spapr/xive: add KVM support

This introduces a set of helpers when KVM is in use, which create the
KVM XIVE device, initialize the interrupt sources at a KVM level and
connect the interrupt presenters to the vCPU.

They also handle the initialization of the TIMA and the source ESB
memory regions of the controller. These have a different type under
KVM. They are 'ram device' memory mappings, similarly to VFIO, exposed
to the guest and the associated VMAs on the host are populated
dynamically with the appropriate pages using a fault handler.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Message-Id: <20190513084245.25755-3-clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

hw/intc/Makefile.objs

@@ -39,6 +39,7 @@ obj-$(CONFIG_XICS_SPAPR) += xics_spapr.o
 obj-$(CONFIG_XICS_KVM) += xics_kvm.o
 obj-$(CONFIG_XIVE) += xive.o
 obj-$(CONFIG_XIVE_SPAPR) += spapr_xive.o
+obj-$(CONFIG_XIVE_KVM) += spapr_xive_kvm.o
 obj-$(CONFIG_POWERNV) += xics_pnv.o pnv_xive.o
 obj-$(CONFIG_ALLWINNER_A10_PIC) += allwinner-a10-pic.o
 obj-$(CONFIG_S390_FLIC) += s390_flic.o

hw/intc/spapr_xive.c

@@ -174,7 +174,7 @@ void spapr_xive_pic_print_info(SpaprXive *xive, Monitor *mon)
     }
 }
 
-static void spapr_xive_map_mmio(SpaprXive *xive)
+void spapr_xive_map_mmio(SpaprXive *xive)
 {
     sysbus_mmio_map(SYS_BUS_DEVICE(xive), 0, xive->vc_base);
     sysbus_mmio_map(SYS_BUS_DEVICE(xive), 1, xive->end_base);
@@ -251,6 +251,9 @@ static void spapr_xive_instance_init(Object *obj)
     object_initialize_child(obj, "end_source", &xive->end_source,
                             sizeof(xive->end_source), TYPE_XIVE_END_SOURCE,
                             &error_abort, NULL);
+
+    /* Not connected to the KVM XIVE device */
+    xive->fd = -1;
 }
 
 static void spapr_xive_realize(DeviceState *dev, Error **errp)
@@ -259,6 +262,7 @@ static void spapr_xive_realize(DeviceState *dev, Error **errp)
     XiveSource *xsrc = &xive->source;
     XiveENDSource *end_xsrc = &xive->end_source;
     Error *local_err = NULL;
+    MachineState *machine = MACHINE(qdev_get_machine());
 
     if (!xive->nr_irqs) {
         error_setg(errp, "Number of interrupt needs to be greater 0");
@@ -305,6 +309,32 @@ static void spapr_xive_realize(DeviceState *dev, Error **errp)
     xive->eat = g_new0(XiveEAS, xive->nr_irqs);
     xive->endt = g_new0(XiveEND, xive->nr_ends);
 
+    xive->nodename = g_strdup_printf("interrupt-controller@%" PRIx64,
+                           xive->tm_base + XIVE_TM_USER_PAGE * (1 << TM_SHIFT));
+
+    qemu_register_reset(spapr_xive_reset, dev);
+
+    if (kvm_enabled() && machine_kernel_irqchip_allowed(machine)) {
+        kvmppc_xive_connect(xive, &local_err);
+        if (local_err && machine_kernel_irqchip_required(machine)) {
+            error_prepend(&local_err,
+                          "kernel_irqchip requested but unavailable: ");
+            error_propagate(errp, local_err);
+            return;
+        }
+
+        if (!local_err) {
+            return;
+        }
+
+        /*
+         * We failed to initialize the XIVE KVM device, fallback to
+         * emulated mode
+         */
+        error_prepend(&local_err, "kernel_irqchip allowed but unavailable: ");
+        warn_report_err(local_err);
+    }
+
     /* TIMA initialization */
     memory_region_init_io(&xive->tm_mmio, OBJECT(xive), &xive_tm_ops, xive,
                           "xive.tima", 4ull << TM_SHIFT);
@@ -316,11 +346,6 @@ static void spapr_xive_realize(DeviceState *dev, Error **errp)
 
     /* Map all regions */
     spapr_xive_map_mmio(xive);
-
-    xive->nodename = g_strdup_printf("interrupt-controller@%" PRIx64,
-                           xive->tm_base + XIVE_TM_USER_PAGE * (1 << TM_SHIFT));
-
-    qemu_register_reset(spapr_xive_reset, dev);
 }
 
 static int spapr_xive_get_eas(XiveRouter *xrtr, uint8_t eas_blk,
@@ -495,6 +520,17 @@ bool spapr_xive_irq_claim(SpaprXive *xive, uint32_t lisn, bool lsi)
     if (lsi) {
         xive_source_irq_set_lsi(xsrc, lisn);
     }
+
+    if (kvm_irqchip_in_kernel()) {
+        Error *local_err = NULL;
+
+        kvmppc_xive_source_reset_one(xsrc, lisn, &local_err);
+        if (local_err) {
+            error_report_err(local_err);
+            return false;
+        }
+    }
+
     return true;
 }
 

hw/intc/spapr_xive_kvm.c

@@ -0,0 +1,237 @@
+/*
+ * QEMU PowerPC sPAPR XIVE interrupt controller model
+ *
+ * Copyright (c) 2017-2019, IBM Corporation.
+ *
+ * This code is licensed under the GPL version 2 or later. See the
+ * COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/log.h"
+#include "qemu/error-report.h"
+#include "qapi/error.h"
+#include "target/ppc/cpu.h"
+#include "sysemu/cpus.h"
+#include "sysemu/kvm.h"
+#include "hw/ppc/spapr.h"
+#include "hw/ppc/spapr_xive.h"
+#include "hw/ppc/xive.h"
+#include "kvm_ppc.h"
+
+#include <sys/ioctl.h>
+
+/*
+ * Helpers for CPU hotplug
+ *
+ * TODO: make a common KVMEnabledCPU layer for XICS and XIVE
+ */
+typedef struct KVMEnabledCPU {
+    unsigned long vcpu_id;
+    QLIST_ENTRY(KVMEnabledCPU) node;
+} KVMEnabledCPU;
+
+static QLIST_HEAD(, KVMEnabledCPU)
+    kvm_enabled_cpus = QLIST_HEAD_INITIALIZER(&kvm_enabled_cpus);
+
+static bool kvm_cpu_is_enabled(CPUState *cs)
+{
+    KVMEnabledCPU *enabled_cpu;
+    unsigned long vcpu_id = kvm_arch_vcpu_id(cs);
+
+    QLIST_FOREACH(enabled_cpu, &kvm_enabled_cpus, node) {
+        if (enabled_cpu->vcpu_id == vcpu_id) {
+            return true;
+        }
+    }
+    return false;
+}
+
+static void kvm_cpu_enable(CPUState *cs)
+{
+    KVMEnabledCPU *enabled_cpu;
+    unsigned long vcpu_id = kvm_arch_vcpu_id(cs);
+
+    enabled_cpu = g_malloc(sizeof(*enabled_cpu));
+    enabled_cpu->vcpu_id = vcpu_id;
+    QLIST_INSERT_HEAD(&kvm_enabled_cpus, enabled_cpu, node);
+}
+
+/*
+ * XIVE Thread Interrupt Management context (KVM)
+ */
+
+void kvmppc_xive_cpu_connect(XiveTCTX *tctx, Error **errp)
+{
+    SpaprXive *xive = SPAPR_MACHINE(qdev_get_machine())->xive;
+    unsigned long vcpu_id;
+    int ret;
+
+    /* Check if CPU was hot unplugged and replugged. */
+    if (kvm_cpu_is_enabled(tctx->cs)) {
+        return;
+    }
+
+    vcpu_id = kvm_arch_vcpu_id(tctx->cs);
+
+    ret = kvm_vcpu_enable_cap(tctx->cs, KVM_CAP_PPC_IRQ_XIVE, 0, xive->fd,
+                              vcpu_id, 0);
+    if (ret < 0) {
+        error_setg(errp, "XIVE: unable to connect CPU%ld to KVM device: %s",
+                   vcpu_id, strerror(errno));
+        return;
+    }
+
+    kvm_cpu_enable(tctx->cs);
+}
+
+/*
+ * XIVE Interrupt Source (KVM)
+ */
+
+/*
+ * At reset, the interrupt sources are simply created and MASKED. We
+ * only need to inform the KVM XIVE device about their type: LSI or
+ * MSI.
+ */
+void kvmppc_xive_source_reset_one(XiveSource *xsrc, int srcno, Error **errp)
+{
+    SpaprXive *xive = SPAPR_XIVE(xsrc->xive);
+    uint64_t state = 0;
+
+    if (xive_source_irq_is_lsi(xsrc, srcno)) {
+        state |= KVM_XIVE_LEVEL_SENSITIVE;
+        if (xsrc->status[srcno] & XIVE_STATUS_ASSERTED) {
+            state |= KVM_XIVE_LEVEL_ASSERTED;
+        }
+    }
+
+    kvm_device_access(xive->fd, KVM_DEV_XIVE_GRP_SOURCE, srcno, &state,
+                      true, errp);
+}
+
+void kvmppc_xive_source_reset(XiveSource *xsrc, Error **errp)
+{
+    int i;
+
+    for (i = 0; i < xsrc->nr_irqs; i++) {
+        Error *local_err = NULL;
+
+        kvmppc_xive_source_reset_one(xsrc, i, &local_err);
+        if (local_err) {
+            error_propagate(errp, local_err);
+            return;
+        }
+    }
+}
+
+void kvmppc_xive_source_set_irq(void *opaque, int srcno, int val)
+{
+    XiveSource *xsrc = opaque;
+    struct kvm_irq_level args;
+    int rc;
+
+    args.irq = srcno;
+    if (!xive_source_irq_is_lsi(xsrc, srcno)) {
+        if (!val) {
+            return;
+        }
+        args.level = KVM_INTERRUPT_SET;
+    } else {
+        if (val) {
+            xsrc->status[srcno] |= XIVE_STATUS_ASSERTED;
+            args.level = KVM_INTERRUPT_SET_LEVEL;
+        } else {
+            xsrc->status[srcno] &= ~XIVE_STATUS_ASSERTED;
+            args.level = KVM_INTERRUPT_UNSET;
+        }
+    }
+    rc = kvm_vm_ioctl(kvm_state, KVM_IRQ_LINE, &args);
+    if (rc < 0) {
+        error_report("XIVE: kvm_irq_line() failed : %s", strerror(errno));
+    }
+}
+
+/*
+ * sPAPR XIVE interrupt controller (KVM)
+ */
+
+static void *kvmppc_xive_mmap(SpaprXive *xive, int pgoff, size_t len,
+                              Error **errp)
+{
+    void *addr;
+    uint32_t page_shift = 16; /* TODO: fix page_shift */
+
+    addr = mmap(NULL, len, PROT_WRITE | PROT_READ, MAP_SHARED, xive->fd,
+                pgoff << page_shift);
+    if (addr == MAP_FAILED) {
+        error_setg_errno(errp, errno, "XIVE: unable to set memory mapping");
+        return NULL;
+    }
+
+    return addr;
+}
+
+/*
+ * All the XIVE memory regions are now backed by mappings from the KVM
+ * XIVE device.
+ */
+void kvmppc_xive_connect(SpaprXive *xive, Error **errp)
+{
+    XiveSource *xsrc = &xive->source;
+    XiveENDSource *end_xsrc = &xive->end_source;
+    Error *local_err = NULL;
+    size_t esb_len = (1ull << xsrc->esb_shift) * xsrc->nr_irqs;
+    size_t tima_len = 4ull << TM_SHIFT;
+
+    if (!kvmppc_has_cap_xive()) {
+        error_setg(errp, "IRQ_XIVE capability must be present for KVM");
+        return;
+    }
+
+    /* First, create the KVM XIVE device */
+    xive->fd = kvm_create_device(kvm_state, KVM_DEV_TYPE_XIVE, false);
+    if (xive->fd < 0) {
+        error_setg_errno(errp, -xive->fd, "XIVE: error creating KVM device");
+        return;
+    }
+
+    /*
+     * 1. Source ESB pages - KVM mapping
+     */
+    xsrc->esb_mmap = kvmppc_xive_mmap(xive, KVM_XIVE_ESB_PAGE_OFFSET, esb_len,
+                                      &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        return;
+    }
+
+    memory_region_init_ram_device_ptr(&xsrc->esb_mmio, OBJECT(xsrc),
+                                      "xive.esb", esb_len, xsrc->esb_mmap);
+    sysbus_init_mmio(SYS_BUS_DEVICE(xive), &xsrc->esb_mmio);
+
+    /*
+     * 2. END ESB pages (No KVM support yet)
+     */
+    sysbus_init_mmio(SYS_BUS_DEVICE(xive), &end_xsrc->esb_mmio);
+
+    /*
+     * 3. TIMA pages - KVM mapping
+     */
+    xive->tm_mmap = kvmppc_xive_mmap(xive, KVM_XIVE_TIMA_PAGE_OFFSET, tima_len,
+                                     &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        return;
+    }
+    memory_region_init_ram_device_ptr(&xive->tm_mmio, OBJECT(xive),
+                                      "xive.tima", tima_len, xive->tm_mmap);
+    sysbus_init_mmio(SYS_BUS_DEVICE(xive), &xive->tm_mmio);
+
+    kvm_kernel_irqchip = true;
+    kvm_msi_via_irqfd_allowed = true;
+    kvm_gsi_direct_mapping = true;
+
+    /* Map all regions */
+    spapr_xive_map_mmio(xive);
+}

hw/intc/xive.c

@@ -555,6 +555,15 @@ static void xive_tctx_realize(DeviceState *dev, Error **errp)
         return;
     }
 
+    /* Connect the presenter to the VCPU (required for CPU hotplug) */
+    if (kvm_irqchip_in_kernel()) {
+        kvmppc_xive_cpu_connect(tctx, &local_err);
+        if (local_err) {
+            error_propagate(errp, local_err);
+            return;
+        }
+    }
+
     qemu_register_reset(xive_tctx_reset, dev);
 }
 
@@ -957,6 +966,10 @@ static void xive_source_reset(void *dev)
 
     /* PQs are initialized to 0b01 (Q=1) which corresponds to "ints off" */
     memset(xsrc->status, XIVE_ESB_OFF, xsrc->nr_irqs);
+
+    if (kvm_irqchip_in_kernel()) {
+        kvmppc_xive_source_reset(xsrc, &error_fatal);
+    }
 }
 
 static void xive_source_realize(DeviceState *dev, Error **errp)
@@ -990,9 +1003,11 @@ static void xive_source_realize(DeviceState *dev, Error **errp)
     xsrc->status = g_malloc0(xsrc->nr_irqs);
     xsrc->lsi_map = bitmap_new(xsrc->nr_irqs);
 
-    memory_region_init_io(&xsrc->esb_mmio, OBJECT(xsrc),
-                          &xive_source_esb_ops, xsrc, "xive.esb",
-                          (1ull << xsrc->esb_shift) * xsrc->nr_irqs);
+    if (!kvm_irqchip_in_kernel()) {
+        memory_region_init_io(&xsrc->esb_mmio, OBJECT(xsrc),
+                              &xive_source_esb_ops, xsrc, "xive.esb",
+                              (1ull << xsrc->esb_shift) * xsrc->nr_irqs);
+    }
 
     qemu_register_reset(xive_source_reset, dev);
 }

hw/ppc/Kconfig

@@ -122,3 +122,8 @@ config XIVE_SPAPR
     default y
     depends on PSERIES
     select XIVE
+
+config XIVE_KVM
+    bool
+    default y
+    depends on XIVE_SPAPR && KVM

hw/ppc/spapr_irq.c

@@ -372,7 +372,11 @@ static void spapr_irq_set_irq_xive(void *opaque, int srcno, int val)
 {
     SpaprMachineState *spapr = opaque;
 
-    xive_source_set_irq(&spapr->xive->source, srcno, val);
+    if (kvm_irqchip_in_kernel()) {
+        kvmppc_xive_source_set_irq(&spapr->xive->source, srcno, val);
+    } else {
+        xive_source_set_irq(&spapr->xive->source, srcno, val);
+    }
 }
 
 static const char *spapr_irq_get_nodename_xive(SpaprMachineState *spapr)

include/hw/ppc/spapr_xive.h

@@ -38,6 +38,10 @@ typedef struct SpaprXive {
     /* TIMA mapping address */
     hwaddr        tm_base;
     MemoryRegion  tm_mmio;
+
+    /* KVM support */
+    int           fd;
+    void          *tm_mmap;
 } SpaprXive;
 
 bool spapr_xive_irq_claim(SpaprXive *xive, uint32_t lisn, bool lsi);
@@ -49,5 +53,11 @@ void spapr_dt_xive(SpaprMachineState *spapr, uint32_t nr_servers, void *fdt,
                    uint32_t phandle);
 void spapr_xive_set_tctx_os_cam(XiveTCTX *tctx);
 void spapr_xive_mmio_set_enabled(SpaprXive *xive, bool enable);
+void spapr_xive_map_mmio(SpaprXive *xive);
+
+/*
+ * KVM XIVE device helpers
+ */
+void kvmppc_xive_connect(SpaprXive *xive, Error **errp);
 
 #endif /* PPC_SPAPR_XIVE_H */

include/hw/ppc/xive.h

@@ -140,6 +140,7 @@
 #ifndef PPC_XIVE_H
 #define PPC_XIVE_H
 
+#include "sysemu/kvm.h"
 #include "hw/qdev-core.h"
 #include "hw/sysbus.h"
 #include "hw/ppc/xive_regs.h"
@@ -194,6 +195,9 @@ typedef struct XiveSource {
     uint32_t        esb_shift;
     MemoryRegion    esb_mmio;
 
+    /* KVM support */
+    void            *esb_mmap;
+
     XiveNotifier    *xive;
 } XiveSource;
 
@@ -423,4 +427,13 @@ static inline uint32_t xive_nvt_cam_line(uint8_t nvt_blk, uint32_t nvt_idx)
     return (nvt_blk << 19) | nvt_idx;
 }
 
+/*
+ * KVM XIVE device helpers
+ */
+
+void kvmppc_xive_source_reset_one(XiveSource *xsrc, int srcno, Error **errp);
+void kvmppc_xive_source_reset(XiveSource *xsrc, Error **errp);
+void kvmppc_xive_source_set_irq(void *opaque, int srcno, int val);
+void kvmppc_xive_cpu_connect(XiveTCTX *tctx, Error **errp);
+
 #endif /* PPC_XIVE_H */

target/ppc/kvm.c

@@ -75,6 +75,7 @@ static int cap_fixup_hcalls;
 static int cap_htm;             /* Hardware transactional memory support */
 static int cap_mmu_radix;
 static int cap_mmu_hash_v3;
+static int cap_xive;
 static int cap_resize_hpt;
 static int cap_ppc_pvr_compat;
 static int cap_ppc_safe_cache;
@@ -146,6 +147,7 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
     cap_htm = kvm_vm_check_extension(s, KVM_CAP_PPC_HTM);
     cap_mmu_radix = kvm_vm_check_extension(s, KVM_CAP_PPC_MMU_RADIX);
     cap_mmu_hash_v3 = kvm_vm_check_extension(s, KVM_CAP_PPC_MMU_HASH_V3);
+    cap_xive = kvm_vm_check_extension(s, KVM_CAP_PPC_IRQ_XIVE);
     cap_resize_hpt = kvm_vm_check_extension(s, KVM_CAP_SPAPR_RESIZE_HPT);
     kvmppc_get_cpu_characteristics(s);
     cap_ppc_nested_kvm_hv = kvm_vm_check_extension(s, KVM_CAP_PPC_NESTED_HV);
@@ -2478,6 +2480,11 @@ static int parse_cap_ppc_count_cache_flush_assist(struct kvm_ppc_cpu_char c)
     return 0;
 }
 
+bool kvmppc_has_cap_xive(void)
+{
+    return cap_xive;
+}
+
 static void kvmppc_get_cpu_characteristics(KVMState *s)
 {
     struct kvm_ppc_cpu_char c;

target/ppc/kvm_ppc.h

@@ -60,6 +60,7 @@ bool kvmppc_has_cap_fixup_hcalls(void);
 bool kvmppc_has_cap_htm(void);
 bool kvmppc_has_cap_mmu_radix(void);
 bool kvmppc_has_cap_mmu_hash_v3(void);
+bool kvmppc_has_cap_xive(void);
 int kvmppc_get_cap_safe_cache(void);
 int kvmppc_get_cap_safe_bounds_check(void);
 int kvmppc_get_cap_safe_indirect_branch(void);
@@ -316,6 +317,11 @@ static inline bool kvmppc_has_cap_mmu_hash_v3(void)
     return false;
 }
 
+static inline bool kvmppc_has_cap_xive(void)
+{
+    return false;
+}
+
 static inline int kvmppc_get_cap_safe_cache(void)
 {
     return 0;