diff options
Diffstat (limited to 'arch/riscv/kvm/vcpu_timer.c')
| -rw-r--r-- | arch/riscv/kvm/vcpu_timer.c | 51 |
1 files changed, 34 insertions, 17 deletions
diff --git a/arch/riscv/kvm/vcpu_timer.c b/arch/riscv/kvm/vcpu_timer.c index 75486b25ac45..85a7262115e1 100644 --- a/arch/riscv/kvm/vcpu_timer.c +++ b/arch/riscv/kvm/vcpu_timer.c @@ -11,8 +11,8 @@ #include <linux/kvm_host.h> #include <linux/uaccess.h> #include <clocksource/timer-riscv.h> -#include <asm/csr.h> #include <asm/delay.h> +#include <asm/kvm_nacl.h> #include <asm/kvm_vcpu_timer.h> static u64 kvm_riscv_current_cycles(struct kvm_guest_timer *gt) @@ -72,12 +72,12 @@ static int kvm_riscv_vcpu_timer_cancel(struct kvm_vcpu_timer *t) static int kvm_riscv_vcpu_update_vstimecmp(struct kvm_vcpu *vcpu, u64 ncycles) { #if defined(CONFIG_32BIT) - csr_write(CSR_VSTIMECMP, ncycles & 0xFFFFFFFF); - csr_write(CSR_VSTIMECMPH, ncycles >> 32); + ncsr_write(CSR_VSTIMECMP, ncycles & 0xFFFFFFFF); + ncsr_write(CSR_VSTIMECMPH, ncycles >> 32); #else - csr_write(CSR_VSTIMECMP, ncycles); + ncsr_write(CSR_VSTIMECMP, ncycles); #endif - return 0; + return 0; } static int kvm_riscv_vcpu_update_hrtimer(struct kvm_vcpu *vcpu, u64 ncycles) @@ -248,18 +248,19 @@ int kvm_riscv_vcpu_timer_init(struct kvm_vcpu *vcpu) if (t->init_done) return -EINVAL; - hrtimer_init(&t->hrt, CLOCK_MONOTONIC, HRTIMER_MODE_REL); t->init_done = true; t->next_set = false; /* Enable sstc for every vcpu if available in hardware */ if (riscv_isa_extension_available(NULL, SSTC)) { t->sstc_enabled = true; - t->hrt.function = kvm_riscv_vcpu_vstimer_expired; + hrtimer_setup(&t->hrt, kvm_riscv_vcpu_vstimer_expired, CLOCK_MONOTONIC, + HRTIMER_MODE_REL); t->timer_next_event = kvm_riscv_vcpu_update_vstimecmp; } else { t->sstc_enabled = false; - t->hrt.function = kvm_riscv_vcpu_hrtimer_expired; + hrtimer_setup(&t->hrt, kvm_riscv_vcpu_hrtimer_expired, CLOCK_MONOTONIC, + HRTIMER_MODE_REL); t->timer_next_event = kvm_riscv_vcpu_update_hrtimer; } @@ -289,10 +290,10 @@ static void kvm_riscv_vcpu_update_timedelta(struct kvm_vcpu *vcpu) struct kvm_guest_timer *gt = &vcpu->kvm->arch.timer; #if defined(CONFIG_32BIT) - csr_write(CSR_HTIMEDELTA, (u32)(gt->time_delta)); - csr_write(CSR_HTIMEDELTAH, (u32)(gt->time_delta >> 32)); + ncsr_write(CSR_HTIMEDELTA, (u32)(gt->time_delta)); + ncsr_write(CSR_HTIMEDELTAH, (u32)(gt->time_delta >> 32)); #else - csr_write(CSR_HTIMEDELTA, gt->time_delta); + ncsr_write(CSR_HTIMEDELTA, gt->time_delta); #endif } @@ -306,10 +307,10 @@ void kvm_riscv_vcpu_timer_restore(struct kvm_vcpu *vcpu) return; #if defined(CONFIG_32BIT) - csr_write(CSR_VSTIMECMP, (u32)t->next_cycles); - csr_write(CSR_VSTIMECMPH, (u32)(t->next_cycles >> 32)); + ncsr_write(CSR_VSTIMECMP, (u32)t->next_cycles); + ncsr_write(CSR_VSTIMECMPH, (u32)(t->next_cycles >> 32)); #else - csr_write(CSR_VSTIMECMP, t->next_cycles); + ncsr_write(CSR_VSTIMECMP, t->next_cycles); #endif /* timer should be enabled for the remaining operations */ @@ -327,10 +328,10 @@ void kvm_riscv_vcpu_timer_sync(struct kvm_vcpu *vcpu) return; #if defined(CONFIG_32BIT) - t->next_cycles = csr_read(CSR_VSTIMECMP); - t->next_cycles |= (u64)csr_read(CSR_VSTIMECMPH) << 32; + t->next_cycles = ncsr_read(CSR_VSTIMECMP); + t->next_cycles |= (u64)ncsr_read(CSR_VSTIMECMPH) << 32; #else - t->next_cycles = csr_read(CSR_VSTIMECMP); + t->next_cycles = ncsr_read(CSR_VSTIMECMP); #endif } @@ -344,8 +345,24 @@ void kvm_riscv_vcpu_timer_save(struct kvm_vcpu *vcpu) /* * The vstimecmp CSRs are saved by kvm_riscv_vcpu_timer_sync() * upon every VM exit so no need to save here. + * + * If VS-timer expires when no VCPU running on a host CPU then + * WFI executed by such host CPU will be effective NOP resulting + * in no power savings. This is because as-per RISC-V Privileged + * specificaiton: "WFI is also required to resume execution for + * locally enabled interrupts pending at any privilege level, + * regardless of the global interrupt enable at each privilege + * level." + * + * To address the above issue, vstimecmp CSR must be set to -1UL + * over here when VCPU is scheduled-out or exits to user space. */ + csr_write(CSR_VSTIMECMP, -1UL); +#if defined(CONFIG_32BIT) + csr_write(CSR_VSTIMECMPH, -1UL); +#endif + /* timer should be enabled for the remaining operations */ if (unlikely(!t->init_done)) return; |