[PATCH v4 7/9] RISC-V: KVM: Use bitmap for irqs_pending and irqs_pending_mask

Anup Patel
2023-04-04T15:36:30Z

To support 64 VCPU local interrupts on RV32 host, we should use
bitmap for irqs_pending and irqs_pending_mask in struct kvm_vcpu_arch.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
---
arch/riscv/include/asm/kvm_host.h | 7 ++--
arch/riscv/kvm/vcpu.c | 53 ++++++++++++++++++++-----------
2 files changed, 38 insertions(+), 22 deletions(-)

diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
index 3157cf748df1..ee0acccb1d3b 100644
--- a/arch/riscv/include/asm/kvm_host.h
+++ b/arch/riscv/include/asm/kvm_host.h
@@ -204,8 +204,9 @@ struct kvm_vcpu_arch {
* in irqs_pending. Our approach is modeled around multiple producer
* and single consumer problem where the consumer is the VCPU itself.
*/
- unsigned long irqs_pending;
- unsigned long irqs_pending_mask;
+#define KVM_RISCV_VCPU_NR_IRQS 64
+ DECLARE_BITMAP(irqs_pending, KVM_RISCV_VCPU_NR_IRQS);
+ DECLARE_BITMAP(irqs_pending_mask, KVM_RISCV_VCPU_NR_IRQS);

/* VCPU Timer */
struct kvm_vcpu_timer timer;
@@ -334,7 +335,7 @@ 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);
void kvm_riscv_vcpu_sync_interrupts(struct kvm_vcpu *vcpu);
-bool kvm_riscv_vcpu_has_interrupts(struct kvm_vcpu *vcpu, unsigned long mask);
+bool kvm_riscv_vcpu_has_interrupts(struct kvm_vcpu *vcpu, u64 mask);
void kvm_riscv_vcpu_power_off(struct kvm_vcpu *vcpu);
void kvm_riscv_vcpu_power_on(struct kvm_vcpu *vcpu);

diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
index 57bdbfc17d48..811c7e9a308c 100644
--- a/arch/riscv/kvm/vcpu.c
+++ b/arch/riscv/kvm/vcpu.c
@@ -141,8 +141,8 @@ static void kvm_riscv_reset_vcpu(struct kvm_vcpu *vcpu)

kvm_riscv_vcpu_aia_reset(vcpu);

- WRITE_ONCE(vcpu->arch.irqs_pending, 0);
- WRITE_ONCE(vcpu->arch.irqs_pending_mask, 0);
+ bitmap_zero(vcpu->arch.irqs_pending, KVM_RISCV_VCPU_NR_IRQS);
+ bitmap_zero(vcpu->arch.irqs_pending_mask, KVM_RISCV_VCPU_NR_IRQS);

kvm_riscv_vcpu_pmu_reset(vcpu);

@@ -474,6 +474,7 @@ static int kvm_riscv_vcpu_general_get_csr(struct kvm_vcpu *vcpu,
if (reg_num == KVM_REG_RISCV_CSR_REG(sip)) {
kvm_riscv_vcpu_flush_interrupts(vcpu);
*out_val = (csr->hvip >> VSIP_TO_HVIP_SHIFT) & VSIP_VALID_MASK;
+ *out_val |= csr->hvip & ~IRQ_LOCAL_MASK;
} else
*out_val = ((unsigned long *)csr)[reg_num];

@@ -497,7 +498,7 @@ static inline int kvm_riscv_vcpu_general_set_csr(struct kvm_vcpu *vcpu,
((unsigned long *)csr)[reg_num] = reg_val;

if (reg_num == KVM_REG_RISCV_CSR_REG(sip))
- WRITE_ONCE(vcpu->arch.irqs_pending_mask, 0);
+ WRITE_ONCE(vcpu->arch.irqs_pending_mask[0], 0);

return 0;
}
@@ -799,9 +800,9 @@ void kvm_riscv_vcpu_flush_interrupts(struct kvm_vcpu *vcpu)
struct kvm_vcpu_csr *csr = &vcpu->arch.guest_csr;
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;
+ if (READ_ONCE(vcpu->arch.irqs_pending_mask[0])) {
+ mask = xchg_acquire(&vcpu->arch.irqs_pending_mask[0], 0);
+ val = READ_ONCE(vcpu->arch.irqs_pending[0]) & mask;

csr->hvip &= ~mask;
csr->hvip |= val;
@@ -825,12 +826,12 @@ void kvm_riscv_vcpu_sync_interrupts(struct kvm_vcpu *vcpu)
if ((csr->hvip ^ hvip) & (1UL << IRQ_VS_SOFT)) {
if (hvip & (1UL << IRQ_VS_SOFT)) {
if (!test_and_set_bit(IRQ_VS_SOFT,
- &v->irqs_pending_mask))
- set_bit(IRQ_VS_SOFT, &v->irqs_pending);
+ v->irqs_pending_mask))
+ set_bit(IRQ_VS_SOFT, v->irqs_pending);
} else {
if (!test_and_set_bit(IRQ_VS_SOFT,
- &v->irqs_pending_mask))
- clear_bit(IRQ_VS_SOFT, &v->irqs_pending);
+ v->irqs_pending_mask))
+ clear_bit(IRQ_VS_SOFT, v->irqs_pending);
}
}

@@ -843,14 +844,20 @@ void kvm_riscv_vcpu_sync_interrupts(struct kvm_vcpu *vcpu)

int kvm_riscv_vcpu_set_interrupt(struct kvm_vcpu *vcpu, unsigned int irq)
{
- if (irq != IRQ_VS_SOFT &&
+ /*
+ * We only allow VS-mode software, timer, and external
+ * interrupts when irq is one of the local interrupts
+ * defined by RISC-V privilege specification.
+ */
+ if (irq < IRQ_LOCAL_MAX &&
+ irq != IRQ_VS_SOFT &&
irq != IRQ_VS_TIMER &&
irq != IRQ_VS_EXT)
return -EINVAL;

- set_bit(irq, &vcpu->arch.irqs_pending);
+ set_bit(irq, vcpu->arch.irqs_pending);
smp_mb__before_atomic();
- set_bit(irq, &vcpu->arch.irqs_pending_mask);
+ set_bit(irq, vcpu->arch.irqs_pending_mask);

kvm_vcpu_kick(vcpu);

@@ -859,25 +866,33 @@ 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)
{
- if (irq != IRQ_VS_SOFT &&
+ /*
+ * We only allow VS-mode software, timer, and external
+ * interrupts when irq is one of the local interrupts
+ * defined by RISC-V privilege specification.
+ */
+ if (irq < IRQ_LOCAL_MAX &&
+ irq != IRQ_VS_SOFT &&
irq != IRQ_VS_TIMER &&
irq != IRQ_VS_EXT)
return -EINVAL;

- clear_bit(irq, &vcpu->arch.irqs_pending);
+ clear_bit(irq, vcpu->arch.irqs_pending);
smp_mb__before_atomic();
- set_bit(irq, &vcpu->arch.irqs_pending_mask);
+ set_bit(irq, vcpu->arch.irqs_pending_mask);

return 0;
}

-bool kvm_riscv_vcpu_has_interrupts(struct kvm_vcpu *vcpu, unsigned long mask)
+bool kvm_riscv_vcpu_has_interrupts(struct kvm_vcpu *vcpu, u64 mask)
{
unsigned long ie;

ie = ((vcpu->arch.guest_csr.vsie & VSIP_VALID_MASK)
- << VSIP_TO_HVIP_SHIFT) & mask;
- if (READ_ONCE(vcpu->arch.irqs_pending) & ie)
+ << VSIP_TO_HVIP_SHIFT) & (unsigned long)mask;
+ ie |= vcpu->arch.guest_csr.vsie & ~IRQ_LOCAL_MASK &
+ (unsigned long)mask;
+ if (READ_ONCE(vcpu->arch.irqs_pending[0]) & ie)
return true;

/* Check AIA high interrupts */
--
2.34.1