[PATCH v18 QEMU 04/18] vfio: Add save and load functions for VFIO PCI devices

[Kirti Wankhede <kwankhede@nvidia.com>]

These functions save and restore PCI device specific data - config
space of PCI device.
Tested save and restore with MSI and MSIX type.

Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Neo Jia <cjia@nvidia.com>
---
 hw/vfio/pci.c                 | 163 ++++++++++++++++++++++++++++++++++++++++++
 include/hw/vfio/vfio-common.h |   2 +
 2 files changed, 165 insertions(+)

diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 6c77c12e44b9..b1239ba5b283 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -41,6 +41,7 @@
 #include "trace.h"
 #include "qapi/error.h"
 #include "migration/blocker.h"
+#include "migration/qemu-file.h"
 
 #define TYPE_VFIO_PCI "vfio-pci"
 #define PCI_VFIO(obj)    OBJECT_CHECK(VFIOPCIDevice, obj, TYPE_VFIO_PCI)
@@ -1632,6 +1633,50 @@ static void vfio_bars_prepare(VFIOPCIDevice *vdev)
     }
 }
 
+static int vfio_bar_validate(VFIOPCIDevice *vdev, int nr)
+{
+    PCIDevice *pdev = &vdev->pdev;
+    VFIOBAR *bar = &vdev->bars[nr];
+    uint64_t addr;
+    uint32_t addr_lo, addr_hi = 0;
+
+    /* Skip unimplemented BARs and the upper half of 64bit BARS. */
+    if (!bar->size) {
+        return 0;
+    }
+
+    addr_lo = pci_default_read_config(pdev, PCI_BASE_ADDRESS_0 + nr * 4, 4);
+
+    addr_lo &= (bar->ioport ? PCI_BASE_ADDRESS_IO_MASK :
+                              PCI_BASE_ADDRESS_MEM_MASK);
+    if (bar->type == PCI_BASE_ADDRESS_MEM_TYPE_64) {
+        addr_hi = pci_default_read_config(pdev,
+                                         PCI_BASE_ADDRESS_0 + (nr + 1) * 4, 4);
+    }
+
+    addr = ((uint64_t)addr_hi << 32) | addr_lo;
+
+    if (!QEMU_IS_ALIGNED(addr, bar->size)) {
+        return -EINVAL;
+    }
+
+    return 0;
+}
+
+static int vfio_bars_validate(VFIOPCIDevice *vdev)
+{
+    int i, ret;
+
+    for (i = 0; i < PCI_ROM_SLOT; i++) {
+        ret = vfio_bar_validate(vdev, i);
+        if (ret) {
+            error_report("vfio: BAR address %d validation failed", i);
+            return ret;
+        }
+    }
+    return 0;
+}
+
 static void vfio_bar_register(VFIOPCIDevice *vdev, int nr)
 {
     VFIOBAR *bar = &vdev->bars[nr];
@@ -2414,11 +2459,129 @@ static Object *vfio_pci_get_object(VFIODevice *vbasedev)
     return OBJECT(vdev);
 }
 
+static void vfio_pci_save_config(VFIODevice *vbasedev, QEMUFile *f)
+{
+    VFIOPCIDevice *vdev = container_of(vbasedev, VFIOPCIDevice, vbasedev);
+    PCIDevice *pdev = &vdev->pdev;
+    uint16_t pci_cmd;
+    int i;
+
+    for (i = 0; i < PCI_ROM_SLOT; i++) {
+        uint32_t bar;
+
+        bar = pci_default_read_config(pdev, PCI_BASE_ADDRESS_0 + i * 4, 4);
+        qemu_put_be32(f, bar);
+    }
+
+    qemu_put_be32(f, vdev->interrupt);
+    if (vdev->interrupt == VFIO_INT_MSI) {
+        uint32_t msi_flags, msi_addr_lo, msi_addr_hi = 0, msi_data;
+        bool msi_64bit;
+
+        msi_flags = pci_default_read_config(pdev, pdev->msi_cap + PCI_MSI_FLAGS,
+                                            2);
+        msi_64bit = (msi_flags & PCI_MSI_FLAGS_64BIT);
+
+        msi_addr_lo = pci_default_read_config(pdev,
+                                         pdev->msi_cap + PCI_MSI_ADDRESS_LO, 4);
+        qemu_put_be32(f, msi_addr_lo);
+
+        if (msi_64bit) {
+            msi_addr_hi = pci_default_read_config(pdev,
+                                             pdev->msi_cap + PCI_MSI_ADDRESS_HI,
+                                             4);
+        }
+        qemu_put_be32(f, msi_addr_hi);
+
+        msi_data = pci_default_read_config(pdev,
+                pdev->msi_cap + (msi_64bit ? PCI_MSI_DATA_64 : PCI_MSI_DATA_32),
+                2);
+        qemu_put_be16(f, msi_data);
+    } else if (vdev->interrupt == VFIO_INT_MSIX) {
+        uint16_t offset;
+
+        /* save enable bit and maskall bit */
+        offset = pci_default_read_config(pdev,
+                                       pdev->msix_cap + PCI_MSIX_FLAGS + 1, 2);
+        qemu_put_be16(f, offset);
+        msix_save(pdev, f);
+    }
+    pci_cmd = pci_default_read_config(pdev, PCI_COMMAND, 2);
+    qemu_put_be16(f, pci_cmd);
+}
+
+static int vfio_pci_load_config(VFIODevice *vbasedev, QEMUFile *f)
+{
+    VFIOPCIDevice *vdev = container_of(vbasedev, VFIOPCIDevice, vbasedev);
+    PCIDevice *pdev = &vdev->pdev;
+    uint32_t interrupt_type;
+    uint32_t msi_flags, msi_addr_lo, msi_addr_hi = 0, msi_data;
+    uint16_t pci_cmd;
+    bool msi_64bit;
+    int i, ret;
+
+    /* retore pci bar configuration */
+    pci_cmd = pci_default_read_config(pdev, PCI_COMMAND, 2);
+    vfio_pci_write_config(pdev, PCI_COMMAND,
+                        pci_cmd & (!(PCI_COMMAND_IO | PCI_COMMAND_MEMORY)), 2);
+    for (i = 0; i < PCI_ROM_SLOT; i++) {
+        uint32_t bar = qemu_get_be32(f);
+
+        vfio_pci_write_config(pdev, PCI_BASE_ADDRESS_0 + i * 4, bar, 4);
+    }
+
+    ret = vfio_bars_validate(vdev);
+    if (ret) {
+        return ret;
+    }
+
+    interrupt_type = qemu_get_be32(f);
+
+    if (interrupt_type == VFIO_INT_MSI) {
+        /* restore msi configuration */
+        msi_flags = pci_default_read_config(pdev,
+                                            pdev->msi_cap + PCI_MSI_FLAGS, 2);
+        msi_64bit = (msi_flags & PCI_MSI_FLAGS_64BIT);
+
+        vfio_pci_write_config(pdev, pdev->msi_cap + PCI_MSI_FLAGS,
+                              msi_flags & (!PCI_MSI_FLAGS_ENABLE), 2);
+
+        msi_addr_lo = qemu_get_be32(f);
+        vfio_pci_write_config(pdev, pdev->msi_cap + PCI_MSI_ADDRESS_LO,
+                              msi_addr_lo, 4);
+
+        msi_addr_hi = qemu_get_be32(f);
+        if (msi_64bit) {
+            vfio_pci_write_config(pdev, pdev->msi_cap + PCI_MSI_ADDRESS_HI,
+                                  msi_addr_hi, 4);
+        }
+        msi_data = qemu_get_be32(f);
+        vfio_pci_write_config(pdev,
+                pdev->msi_cap + (msi_64bit ? PCI_MSI_DATA_64 : PCI_MSI_DATA_32),
+                msi_data, 2);
+
+        vfio_pci_write_config(pdev, pdev->msi_cap + PCI_MSI_FLAGS,
+                              msi_flags | PCI_MSI_FLAGS_ENABLE, 2);
+    } else if (interrupt_type == VFIO_INT_MSIX) {
+        uint16_t offset = qemu_get_be16(f);
+
+        /* load enable bit and maskall bit */
+        vfio_pci_write_config(pdev, pdev->msix_cap + PCI_MSIX_FLAGS + 1,
+                              offset, 2);
+        msix_load(pdev, f);
+    }
+    pci_cmd = qemu_get_be16(f);
+    vfio_pci_write_config(pdev, PCI_COMMAND, pci_cmd, 2);
+    return 0;
+}
+
 static VFIODeviceOps vfio_pci_ops = {
     .vfio_compute_needs_reset = vfio_pci_compute_needs_reset,
     .vfio_hot_reset_multi = vfio_pci_hot_reset_multi,
     .vfio_eoi = vfio_intx_eoi,
     .vfio_get_object = vfio_pci_get_object,
+    .vfio_save_config = vfio_pci_save_config,
+    .vfio_load_config = vfio_pci_load_config,
 };
 
 int vfio_populate_vga(VFIOPCIDevice *vdev, Error **errp)
diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
index 74261feaeac9..d69a7f3ae31e 100644
--- a/include/hw/vfio/vfio-common.h
+++ b/include/hw/vfio/vfio-common.h
@@ -120,6 +120,8 @@ struct VFIODeviceOps {
     int (*vfio_hot_reset_multi)(VFIODevice *vdev);
     void (*vfio_eoi)(VFIODevice *vdev);
     Object *(*vfio_get_object)(VFIODevice *vdev);
+    void (*vfio_save_config)(VFIODevice *vdev, QEMUFile *f);
+    int (*vfio_load_config)(VFIODevice *vdev, QEMUFile *f);
 };
 
 typedef struct VFIOGroup {
-- 
2.7.0