Re: [PATCH 6/7] PCI: hv: Use hv_hvcall_*() to set up hypercall arguments

[Bjorn Helgaas]

On Wed, Feb 26, 2025 at 12:06:11PM -0800, mhkelley58@xxxxxxxxx wrote:
> From: Michael Kelley <mhklinux@xxxxxxxxxxx>
> 
> Update hypercall call sites to use the new hv_hvcall_*() functions
> to set up hypercall arguments. Since these functions zero the
> fixed portion of input memory, remove now redundant calls to memset().
> 
> Signed-off-by: Michael Kelley <mhklinux@xxxxxxxxxxx>

Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>

Since most of this series touches arch/x86/hyperv/ and drivers/hv/, I
assume this will be merged via some non-PCI tree.

> ---
>  drivers/pci/controller/pci-hyperv.c | 14 ++++++--------
>  include/hyperv/hvgdk_mini.h         |  2 +-
>  2 files changed, 7 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
> index 44d7f4339306..b7bfda00544d 100644
> --- a/drivers/pci/controller/pci-hyperv.c
> +++ b/drivers/pci/controller/pci-hyperv.c
> @@ -638,8 +638,8 @@ static void hv_arch_irq_unmask(struct irq_data *data)
>  
>  	local_irq_save(flags);
>  
> -	params = *this_cpu_ptr(hyperv_pcpu_input_arg);
> -	memset(params, 0, sizeof(*params));
> +	hv_hvcall_in_array(&params, sizeof(*params),
> +			sizeof(params->int_target.vp_set.bank_contents[0]));
>  	params->partition_id = HV_PARTITION_ID_SELF;
>  	params->int_entry.source = HV_INTERRUPT_SOURCE_MSI;
>  	params->int_entry.msi_entry.address.as_uint32 = int_desc->address & 0xffffffff;
> @@ -1034,11 +1034,9 @@ static void hv_pci_read_mmio(struct device *dev, phys_addr_t gpa, int size, u32
>  
>  	/*
>  	 * Must be called with interrupts disabled so it is safe
> -	 * to use the per-cpu input argument page.  Use it for
> -	 * both input and output.
> +	 * to use the per-cpu argument page.
>  	 */
> -	in = *this_cpu_ptr(hyperv_pcpu_input_arg);
> -	out = *this_cpu_ptr(hyperv_pcpu_input_arg) + sizeof(*in);
> +	hv_hvcall_inout(&in, sizeof(*in), &out, sizeof(*out));
>  	in->gpa = gpa;
>  	in->size = size;
>  
> @@ -1067,9 +1065,9 @@ static void hv_pci_write_mmio(struct device *dev, phys_addr_t gpa, int size, u32
>  
>  	/*
>  	 * Must be called with interrupts disabled so it is safe
> -	 * to use the per-cpu input argument memory.
> +	 * to use the per-cpu argument page.
>  	 */
> -	in = *this_cpu_ptr(hyperv_pcpu_input_arg);
> +	hv_hvcall_in_array(&in, sizeof(*in), sizeof(in->data[0]));
>  	in->gpa = gpa;
>  	in->size = size;
>  	switch (size) {
> diff --git a/include/hyperv/hvgdk_mini.h b/include/hyperv/hvgdk_mini.h
> index 70e5d7ee40c8..cb25ac1e3ac5 100644
> --- a/include/hyperv/hvgdk_mini.h
> +++ b/include/hyperv/hvgdk_mini.h
> @@ -1342,7 +1342,7 @@ struct hv_mmio_write_input {
>  	u64 gpa;
>  	u32 size;
>  	u32 reserved;
> -	u8 data[HV_HYPERCALL_MMIO_MAX_DATA_LENGTH];
> +	u8 data[];
>  } __packed;
>  
>  #endif /* _HV_HVGDK_MINI_H */
> -- 
> 2.25.1
>