Commit c748814b authored by Pierre Morel's avatar Pierre Morel Committed by Cornelia Huck
Browse files

s390x/pci: factor out endianess conversion 



There are two places where the same endianness conversion
is done.
Let's factor this out into a static function.

Note that the conversion must always be done for data in a register:

The S390 BE guest converted date to le before issuing the instruction.

After interception in a BE host:
ZPCI VFIO using pwrite must make the conversion back for the BE kernel.
Kernel will do BE to le translation when loading the register for the
real instruction.

After interception in a le host:
TCG stores a BE register in le, swapping bytes.
But since the data in the register was already le it is now BE
ZPCI VFIO must convert it to le before writing to the PCI memory.

In both cases ZPCI VFIO must swap the bytes from the register.

Signed-off-by: default avatarPierre Morel <pmorel@linux.vnet.ibm.com>
Reviewed-by: default avatarYi Min Zhao <zyimin@linux.vnet.ibm.com>
Message-Id: <1512046530-17773-2-git-send-email-pmorel@linux.vnet.ibm.com>
Signed-off-by: default avatarCornelia Huck <cohuck@redhat.com>
parent cb3129c3

hw/s390x/s390-pci-inst.c

+32 −26
Original line number Diff line number Diff line
@@ -318,6 +318,36 @@ out: 
    return 0;

}



/**

 * Swap data contained in s390x big endian registers to little endian

 * PCI bars.

 *

 * @ptr: a pointer to a uint64_t data field

 * @len: the length of the valid data, must be 1,2,4 or 8

 */

static int zpci_endian_swap(uint64_t *ptr, uint8_t len)

{

    uint64_t data = *ptr;



    switch (len) {

    case 1:

        break;

    case 2:

        data = bswap16(data);

        break;

    case 4:

        data = bswap32(data);

        break;

    case 8:

        data = bswap64(data);

        break;

    default:

        return -EINVAL;

    }

    *ptr = data;

    return 0;

}



int pcilg_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2, uintptr_t ra)

{

    CPUS390XState *env = &cpu->env;
@@ -389,19 +419,7 @@ int pcilg_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2, uintptr_t ra) 
        data =  pci_host_config_read_common(

                   pbdev->pdev, offset, pci_config_size(pbdev->pdev), len);



        switch (len) {

        case 1:

            break;

        case 2:

            data = bswap16(data);

            break;

        case 4:

            data = bswap32(data);

            break;

        case 8:

            data = bswap64(data);

            break;

        default:

        if (zpci_endian_swap(&data, len)) {

            s390_program_interrupt(env, PGM_OPERAND, 4, ra);

            return 0;

        }
@@ -504,19 +522,7 @@ int pcistg_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2, uintptr_t ra) 
            s390_program_interrupt(env, PGM_OPERAND, 4, ra);

            return 0;

        }

        switch (len) {

        case 1:

            break;

        case 2:

            data = bswap16(data);

            break;

        case 4:

            data = bswap32(data);

            break;

        case 8:

            data = bswap64(data);

            break;

        default:

        if (zpci_endian_swap(&data, len)) {

            s390_program_interrupt(env, PGM_OPERAND, 4, ra);

            return 0;

        }