Re: [Qemu-devel] [PATCH v4 03/13] vfio: Add save and load functions for VFIO PCI devices

[Yan Zhao <yan.y.zhao@intel.com>]

On Fri, Jun 21, 2019 at 02:44:30PM +0800, Kirti Wankhede wrote:
> 
> 
> On 6/21/2019 5:42 AM, Yan Zhao wrote:
> > On Thu, Jun 20, 2019 at 10:37:31PM +0800, Kirti Wankhede wrote:
> >> 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 | 112 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> >>  hw/vfio/pci.h |  29 +++++++++++++++
> >>  2 files changed, 141 insertions(+)
> >>
> >> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> >> index ce3fe96efe2c..09a0821a5b1c 100644
> >> --- a/hw/vfio/pci.c
> >> +++ b/hw/vfio/pci.c
> >> @@ -1187,6 +1187,118 @@ void vfio_pci_write_config(PCIDevice *pdev,
> >>      }
> >>  }
> >>  
> >> +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_be32(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);
> >> +}
> >> +
> >> +void 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;
> >> +
> >> +    /* 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);
> >> +    }
> >> +    vfio_pci_write_config(pdev, PCI_COMMAND,
> >> +                          pci_cmd | PCI_COMMAND_IO | PCI_COMMAND_MEMORY, 2);
> >> +
> >> +    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);
> >> +}
> >> +
> > per the previous discussion, pci config state save/restore are better
> > defined in fileds of VMStateDescription.
> > 
> > 
> 
> With that route there is no pre-copy phase and we do want pre-copy phase
> for VFIO devices. Vendor driver can skip pre-copy phase by doing nothing
> on any read/write operation during pre-copy phase.
> 
> Thanks,
> Kirti
>
hi Kirti
It is able to register both VMSTateDescritpion and SaveVMHandlers at the
same time.

Thanks
Yan

> >>  /*
> >>   * Interrupt setup
> >>   */
> >> diff --git a/hw/vfio/pci.h b/hw/vfio/pci.h
> >> index 834a90d64686..847be5f56478 100644
> >> --- a/hw/vfio/pci.h
> >> +++ b/hw/vfio/pci.h
> >> @@ -19,6 +19,7 @@
> >>  #include "qemu/queue.h"
> >>  #include "qemu/timer.h"
> >>  
> >> +#ifdef CONFIG_LINUX
> >>  #define PCI_ANY_ID (~0)
> >>  
> >>  struct VFIOPCIDevice;
> >> @@ -202,4 +203,32 @@ void vfio_display_reset(VFIOPCIDevice *vdev);
> >>  int vfio_display_probe(VFIOPCIDevice *vdev, Error **errp);
> >>  void vfio_display_finalize(VFIOPCIDevice *vdev);
> >>  
> >> +void vfio_pci_save_config(VFIODevice *vbasedev, QEMUFile *f);
> >> +void vfio_pci_load_config(VFIODevice *vbasedev, QEMUFile *f);
> >> +
> >> +static inline Object *vfio_pci_get_object(VFIODevice *vbasedev)
> >> +{
> >> +    VFIOPCIDevice *vdev = container_of(vbasedev, VFIOPCIDevice, vbasedev);
> >> +
> >> +    return OBJECT(vdev);
> >> +}
> >> +
> >> +#else
> >> +static inline void vfio_pci_save_config(VFIODevice *vbasedev, QEMUFile *f)
> >> +{
> >> +    g_assert(false);
> >> +}
> >> +
> >> +static inline void vfio_pci_load_config(VFIODevice *vbasedev, QEMUFile *f)
> >> +{
> >> +    g_assert(false);
> >> +}
> >> +
> >> +static inline Object *vfio_pci_get_object(VFIODevice *vbasedev)
> >> +{
> >> +    return NULL;
> >> +}
> >> +
> >> +#endif
> >> +
> >>  #endif /* HW_VFIO_VFIO_PCI_H */
> >> -- 
> >> 2.7.0
> >>