On Wed, Mar 17, 2010 at 04:46:47PM +0800, Cui, Dexuan wrote:
> The old commit a234848f works only when the device supports D3hot; when the
> device only supports D3cold, the device doesn't work properly after resuming
> from Dom0 S3.
> A better workaround is invoking the PHYSDEVOP_restore_msi hypercall.
> The patch reverts the old commit and invokes the hypercall.
>
> Signed-off-by: Dexuan Cui <dexuan.cui@xxxxxxxxx>
>
> diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
> index b40c6d0..c6bffe2 100644
> --- a/drivers/pci/msi.c
> +++ b/drivers/pci/msi.c
> @@ -20,6 +20,7 @@
> #include <asm/errno.h>
> #include <asm/io.h>
>
> +#include <asm/xen/hypercall.h>
> #include <asm/xen/hypervisor.h>
>
> #include "pci.h"
> @@ -271,8 +272,7 @@ void write_msi_msg(unsigned int irq, struct msi_msg *msg)
> {
> struct irq_desc *desc = irq_to_desc(irq);
>
> - if (!xen_initial_domain())
> - write_msi_msg_desc(desc, msg);
> + write_msi_msg_desc(desc, msg);
Nice. That will remove the other platofmr build problem.
> }
>
> static int msi_free_irqs(struct pci_dev* dev);
> @@ -347,6 +347,20 @@ static void __pci_restore_msix_state(struct pci_dev *dev)
>
> void pci_restore_msi_state(struct pci_dev *dev)
> {
> + if (xen_initial_domain()) {
That won't do. If you try to compile this kernel on other platforms (say
PPC), this will throw a huge problem.
> + struct physdev_restore_msi physdev;
> +
> + if (!dev->msi_enabled && !dev->msix_enabled)
> + return;
This seems redundant.
I think the problem you are trying to address is doing to show up when
doing PC passthrough using pciback and xen-pcifront.
The mechanims that was employed there to make it work, was to utilize
the arch_setup_msi_irqs in (arch/x86/kernel/apic/io_apic.c) and make it
call functions in arch/x86/pci/xen.c. That code then figures out if you
are running in priviliged or un-priviliged mode and makes the appropiate
call.
Perhaps you should using that idea and expand on it. I would suggest you
take a look at the how PPC implements this and see if there is something
that can be borrowed from their mechanism.
> +
> + pci_intx_for_msi(dev, 0);
> +
> + physdev.bus = dev->bus->number;
> + physdev.devfn = dev->devfn;
> + HYPERVISOR_physdev_op(PHYSDEVOP_restore_msi, &physdev);
> +
> + return;
> + }
> __pci_restore_msi_state(dev);
> __pci_restore_msix_state(dev);
> }
> diff --git a/include/xen/interface/physdev.h b/include/xen/interface/physdev.h
> index ac5de37..516d2b4 100644
> --- a/include/xen/interface/physdev.h
> +++ b/include/xen/interface/physdev.h
> @@ -144,6 +144,13 @@ struct physdev_manage_pci {
> uint8_t devfn;
> };
>
> +#define PHYSDEVOP_restore_msi 19
> +struct physdev_restore_msi {
> + /* IN */
> + uint8_t bus;
> + uint8_t devfn;
> +};
> +
> #define PHYSDEVOP_manage_pci_add_ext 20
> struct physdev_manage_pci_ext {
> /* IN */
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