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Message-ID: <20190802074620.115029-7-anup.patel@wdc.com>
Date: Fri, 2 Aug 2019 07:47:31 +0000
From: Anup Patel <Anup.Patel@....com>
To: Palmer Dabbelt <palmer@...ive.com>,
Paul Walmsley <paul.walmsley@...ive.com>,
Paolo Bonzini <pbonzini@...hat.com>,
Radim K <rkrcmar@...hat.com>
CC: Daniel Lezcano <daniel.lezcano@...aro.org>,
Thomas Gleixner <tglx@...utronix.de>,
Atish Patra <Atish.Patra@....com>,
Alistair Francis <Alistair.Francis@....com>,
Damien Le Moal <Damien.LeMoal@....com>,
Christoph Hellwig <hch@...radead.org>,
Anup Patel <anup@...infault.org>,
"kvm@...r.kernel.org" <kvm@...r.kernel.org>,
"linux-riscv@...ts.infradead.org" <linux-riscv@...ts.infradead.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
Anup Patel <Anup.Patel@....com>
Subject: [RFC PATCH v2 06/19] RISC-V: KVM: Implement VCPU interrupts and
requests handling
This patch implements VCPU interrupts and requests which are both
asynchronous events.
The VCPU interrupts can be set/unset using KVM_INTERRUPT ioctl from
user-space. In future, the in-kernel IRQCHIP emulation will use
kvm_riscv_vcpu_set_interrupt() and kvm_riscv_vcpu_unset_interrupt()
functions to set/unset VCPU interrupts.
Important VCPU requests implemented by this patch are:
KVM_REQ_SLEEP - set whenever VCPU itself goes to sleep state
KVM_REQ_VCPU_RESET - set whenever VCPU reset is requested
The WFI trap-n-emulate (added later) will use KVM_REQ_SLEEP request
and kvm_riscv_vcpu_has_interrupt() function.
The KVM_REQ_VCPU_RESET request will be used by SBI emulation (added
later) to power-up a VCPU in power-off state. The user-space can use
the GET_MPSTATE/SET_MPSTATE ioctls to get/set power state of a VCPU.
Signed-off-by: Anup Patel <anup.patel@....com>
---
arch/riscv/include/asm/kvm_host.h | 18 +++-
arch/riscv/include/uapi/asm/kvm.h | 3 +
arch/riscv/kvm/vcpu.c | 157 ++++++++++++++++++++++++++----
3 files changed, 158 insertions(+), 20 deletions(-)
diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
index 7fda09327d39..a6d81e5eb064 100644
--- a/arch/riscv/include/asm/kvm_host.h
+++ b/arch/riscv/include/asm/kvm_host.h
@@ -26,8 +26,7 @@
#define KVM_REQ_SLEEP \
KVM_ARCH_REQ_FLAGS(0, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP)
-#define KVM_REQ_IRQ_PENDING KVM_ARCH_REQ(1)
-#define KVM_REQ_VCPU_RESET KVM_ARCH_REQ(2)
+#define KVM_REQ_VCPU_RESET KVM_ARCH_REQ(1)
struct kvm_vm_stat {
ulong remote_tlb_flush;
@@ -123,6 +122,13 @@ struct kvm_vcpu_arch {
/* CPU CSR context upon Guest VCPU reset */
struct kvm_vcpu_csr guest_reset_csr;
+ /* VCPU interrupts */
+ unsigned long irqs_pending;
+ unsigned long irqs_pending_mask;
+
+ /* VCPU power-off state */
+ bool power_off;
+
/* Don't run the VCPU (blocked) */
bool pause;
};
@@ -144,4 +150,12 @@ int kvm_riscv_vcpu_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
static inline void __kvm_riscv_switch_to(struct kvm_vcpu_arch *vcpu_arch) {}
+int kvm_riscv_vcpu_set_interrupt(struct kvm_vcpu *vcpu, unsigned int irq);
+int kvm_riscv_vcpu_unset_interrupt(struct kvm_vcpu *vcpu, unsigned int irq);
+void kvm_riscv_vcpu_flush_interrupts(struct kvm_vcpu *vcpu, bool update_hw);
+void kvm_riscv_vcpu_sync_interrupts(struct kvm_vcpu *vcpu);
+bool kvm_riscv_vcpu_has_interrupt(struct kvm_vcpu *vcpu);
+void kvm_riscv_vcpu_power_off(struct kvm_vcpu *vcpu);
+void kvm_riscv_vcpu_power_on(struct kvm_vcpu *vcpu);
+
#endif /* __RISCV_KVM_HOST_H__ */
diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h
index d15875818b6e..6dbc056d58ba 100644
--- a/arch/riscv/include/uapi/asm/kvm.h
+++ b/arch/riscv/include/uapi/asm/kvm.h
@@ -18,6 +18,9 @@
#define KVM_COALESCED_MMIO_PAGE_OFFSET 1
+#define KVM_INTERRUPT_SET -1U
+#define KVM_INTERRUPT_UNSET -2U
+
/* for KVM_GET_REGS and KVM_SET_REGS */
struct kvm_regs {
};
diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
index 45af069c1665..8e1ebdf1ef15 100644
--- a/arch/riscv/kvm/vcpu.c
+++ b/arch/riscv/kvm/vcpu.c
@@ -50,6 +50,9 @@ static void kvm_riscv_reset_vcpu(struct kvm_vcpu *vcpu)
memcpy(csr, reset_csr, sizeof(*csr));
memcpy(cntx, reset_cntx, sizeof(*cntx));
+
+ WRITE_ONCE(vcpu->arch.irqs_pending, 0);
+ WRITE_ONCE(vcpu->arch.irqs_pending_mask, 0);
}
struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id)
@@ -116,8 +119,7 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
{
- /* TODO: */
- return 0;
+ return READ_ONCE(vcpu->arch.irqs_pending) & (1UL << IRQ_S_TIMER);
}
void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu)
@@ -130,20 +132,18 @@ void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu)
int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu)
{
- /* TODO: */
- return 0;
+ return (kvm_riscv_vcpu_has_interrupt(vcpu) &&
+ !vcpu->arch.power_off && !vcpu->arch.pause);
}
int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu)
{
- /* TODO: */
- return 0;
+ return kvm_vcpu_exiting_guest_mode(vcpu) == IN_GUEST_MODE;
}
bool kvm_arch_vcpu_in_kernel(struct kvm_vcpu *vcpu)
{
- /* TODO: */
- return false;
+ return (vcpu->arch.guest_context.sstatus & SR_SPP) ? true : false;
}
bool kvm_arch_has_vcpu_debugfs(void)
@@ -164,7 +164,21 @@ vm_fault_t kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf)
long kvm_arch_vcpu_async_ioctl(struct file *filp,
unsigned int ioctl, unsigned long arg)
{
- /* TODO; */
+ struct kvm_vcpu *vcpu = filp->private_data;
+ void __user *argp = (void __user *)arg;
+
+ if (ioctl == KVM_INTERRUPT) {
+ struct kvm_interrupt irq;
+
+ if (copy_from_user(&irq, argp, sizeof(irq)))
+ return -EFAULT;
+
+ if (irq.irq == KVM_INTERRUPT_SET)
+ return kvm_riscv_vcpu_set_interrupt(vcpu, IRQ_S_EXT);
+ else
+ return kvm_riscv_vcpu_unset_interrupt(vcpu, IRQ_S_EXT);
+ }
+
return -ENOIOCTLCMD;
}
@@ -213,18 +227,105 @@ int kvm_arch_vcpu_ioctl_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
return -EINVAL;
}
+void kvm_riscv_vcpu_flush_interrupts(struct kvm_vcpu *vcpu, bool update_hw)
+{
+ unsigned long mask, val;
+
+ if (READ_ONCE(vcpu->arch.irqs_pending_mask)) {
+ mask = xchg_acquire(&vcpu->arch.irqs_pending_mask, 0);
+ val = READ_ONCE(vcpu->arch.irqs_pending) & mask;
+
+ vcpu->arch.guest_csr.vsip &= ~mask;
+ vcpu->arch.guest_csr.vsip |= val;
+
+ if (update_hw)
+ csr_write(CSR_VSIP, vcpu->arch.guest_csr.vsip);
+ }
+}
+
+void kvm_riscv_vcpu_sync_interrupts(struct kvm_vcpu *vcpu)
+{
+ vcpu->arch.guest_csr.vsip = csr_read(CSR_VSIP);
+ vcpu->arch.guest_csr.vsie = csr_read(CSR_VSIE);
+}
+
+int kvm_riscv_vcpu_set_interrupt(struct kvm_vcpu *vcpu, unsigned int irq)
+{
+ if (irq != IRQ_S_SOFT &&
+ irq != IRQ_S_TIMER &&
+ irq != IRQ_S_EXT)
+ return -EINVAL;
+
+ set_bit(irq, &vcpu->arch.irqs_pending);
+ smp_mb__before_atomic();
+ set_bit(irq, &vcpu->arch.irqs_pending_mask);
+
+ kvm_vcpu_kick(vcpu);
+
+ return 0;
+}
+
+int kvm_riscv_vcpu_unset_interrupt(struct kvm_vcpu *vcpu, unsigned int irq)
+{
+ if (irq != IRQ_S_SOFT &&
+ irq != IRQ_S_TIMER &&
+ irq != IRQ_S_EXT)
+ return -EINVAL;
+
+ clear_bit(irq, &vcpu->arch.irqs_pending);
+ smp_mb__before_atomic();
+ set_bit(irq, &vcpu->arch.irqs_pending_mask);
+
+ return 0;
+}
+
+bool kvm_riscv_vcpu_has_interrupt(struct kvm_vcpu *vcpu)
+{
+ return (READ_ONCE(vcpu->arch.irqs_pending) &
+ vcpu->arch.guest_csr.vsie) ? true : false;
+}
+
+void kvm_riscv_vcpu_power_off(struct kvm_vcpu *vcpu)
+{
+ vcpu->arch.power_off = true;
+ kvm_make_request(KVM_REQ_SLEEP, vcpu);
+ kvm_vcpu_kick(vcpu);
+}
+
+void kvm_riscv_vcpu_power_on(struct kvm_vcpu *vcpu)
+{
+ vcpu->arch.power_off = false;
+ kvm_vcpu_wake_up(vcpu);
+}
+
int kvm_arch_vcpu_ioctl_get_mpstate(struct kvm_vcpu *vcpu,
struct kvm_mp_state *mp_state)
{
- /* TODO: */
+ if (vcpu->arch.power_off)
+ mp_state->mp_state = KVM_MP_STATE_STOPPED;
+ else
+ mp_state->mp_state = KVM_MP_STATE_RUNNABLE;
+
return 0;
}
int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu,
struct kvm_mp_state *mp_state)
{
- /* TODO: */
- return 0;
+ int ret = 0;
+
+ switch (mp_state->mp_state) {
+ case KVM_MP_STATE_RUNNABLE:
+ vcpu->arch.power_off = false;
+ break;
+ case KVM_MP_STATE_STOPPED:
+ kvm_riscv_vcpu_power_off(vcpu);
+ break;
+ default:
+ ret = -EINVAL;
+ }
+
+ return ret;
}
int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
@@ -248,14 +349,25 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
static void kvm_riscv_check_vcpu_requests(struct kvm_vcpu *vcpu)
{
+ struct swait_queue_head *wq = kvm_arch_vcpu_wq(vcpu);
+
if (kvm_request_pending(vcpu)) {
- /* TODO: */
+ if (kvm_check_request(KVM_REQ_SLEEP, vcpu)) {
+ swait_event_interruptible_exclusive(*wq,
+ ((!vcpu->arch.power_off) &&
+ (!vcpu->arch.pause)));
+
+ if (vcpu->arch.power_off || vcpu->arch.pause) {
+ /*
+ * Awaken to handle a signal, request to
+ * sleep again later.
+ */
+ kvm_make_request(KVM_REQ_SLEEP, vcpu);
+ }
+ }
- /*
- * Clear IRQ_PENDING requests that were made to guarantee
- * that a VCPU sees new virtual interrupts.
- */
- kvm_check_request(KVM_REQ_IRQ_PENDING, vcpu);
+ if (kvm_check_request(KVM_REQ_VCPU_RESET, vcpu))
+ kvm_riscv_reset_vcpu(vcpu);
}
}
@@ -310,6 +422,12 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
*/
smp_store_mb(vcpu->mode, IN_GUEST_MODE);
+ /*
+ * We might have got VCPU interrupts updated asynchronously
+ * so update it in HW.
+ */
+ kvm_riscv_vcpu_flush_interrupts(vcpu, true);
+
if (ret <= 0 ||
kvm_request_pending(vcpu)) {
vcpu->mode = OUTSIDE_GUEST_MODE;
@@ -332,6 +450,9 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
scause = csr_read(CSR_SCAUSE);
stval = csr_read(CSR_STVAL);
+ /* Syncup interrupts state with HW */
+ kvm_riscv_vcpu_sync_interrupts(vcpu);
+
/*
* We may have taken a host interrupt in VS/VU-mode (i.e.
* while executing the guest). This interrupt is still
--
2.17.1
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