On 7/6/2025 8:13 PM, Michael Kelley wrote:
> From: Nuno Das Neves <nunodasneves@xxxxxxxxxxxxxxxxxxx> Sent: Thursday, July 3, 2025 3:45 PM
>>
>> When running nested, these hypercalls must be sent to the L0 hypervisor
>> or VMBus will fail.
>>
>> Remove hv_do_nested_hypercall() and hv_do_fast_nested_hypercall8()
>> altogether and open-code these cases, since there are only 2 and all
>> they do is add the nested bit.
>>
>> Signed-off-by: Nuno Das Neves <nunodasneves@xxxxxxxxxxxxxxxxxxx>
>> Reviewed-by: Roman Kisel <romank@xxxxxxxxxxxxxxxxxxx>
>> ---
>> arch/x86/include/asm/mshyperv.h | 20 --------------------
>> drivers/hv/connection.c | 7 +++++--
>> drivers/hv/hv.c | 6 ++++--
>> 3 files changed, 9 insertions(+), 24 deletions(-)
>>
>> diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
>> index 5ec92e3e2e37..e00a8431ef8e 100644
>> --- a/arch/x86/include/asm/mshyperv.h
>> +++ b/arch/x86/include/asm/mshyperv.h
>> @@ -111,12 +111,6 @@ static inline u64 hv_do_hypercall(u64 control, void *input,
>> void *output)
>> return hv_status;
>> }
>>
>> -/* Hypercall to the L0 hypervisor */
>> -static inline u64 hv_do_nested_hypercall(u64 control, void *input, void *output)
>> -{
>> - return hv_do_hypercall(control | HV_HYPERCALL_NESTED, input, output);
>> -}
>> -
>> /* Fast hypercall with 8 bytes of input and no output */
>> static inline u64 _hv_do_fast_hypercall8(u64 control, u64 input1)
>> {
>> @@ -164,13 +158,6 @@ static inline u64 hv_do_fast_hypercall8(u16 code, u64 input1)
>> return _hv_do_fast_hypercall8(control, input1);
>> }
>>
>> -static inline u64 hv_do_fast_nested_hypercall8(u16 code, u64 input1)
>> -{
>> - u64 control = (u64)code | HV_HYPERCALL_FAST_BIT | HV_HYPERCALL_NESTED;
>> -
>> - return _hv_do_fast_hypercall8(control, input1);
>> -}
>> -
>> /* Fast hypercall with 16 bytes of input */
>> static inline u64 _hv_do_fast_hypercall16(u64 control, u64 input1, u64 input2)
>> {
>> @@ -222,13 +209,6 @@ static inline u64 hv_do_fast_hypercall16(u16 code, u64 input1, u64 input2)
>> return _hv_do_fast_hypercall16(control, input1, input2);
>> }
>>
>> -static inline u64 hv_do_fast_nested_hypercall16(u16 code, u64 input1, u64 input2)
>> -{
>> - u64 control = (u64)code | HV_HYPERCALL_FAST_BIT | HV_HYPERCALL_NESTED;
>> -
>> - return _hv_do_fast_hypercall16(control, input1, input2);
>> -}
>> -
>> extern struct hv_vp_assist_page **hv_vp_assist_page;
>>
>> static inline struct hv_vp_assist_page *hv_get_vp_assist_page(unsigned int cpu)
>> diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
>> index be490c598785..47c93cee1ef6 100644
>> --- a/drivers/hv/connection.c
>> +++ b/drivers/hv/connection.c
>> @@ -518,8 +518,11 @@ void vmbus_set_event(struct vmbus_channel *channel)
>> channel->sig_event, 0);
>> else
>> WARN_ON_ONCE(1);
>> - } else {
>> - hv_do_fast_hypercall8(HVCALL_SIGNAL_EVENT, channel->sig_event);
>> + } else if (hv_nested) {
>
> As coded, this won't make any hypercall for the non-nested case.
> The "else if (hv_nested)" should be just "else".
Ah, forgot to change this line. Thank you for catching it
Nuno
>
> Michael
>
>> + u64 control = HVCALL_SIGNAL_EVENT;
>> +
>> + control |= hv_nested ? HV_HYPERCALL_NESTED : 0;
>> + hv_do_fast_hypercall8(control, channel->sig_event);
>> }
>> }
>> EXPORT_SYMBOL_GPL(vmbus_set_event);
>> diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
>> index 308c8f279df8..b14c5f9e0ef2 100644
>> --- a/drivers/hv/hv.c
>> +++ b/drivers/hv/hv.c
>> @@ -85,8 +85,10 @@ int hv_post_message(union hv_connection_id connection_id,
>> else
>> status = HV_STATUS_INVALID_PARAMETER;
>> } else {
>> - status = hv_do_hypercall(HVCALL_POST_MESSAGE,
>> - aligned_msg, NULL);
>> + u64 control = HVCALL_POST_MESSAGE;
>> +
>> + control |= hv_nested ? HV_HYPERCALL_NESTED : 0;
>> + status = hv_do_hypercall(control, aligned_msg, NULL);
>> }
>>
>> local_irq_restore(flags);
>> --
>> 2.34.1
