include: Add a header to define host PCI MMIO functions

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.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Farhan Ali <alifm@linux.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-id: 20250430185012.2303-3-alifm@linux.ibm.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 136 insertions, 0 deletions

diff --git a/include/qemu/host-pci-mmio.h b/include/qemu/host-pci-mmio.h
new file mode 100644
index 0000000..a8ed993
--- /dev/null
+++ b/include/qemu/host-pci-mmio.h
@@ -0,0 +1,136 @@
+/*
+ * 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)
+{
+    uint8_t ret = 0;
+#ifdef __s390x__
+    ret = s390x_pci_mmio_read_8(ioaddr);
+#else
+    ret = ldub_p(ioaddr);
+#endif
+
+    return ret;
+}
+
+static inline uint16_t host_pci_lduw_le_p(const void *ioaddr)
+{
+    uint16_t ret = 0;
+#ifdef __s390x__
+    ret = le16_to_cpu(s390x_pci_mmio_read_16(ioaddr));
+#else
+    ret = lduw_le_p(ioaddr);
+#endif
+
+    return ret;
+}
+
+static inline uint32_t host_pci_ldl_le_p(const void *ioaddr)
+{
+    uint32_t ret = 0;
+#ifdef __s390x__
+    ret = le32_to_cpu(s390x_pci_mmio_read_32(ioaddr));
+#else
+    ret = ldl_le_p(ioaddr);
+#endif
+
+    return ret;
+}
+
+static inline uint64_t host_pci_ldq_le_p(const void *ioaddr)
+{
+    uint64_t ret = 0;
+#ifdef __s390x__
+    ret = le64_to_cpu(s390x_pci_mmio_read_64(ioaddr));
+#else
+    ret = ldq_le_p(ioaddr);
+#endif
+
+    return ret;
+}
+
+static inline void host_pci_stb_p(void *ioaddr, uint8_t val)
+{
+#ifdef __s390x__
+    s390x_pci_mmio_write_8(ioaddr, val);
+#else
+    stb_p(ioaddr, val);
+#endif
+}
+
+static inline void host_pci_stw_le_p(void *ioaddr, uint16_t val)
+{
+#ifdef __s390x__
+    s390x_pci_mmio_write_16(ioaddr, cpu_to_le16(val));
+#else
+    stw_le_p(ioaddr, val);
+#endif
+}
+
+static inline void host_pci_stl_le_p(void *ioaddr, uint32_t val)
+{
+#ifdef __s390x__
+    s390x_pci_mmio_write_32(ioaddr, cpu_to_le32(val));
+#else
+    stl_le_p(ioaddr, val);
+#endif
+}
+
+static inline void host_pci_stq_le_p(void *ioaddr, uint64_t val)
+{
+#ifdef __s390x__
+    s390x_pci_mmio_write_64(ioaddr, cpu_to_le64(val));
+#else
+    stq_le_p(ioaddr, val);
+#endif
+}
+
+static inline uint64_t host_pci_ldn_le_p(const void *ioaddr, int sz)
+{
+    switch (sz) {
+    case 1:
+        return host_pci_ldub_p(ioaddr);
+    case 2:
+        return host_pci_lduw_le_p(ioaddr);
+    case 4:
+        return host_pci_ldl_le_p(ioaddr);
+    case 8:
+        return host_pci_ldq_le_p(ioaddr);
+    default:
+        g_assert_not_reached();
+    }
+}
+
+static inline void host_pci_stn_le_p(void *ioaddr, int sz, uint64_t v)
+{
+    switch (sz) {
+    case 1:
+        host_pci_stb_p(ioaddr, v);
+        break;
+    case 2:
+        host_pci_stw_le_p(ioaddr, v);
+        break;
+    case 4:
+        host_pci_stl_le_p(ioaddr, v);
+        break;
+    case 8:
+        host_pci_stq_le_p(ioaddr, v);
+        break;
+    default:
+        g_assert_not_reached();
+    }
+}
+
+#endif