q35: ioapic: add support for emulated IOAPIC IR

This patch translates all IOAPIC interrupts into MSI ones. One pseudo
ioapic address space is added to transfer the MSI message. By default,
it will be system memory address space. When IR is enabled, it will be
IOMMU address space.

Currently, only emulated IOAPIC is supported.

Idea suggested by Jan Kiszka and Rita Sinha in the following patch:

https://lists.gnu.org/archive/html/qemu-devel/2016-03/msg01933.html

Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index ccfcc69347dfbb5dbf2e2dfbd33b187bb6ab4f69..6ba5520283f571d47a826187cecf9e75fd5381bf 100644 (file)
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -28,6 +28,7 @@
 #include "hw/i386/pc.h"
 #include "hw/boards.h"
 #include "hw/i386/x86-iommu.h"
+#include "hw/pci-host/q35.h"
 
 /*#define DEBUG_INTEL_IOMMU*/
 #ifdef DEBUG_INTEL_IOMMU
@@ -2367,7 +2368,8 @@ static AddressSpace *vtd_host_dma_iommu(PCIBus *bus, void *opaque, int devfn)
 
 static void vtd_realize(DeviceState *dev, Error **errp)
 {
-    PCIBus *bus = PC_MACHINE(qdev_get_machine())->bus;
+    PCMachineState *pcms = PC_MACHINE(qdev_get_machine());
+    PCIBus *bus = pcms->bus;
     IntelIOMMUState *s = INTEL_IOMMU_DEVICE(dev);
 
     VTD_DPRINTF(GENERAL, "");
@@ -2383,6 +2385,8 @@ static void vtd_realize(DeviceState *dev, Error **errp)
     vtd_init(s);
     sysbus_mmio_map(SYS_BUS_DEVICE(s), 0, Q35_HOST_BRIDGE_IOMMU_ADDR);
     pci_setup_iommu(bus, vtd_host_dma_iommu, dev);
+    /* Pseudo address space under root PCI bus. */
+    pcms->ioapic_as = vtd_host_dma_iommu(bus, s, Q35_PSEUDO_DEVFN_IOAPIC);
 }
 
 static void vtd_class_init(ObjectClass *klass, void *data)

diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 719884ff88c58afc53b402f1cddd44486db98cf0..979f36d99f24580e62426883f1833710e2b9f9a1 100644 (file)
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -1475,6 +1475,9 @@ void pc_memory_init(PCMachineState *pcms,
         rom_add_option(option_rom[i].name, option_rom[i].bootindex);
     }
     pcms->fw_cfg = fw_cfg;
+
+    /* Init default IOAPIC address space */
+    pcms->ioapic_as = &address_space_memory;
 }
 
 qemu_irq pc_allocate_cpu_irq(void)

diff --git a/hw/intc/ioapic.c b/hw/intc/ioapic.c
index 273bb0854cbb048475427d6b4814264556c24e26..36dd42af2054849e423fc6ba1eef29aee84ca500 100644 (file)
--- a/hw/intc/ioapic.c
+++ b/hw/intc/ioapic.c
@@ -29,6 +29,8 @@
 #include "hw/i386/ioapic_internal.h"
 #include "include/hw/pci/msi.h"
 #include "sysemu/kvm.h"
+#include "target-i386/cpu.h"
+#include "hw/i386/apic-msidef.h"
 
 //#define DEBUG_IOAPIC
 
@@ -50,13 +52,15 @@ extern int ioapic_no;
 
 static void ioapic_service(IOAPICCommonState *s)
 {
+    AddressSpace *ioapic_as = PC_MACHINE(qdev_get_machine())->ioapic_as;
+    uint32_t addr, data;
     uint8_t i;
     uint8_t trig_mode;
     uint8_t vector;
     uint8_t delivery_mode;
     uint32_t mask;
     uint64_t entry;
-    uint8_t dest;
+    uint16_t dest_idx;
     uint8_t dest_mode;
 
     for (i = 0; i < IOAPIC_NUM_PINS; i++) {
@@ -67,7 +71,14 @@ static void ioapic_service(IOAPICCommonState *s)
             entry = s->ioredtbl[i];
             if (!(entry & IOAPIC_LVT_MASKED)) {
                 trig_mode = ((entry >> IOAPIC_LVT_TRIGGER_MODE_SHIFT) & 1);
-                dest = entry >> IOAPIC_LVT_DEST_SHIFT;
+                /*
+                 * By default, this would be dest_id[8] +
+                 * reserved[8]. When IR is enabled, this would be
+                 * interrupt_index[15] + interrupt_format[1]. This
+                 * field never means anything, but only used to
+                 * generate corresponding MSI.
+                 */
+                dest_idx = entry >> IOAPIC_LVT_DEST_IDX_SHIFT;
                 dest_mode = (entry >> IOAPIC_LVT_DEST_MODE_SHIFT) & 1;
                 delivery_mode =
                     (entry >> IOAPIC_LVT_DELIV_MODE_SHIFT) & IOAPIC_DM_MASK;
@@ -97,8 +108,17 @@ static void ioapic_service(IOAPICCommonState *s)
 #else
                 (void)coalesce;
 #endif
-                apic_deliver_irq(dest, dest_mode, delivery_mode, vector,
-                                 trig_mode);
+                /* No matter whether IR is enabled, we translate
+                 * the IOAPIC message into a MSI one, and its
+                 * address space will decide whether we need a
+                 * translation. */
+                addr = APIC_DEFAULT_ADDRESS | \
+                    (dest_idx << MSI_ADDR_DEST_IDX_SHIFT) |
+                    (dest_mode << MSI_ADDR_DEST_MODE_SHIFT);
+                data = (vector << MSI_DATA_VECTOR_SHIFT) |
+                    (trig_mode << MSI_DATA_TRIGGER_SHIFT) |
+                    (delivery_mode << MSI_DATA_DELIVERY_MODE_SHIFT);
+                stl_le_phys(ioapic_as, addr, data);
             }
         }
     }

diff --git a/include/hw/i386/apic-msidef.h b/include/hw/i386/apic-msidef.h
index 6e2eb71f2f4fe99f3e2ce78da8b429def4d6aa44..8b4d4cca55247e5e7795de3645e126e6d37ab550 100644 (file)
--- a/include/hw/i386/apic-msidef.h
+++ b/include/hw/i386/apic-msidef.h
@@ -25,6 +25,7 @@
 #define MSI_ADDR_REDIRECTION_SHIFT      3
 
 #define MSI_ADDR_DEST_ID_SHIFT          12
+#define MSI_ADDR_DEST_IDX_SHIFT         4
 #define  MSI_ADDR_DEST_ID_MASK          0x00ffff0
 
 #endif /* HW_APIC_MSIDEF_H */

diff --git a/include/hw/i386/ioapic_internal.h b/include/hw/i386/ioapic_internal.h
index 0542aa1131c504ef9a9f71e9a970432d42986f72..5c901ae78f3ba14d0bd6045c4a70abdfa7d65c26 100644 (file)
--- a/include/hw/i386/ioapic_internal.h
+++ b/include/hw/i386/ioapic_internal.h
@@ -31,6 +31,7 @@
 #define IOAPIC_VERSION                  0x11
 
 #define IOAPIC_LVT_DEST_SHIFT           56
+#define IOAPIC_LVT_DEST_IDX_SHIFT       48
 #define IOAPIC_LVT_MASKED_SHIFT         16
 #define IOAPIC_LVT_TRIGGER_MODE_SHIFT   15
 #define IOAPIC_LVT_REMOTE_IRR_SHIFT     14

diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index e38c95a4da18d81a66c040687cc0f54bc968d220..9811125492474789ea349c011230fa8c5d30147a 100644 (file)
--- a/include/hw/i386/pc.h
+++ b/include/hw/i386/pc.h
@@ -72,6 +72,10 @@ struct PCMachineState {
     /* NUMA information: */
     uint64_t numa_nodes;
     uint64_t *node_mem;
+
+    /* Address space used by IOAPIC device. All IOAPIC interrupts
+     * will be translated to MSI messages in the address space. */
+    AddressSpace *ioapic_as;
 };
 
 #define PC_MACHINE_ACPI_DEVICE_PROP "acpi-device"