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(unknown [210.73.43.101]) by APP-05 (Coremail) with SMTP id zQCowADHaBI+t8toBKqGAw--.13402S2; Thu, 18 Sep 2025 15:39:43 +0800 (CST) From: Zhe Qiao To: anup@brainfault.org, atish.patra@linux.dev, paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, alex@ghiti.fr, qiaozhe@iscas.ac.cn Cc: linux-riscv@lists.infradead.org, kvm-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Subject: [PATCH] RISCV: KVM: Add support for userspace to suspend a vCPU Date: Thu, 18 Sep 2025 15:39:27 +0800 Message-ID: <20250918073927.403410-1-qiaozhe@iscas.ac.cn> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: zQCowADHaBI+t8toBKqGAw--.13402S2 X-Coremail-Antispam: 1UD129KBjvJXoWxWw4rCr1fKw1rJFyfJw1fWFg_yoW5ZFy7pF sFkrs09w4rGryxCw13J3yDur15WrsYgrnxury29rW5Gr45KrWrAr4v9rW5JF1UJFW8XF1I yFn8K3WUC3W5twUanT9S1TB71UUUUUDqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUU9K14x267AKxVW8JVW5JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26r4j6ryUM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4j 6F4UM28EF7xvwVC2z280aVAFwI0_Cr1j6rxdM28EF7xvwVC2z280aVCY1x0267AKxVW0oV Cq3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0 I7IYx2IY67AKxVWUXVWUAwAv7VC2z280aVAFwI0_Gr0_Cr1lOx8S6xCaFVCjc4AY6r1j6r 4UM4x0Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2IErcIFxwACI402YVCY1x02628v n2kIc2xKxwCY1x0262kKe7AKxVWUtVW8ZwCY02Avz4vE14v_GF4l42xK82IYc2Ij64vIr4 1l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x8GjcxK 67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r1q6r43MIIYrxkI7VAKI48JMIIF0xvE2Ix0cI 8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26r4j6F4UMIIF0xvE42xK8VAv wI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVWUJVW8JwCI42IY6I8E87Iv6xkF7I0E14 v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjfUeJ5rDUUUU X-CM-SenderInfo: ptld061kh6x2xfdvhtffof0/ Add RISC-V architecture support for the KVM_MP_STATE_SUSPENDED vCPU state, indicating that a vCPU is in suspended mode. While suspended, the vCPU will block execution until a wakeup event is detected. Introduce a new system event type, KVM_SYSTEM_EVENT_WAKEUP, to notify userspace when KVM has recognized such a wakeup event. It is then userspace=E2=80=99s responsibility to either make the vCPU runnable again or keep it suspended until the next wakeup event occurs. Signed-off-by: Zhe Qiao --- arch/riscv/include/asm/kvm_host.h | 2 ++ arch/riscv/kvm/vcpu.c | 37 +++++++++++++++++++++++++++++++ 2 files changed, 39 insertions(+) diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm= _host.h index d71d3299a335..dbc6391407ae 100644 --- a/arch/riscv/include/asm/kvm_host.h +++ b/arch/riscv/include/asm/kvm_host.h @@ -43,6 +43,8 @@ #define KVM_REQ_HFENCE \ KVM_ARCH_REQ_FLAGS(5, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP) #define KVM_REQ_STEAL_UPDATE KVM_ARCH_REQ(6) +#define KVM_REQ_SUSPEND \ + KVM_ARCH_REQ_FLAGS(7, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP) =20 #define __KVM_HAVE_ARCH_FLUSH_REMOTE_TLBS_RANGE =20 diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c index 3ebcfffaa978..0881c78476b1 100644 --- a/arch/riscv/kvm/vcpu.c +++ b/arch/riscv/kvm/vcpu.c @@ -496,6 +496,18 @@ int kvm_arch_vcpu_ioctl_get_mpstate(struct kvm_vcpu *v= cpu, return 0; } =20 +static void kvm_riscv_vcpu_suspend(struct kvm_vcpu *vcpu) +{ + WRITE_ONCE(vcpu->arch.mp_state.mp_state, KVM_MP_STATE_SUSPENDED); + kvm_make_request(KVM_REQ_SUSPEND, vcpu); + kvm_vcpu_kick(vcpu); +} + +static bool kvm_riscv_vcpu_suspended(struct kvm_vcpu *vcpu) +{ + return READ_ONCE(vcpu->arch.mp_state.mp_state) =3D=3D KVM_MP_STATE_SUSPEN= DED; +} + int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu, struct kvm_mp_state *mp_state) { @@ -516,6 +528,9 @@ int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vc= pu, else ret =3D -EINVAL; break; + case KVM_MP_STATE_SUSPENDED: + kvm_riscv_vcpu_suspend(vcpu); + break; default: ret =3D -EINVAL; } @@ -682,6 +697,25 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) } } =20 +static int kvm_riscv_handle_suspend(struct kvm_vcpu *vcpu) +{ + if (!kvm_riscv_vcpu_suspended(vcpu)) + return 1; + + kvm_riscv_vcpu_wfi(vcpu); + + kvm_make_request(KVM_REQ_SUSPEND, vcpu); + + if (kvm_arch_vcpu_runnable(vcpu)) { + memset(&vcpu->run->system_event, 0, sizeof(vcpu->run->system_event)); + vcpu->run->system_event.type =3D KVM_SYSTEM_EVENT_WAKEUP; + vcpu->run->exit_reason =3D KVM_EXIT_SYSTEM_EVENT; + return 0; + } + + return 1; +} + /** * kvm_riscv_check_vcpu_requests - check and handle pending vCPU requests * @vcpu: the VCPU pointer @@ -731,6 +765,9 @@ static int kvm_riscv_check_vcpu_requests(struct kvm_vcp= u *vcpu) if (kvm_check_request(KVM_REQ_STEAL_UPDATE, vcpu)) kvm_riscv_vcpu_record_steal_time(vcpu); =20 + if (kvm_check_request(KVM_REQ_SUSPEND, vcpu)) + kvm_riscv_handle_suspend(vcpu); + if (kvm_dirty_ring_check_request(vcpu)) return 0; } --=20 2.43.0