Re: [RFC KERNEL PATCH v2 2/3] xen/pvh: Unmask irq for passthrough device in PVH dom0

[Juergen Gross <jgross@xxxxxxxx>]

On 07.12.23 03:18, Stefano Stabellini wrote:
> On Tue, 5 Dec 2023, Chen, Jiqian wrote:
> > When PVH dom0 enable a device, it will get trigger and polarity from ACPI (see 
> > acpi_pci_irq_enable)
> > I have a version of patch which tried that way, see below:
> This approach looks much better. I think this patch is OKish. Juergen,
> what do you think?
The approach seems to be fine.


Juergen

> > diff --git a/arch/x86/xen/enlighten_pvh.c b/arch/x86/xen/enlighten_pvh.c
> > index ada3868c02c2..43e1bda9f946 100644
> > --- a/arch/x86/xen/enlighten_pvh.c
> > +++ b/arch/x86/xen/enlighten_pvh.c
> > @@ -1,6 +1,7 @@
> >   // SPDX-License-Identifier: GPL-2.0
> >   #include <linux/acpi.h>
> >   #include <linux/export.h>
> > +#include <linux/pci.h>
> >
> >   #include <xen/hvc-console.h>
> >
> > @@ -25,6 +26,127 @@
> >   bool __ro_after_init xen_pvh;
> >   EXPORT_SYMBOL_GPL(xen_pvh);
> >
> > +typedef struct gsi_info {
> > +       int gsi;
> > +       int trigger;
> > +       int polarity;
> > +       int pirq;
> > +} gsi_info_t;
> > +
> > +struct acpi_prt_entry {
> > +       struct acpi_pci_id      id;
> > +       u8                      pin;
> > +       acpi_handle             link;
> > +       u32                     index;          /* GSI, or link _CRS index */
> > +};
> > +
> > +static int xen_pvh_get_gsi_info(struct pci_dev *dev,
> > +                                                               gsi_info_t 
> > *gsi_info)
> > +{
> > +       int gsi;
> > +       u8 pin = 0;
> > +       struct acpi_prt_entry *entry;
> > +       int trigger = ACPI_LEVEL_SENSITIVE;
> > +       int polarity = acpi_irq_model == ACPI_IRQ_MODEL_GIC ?
> > +                                     ACPI_ACTIVE_HIGH : ACPI_ACTIVE_LOW;
> > +
> > +       if (dev)
> > +               pin = dev->pin;
> > +       if (!pin) {
> > +               xen_raw_printk("No interrupt pin configured\n");
> > +               return -EINVAL;
> > +       }
> > +
> > +       entry = acpi_pci_irq_lookup(dev, pin);
> > +       if (entry) {
> > +               if (entry->link)
> > +                       gsi = acpi_pci_link_allocate_irq(entry->link,
> > +                                                        entry->index,
> > +                                                        &trigger, &polarity,
> > +                                                        NULL);
> > +               else
> > +                       gsi = entry->index;
> > +       } else
> > +               return -EINVAL;
> > +
> > +       gsi_info->gsi = gsi;
> > +       gsi_info->trigger = trigger;
> > +       gsi_info->polarity = polarity;
> > +
> > +       return 0;
> > +}
> > +
> > +static int xen_pvh_map_pirq(gsi_info_t *gsi_info)
> > +{
> > +       struct physdev_map_pirq map_irq;
> > +       int ret;
> > +
> > +       map_irq.domid = DOMID_SELF;
> > +       map_irq.type = MAP_PIRQ_TYPE_GSI;
> > +       map_irq.index = gsi_info->gsi;
> > +       map_irq.pirq = gsi_info->gsi;
> > +
> > +       ret = HYPERVISOR_physdev_op(PHYSDEVOP_map_pirq, &map_irq);
> > +       gsi_info->pirq = map_irq.pirq;
> > +
> > +       return ret;
> > +}
> > +
> > +static int xen_pvh_unmap_pirq(gsi_info_t *gsi_info)
> > +{
> > +       struct physdev_unmap_pirq unmap_irq;
> > +
> > +       unmap_irq.domid = DOMID_SELF;
> > +       unmap_irq.pirq = gsi_info->pirq;
> > +
> > +       return HYPERVISOR_physdev_op(PHYSDEVOP_unmap_pirq, &unmap_irq);
> > +}
> > +
> > +static int xen_pvh_setup_gsi(gsi_info_t *gsi_info)
> > +{
> > +       struct physdev_setup_gsi setup_gsi;
> > +
> > +       setup_gsi.gsi = gsi_info->gsi;
> > +       setup_gsi.triggering = (gsi_info->trigger == ACPI_EDGE_SENSITIVE ? 0 : 
> > 1);
> > +       setup_gsi.polarity = (gsi_info->polarity == ACPI_ACTIVE_HIGH ? 0 : 1);
> > +
> > +       return HYPERVISOR_physdev_op(PHYSDEVOP_setup_gsi, &setup_gsi);
> > +}
> > +
> > +int xen_pvh_passthrough_gsi(struct pci_dev *dev)
> > +{
> > +       int ret;
> > +       gsi_info_t gsi_info;
> > +
> > +       if (!dev) {
> > +               return -EINVAL;
> > +       }
> > +
> > +       ret = xen_pvh_get_gsi_info(dev, &gsi_info);
> > +       if (ret) {
> > +               xen_raw_printk("Fail to get gsi info!\n");
> > +               return ret;
> > +       }
> > +
> > +       ret = xen_pvh_map_pirq(&gsi_info);
> > +       if (ret) {
> > +               xen_raw_printk("Fail to map pirq for gsi (%d)!\n", 
> > gsi_info.gsi);
> > +               return ret;
> > +       }
> > +
> > +       ret = xen_pvh_setup_gsi(&gsi_info);
> > +       if (ret == -EEXIST) {
> > +               ret = 0;
> > +               xen_raw_printk("Already setup the GSI :%u\n", gsi_info.gsi);
> > +       } else if (ret) {
> > +               xen_raw_printk("Fail to setup gsi (%d)!\n", gsi_info.gsi);
> > +               xen_pvh_unmap_pirq(&gsi_info);
> > +       }
> > +
> > +       return ret;
> > +}
> > +EXPORT_SYMBOL_GPL(xen_pvh_passthrough_gsi);
> > +
> >   void __init xen_pvh_init(struct boot_params *boot_params)
> >   {
> >          u32 msr;
> > diff --git a/drivers/acpi/pci_irq.c b/drivers/acpi/pci_irq.c
> > index ff30ceca2203..630fe0a34bc6 100644
> > --- a/drivers/acpi/pci_irq.c
> > +++ b/drivers/acpi/pci_irq.c
> > @@ -288,7 +288,7 @@ static int acpi_reroute_boot_interrupt(struct pci_dev *dev,
> >   }
> >   #endif /* CONFIG_X86_IO_APIC */
> >
> > -static struct acpi_prt_entry *acpi_pci_irq_lookup(struct pci_dev *dev, int pin)
> > +struct acpi_prt_entry *acpi_pci_irq_lookup(struct pci_dev *dev, int pin)
> >   {
> >          struct acpi_prt_entry *entry = NULL;
> >          struct pci_dev *bridge;
> > diff --git a/drivers/xen/xen-pciback/pci_stub.c 
> > b/drivers/xen/xen-pciback/pci_stub.c
> > index e34b623e4b41..1abd4dad6f40 100644
> > --- a/drivers/xen/xen-pciback/pci_stub.c
> > +++ b/drivers/xen/xen-pciback/pci_stub.c
> > @@ -20,6 +20,7 @@
> >   #include <linux/atomic.h>
> >   #include <xen/events.h>
> >   #include <xen/pci.h>
> > +#include <xen/acpi.h>
> >   #include <xen/xen.h>
> >   #include <asm/xen/hypervisor.h>
> >   #include <xen/interface/physdev.h>
> > @@ -399,6 +400,12 @@ static int pcistub_init_device(struct pci_dev *dev)
> >          if (err)
> >                  goto config_release;
> >
> > +       if (xen_initial_domain() && xen_pvh_domain()) {
> > +               err = xen_pvh_passthrough_gsi(dev);
> > +               if (err)
> > +                       goto config_release;
> > +       }
> > +
> >          if (dev->msix_cap) {
> >                  struct physdev_pci_device ppdev = {
> >                          .seg = pci_domain_nr(dev->bus),
> > diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> > index 641dc4843987..368d56ba2c5e 100644
> > --- a/include/linux/acpi.h
> > +++ b/include/linux/acpi.h
> > @@ -375,6 +375,7 @@ void acpi_unregister_gsi (u32 gsi);
> >
> >   struct pci_dev;
> >
> > +struct acpi_prt_entry *acpi_pci_irq_lookup(struct pci_dev *dev, int pin);
> >   int acpi_pci_irq_enable (struct pci_dev *dev);
> >   void acpi_penalize_isa_irq(int irq, int active);
> >   bool acpi_isa_irq_available(int irq);
> > diff --git a/include/xen/acpi.h b/include/xen/acpi.h
> > index b1e11863144d..ce7f5554f88e 100644
> > --- a/include/xen/acpi.h
> > +++ b/include/xen/acpi.h
> > @@ -67,6 +67,7 @@ static inline void xen_acpi_sleep_register(void)
> >                  acpi_suspend_lowlevel = xen_acpi_suspend_lowlevel;
> >          }
> >   }
> > +int xen_pvh_passthrough_gsi(struct pci_dev *dev);
> >   #else
> >   static inline void xen_acpi_sleep_register(void)
> >   {
> >
> > > Jan
> > --
> > Best regards,
> > Jiqian Chen.

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