@@ -23,6 +23,7 @@
#include "qemu/error-report.h"
#include "hw/sysbus.h"
#include "target/riscv/cpu.h"
+#include "sysemu/sysemu.h"
#include "hw/riscv/sifive_plic.h"
#define RISCV_DEBUG_PLIC 0
@@ -447,6 +448,18 @@ static void sifive_plic_realize(DeviceState *dev, Error **errp)
for (i = 0; i <= plic->num_sources; i++) {
plic->irqs[i] = qemu_allocate_irq(sifive_plic_irq_request, plic, i);
}
+
+ /* We can't allow the supervisor to control SEIP as this would allow the
+ * supervisor to clear a pending external interrupt which will result in
+ * lost a interrupt in the case a PLIC is attached. The SEIP bit must be
+ * hardware controlled when a PLIC is attached. */
+ for (i = 0; i < smp_cpus; i++) {
+ RISCVCPU *cpu = RISCV_CPU(qemu_get_cpu(i));
+ if (riscv_cpu_claim_interrupts(cpu, MIP_SEIP) < 0) {
+ error_report("sifive_plic_realize: SEIP already claimed");
+ exit(1);
+ }
+ }
}
static void sifive_plic_class_init(ObjectClass *klass, void *data)
@@ -138,6 +138,7 @@ struct CPURISCVState {
* mip is 32-bits to allow atomic_read on 32-bit hosts.
*/
uint32_t mip;
+ uint32_t miclaim;
target_ulong mie;
target_ulong mideleg;
@@ -262,6 +263,7 @@ void riscv_cpu_list(FILE *f, fprintf_function cpu_fprintf);
#define cpu_mmu_index riscv_cpu_mmu_index
#ifndef CONFIG_USER_ONLY
+int riscv_cpu_claim_interrupts(RISCVCPU *cpu, uint32_t interrupts);
uint32_t riscv_cpu_update_mip(RISCVCPU *cpu, uint32_t mask, uint32_t value);
#define BOOL_TO_MASK(x) (-!!(x)) /* helper for riscv_cpu_update_mip value */
#endif
@@ -72,6 +72,17 @@ bool riscv_cpu_exec_interrupt(CPUState *cs, int interrupt_request)
#if !defined(CONFIG_USER_ONLY)
+int riscv_cpu_claim_interrupts(RISCVCPU *cpu, uint32_t interrupts)
+{
+ CPURISCVState *env = &cpu->env;
+ if (env->miclaim & interrupts) {
+ return -1;
+ } else {
+ env->miclaim |= interrupts;
+ return 0;
+ }
+}
+
/* iothread_mutex must be held */
uint32_t riscv_cpu_update_mip(RISCVCPU *cpu, uint32_t mask, uint32_t value)
{
@@ -502,15 +502,11 @@ static int rmw_mip(CPURISCVState *env, int csrno, target_ulong *ret_value,
target_ulong new_value, target_ulong write_mask)
{
RISCVCPU *cpu = riscv_env_get_cpu(env);
- target_ulong mask = write_mask & delegable_ints;
- uint32_t old_mip;
- /* We can't allow the supervisor to control SEIP as this would allow the
- * supervisor to clear a pending external interrupt which will result in
- * lost a interrupt in the case a PLIC is attached. The SEIP bit must be
- * hardware controlled when a PLIC is attached. This should be an option
- * for CPUs with software-delegated Supervisor External Interrupts. */
- mask &= ~MIP_SEIP;
+ /* Allow software control of delegable interrupts not claimed by hardware */
+ target_ulong mask = write_mask & delegable_ints & ~env->miclaim;
+
+ uint32_t old_mip;
if (mask) {
qemu_mutex_lock_iothread();
We can't allow the supervisor to control SEIP as this would allow the supervisor to clear a pending external interrupt which will result in lost a interrupt in the case a PLIC is attached. The SEIP bit must be hardware controlled when a PLIC is attached. This logic was previously hard-coded so SEIP was always masked even if no PLIC was attached. This patch adds riscv_cpu_claim_interrupts so that the PLIC can register control of SEIP. In the case of models without a PLIC (spike), the SEIP bit remains software controlled. This interface allows for hardware control of supervisor timer and software interrupts by other interrupt controller models. Cc: Palmer Dabbelt <palmer@sifive.com> Cc: Sagar Karandikar <sagark@eecs.berkeley.edu> Cc: Bastian Koppelmann <kbastian@mail.uni-paderborn.de> Cc: Alistair Francis <Alistair.Francis@wdc.com> Signed-off-by: Michael Clark <mjc@sifive.com> --- hw/riscv/sifive_plic.c | 13 +++++++++++++ target/riscv/cpu.h | 2 ++ target/riscv/cpu_helper.c | 11 +++++++++++ target/riscv/csr.c | 12 ++++-------- 4 files changed, 30 insertions(+), 8 deletions(-)