[PATCH] ahci: Set upper 32-bit registers to zero

[Ladi Prosek]

If the HBA supports 64-bit addressing, the registers may contain
non-zero values, for example after reboot as a leftover from the
OS driving the adapter.

Signed-off-by: Ladi Prosek 
---
 src/hw/ahci.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/hw/ahci.c b/src/hw/ahci.c
index 261a7d2..2eee192 100644
--- a/src/hw/ahci.c
+++ b/src/hw/ahci.c
@@ -361,6 +361,11 @@ ahci_port_alloc(struct ahci_ctrl_s *ctrl, u32 pnr)

ahci_port_writel(ctrl, pnr, PORT_LST_ADDR, (u32)port->list);
     ahci_port_writel(ctrl, pnr, PORT_FIS_ADDR, (u32)port->fis);
+    if (ctrl->caps & HOST_CAP_64) {
+        ahci_port_writel(ctrl, pnr, PORT_LST_ADDR_HI, 0);
+        ahci_port_writel(ctrl, pnr, PORT_FIS_ADDR_HI, 0);
+    }
+
     return port;
 }

[Paolo Bonzini]

On 13/01/2017 10:48, Ladi Prosek wrote:
> If the HBA supports 64-bit addressing, the registers may contain
> non-zero values, for example after reboot as a leftover from the
> OS driving the adapter.
> Signed-off-by: Ladi Prosek
>
> src/hw/ahci.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/src/hw/ahci.c b/src/hw/ahci.c
> index 261a7d2..2eee192 100644
> --- a/src/hw/ahci.c
> +++ b/src/hw/ahci.c
> @@ -361,6 +361,11 @@ ahci_port_alloc(struct ahci_ctrl_s *ctrl, u32 pnr)
>  ahci_port_writel(ctrl, pnr, PORT_LST_ADDR, (u32)port->list);
>  ahci_port_writel(ctrl, pnr, PORT_FIS_ADDR, (u32)port->fis);
> if (ctrl->caps & HOST_CAP_64) {
>    ahci_port_writel(ctrl, pnr, PORT_LST_ADDR_HI, 0);
>    ahci_port_writel(ctrl, pnr, PORT_FIS_ADDR_HI, 0);
> }
> return port;
>
> }

Weird as it may seem, HBA reset doesn't clear the address fields
according to the spec.

Reviewed-by: Paolo Bonzini

[Kevin O'Connor]

On Tue, Jan 17, 2017 at 09:46:10AM +0100, Paolo Bonzini wrote:
> On 13/01/2017 10:48, Ladi Prosek wrote:
> > If the HBA supports 64-bit addressing, the registers may contain
> > non-zero values, for example after reboot as a leftover from the
> > OS driving the adapter.
> > Signed-off-by: Ladi Prosek
> >
> > src/hw/ahci.c | 5 +++++
> >  1 file changed, 5 insertions(+)
> >
> > diff --git a/src/hw/ahci.c b/src/hw/ahci.c
> > index 261a7d2..2eee192 100644
> > --- a/src/hw/ahci.c
> > +++ b/src/hw/ahci.c
> > @@ -361,6 +361,11 @@ ahci_port_alloc(struct ahci_ctrl_s *ctrl, u32 pnr)
> >  ahci_port_writel(ctrl, pnr, PORT_LST_ADDR, (u32)port->list);
> >  ahci_port_writel(ctrl, pnr, PORT_FIS_ADDR, (u32)port->fis);
> > if (ctrl->caps & HOST_CAP_64) {
> >    ahci_port_writel(ctrl, pnr, PORT_LST_ADDR_HI, 0);
> >    ahci_port_writel(ctrl, pnr, PORT_FIS_ADDR_HI, 0);
> > }
> > return port;
> >
> > }
>
> Weird as it may seem, HBA reset doesn't clear the address fields
> according to the spec.
>
> Reviewed-by: Paolo Bonzini

Thanks.  I committed this change.

-Kevin