Re: [PATCH kvmtool 15/21] vfio: Refactor ioport trap handler

Andre Przywara
2021-02-18T16:16:13Z

On Tue, 16 Feb 2021 14:47:31 +0000
Alexandru Elisei <alexandru.elisei@arm.com> wrote:

> Hi Andre,
>
> Looks good, one nitpick below.
>
> On 12/10/20 2:29 PM, Andre Przywara wrote:
> > With the planned retirement of the special ioport emulation code, we
> > need to provide an emulation function compatible with the MMIO prototype.
> >
> > Adjust the I/O port trap handler to use that new function, and provide
> > shims to implement the old ioport interface, for now.
> >
> > Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> > ---
> > vfio/core.c | 51 ++++++++++++++++++++++++++++++++++++---------------
> > 1 file changed, 36 insertions(+), 15 deletions(-)
> >
> > diff --git a/vfio/core.c b/vfio/core.c
> > index 0b45e78b..f55f1f87 100644
> > --- a/vfio/core.c
> > +++ b/vfio/core.c
> > @@ -81,15 +81,12 @@ out_free_buf:
> > return ret;
> > }
> >
> > -static bool vfio_ioport_in(struct ioport *ioport, struct kvm_cpu *vcpu,
> > - u16 port, void *data, int len)
> > +static bool _vfio_ioport_in(struct vfio_region *region, u32 offset,
> > + void *data, int len)
> > {
> > - u32 val;
> > - ssize_t nr;
> > - struct vfio_region *region = ioport->priv;
> > struct vfio_device *vdev = region->vdev;
> > -
> > - u32 offset = port - region->port_base;
> > + ssize_t nr;
> > + u32 val;
> >
> > if (!(region->info.flags & VFIO_REGION_INFO_FLAG_READ))
> > return false;
> > @@ -97,7 +94,7 @@ static bool vfio_ioport_in(struct ioport *ioport, struct kvm_cpu *vcpu,
> > nr = pread(vdev->fd, &val, len, region->info.offset + offset);
> > if (nr != len) {
> > vfio_dev_err(vdev, "could not read %d bytes from I/O port 0x%x\n",
> > - len, port);
> > + len, offset);
>
> To keep things functionally identical, shouldn't that be offset +
> region->port_base? I think it's easier to identify the device when we have the PCI
> ioport address.

Yeah, true. Although I think "vfio_dev_err(vdev, ..." already indicates
the device at fault, but indeed the actual ioport address is more
canonical to use.

Thanks,
Andre

>
> Thanks,
>
> Alex
>
> > return false;
> > }
> >
> > @@ -118,15 +115,13 @@ static bool vfio_ioport_in(struct ioport *ioport, struct kvm_cpu *vcpu,
> > return true;
> > }
> >
> > -static bool vfio_ioport_out(struct ioport *ioport, struct kvm_cpu *vcpu,
> > - u16 port, void *data, int len)
> > +static bool _vfio_ioport_out(struct vfio_region *region, u32 offset,
> > + void *data, int len)
> > {
> > - u32 val;
> > - ssize_t nr;
> > - struct vfio_region *region = ioport->priv;
> > struct vfio_device *vdev = region->vdev;
> > + ssize_t nr;
> > + u32 val;
> >
> > - u32 offset = port - region->port_base;
> >
> > if (!(region->info.flags & VFIO_REGION_INFO_FLAG_WRITE))
> > return false;
> > @@ -148,11 +143,37 @@ static bool vfio_ioport_out(struct ioport *ioport, struct kvm_cpu *vcpu,
> > nr = pwrite(vdev->fd, &val, len, region->info.offset + offset);
> > if (nr != len)
> > vfio_dev_err(vdev, "could not write %d bytes to I/O port 0x%x",
> > - len, port);
> > + len, offset);
> >
> > return nr == len;
> > }
> >
> > +static void vfio_ioport_mmio(struct kvm_cpu *vcpu, u64 addr, u8 *data, u32 len,
> > + u8 is_write, void *ptr)
> > +{
> > + struct vfio_region *region = ptr;
> > + u32 offset = addr - region->port_base;
> > +
> > + if (is_write)
> > + _vfio_ioport_out(region, offset, data, len);
> > + else
> > + _vfio_ioport_in(region, offset, data, len);
> > +}
> > +
> > +static bool vfio_ioport_out(struct ioport *ioport, struct kvm_cpu *vcpu,
> > + u16 port, void *data, int len)
> > +{
> > + vfio_ioport_mmio(vcpu, port, data, len, true, ioport->priv);
> > + return true;
> > +}
> > +
> > +static bool vfio_ioport_in(struct ioport *ioport, struct kvm_cpu *vcpu,
> > + u16 port, void *data, int len)
> > +{
> > + vfio_ioport_mmio(vcpu, port, data, len, false, ioport->priv);
> > + return true;
> > +}
> > +
> > static struct ioport_operations vfio_ioport_ops = {
> > .io_in = vfio_ioport_in,
> > .io_out = vfio_ioport_out,