On Tue, 29 Sep 2020 12:03:38 +0300 Diana Craciun <[email protected]> wrote:
> The software uses a memory-mapped I/O command interface (MC portals) to > communicate with the MC hardware. This command interface is used to > discover, enumerate, configure and remove DPAA2 objects. The DPAA2 > objects use MSIs, so the command interface needs to be emulated > such that the correct MSI is configured in the hardware (the guest > has the virtual MSIs). > > This patch is adding read/write support for fsl-mc devices. The mc > commands are emulated by the userspace. The host is just passing > the correct command to the hardware. > > Also the current patch limits userspace to write complete > 64byte command once and read 64byte response by one ioctl. > > Signed-off-by: Bharat Bhushan <[email protected]> > Signed-off-by: Diana Craciun <[email protected]> > --- > drivers/vfio/fsl-mc/vfio_fsl_mc.c | 118 +++++++++++++++++++++- > drivers/vfio/fsl-mc/vfio_fsl_mc_private.h | 1 + > 2 files changed, 116 insertions(+), 3 deletions(-) > > diff --git a/drivers/vfio/fsl-mc/vfio_fsl_mc.c > b/drivers/vfio/fsl-mc/vfio_fsl_mc.c > index 82157837f37a..0aff99cdf722 100644 > --- a/drivers/vfio/fsl-mc/vfio_fsl_mc.c > +++ b/drivers/vfio/fsl-mc/vfio_fsl_mc.c > @@ -12,6 +12,7 @@ > #include <linux/types.h> > #include <linux/vfio.h> > #include <linux/fsl/mc.h> > +#include <linux/delay.h> > > #include "vfio_fsl_mc_private.h" > > @@ -115,7 +116,9 @@ static int vfio_fsl_mc_regions_init(struct > vfio_fsl_mc_device *vdev) > !(vdev->regions[i].size & ~PAGE_MASK)) > vdev->regions[i].flags |= > VFIO_REGION_INFO_FLAG_MMAP; > - > + vdev->regions[i].flags |= VFIO_REGION_INFO_FLAG_READ; > + if (!(mc_dev->regions[i].flags & IORESOURCE_READONLY)) > + vdev->regions[i].flags |= VFIO_REGION_INFO_FLAG_WRITE; > } > > return 0; > @@ -123,6 +126,11 @@ static int vfio_fsl_mc_regions_init(struct > vfio_fsl_mc_device *vdev) > > static void vfio_fsl_mc_regions_cleanup(struct vfio_fsl_mc_device *vdev) > { > + struct fsl_mc_device *mc_dev = vdev->mc_dev; > + int i; > + > + for (i = 0; i < mc_dev->obj_desc.region_count; i++) > + iounmap(vdev->regions[i].ioaddr); > kfree(vdev->regions); > } > > @@ -301,13 +309,117 @@ static long vfio_fsl_mc_ioctl(void *device_data, > unsigned int cmd, > static ssize_t vfio_fsl_mc_read(void *device_data, char __user *buf, > size_t count, loff_t *ppos) > { > - return -EINVAL; > + struct vfio_fsl_mc_device *vdev = device_data; > + unsigned int index = VFIO_FSL_MC_OFFSET_TO_INDEX(*ppos); > + loff_t off = *ppos & VFIO_FSL_MC_OFFSET_MASK; > + struct fsl_mc_device *mc_dev = vdev->mc_dev; > + struct vfio_fsl_mc_region *region; > + u64 data[8]; > + int i; > + > + if (index >= mc_dev->obj_desc.region_count) > + return -EINVAL; > + > + region = &vdev->regions[index]; > + > + if (!(region->flags & VFIO_REGION_INFO_FLAG_READ)) > + return -EINVAL; Nit, there are no regions w/o read access according to the regions_init code above. Maybe this is just for symmetry with write? Keep it if you prefer. Thanks, Alex > + > + if (!region->ioaddr) { > + region->ioaddr = ioremap(region->addr, region->size); > + if (!region->ioaddr) > + return -ENOMEM; > + } > + > + if (count != 64 || off != 0) > + return -EINVAL; > + > + for (i = 7; i >= 0; i--) > + data[i] = readq(region->ioaddr + i * sizeof(uint64_t)); > + > + if (copy_to_user(buf, data, 64)) > + return -EFAULT; > + > + return count; > +} > + > +#define MC_CMD_COMPLETION_TIMEOUT_MS 5000 > +#define MC_CMD_COMPLETION_POLLING_MAX_SLEEP_USECS 500 > + > +static int vfio_fsl_mc_send_command(void __iomem *ioaddr, uint64_t *cmd_data) > +{ > + int i; > + enum mc_cmd_status status; > + unsigned long timeout_usecs = MC_CMD_COMPLETION_TIMEOUT_MS * 1000; > + > + /* Write at command parameter into portal */ > + for (i = 7; i >= 1; i--) > + writeq_relaxed(cmd_data[i], ioaddr + i * sizeof(uint64_t)); > + > + /* Write command header in the end */ > + writeq(cmd_data[0], ioaddr); > + > + /* Wait for response before returning to user-space > + * This can be optimized in future to even prepare response > + * before returning to user-space and avoid read ioctl. > + */ > + for (;;) { > + u64 header; > + struct mc_cmd_header *resp_hdr; > + > + header = cpu_to_le64(readq_relaxed(ioaddr)); > + > + resp_hdr = (struct mc_cmd_header *)&header; > + status = (enum mc_cmd_status)resp_hdr->status; > + if (status != MC_CMD_STATUS_READY) > + break; > + > + udelay(MC_CMD_COMPLETION_POLLING_MAX_SLEEP_USECS); > + timeout_usecs -= MC_CMD_COMPLETION_POLLING_MAX_SLEEP_USECS; > + if (timeout_usecs == 0) > + return -ETIMEDOUT; > + } > + > + return 0; > } > > static ssize_t vfio_fsl_mc_write(void *device_data, const char __user *buf, > size_t count, loff_t *ppos) > { > - return -EINVAL; > + struct vfio_fsl_mc_device *vdev = device_data; > + unsigned int index = VFIO_FSL_MC_OFFSET_TO_INDEX(*ppos); > + loff_t off = *ppos & VFIO_FSL_MC_OFFSET_MASK; > + struct fsl_mc_device *mc_dev = vdev->mc_dev; > + struct vfio_fsl_mc_region *region; > + u64 data[8]; > + int ret; > + > + if (index >= mc_dev->obj_desc.region_count) > + return -EINVAL; > + > + region = &vdev->regions[index]; > + > + if (!(region->flags & VFIO_REGION_INFO_FLAG_WRITE)) > + return -EINVAL; > + > + if (!region->ioaddr) { > + region->ioaddr = ioremap(region->addr, region->size); > + if (!region->ioaddr) > + return -ENOMEM; > + } > + > + if (count != 64 || off != 0) > + return -EINVAL; > + > + if (copy_from_user(&data, buf, 64)) > + return -EFAULT; > + > + ret = vfio_fsl_mc_send_command(region->ioaddr, data); > + if (ret) > + return ret; > + > + return count; > + > } > > static int vfio_fsl_mc_mmap_mmio(struct vfio_fsl_mc_region region, > diff --git a/drivers/vfio/fsl-mc/vfio_fsl_mc_private.h > b/drivers/vfio/fsl-mc/vfio_fsl_mc_private.h > index 7aa49b9ba60d..a97ee691ed47 100644 > --- a/drivers/vfio/fsl-mc/vfio_fsl_mc_private.h > +++ b/drivers/vfio/fsl-mc/vfio_fsl_mc_private.h > @@ -32,6 +32,7 @@ struct vfio_fsl_mc_region { > u32 type; > u64 addr; > resource_size_t size; > + void __iomem *ioaddr; > }; > > struct vfio_fsl_mc_device {
