[RFC KERNEL PATCH v4 2/3] xen/pvh: Setup gsi for passthrough device

Jiqian Chen
2024-01-05T06:22:55Z

In PVH dom0, the gsis don't get registered, but the gsi of
a passthrough device must be configured for it to be able to be
mapped into a domU.

When assign a device to passthrough, proactively setup the gsi
of the device during that process.

Co-developed-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Jiqian Chen <Jiqian.Chen@amd.com>
---
arch/x86/xen/enlighten_pvh.c | 90 ++++++++++++++++++++++++++++++
drivers/acpi/pci_irq.c | 2 +-
drivers/xen/xen-pciback/pci_stub.c | 8 +++
include/linux/acpi.h | 1 +
include/xen/acpi.h | 6 ++
5 files changed, 106 insertions(+), 1 deletion(-)

diff --git a/arch/x86/xen/enlighten_pvh.c b/arch/x86/xen/enlighten_pvh.c
index ada3868c02c2..ecadd966c684 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 +26,95 @@
bool __ro_after_init xen_pvh;
EXPORT_SYMBOL_GPL(xen_pvh);

+typedef struct gsi_info {
+ int gsi;
+ int trigger;
+ int polarity;
+} 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 (!dev || !pin || !gsi_info)
+ 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
+ gsi = -1;
+
+ if (gsi < 0)
+ return -EINVAL;
+
+ gsi_info->gsi = gsi;
+ gsi_info->trigger = trigger;
+ gsi_info->polarity = polarity;
+
+ return 0;
+}
+
+static int xen_pvh_setup_gsi(gsi_info_t *gsi_info)
+{
+ struct physdev_setup_gsi setup_gsi;
+
+ if (!gsi_info)
+ return -EINVAL;
+
+ 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_setup_gsi(&gsi_info);
+ if (ret == -EEXIST) {
+ xen_raw_printk("Already setup the GSI :%d\n", gsi_info.gsi);
+ ret = 0;
+ } else if (ret)
+ xen_raw_printk("Fail to setup GSI (%d)!\n", gsi_info.gsi);
+
+ 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 46c40ec8a18e..22d4380d2b04 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>
@@ -435,6 +436,13 @@ static int pcistub_init_device(struct pci_dev *dev)
goto config_release;
pci_restore_state(dev);
}
+
+ if (xen_initial_domain() && xen_pvh_domain()) {
+ err = xen_pvh_passthrough_gsi(dev);
+ if (err)
+ goto config_release;
+ }
+
/* Now disable the device (this also ensures some private device
* data is setup before we export)
*/
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 4db54e928b36..7ea3be981cc3 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -360,6 +360,7 @@ 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..17c4d37f1e60 100644
--- a/include/xen/acpi.h
+++ b/include/xen/acpi.h
@@ -67,10 +67,16 @@ 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)
{
}
+
+static inline int xen_pvh_passthrough_gsi(struct pci_dev *dev)
+{
+ return -1;
+}
#endif

#endif /* _XEN_ACPI_H */
--
2.34.1