On Tue, 2026-01-27 at 11:15 -0500, [email protected] wrote:
> From: Jared Rossi <[email protected]>
> 
> Define selected s390x PCI instructions.
> 
> Signed-off-by: Jared Rossi <[email protected]>
> ---
>  pc-bios/s390-ccw/Makefile |   2 +-
>  pc-bios/s390-ccw/pci.c    | 194 ++++++++++++++++++++++++++++++++++++++
>  pc-bios/s390-ccw/pci.h    |  80 ++++++++++++++++
>  3 files changed, 275 insertions(+), 1 deletion(-)
>  create mode 100644 pc-bios/s390-ccw/pci.c
>  create mode 100644 pc-bios/s390-ccw/pci.h
> 
> diff --git a/pc-bios/s390-ccw/Makefile b/pc-bios/s390-ccw/Makefile
> index 9c29548f84..a62fc9d766 100644
> --- a/pc-bios/s390-ccw/Makefile
> +++ b/pc-bios/s390-ccw/Makefile
> @@ -35,7 +35,7 @@ QEMU_DGFLAGS = -MMD -MP -MT $@ -MF $(@D)/$(*F).d
>  
>  OBJECTS = start.o main.o bootmap.o jump2ipl.o sclp.o menu.o netmain.o \
>         virtio.o virtio-net.o virtio-scsi.o virtio-blkdev.o cio.o dasd-ipl.o \
> -       virtio-ccw.o clp.o
> +       virtio-ccw.o clp.o pci.o
>  
>  SLOF_DIR := $(SRC_PATH)/../../roms/SLOF
>  
> diff --git a/pc-bios/s390-ccw/pci.c b/pc-bios/s390-ccw/pci.c
> new file mode 100644
> index 0000000000..9656be45ca
> --- /dev/null
> +++ b/pc-bios/s390-ccw/pci.c
> @@ -0,0 +1,194 @@
> +/*
> + * s390x PCI funcionality

functionality

> + *
> + * Copyright 2025 IBM Corp.
> + * Author(s): Jared Rossi <[email protected]>
> + *
> + * SPDX-License-Identifier: GPL-2.0-or-later
> + */
> +
> +#include "clp.h"
> +#include "pci.h"
> +#include "bswap.h"
> +#include <stdio.h>
> +#include <stdbool.h>
> +
> +/* PCI load */
> +static inline int pcilg(uint64_t *data, uint64_t req, uint64_t offset,
> +                        uint8_t *status)
> +{
> +    union register_pair req_off = {.even = req, .odd = offset};
> +    int cc = -1;
> +    uint64_t __data;
> +
> +    asm volatile (
> +        "     .insn   rre,0xb9d20000,%[data],%[req_off]\n"
> +        "     ipm     %[cc]\n"
> +        "     srl     %[cc],28\n"
> +        : [cc] "+d" (cc), [data] "=d" (__data),
> +          [req_off] "+d" (req_off.pair) :: "cc");
> +    *status = req_off.even >> 24 & 0xff;
> +    *data = __data;
> +    return cc;
> +}
> +
> +/* PCI store */
> +static inline int pcistg(uint64_t data, uint64_t req, uint64_t offset,
> +                         uint8_t *status)
> +{
> +    union register_pair req_off = {.even = req, .odd = offset};
> +    int cc = -1;
> +
> +    asm volatile (
> +        "     .insn   rre,0xb9d00000,%[data],%[req_off]\n"
> +        "     ipm     %[cc]\n"
> +        "     srl     %[cc],28\n"
> +        : [cc] "+d" (cc), [req_off] "+d" (req_off.pair)
> +        : [data] "d" (data)
> +        : "cc");
> +    *status = req_off.even >> 24 & 0xff;
> +    return cc;
> +}
> +
> +/* store PCI function controls */
> +static inline int stpcifc(uint64_t req, PciFib *fib, uint8_t *status)
> +{
> +    uint8_t cc;
> +
> +    asm volatile (
> +        "     .insn   rxy,0xe300000000d4,%[req],%[fib]\n"
> +        "     ipm     %[cc]\n"
> +        "     srl     %[cc],28\n"
> +        : [cc] "=d" (cc), [req] "+d" (req), [fib] "+Q" (*fib)
> +        : : "cc");
> +    *status = req >> 24 & 0xff;
> +    return cc;
> +}
> +
> +/* modify PCI function controls */
> +static inline int mpcifc(uint64_t req, PciFib *fib, uint8_t *status)
> +{
> +    uint8_t cc;
> +
> +    asm volatile (
> +        "     .insn   rxy,0xe300000000d0,%[req],%[fib]\n"
> +        "     ipm     %[cc]\n"
> +        "     srl     %[cc],28\n"
> +        : [cc] "=d" (cc), [req] "+d" (req), [fib] "+Q" (*fib)
> +        : : "cc");
> +    *status = req >> 24 & 0xff;
> +    return cc;
> +}
> +
> +int pci_write(uint32_t fhandle, uint64_t offset, uint8_t pcias, uint64_t 
> data,
> +              uint8_t len)
> +{
> +
> +    uint64_t req = ZPCI_CREATE_REQ(fhandle, pcias, len);
> +    uint8_t status;
> +    int rc;
> +
> +    /* len must be non-zero power of 2 with a maximum of 8 bytes per write */
> +    switch (len) {
> +    case 1:
> +    case 2:
> +    case 4:
> +    case 8:
> +        rc = pcistg(data, req, offset, &status);
> +        break;
> +    default:
> +        rc = -1;
> +    }
> +
> +    /* Error condition detected */
> +    if (rc == 1) {
> +        printf("PCI store failed with status condition %d\n", status);
> +        return -1;
> +    }
> +
> +    return rc ? -1 : 0;
> +}
> +
> +int pci_read(uint32_t fhandle, uint64_t offset, uint8_t pcias, void *buf,
> +             uint8_t len)
> +{
> +    uint64_t req, data;
> +    uint8_t status;
> +    int rc;
> +
> +    req = ZPCI_CREATE_REQ(fhandle, pcias, len);
> +    rc = pcilg(&data, req, offset, &status);
> +
> +    /* Error condition detected */
> +    if (rc == 1) {
> +        printf("PCI load failed with status condition %d\n", status);
> +        return -1;
> +    }
> +
> +    switch (len) {
> +    case 1:
> +        *(uint8_t *)buf = data;
> +        break;
> +    case 2:
> +        *(uint16_t *)buf = data;
> +        break;
> +    case 4:
> +        *(uint32_t *)buf = data;
> +        break;
> +    case 8:
> +        *(uint64_t *)buf = data;
> +        break;
> +    default:
> +        return -1;
> +    }
> +
> +    return rc ? -1 : 0;
> +}
> +
> +int pci_dev_enable(PciDevice *pcidev)
> +{
> +    int rc;
> +
> +    rc = enable_pci_function(&pcidev->fhandle);
> +    if (rc) {
> +        return rc;
> +    }
> +
> +    pcidev->status = PCIST_ENABLED;
> +
> +    return pci_get_fib(&pcidev->fib, pcidev->fhandle);

Is pcidev->status meant to be left "enabled" if this fails? Seems that the 
error cases would be
unexpected, but severe.

Oh... But pci_dev_enable doesn't seem to be called anywhere 
(enable_pci_function is called by
virtio_pci_setup_device, in patch 11). Nor pci_get/set_fib below... So maybe 
all these chunks are
not needed? (Ditto the related structs in pci.h, below)

> +}
> +
> +int pci_get_fib(PciFib *fib, uint32_t fhandle)
> +{
> +    uint64_t req = ZPCI_CREATE_REQ(fhandle, 0, 0);
> +    uint8_t status;
> +    int rc;
> +
> +    rc = stpcifc(req, fib, &status);
> +
> +    if (rc == 1) {
> +        return status;
> +    } else if (rc) {
> +        return rc;
> +    }
> +
> +    return 0;
> +}
> +
> +int pci_set_fib(PciFib *fib, uint32_t fhandle, uint8_t dma_as, uint8_t 
> opcontrol)
> +{
> +    uint64_t req = ZPCI_CREATE_REQ(fhandle, dma_as, opcontrol);
> +    uint8_t status;
> +    int rc;
> +
> +    rc = mpcifc(req, fib, &status);
> +
> +    if (rc == 1) {
> +        return status;
> +    } else if (rc) {
> +        return rc;
> +    }
> +
> +    return 0;
> +}
> diff --git a/pc-bios/s390-ccw/pci.h b/pc-bios/s390-ccw/pci.h
> new file mode 100644
> index 0000000000..ff8d5687f4
> --- /dev/null
> +++ b/pc-bios/s390-ccw/pci.h
> @@ -0,0 +1,80 @@
> +/*
> + * s390x PCI definitions
> + *
> + * Copyright 2025 IBM Corp.
> + * Author(s): Jared Rossi <[email protected]>
> + *
> + * SPDX-License-Identifier: GPL-2.0-or-later
> + */
> +
> +#ifndef PCI_H
> +#define PCI_H
> +
> +#include <stdint.h>
> +#include <stdbool.h>
> +#include "clp.h"
> +
> +#define ZPCI_CREATE_REQ(handle, space, len)                    \
> +    ((uint64_t) handle << 32 | space << 16 | len)
> +
> +union register_pair {
> +    unsigned __int128 pair;
> +    struct {
> +        unsigned long even;
> +        unsigned long odd;
> +    };
> +};
> +
> +#define PCIFIB_FC_ENABLED      0x80
> +#define PCIFIB_FC_ERROR        0x40
> +#define PCIFIB_FC_BLOCKED      0x20
> +#define PCIFIB_FC_DMAREG       0x10
> +
> +#define PCIST_DISABLED         0x0
> +#define PCIST_ENABLED          0x1
> +
> +#define PCI_CFGBAR             0xF  /* Base Address Register for config 
> space */
> +#define PCI_CAPABILITY_LIST    0x34 /* Offset of first capability list entry 
> */
> +
> +struct PciFib {
> +    uint32_t reserved0[2];
> +    uint8_t fcflags;
> +    uint8_t reserved1[3];
> +    uint32_t reserved2;
> +    uint64_t pba;
> +    uint64_t pal;
> +    uint64_t iota;
> +    uint16_t isc:4;
> +    uint16_t noi:12;
> +    uint8_t reserved3:2;
> +    uint8_t aibvo:6;
> +    uint8_t s:1;
> +    uint8_t reserved4:1;
> +    uint8_t aisbo:6;
> +    uint32_t reserved5;
> +    uint64_t aibv;
> +    uint64_t aisb;
> +    uint64_t fmba;
> +    uint32_t reserved6[2];
> +};
> +typedef struct PciFib PciFib;
> +
> +struct PciDevice {
> +    uint16_t device_id;
> +    uint16_t vendor_id;
> +    uint32_t fid;
> +    uint32_t fhandle;
> +    uint8_t status;
> +    PciFib fib;
> +};
> +typedef struct PciDevice PciDevice;
> +
> +int pci_dev_enable(PciDevice *pcidev);
> +int pci_get_fib(PciFib *fib, uint32_t fhandle);
> +int pci_set_fib(PciFib *fib, uint32_t fhandle, uint8_t dma_as, uint8_t 
> opcontrol);
> +int pci_write(uint32_t fhandle, uint64_t offset, uint8_t pcias, uint64_t 
> data,
> +              uint8_t len);
> +int pci_read(uint32_t fhandle, uint64_t offset, uint8_t pcias, void *buf,
> +             uint8_t len);
> +
> +#endif

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