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pc-bios/s390-ccw: Introduce virtio-pci functions

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Define common functionality for interacting with virtio-pci devices.

Signed-off-by: Jared Rossi <jrossi@linux.ibm.com>
Acked-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Eric Farman <farman@linux.ibm.com>
Message-ID: <20260309003601.242634-12-jrossi@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
This commit is contained in:
Jared Rossi
2026-03-08 20:35:57 -04:00
committed by Thomas Huth
parent 5ed17bb32a
commit 40d80aedd5
4 changed files with 251 additions and 1 deletions
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2
pc-bios/s390-ccw/Makefile
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@@ -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 pci.o
virtio-ccw.o clp.o pci.o virtio-pci.o
SLOF_DIR := $(SRC_PATH)/../../roms/SLOF

167
pc-bios/s390-ccw/virtio-pci.c Normal file
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@@ -0,0 +1,167 @@
/*
* Functionality for virtio-pci
*
* Copyright 2025 IBM Corp.
* Author(s): Jared Rossi <jrossi@linux.ibm.com>
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "clp.h"
#include "pci.h"
#include "helper.h"
#include "virtio.h"
#include "bswap.h"
#include "virtio-pci.h"
#include "s390-time.h"
#include <stdio.h>
/* Variable offsets used for reads/writes to modern memory regions */
VirtioPciCap c_cap; /* Common capabilities */
VirtioPciCap d_cap; /* Device capabilities */
VirtioPciCap n_cap; /* Notify capabilities */
uint32_t notify_mult;
uint16_t q_notify_offset;
static int virtio_pci_set_status(uint8_t status)
{
int rc = vpci_write_byte(c_cap.off + VPCI_C_OFFSET_STATUS, c_cap.bar, status);
if (rc) {
puts("Failed to write virtio-pci status");
return -EIO;
}
return 0;
}
static int virtio_pci_get_status(uint8_t *status)
{
int rc = vpci_read_byte(c_cap.off + VPCI_C_OFFSET_STATUS, c_cap.bar, status);
if (rc) {
puts("Failed to read virtio-pci status");
return -EIO;
}
return 0;
}
/* virtio spec v1.3 section 4.1.2.1 */
void virtio_pci_id2type(VDev *vdev, uint16_t device_id)
{
switch (device_id) {
case 0x1042:
case 0x1001:
vdev->dev_type = VIRTIO_ID_BLOCK;
break;
default:
vdev->dev_type = 0;
}
}
int virtio_pci_reset(VDev *vdev)
{
int rc;
uint8_t status = 0;
rc = virtio_pci_set_status(status);
rc |= virtio_pci_get_status(&status);
if (rc || status) {
puts("Failed to reset virtio-pci device");
return 1;
}
return 0;
}
long virtio_pci_notify(int vq_id)
{
uint32_t offset = n_cap.off + notify_mult * q_notify_offset;
return vpci_bswap16_write(offset, n_cap.bar, (uint16_t) vq_id);
}
/*
* Wrappers to byte swap common data sizes then write
*/
int vpci_write_byte(uint64_t offset, uint8_t pcias, uint8_t data)
{
return pci_write(virtio_get_device()->pci_fh, offset, pcias, (uint64_t) data, 1);
}
int vpci_bswap16_write(uint64_t offset, uint8_t pcias, uint16_t data)
{
uint64_t le_data = bswap16(data);
return pci_write(virtio_get_device()->pci_fh, offset, pcias, le_data, 2);
}
int vpci_bswap32_write(uint64_t offset, uint8_t pcias, uint32_t data)
{
uint64_t le_data = bswap32(data);
return pci_write(virtio_get_device()->pci_fh, offset, pcias, le_data, 4);
}
int vpci_bswap64_write(uint64_t offset, uint8_t pcias, uint64_t data)
{
uint64_t le_data = bswap64(data);
return pci_write(virtio_get_device()->pci_fh, offset, pcias, le_data, 8);
}
/*
* Wrappers to read common data sizes then byte swap
*/
int vpci_read_byte(uint64_t offset, uint8_t pcias, uint8_t *buf)
{
return pci_read(virtio_get_device()->pci_fh, offset, pcias, buf, 1);
}
int vpci_read_bswap16(uint64_t offset, uint8_t pcias, uint16_t *buf)
{
int rc = pci_read(virtio_get_device()->pci_fh, offset, pcias, buf, 2);
*buf = bswap16(*buf);
return rc;
}
int vpci_read_bswap32(uint64_t offset, uint8_t pcias, uint32_t *buf)
{
int rc = pci_read(virtio_get_device()->pci_fh, offset, pcias, buf, 4);
*buf = bswap32(*buf);
return rc;
}
int vpci_read_bswap64(uint64_t offset, uint8_t pcias, uint64_t *buf)
{
int rc = pci_read(virtio_get_device()->pci_fh, offset, pcias, buf, 8);
*buf = bswap64(*buf);
return rc;
}
/*
* Read to an arbitrary length buffer without byte swapping
*/
int vpci_read_flex(uint64_t offset, uint8_t pcias, void *buf, int len)
{
uint8_t readlen;
int rc;
int remaining = len;
/* Read bytes in powers of 2, up to a maximum of 8 bytes per read */
while (remaining) {
for (int i = 3; i >= 0; i--) {
readlen = 1 << i;
if (remaining >= readlen) {
break;
}
}
rc = pci_read(virtio_get_device()->pci_fh, offset, pcias, buf, readlen);
if (rc) {
return -1;
}
remaining -= readlen;
buf += readlen;
offset += readlen;
}
return 0;
}

80
pc-bios/s390-ccw/virtio-pci.h Normal file
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@@ -0,0 +1,80 @@
/*
* Definitions for virtio-pci
*
* Copyright 2025 IBM Corp.
* Author(s): Jared Rossi <jrossi@linux.ibm.com>
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#ifndef VIRTIO_PCI_H
#define VIRTIO_PCI_H
/* Common configuration */
#define VPCI_CAP_COMMON_CFG 1
/* Notifications */
#define VPCI_CAP_NOTIFY_CFG 2
/* ISR access */
#define VPCI_CAP_ISR_CFG 3
/* Device specific configuration */
#define VPCI_CAP_DEVICE_CFG 4
/* PCI configuration access */
#define VPCI_CAP_PCI_CFG 5
/* Additional shared memory capability */
#define VPCI_CAP_SHARED_MEMORY_CFG 8
/* PCI vendor data configuration */
#define VPCI_CAP_VENDOR_CFG 9
/* Offsets within capability header */
#define VPCI_CAP_VNDR 0
#define VPCI_CAP_NEXT 1
#define VPCI_CAP_LEN 2
#define VPCI_CAP_CFG_TYPE 3
#define VPCI_CAP_BAR 4
#define VPCI_CAP_OFFSET 8
#define VPCI_CAP_LENGTH 12
#define VPCI_N_CAP_MULT 16 /* Notify multiplier, VPCI_CAP_NOTIFY_CFG only */
/* Common Area Offsets for virtio-pci queue */
#define VPCI_C_OFFSET_DFSELECT 0
#define VPCI_C_OFFSET_DF 4
#define VPCI_C_OFFSET_GFSELECT 8
#define VPCI_C_OFFSET_GF 12
#define VPCI_C_COMMON_NUMQ 18
#define VPCI_C_OFFSET_STATUS 20
#define VPCI_C_OFFSET_Q_SELECT 22
#define VPCI_C_OFFSET_Q_SIZE 24
#define VPCI_C_OFFSET_Q_ENABLE 28
#define VPCI_C_OFFSET_Q_NOFF 30
#define VPCI_C_OFFSET_Q_DESCLO 32
#define VPCI_C_OFFSET_Q_DESCHI 36
#define VPCI_C_OFFSET_Q_AVAILLO 40
#define VPCI_C_OFFSET_Q_AVAILHI 44
#define VPCI_C_OFFSET_Q_USEDLO 48
#define VPCI_C_OFFSET_Q_USEDHI 52
#define VIRTIO_F_VERSION_1 1 /* Feature bit 32 */
struct VirtioPciCap {
uint8_t bar; /* Which PCIAS it's in */
uint32_t off; /* Offset within bar */
};
typedef struct VirtioPciCap VirtioPciCap;
void virtio_pci_id2type(VDev *vdev, uint16_t device_id);
int virtio_pci_reset(VDev *vdev);
long virtio_pci_notify(int vq_id);
int vpci_read_flex(uint64_t offset, uint8_t pcias, void *buf, int len);
int vpci_read_bswap64(uint64_t offset, uint8_t pcias, uint64_t *buf);
int vpci_read_bswap32(uint64_t offset, uint8_t pcias, uint32_t *buf);
int vpci_read_bswap16(uint64_t offset, uint8_t pcias, uint16_t *buf);
int vpci_read_byte(uint64_t offset, uint8_t pcias, uint8_t *buf);
int vpci_bswap64_write(uint64_t offset, uint8_t pcias, uint64_t data);
int vpci_bswap32_write(uint64_t offset, uint8_t pcias, uint32_t data);
int vpci_bswap16_write(uint64_t offset, uint8_t pcias, uint16_t data);
int vpci_write_byte(uint64_t offset, uint8_t pcias, uint8_t data);
#endif

3
pc-bios/s390-ccw/virtio.h
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@@ -18,6 +18,8 @@
#define VIRTIO_CONFIG_S_DRIVER 2
/* Driver has used its parts of the config, and is happy */
#define VIRTIO_CONFIG_S_DRIVER_OK 4
/* Feature negotiation complete */
#define VIRTIO_CONFIG_S_FEATURES_OK 8
/* We've given up on this device. */
#define VIRTIO_CONFIG_S_FAILED 0x80
@@ -255,6 +257,7 @@ struct VDev {
uint8_t scsi_dev_heads;
bool scsi_device_selected;
ScsiDevice selected_scsi_device;
uint32_t pci_fh;
uint32_t max_transfer;
uint32_t guest_features[2];
};