > -		ret = output->value.reg8 & HV_X64_VTL_MASK;
> > +		ret = output->as64.low & HV_X64_VTL_MASK;
> >   	} else {
> >   		pr_err("Failed to get VTL(error: %lld) exiting...\n", ret);
> >   		BUG();
> > diff --git a/include/hyperv/hvgdk_mini.h b/include/hyperv/hvgdk_mini.h
> > index db3d1aaf7330..0b1a10828f33 100644
> > --- a/include/hyperv/hvgdk_mini.h
> > +++ b/include/hyperv/hvgdk_mini.h
> > @@ -1107,7 +1107,6 @@ union hv_register_value {
> >   	union hv_x64_pending_interruption_register pending_interruption;
> >   };
> >   
> > -#if defined(CONFIG_ARM64)
> >   /* HvGetVpRegisters returns an array of these output elements */
> >   struct hv_get_vp_registers_output {
> >   	union {
> > @@ -1124,8 +1123,6 @@ struct hv_get_vp_registers_output {
> >   	};
> >   };
> >   
> > -#endif /* CONFIG_ARM64 */
> > -
> >   struct hv_register_assoc {
> >   	u32 name;			/* enum hv_register_name */
> >   	u32 reserved1;
> > --
> > 2.34.1

--
Thank you,
Roman