From: Anup Patel apatel@ventanamicro.com
[ Upstream commit cea8896bd936135559253e9b23340cfa1cdf0caf ]
The kvm_riscv_vcpu_timer_pending() checks per-VCPU next_cycles and per-VCPU software injected VS timer interrupt. This function returns incorrect value when Sstc is available because the per-VCPU next_cycles are only updated by kvm_riscv_vcpu_timer_save() called from kvm_arch_vcpu_put(). As a result, when Sstc is available the VCPU does not block properly upon WFI traps.
To fix the above issue, we introduce kvm_riscv_vcpu_timer_sync() which will update per-VCPU next_cycles upon every VM exit instead of kvm_riscv_vcpu_timer_save().
Fixes: 8f5cb44b1bae ("RISC-V: KVM: Support sstc extension") Signed-off-by: Anup Patel apatel@ventanamicro.com Reviewed-by: Atish Patra atishp@rivosinc.com Signed-off-by: Anup Patel anup@brainfault.org Signed-off-by: Sasha Levin sashal@kernel.org --- arch/riscv/include/asm/kvm_vcpu_timer.h | 1 + arch/riscv/kvm/vcpu.c | 3 +++ arch/riscv/kvm/vcpu_timer.c | 17 +++++++++++++++-- 3 files changed, 19 insertions(+), 2 deletions(-)
diff --git a/arch/riscv/include/asm/kvm_vcpu_timer.h b/arch/riscv/include/asm/kvm_vcpu_timer.h index 0d8fdb8ec63a..82f7260301da 100644 --- a/arch/riscv/include/asm/kvm_vcpu_timer.h +++ b/arch/riscv/include/asm/kvm_vcpu_timer.h @@ -45,6 +45,7 @@ int kvm_riscv_vcpu_timer_deinit(struct kvm_vcpu *vcpu); int kvm_riscv_vcpu_timer_reset(struct kvm_vcpu *vcpu); void kvm_riscv_vcpu_timer_restore(struct kvm_vcpu *vcpu); void kvm_riscv_guest_timer_init(struct kvm *kvm); +void kvm_riscv_vcpu_timer_sync(struct kvm_vcpu *vcpu); void kvm_riscv_vcpu_timer_save(struct kvm_vcpu *vcpu); bool kvm_riscv_vcpu_timer_pending(struct kvm_vcpu *vcpu);
diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c index 2ef33d5d94d1..f692c0716aa7 100644 --- a/arch/riscv/kvm/vcpu.c +++ b/arch/riscv/kvm/vcpu.c @@ -698,6 +698,9 @@ void kvm_riscv_vcpu_sync_interrupts(struct kvm_vcpu *vcpu) clear_bit(IRQ_VS_SOFT, &v->irqs_pending); } } + + /* Sync-up timer CSRs */ + kvm_riscv_vcpu_timer_sync(vcpu); }
int kvm_riscv_vcpu_set_interrupt(struct kvm_vcpu *vcpu, unsigned int irq) diff --git a/arch/riscv/kvm/vcpu_timer.c b/arch/riscv/kvm/vcpu_timer.c index 185f2386a747..ad34519c8a13 100644 --- a/arch/riscv/kvm/vcpu_timer.c +++ b/arch/riscv/kvm/vcpu_timer.c @@ -320,20 +320,33 @@ void kvm_riscv_vcpu_timer_restore(struct kvm_vcpu *vcpu) kvm_riscv_vcpu_timer_unblocking(vcpu); }
-void kvm_riscv_vcpu_timer_save(struct kvm_vcpu *vcpu) +void kvm_riscv_vcpu_timer_sync(struct kvm_vcpu *vcpu) { struct kvm_vcpu_timer *t = &vcpu->arch.timer;
if (!t->sstc_enabled) return;
- t = &vcpu->arch.timer; #if defined(CONFIG_32BIT) t->next_cycles = csr_read(CSR_VSTIMECMP); t->next_cycles |= (u64)csr_read(CSR_VSTIMECMPH) << 32; #else t->next_cycles = csr_read(CSR_VSTIMECMP); #endif +} + +void kvm_riscv_vcpu_timer_save(struct kvm_vcpu *vcpu) +{ + struct kvm_vcpu_timer *t = &vcpu->arch.timer; + + if (!t->sstc_enabled) + return; + + /* + * The vstimecmp CSRs are saved by kvm_riscv_vcpu_timer_sync() + * upon every VM exit so no need to save here. + */ + /* timer should be enabled for the remaining operations */ if (unlikely(!t->init_done)) return;