diff options
Diffstat (limited to 'arch/mips/kvm')
| -rw-r--r-- | arch/mips/kvm/emulate.c | 89 | ||||
| -rw-r--r-- | arch/mips/kvm/tlb.c | 2 | ||||
| -rw-r--r-- | arch/mips/kvm/trap_emul.c | 4 |
3 files changed, 53 insertions, 42 deletions
diff --git a/arch/mips/kvm/emulate.c b/arch/mips/kvm/emulate.c index b37954cc8..b8b7860ec 100644 --- a/arch/mips/kvm/emulate.c +++ b/arch/mips/kvm/emulate.c @@ -302,12 +302,31 @@ static inline ktime_t kvm_mips_count_time(struct kvm_vcpu *vcpu) */ static uint32_t kvm_mips_read_count_running(struct kvm_vcpu *vcpu, ktime_t now) { - ktime_t expires; + struct mips_coproc *cop0 = vcpu->arch.cop0; + ktime_t expires, threshold; + uint32_t count, compare; int running; - /* Is the hrtimer pending? */ + /* Calculate the biased and scaled guest CP0_Count */ + count = vcpu->arch.count_bias + kvm_mips_ktime_to_count(vcpu, now); + compare = kvm_read_c0_guest_compare(cop0); + + /* + * Find whether CP0_Count has reached the closest timer interrupt. If + * not, we shouldn't inject it. + */ + if ((int32_t)(count - compare) < 0) + return count; + + /* + * The CP0_Count we're going to return has already reached the closest + * timer interrupt. Quickly check if it really is a new interrupt by + * looking at whether the interval until the hrtimer expiry time is + * less than 1/4 of the timer period. + */ expires = hrtimer_get_expires(&vcpu->arch.comparecount_timer); - if (ktime_compare(now, expires) >= 0) { + threshold = ktime_add_ns(now, vcpu->arch.count_period / 4); + if (ktime_before(expires, threshold)) { /* * Cancel it while we handle it so there's no chance of * interference with the timeout handler. @@ -329,8 +348,7 @@ static uint32_t kvm_mips_read_count_running(struct kvm_vcpu *vcpu, ktime_t now) } } - /* Return the biased and scaled guest CP0_Count */ - return vcpu->arch.count_bias + kvm_mips_ktime_to_count(vcpu, now); + return count; } /** @@ -420,32 +438,6 @@ static void kvm_mips_resume_hrtimer(struct kvm_vcpu *vcpu, } /** - * kvm_mips_update_hrtimer() - Update next expiry time of hrtimer. - * @vcpu: Virtual CPU. - * - * Recalculates and updates the expiry time of the hrtimer. This can be used - * after timer parameters have been altered which do not depend on the time that - * the change occurs (in those cases kvm_mips_freeze_hrtimer() and - * kvm_mips_resume_hrtimer() are used directly). - * - * It is guaranteed that no timer interrupts will be lost in the process. - * - * Assumes !kvm_mips_count_disabled(@vcpu) (guest CP0_Count timer is running). - */ -static void kvm_mips_update_hrtimer(struct kvm_vcpu *vcpu) -{ - ktime_t now; - uint32_t count; - - /* - * freeze_hrtimer takes care of a timer interrupts <= count, and - * resume_hrtimer the hrtimer takes care of a timer interrupts > count. - */ - now = kvm_mips_freeze_hrtimer(vcpu, &count); - kvm_mips_resume_hrtimer(vcpu, now, count); -} - -/** * kvm_mips_write_count() - Modify the count and update timer. * @vcpu: Virtual CPU. * @count: Guest CP0_Count value to set. @@ -540,23 +532,42 @@ int kvm_mips_set_count_hz(struct kvm_vcpu *vcpu, s64 count_hz) * kvm_mips_write_compare() - Modify compare and update timer. * @vcpu: Virtual CPU. * @compare: New CP0_Compare value. + * @ack: Whether to acknowledge timer interrupt. * * Update CP0_Compare to a new value and update the timeout. + * If @ack, atomically acknowledge any pending timer interrupt, otherwise ensure + * any pending timer interrupt is preserved. */ -void kvm_mips_write_compare(struct kvm_vcpu *vcpu, uint32_t compare) +void kvm_mips_write_compare(struct kvm_vcpu *vcpu, uint32_t compare, bool ack) { struct mips_coproc *cop0 = vcpu->arch.cop0; + int dc; + u32 old_compare = kvm_read_c0_guest_compare(cop0); + ktime_t now; + uint32_t count; /* if unchanged, must just be an ack */ - if (kvm_read_c0_guest_compare(cop0) == compare) + if (old_compare == compare) { + if (!ack) + return; + kvm_mips_callbacks->dequeue_timer_int(vcpu); + kvm_write_c0_guest_compare(cop0, compare); return; + } + + /* freeze_hrtimer() takes care of timer interrupts <= count */ + dc = kvm_mips_count_disabled(vcpu); + if (!dc) + now = kvm_mips_freeze_hrtimer(vcpu, &count); + + if (ack) + kvm_mips_callbacks->dequeue_timer_int(vcpu); - /* Update compare */ kvm_write_c0_guest_compare(cop0, compare); - /* Update timeout if count enabled */ - if (!kvm_mips_count_disabled(vcpu)) - kvm_mips_update_hrtimer(vcpu); + /* resume_hrtimer() takes care of timer interrupts > count */ + if (!dc) + kvm_mips_resume_hrtimer(vcpu, now, count); } /** @@ -1095,9 +1106,9 @@ enum emulation_result kvm_mips_emulate_CP0(uint32_t inst, uint32_t *opc, /* If we are writing to COMPARE */ /* Clear pending timer interrupt, if any */ - kvm_mips_callbacks->dequeue_timer_int(vcpu); kvm_mips_write_compare(vcpu, - vcpu->arch.gprs[rt]); + vcpu->arch.gprs[rt], + true); } else if ((rd == MIPS_CP0_STATUS) && (sel == 0)) { unsigned int old_val, val, change; diff --git a/arch/mips/kvm/tlb.c b/arch/mips/kvm/tlb.c index a08c43946..e0e1d0a61 100644 --- a/arch/mips/kvm/tlb.c +++ b/arch/mips/kvm/tlb.c @@ -632,7 +632,7 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) kvm_debug("%s: vcpu %p, cpu: %d\n", __func__, vcpu, cpu); - /* Alocate new kernel and user ASIDs if needed */ + /* Allocate new kernel and user ASIDs if needed */ local_irq_save(flags); diff --git a/arch/mips/kvm/trap_emul.c b/arch/mips/kvm/trap_emul.c index ad9880005..caa5ea103 100644 --- a/arch/mips/kvm/trap_emul.c +++ b/arch/mips/kvm/trap_emul.c @@ -500,7 +500,7 @@ static int kvm_trap_emul_vcpu_setup(struct kvm_vcpu *vcpu) kvm_write_c0_guest_config7(cop0, (MIPS_CONF7_WII) | (1 << 10)); /* - * Setup IntCtl defaults, compatibilty mode for timer interrupts (HW5) + * Setup IntCtl defaults, compatibility mode for timer interrupts (HW5) */ kvm_write_c0_guest_intctl(cop0, 0xFC000000); @@ -546,7 +546,7 @@ static int kvm_trap_emul_set_one_reg(struct kvm_vcpu *vcpu, kvm_mips_write_count(vcpu, v); break; case KVM_REG_MIPS_CP0_COMPARE: - kvm_mips_write_compare(vcpu, v); + kvm_mips_write_compare(vcpu, v, false); break; case KVM_REG_MIPS_CP0_CAUSE: /* |