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target/riscv: Create an KVM AIA irqchip 
We create a vAIA chip by using the KVM_DEV_TYPE_RISCV_AIA and then set up
the chip with the KVM_DEV_RISCV_AIA_GRP_* APIs.
We also extend KVM accelerator to specify the KVM AIA mode. The "riscv-aia"
parameter is passed along with --accel in QEMU command-line.
1) "riscv-aia=emul": IMSIC is emulated by hypervisor
2) "riscv-aia=hwaccel": use hardware guest IMSIC
3) "riscv-aia=auto": use the hardware guest IMSICs whenever available
                     otherwise we fallback to software emulation.

Signed-off-by: Yong-Xuan Wang <yongxuan.wang@sifive.com>
Reviewed-by: Jim Shu <jim.shu@sifive.com>
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Message-ID: <20230727102439.22554-4-yongxuan.wang@sifive.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
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yong-xuan authored and alistair23 committed Sep 11, 2023
1 parent 97b9f5e commit 9634ef7
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186 changes: 186 additions & 0 deletions target/riscv/kvm.c
View file
Expand Up @@ -36,13 +36,15 @@
#include "exec/address-spaces.h"
#include "hw/boards.h"
#include "hw/irq.h"
#include "hw/intc/riscv_imsic.h"
#include "qemu/log.h"
#include "hw/loader.h"
#include "kvm_riscv.h"
#include "sbi_ecall_interface.h"
#include "chardev/char-fe.h"
#include "migration/migration.h"
#include "sysemu/runstate.h"
#include "hw/riscv/numa.h"

static uint64_t kvm_riscv_reg_id(CPURISCVState *env, uint64_t type,
uint64_t idx)
Expand Down Expand Up @@ -1035,6 +1037,190 @@ bool kvm_arch_cpu_check_are_resettable(void)
return true;
}

static int aia_mode;

static const char *kvm_aia_mode_str(uint64_t mode)
{
switch (mode) {
case KVM_DEV_RISCV_AIA_MODE_EMUL:
return "emul";
case KVM_DEV_RISCV_AIA_MODE_HWACCEL:
return "hwaccel";
case KVM_DEV_RISCV_AIA_MODE_AUTO:
default:
return "auto";
};
}

static char *riscv_get_kvm_aia(Object *obj, Error **errp)
{
return g_strdup(kvm_aia_mode_str(aia_mode));
}

static void riscv_set_kvm_aia(Object *obj, const char *val, Error **errp)
{
if (!strcmp(val, "emul")) {
aia_mode = KVM_DEV_RISCV_AIA_MODE_EMUL;
} else if (!strcmp(val, "hwaccel")) {
aia_mode = KVM_DEV_RISCV_AIA_MODE_HWACCEL;
} else if (!strcmp(val, "auto")) {
aia_mode = KVM_DEV_RISCV_AIA_MODE_AUTO;
} else {
error_setg(errp, "Invalid KVM AIA mode");
error_append_hint(errp, "Valid values are emul, hwaccel, and auto.\n");
}
}

void kvm_arch_accel_class_init(ObjectClass *oc)
{
object_class_property_add_str(oc, "riscv-aia", riscv_get_kvm_aia,
riscv_set_kvm_aia);
object_class_property_set_description(oc, "riscv-aia",
"Set KVM AIA mode. Valid values are "
"emul, hwaccel, and auto. Default "
"is auto.");
object_property_set_default_str(object_class_property_find(oc, "riscv-aia"),
"auto");
}

void kvm_riscv_aia_create(MachineState *machine, uint64_t group_shift,
uint64_t aia_irq_num, uint64_t aia_msi_num,
uint64_t aplic_base, uint64_t imsic_base,
uint64_t guest_num)
{
int ret, i;
int aia_fd = -1;
uint64_t default_aia_mode;
uint64_t socket_count = riscv_socket_count(machine);
uint64_t max_hart_per_socket = 0;
uint64_t socket, base_hart, hart_count, socket_imsic_base, imsic_addr;
uint64_t socket_bits, hart_bits, guest_bits;

aia_fd = kvm_create_device(kvm_state, KVM_DEV_TYPE_RISCV_AIA, false);

if (aia_fd < 0) {
error_report("Unable to create in-kernel irqchip");
exit(1);
}

ret = kvm_device_access(aia_fd, KVM_DEV_RISCV_AIA_GRP_CONFIG,
KVM_DEV_RISCV_AIA_CONFIG_MODE,
&default_aia_mode, false, NULL);
if (ret < 0) {
error_report("KVM AIA: failed to get current KVM AIA mode");
exit(1);
}
qemu_log("KVM AIA: default mode is %s\n",
kvm_aia_mode_str(default_aia_mode));

if (default_aia_mode != aia_mode) {
ret = kvm_device_access(aia_fd, KVM_DEV_RISCV_AIA_GRP_CONFIG,
KVM_DEV_RISCV_AIA_CONFIG_MODE,
&aia_mode, true, NULL);
if (ret < 0)
warn_report("KVM AIA: failed to set KVM AIA mode");
else
qemu_log("KVM AIA: set current mode to %s\n",
kvm_aia_mode_str(aia_mode));
}

ret = kvm_device_access(aia_fd, KVM_DEV_RISCV_AIA_GRP_CONFIG,
KVM_DEV_RISCV_AIA_CONFIG_SRCS,
&aia_irq_num, true, NULL);
if (ret < 0) {
error_report("KVM AIA: failed to set number of input irq lines");
exit(1);
}

ret = kvm_device_access(aia_fd, KVM_DEV_RISCV_AIA_GRP_CONFIG,
KVM_DEV_RISCV_AIA_CONFIG_IDS,
&aia_msi_num, true, NULL);
if (ret < 0) {
error_report("KVM AIA: failed to set number of msi");
exit(1);
}

socket_bits = find_last_bit(&socket_count, BITS_PER_LONG) + 1;
ret = kvm_device_access(aia_fd, KVM_DEV_RISCV_AIA_GRP_CONFIG,
KVM_DEV_RISCV_AIA_CONFIG_GROUP_BITS,
&socket_bits, true, NULL);
if (ret < 0) {
error_report("KVM AIA: failed to set group_bits");
exit(1);
}

ret = kvm_device_access(aia_fd, KVM_DEV_RISCV_AIA_GRP_CONFIG,
KVM_DEV_RISCV_AIA_CONFIG_GROUP_SHIFT,
&group_shift, true, NULL);
if (ret < 0) {
error_report("KVM AIA: failed to set group_shift");
exit(1);
}

guest_bits = guest_num == 0 ? 0 :
find_last_bit(&guest_num, BITS_PER_LONG) + 1;
ret = kvm_device_access(aia_fd, KVM_DEV_RISCV_AIA_GRP_CONFIG,
KVM_DEV_RISCV_AIA_CONFIG_GUEST_BITS,
&guest_bits, true, NULL);
if (ret < 0) {
error_report("KVM AIA: failed to set guest_bits");
exit(1);
}

ret = kvm_device_access(aia_fd, KVM_DEV_RISCV_AIA_GRP_ADDR,
KVM_DEV_RISCV_AIA_ADDR_APLIC,
&aplic_base, true, NULL);
if (ret < 0) {
error_report("KVM AIA: failed to set the base address of APLIC");
exit(1);
}

for (socket = 0; socket < socket_count; socket++) {
socket_imsic_base = imsic_base + socket * (1U << group_shift);
hart_count = riscv_socket_hart_count(machine, socket);
base_hart = riscv_socket_first_hartid(machine, socket);

if (max_hart_per_socket < hart_count) {
max_hart_per_socket = hart_count;
}

for (i = 0; i < hart_count; i++) {
imsic_addr = socket_imsic_base + i * IMSIC_HART_SIZE(guest_bits);
ret = kvm_device_access(aia_fd, KVM_DEV_RISCV_AIA_GRP_ADDR,
KVM_DEV_RISCV_AIA_ADDR_IMSIC(i + base_hart),
&imsic_addr, true, NULL);
if (ret < 0) {
error_report("KVM AIA: failed to set the IMSIC address for hart %d", i);
exit(1);
}
}
}

hart_bits = find_last_bit(&max_hart_per_socket, BITS_PER_LONG) + 1;
ret = kvm_device_access(aia_fd, KVM_DEV_RISCV_AIA_GRP_CONFIG,
KVM_DEV_RISCV_AIA_CONFIG_HART_BITS,
&hart_bits, true, NULL);
if (ret < 0) {
error_report("KVM AIA: failed to set hart_bits");
exit(1);
}

if (kvm_has_gsi_routing()) {
for (uint64_t idx = 0; idx < aia_irq_num + 1; ++idx) {
/* KVM AIA only has one APLIC instance */
kvm_irqchip_add_irq_route(kvm_state, idx, 0, idx);
}
kvm_gsi_routing_allowed = true;
kvm_irqchip_commit_routes(kvm_state);
}

ret = kvm_device_access(aia_fd, KVM_DEV_RISCV_AIA_GRP_CTRL,
KVM_DEV_RISCV_AIA_CTRL_INIT,
NULL, true, NULL);
if (ret < 0) {
error_report("KVM AIA: initialized fail");
exit(1);
}

kvm_msi_via_irqfd_allowed = kvm_irqfds_enabled();
}
4 changes: 4 additions & 0 deletions target/riscv/kvm_riscv.h
View file
Expand Up @@ -22,5 +22,9 @@
void kvm_riscv_init_user_properties(Object *cpu_obj);
void kvm_riscv_reset_vcpu(RISCVCPU *cpu);
void kvm_riscv_set_irq(RISCVCPU *cpu, int irq, int level);
void kvm_riscv_aia_create(MachineState *machine, uint64_t group_shift,
uint64_t aia_irq_num, uint64_t aia_msi_num,
uint64_t aplic_base, uint64_t imsic_base,
uint64_t guest_num);

#endif

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