Re: [PATCH v4 2/3] include: Add a header to define host PCI MMIO functions

[Farhan Ali <alifm@linux.ibm.com>]

On 4/14/2025 11:43 PM, Philippe Mathieu-Daudé wrote:
> Hi,
>
> On 14/4/25 23:36, Farhan Ali wrote:
>> Add a generic API for host PCI MMIO reads/writes
>> (e.g. Linux VFIO BAR accesses). The functions access
>> little endian memory and returns the result in
>> host cpu endianness.
>>
>> Signed-off-by: Farhan Ali <alifm@linux.ibm.com>
>> ---
>>   include/qemu/host-pci-mmio.h | 141 +++++++++++++++++++++++++++++++++++
>>   1 file changed, 141 insertions(+)
>>   create mode 100644 include/qemu/host-pci-mmio.h
>>
>> diff --git a/include/qemu/host-pci-mmio.h b/include/qemu/host-pci-mmio.h
>> new file mode 100644
>> index 0000000000..de17d67e3a
>> --- /dev/null
>> +++ b/include/qemu/host-pci-mmio.h
>> @@ -0,0 +1,141 @@
>> +/*
>> + * API for host PCI MMIO accesses (e.g. Linux VFIO BARs)
>> + *
>> + * Copyright 2025 IBM Corp.
>> + * Author(s): Farhan Ali <alifm@linux.ibm.com>
>> + *
>> + * SPDX-License-Identifier: GPL-2.0-or-later
>> + */
>> +
>> +#ifndef HOST_PCI_MMIO_H
>> +#define HOST_PCI_MMIO_H
>> +
>> +#include "qemu/bswap.h"
>> +#include "qemu/s390x_pci_mmio.h"
>> +
>> +
>> +static inline uint8_t host_pci_ldub_p(const void *ioaddr)
>
> Is it really worth inlining?
>
Hi Philippe,

I think so, we inline the ld/st generic helper functions in bswap.h. 
Curious, why do you think its not necessary?

Thanks

Farhan

>> +{
>> +    uint8_t ret = 0;
>> +#ifdef __s390x__
>> +    ret = s390x_pci_mmio_read_8(ioaddr);
>> +#else
>> +    ret = ldub_he_p(ioaddr);
>> +#endif
>> +
>> +    return ret;
>> +}
>
>