On Sat, Nov 20, 2021 at 1:17 PM Yifei Jiang <jiangyifei@xxxxxxxxxx> wrote:
>
> Extend riscv_cpu_update_mip() to support setting external interrupt
> by KVM. It will call kvm_riscv_set_irq() to change the IRQ state in
> the KVM module When kvm is enabled and the MIP_SEIP bit is set in "mask"
>
> In addition, bacause target/riscv/cpu_helper.c is used to TCG, so move
> riscv_cpu_update_mip() to target/riscv/cpu.c from target/riscv/cpu_helper.c
>
> Signed-off-by: Yifei Jiang <jiangyifei@xxxxxxxxxx>
> Signed-off-by: Mingwang Li <limingwang@xxxxxxxxxx>
> Reviewed-by: Alistair Francis <alistair.francis@xxxxxxx>
> ---
> target/riscv/cpu.c | 34 ++++++++++++++++++++++++++++++++++
> target/riscv/cpu_helper.c | 27 ---------------------------
> target/riscv/kvm-stub.c | 5 +++++
> target/riscv/kvm.c | 20 ++++++++++++++++++++
> target/riscv/kvm_riscv.h | 1 +
> 5 files changed, 60 insertions(+), 27 deletions(-)
>
> diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
> index 1c944872a3..a464845c99 100644
> --- a/target/riscv/cpu.c
> +++ b/target/riscv/cpu.c
> @@ -21,6 +21,7 @@
> #include "qemu/qemu-print.h"
> #include "qemu/ctype.h"
> #include "qemu/log.h"
> +#include "qemu/main-loop.h"
> #include "cpu.h"
> #include "internals.h"
> #include "exec/exec-all.h"
> @@ -131,6 +132,39 @@ static void set_feature(CPURISCVState *env, int feature)
> env->features |= (1ULL << feature);
> }
>
> +#ifndef CONFIG_USER_ONLY
> +uint32_t riscv_cpu_update_mip(RISCVCPU *cpu, uint32_t mask, uint32_t value)
> +{
> + CPURISCVState *env = &cpu->env;
> + CPUState *cs = CPU(cpu);
> + uint32_t old = env->mip;
> + bool locked = false;
> +
> + if (!qemu_mutex_iothread_locked()) {
> + locked = true;
> + qemu_mutex_lock_iothread();
> + }
> +
> + env->mip = (env->mip & ~mask) | (value & mask);
> +
> + if (kvm_enabled() && (mask & MIP_SEIP)) {
> + kvm_riscv_set_irq(RISCV_CPU(cpu), IRQ_S_EXT, value & MIP_SEIP);
> + }
> +
> + if (env->mip) {
> + cpu_interrupt(cs, CPU_INTERRUPT_HARD);
> + } else {
> + cpu_reset_interrupt(cs, CPU_INTERRUPT_HARD);
> + }
> +
> + if (locked) {
> + qemu_mutex_unlock_iothread();
> + }
> +
> + return old;
> +}
> +#endif
> +
We should not change riscv_cpu_update_mip() for injecting KVM interrupts
because this function touches the user-space state of MIP csr but for KVM
the SIP csr state is always in kernel-space.
Further, the KVM kernel-space ensures synchronization so we don't need
to do qemu_mutex_lock/unlock_iothread() for KVM interrupts.
I would suggest to extend riscv_cpu_set_irq() for KVM interrupts. When
KVM is enabled, the riscv_cpu_set_irq() should throw warning/abort for
any interrupt other than S-mode external interrupts.
Regards,
Anup
> static void set_resetvec(CPURISCVState *env, target_ulong resetvec)
> {
> #ifndef CONFIG_USER_ONLY
> diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
> index 9eeed38c7e..5e36c35b15 100644
> --- a/target/riscv/cpu_helper.c
> +++ b/target/riscv/cpu_helper.c
> @@ -286,33 +286,6 @@ int riscv_cpu_claim_interrupts(RISCVCPU *cpu, uint32_t interrupts)
> }
> }
>
> -uint32_t riscv_cpu_update_mip(RISCVCPU *cpu, uint32_t mask, uint32_t value)
> -{
> - CPURISCVState *env = &cpu->env;
> - CPUState *cs = CPU(cpu);
> - uint32_t old = env->mip;
> - bool locked = false;
> -
> - if (!qemu_mutex_iothread_locked()) {
> - locked = true;
> - qemu_mutex_lock_iothread();
> - }
> -
> - env->mip = (env->mip & ~mask) | (value & mask);
> -
> - if (env->mip) {
> - cpu_interrupt(cs, CPU_INTERRUPT_HARD);
> - } else {
> - cpu_reset_interrupt(cs, CPU_INTERRUPT_HARD);
> - }
> -
> - if (locked) {
> - qemu_mutex_unlock_iothread();
> - }
> -
> - return old;
> -}
> -
> void riscv_cpu_set_rdtime_fn(CPURISCVState *env, uint64_t (*fn)(uint32_t),
> uint32_t arg)
> {
> diff --git a/target/riscv/kvm-stub.c b/target/riscv/kvm-stub.c
> index 39b96fe3f4..4e8fc31a21 100644
> --- a/target/riscv/kvm-stub.c
> +++ b/target/riscv/kvm-stub.c
> @@ -23,3 +23,8 @@ void kvm_riscv_reset_vcpu(RISCVCPU *cpu)
> {
> abort();
> }
> +
> +void kvm_riscv_set_irq(RISCVCPU *cpu, int irq, int level)
> +{
> + abort();
> +}
> diff --git a/target/riscv/kvm.c b/target/riscv/kvm.c
> index 7f3ffcc2b4..8da2648d1a 100644
> --- a/target/riscv/kvm.c
> +++ b/target/riscv/kvm.c
> @@ -458,6 +458,26 @@ void kvm_riscv_reset_vcpu(RISCVCPU *cpu)
> env->satp = 0;
> }
>
> +void kvm_riscv_set_irq(RISCVCPU *cpu, int irq, int level)
> +{
> + int ret;
> + unsigned virq = level ? KVM_INTERRUPT_SET : KVM_INTERRUPT_UNSET;
> +
> + if (irq != IRQ_S_EXT) {
> + return;
> + }
> +
> + if (!kvm_enabled()) {
> + return;
> + }
> +
> + ret = kvm_vcpu_ioctl(CPU(cpu), KVM_INTERRUPT, &virq);
> + if (ret < 0) {
> + perror("Set irq failed");
> + abort();
> + }
> +}
> +
> bool kvm_arch_cpu_check_are_resettable(void)
> {
> return true;
> diff --git a/target/riscv/kvm_riscv.h b/target/riscv/kvm_riscv.h
> index f38c82bf59..ed281bdce0 100644
> --- a/target/riscv/kvm_riscv.h
> +++ b/target/riscv/kvm_riscv.h
> @@ -20,5 +20,6 @@
> #define QEMU_KVM_RISCV_H
>
> void kvm_riscv_reset_vcpu(RISCVCPU *cpu);
> +void kvm_riscv_set_irq(RISCVCPU *cpu, int irq, int level);
>
> #endif
> --
> 2.19.1
>
>
> --
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