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Date:   Wed, 6 Dec 2023 18:18:09 -0800 (PST)
From:   Stefano Stabellini <sstabellini@kernel.org>
To:     "Chen, Jiqian" <Jiqian.Chen@amd.com>
cc:     Jan Beulich <jbeulich@suse.com>,
        =?UTF-8?Q?Roger_Pau_Monn=C3=A9?= <roger.pau@citrix.com>,
        Stefano Stabellini <sstabellini@kernel.org>,
        Juergen Gross <jgross@suse.com>,
        Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Boris Ostrovsky <boris.ostrovsky@oracle.com>,
        "Rafael J . Wysocki" <rafael@kernel.org>,
        Len Brown <lenb@kernel.org>,
        Bjorn Helgaas <bhelgaas@google.com>,
        "xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-acpi@vger.kernel.org" <linux-acpi@vger.kernel.org>,
        "Stabellini, Stefano" <stefano.stabellini@amd.com>,
        "Deucher, Alexander" <Alexander.Deucher@amd.com>,
        "Koenig, Christian" <Christian.Koenig@amd.com>,
        "Hildebrand, Stewart" <Stewart.Hildebrand@amd.com>,
        "Ragiadakou, Xenia" <Xenia.Ragiadakou@amd.com>,
        "Huang, Honglei1" <Honglei1.Huang@amd.com>,
        "Zhang, Julia" <Julia.Zhang@amd.com>,
        "Huang, Ray" <Ray.Huang@amd.com>
Subject: Re: [RFC KERNEL PATCH v2 2/3] xen/pvh: Unmask irq for passthrough
 device in PVH dom0
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Message-ID: <alpine.DEB.2.22.394.2312061818030.1265976@ubuntu-linux-20-04-desktop>
References: <20231124103123.3263471-1-Jiqian.Chen@amd.com> <20231124103123.3263471-3-Jiqian.Chen@amd.com> <alpine.DEB.2.22.394.2311291950350.3533093@ubuntu-linux-20-04-desktop> <ZWiyBP4Lzz5lXraP@macbook> <alpine.DEB.2.22.394.2311301912350.110490@ubuntu-linux-20-04-desktop>
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Precedence: bulk

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.
>