On Tue, 2019-09-17 at 11:41 +0100, Lorenzo Pieralisi wrote:
> On Mon, Sep 16, 2019 at 07:54:35AM -0600, Jon Derrick wrote:
> > The shadow offset scratchpad was moved to 0x2000-0x2010. Update the
> > location to get the correct shadow offset.
>
> Hi Jon,
>
> what does "was moved" mean ? Would this code still work on previous HW ?
>
The previous code won't work on (not yet released) hw. Guests using the
domain will see the wrong offset and enumerate the domain incorrectly.
> We must make sure that the address move is managed seamlessly by the
> kernel.
If we need to avoid changing addressing within stable, then that's
fine. But otherwise is there an issue merging with 5.4?
>
> For the time being I have to drop this fix and it is extremely
> tight to get it in v5.4, I can't send stable changes that we may
> have to revert.
Aren't we in the beginning of the merge window?
>
> Thanks,
> Lorenzo
>
> > Cc: stable@xxxxxxxxxxxxxxx # v5.2+
> > Fixes: 6788958e ("PCI: vmd: Assign membar addresses from shadow registers")
> > Signed-off-by: Jon Derrick <jonathan.derrick@xxxxxxxxx>
> > ---
> > drivers/pci/controller/vmd.c | 9 ++++++---
> > 1 file changed, 6 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c
> > index 2e4da3f51d6b..a35d3f3996d7 100644
> > --- a/drivers/pci/controller/vmd.c
> > +++ b/drivers/pci/controller/vmd.c
> > @@ -31,6 +31,9 @@
> > #define PCI_REG_VMLOCK 0x70
> > #define MB2_SHADOW_EN(vmlock) (vmlock & 0x2)
> >
> > +#define MB2_SHADOW_OFFSET 0x2000
> > +#define MB2_SHADOW_SIZE 16
> > +
> > enum vmd_features {
> > /*
> > * Device may contain registers which hint the physical location of the
> > @@ -578,7 +581,7 @@ static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features)
> > u32 vmlock;
> > int ret;
> >
> > - membar2_offset = 0x2018;
> > + membar2_offset = MB2_SHADOW_OFFSET + MB2_SHADOW_SIZE;
> > ret = pci_read_config_dword(vmd->dev, PCI_REG_VMLOCK, &vmlock);
> > if (ret || vmlock == ~0)
> > return -ENODEV;
> > @@ -590,9 +593,9 @@ static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features)
> > if (!membar2)
> > return -ENOMEM;
> > offset[0] = vmd->dev->resource[VMD_MEMBAR1].start -
> > - readq(membar2 + 0x2008);
> > + readq(membar2 + MB2_SHADOW_OFFSET);
> > offset[1] = vmd->dev->resource[VMD_MEMBAR2].start -
> > - readq(membar2 + 0x2010);
> > + readq(membar2 + MB2_SHADOW_OFFSET + 8);
> > pci_iounmap(vmd->dev, membar2);
> > }
> > }
> > --
> > 2.20.1
> >
