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

["Chen, Jiqian" <Jiqian.Chen@xxxxxxx>]

(Adding Juergen to the "To" list.)

Hi Juergen, 
Looking forward to your opinions.

On 2023/12/7 10:18, 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?
> 
> 
>> 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.
>>

-- 
Best regards,
Jiqian Chen.