From e9f4275732add046fed4a548b8dbb98dbe500d2f Mon Sep 17 00:00:00 2001 From: Beth Kon Date: Tue, 7 Jul 2009 11:50:38 -0400 Subject: [PATCH] KVM: PIT support for HPET legacy mode When kvm is in hpet_legacy_mode, the hpet is providing the timer interrupt and the pit should not be. So in legacy mode, the pit timer is destroyed, but the *state* of the pit is maintained. So if kvm or the guest tries to modify the state of the pit, this modification is accepted, *except* that the timer isn't actually started. When we exit hpet_legacy_mode, the current state of the pit (which is up to date since we've been accepting modifications) is used to restart the pit timer. The saved_mode code in kvm_pit_load_count temporarily changes mode to 0xff in order to destroy the timer, but then restores the actual value, again maintaining "current" state of the pit for possible later reenablement. [avi: add some reserved storage in the ioctl; make SET_PIT2 IOW] [marcelo: fix memory corruption due to reserved storage] Signed-off-by: Beth Kon Signed-off-by: Marcelo Tosatti Signed-off-by: Avi Kivity --- arch/x86/include/asm/kvm.h | 9 +++++++ arch/x86/kvm/i8254.c | 22 +++++++++++++---- arch/x86/kvm/i8254.h | 3 ++- arch/x86/kvm/x86.c | 59 +++++++++++++++++++++++++++++++++++++++++++++- include/linux/kvm.h | 6 +++++ 5 files changed, 93 insertions(+), 6 deletions(-) diff --git a/arch/x86/include/asm/kvm.h b/arch/x86/include/asm/kvm.h index 708b9c3..4a5fe91 100644 --- a/arch/x86/include/asm/kvm.h +++ b/arch/x86/include/asm/kvm.h @@ -18,6 +18,7 @@ #define __KVM_HAVE_GUEST_DEBUG #define __KVM_HAVE_MSIX #define __KVM_HAVE_MCE +#define __KVM_HAVE_PIT_STATE2 /* Architectural interrupt line count. */ #define KVM_NR_INTERRUPTS 256 @@ -237,6 +238,14 @@ struct kvm_pit_state { struct kvm_pit_channel_state channels[3]; }; +#define KVM_PIT_FLAGS_HPET_LEGACY 0x00000001 + +struct kvm_pit_state2 { + struct kvm_pit_channel_state channels[3]; + __u32 flags; + __u32 reserved[9]; +}; + struct kvm_reinject_control { __u8 pit_reinject; __u8 reserved[31]; diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c index 8c3ac30..9b62c57 100644 --- a/arch/x86/kvm/i8254.c +++ b/arch/x86/kvm/i8254.c @@ -332,20 +332,33 @@ static void pit_load_count(struct kvm *kvm, int channel, u32 val) case 1: /* FIXME: enhance mode 4 precision */ case 4: - create_pit_timer(ps, val, 0); + if (!(ps->flags & KVM_PIT_FLAGS_HPET_LEGACY)) { + create_pit_timer(ps, val, 0); + } break; case 2: case 3: - create_pit_timer(ps, val, 1); + if (!(ps->flags & KVM_PIT_FLAGS_HPET_LEGACY)){ + create_pit_timer(ps, val, 1); + } break; default: destroy_pit_timer(&ps->pit_timer); } } -void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val) +void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val, int hpet_legacy_start) { - pit_load_count(kvm, channel, val); + u8 saved_mode; + if (hpet_legacy_start) { + /* save existing mode for later reenablement */ + saved_mode = kvm->arch.vpit->pit_state.channels[0].mode; + kvm->arch.vpit->pit_state.channels[0].mode = 0xff; /* disable timer */ + pit_load_count(kvm, channel, val); + kvm->arch.vpit->pit_state.channels[0].mode = saved_mode; + } else { + pit_load_count(kvm, channel, val); + } } static inline struct kvm_pit *dev_to_pit(struct kvm_io_device *dev) @@ -554,6 +567,7 @@ void kvm_pit_reset(struct kvm_pit *pit) struct kvm_kpit_channel_state *c; mutex_lock(&pit->pit_state.lock); + pit->pit_state.flags = 0; for (i = 0; i < 3; i++) { c = &pit->pit_state.channels[i]; c->mode = 0xff; diff --git a/arch/x86/kvm/i8254.h b/arch/x86/kvm/i8254.h index b267018..d4c1c7f 100644 --- a/arch/x86/kvm/i8254.h +++ b/arch/x86/kvm/i8254.h @@ -21,6 +21,7 @@ struct kvm_kpit_channel_state { struct kvm_kpit_state { struct kvm_kpit_channel_state channels[3]; + u32 flags; struct kvm_timer pit_timer; bool is_periodic; u32 speaker_data_on; @@ -49,7 +50,7 @@ struct kvm_pit { #define KVM_PIT_CHANNEL_MASK 0x3 void kvm_inject_pit_timer_irqs(struct kvm_vcpu *vcpu); -void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val); +void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val, int hpet_legacy_start); struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags); void kvm_free_pit(struct kvm *kvm); void kvm_pit_reset(struct kvm_pit *pit); diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index dfb0e37..2214384 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1213,6 +1213,7 @@ int kvm_dev_ioctl_check_extension(long ext) case KVM_CAP_ASSIGN_DEV_IRQ: case KVM_CAP_IRQFD: case KVM_CAP_PIT2: + case KVM_CAP_PIT_STATE2: r = 1; break; case KVM_CAP_COALESCED_MMIO: @@ -2078,7 +2079,36 @@ static int kvm_vm_ioctl_set_pit(struct kvm *kvm, struct kvm_pit_state *ps) mutex_lock(&kvm->arch.vpit->pit_state.lock); memcpy(&kvm->arch.vpit->pit_state, ps, sizeof(struct kvm_pit_state)); - kvm_pit_load_count(kvm, 0, ps->channels[0].count); + kvm_pit_load_count(kvm, 0, ps->channels[0].count, 0); + mutex_unlock(&kvm->arch.vpit->pit_state.lock); + return r; +} + +static int kvm_vm_ioctl_get_pit2(struct kvm *kvm, struct kvm_pit_state2 *ps) +{ + int r = 0; + + mutex_lock(&kvm->arch.vpit->pit_state.lock); + memcpy(ps->channels, &kvm->arch.vpit->pit_state.channels, + sizeof(ps->channels)); + ps->flags = kvm->arch.vpit->pit_state.flags; + mutex_unlock(&kvm->arch.vpit->pit_state.lock); + return r; +} + +static int kvm_vm_ioctl_set_pit2(struct kvm *kvm, struct kvm_pit_state2 *ps) +{ + int r = 0, start = 0; + u32 prev_legacy, cur_legacy; + mutex_lock(&kvm->arch.vpit->pit_state.lock); + prev_legacy = kvm->arch.vpit->pit_state.flags & KVM_PIT_FLAGS_HPET_LEGACY; + cur_legacy = ps->flags & KVM_PIT_FLAGS_HPET_LEGACY; + if (!prev_legacy && cur_legacy) + start = 1; + memcpy(&kvm->arch.vpit->pit_state.channels, &ps->channels, + sizeof(kvm->arch.vpit->pit_state.channels)); + kvm->arch.vpit->pit_state.flags = ps->flags; + kvm_pit_load_count(kvm, 0, kvm->arch.vpit->pit_state.channels[0].count, start); mutex_unlock(&kvm->arch.vpit->pit_state.lock); return r; } @@ -2140,6 +2170,7 @@ long kvm_arch_vm_ioctl(struct file *filp, */ union { struct kvm_pit_state ps; + struct kvm_pit_state2 ps2; struct kvm_memory_alias alias; struct kvm_pit_config pit_config; } u; @@ -2322,6 +2353,32 @@ long kvm_arch_vm_ioctl(struct file *filp, r = 0; break; } + case KVM_GET_PIT2: { + r = -ENXIO; + if (!kvm->arch.vpit) + goto out; + r = kvm_vm_ioctl_get_pit2(kvm, &u.ps2); + if (r) + goto out; + r = -EFAULT; + if (copy_to_user(argp, &u.ps2, sizeof(u.ps2))) + goto out; + r = 0; + break; + } + case KVM_SET_PIT2: { + r = -EFAULT; + if (copy_from_user(&u.ps2, argp, sizeof(u.ps2))) + goto out; + r = -ENXIO; + if (!kvm->arch.vpit) + goto out; + r = kvm_vm_ioctl_set_pit2(kvm, &u.ps2); + if (r) + goto out; + r = 0; + break; + } case KVM_REINJECT_CONTROL: { struct kvm_reinject_control control; r = -EFAULT; diff --git a/include/linux/kvm.h b/include/linux/kvm.h index 76c6408..a74a1fc 100644 --- a/include/linux/kvm.h +++ b/include/linux/kvm.h @@ -409,6 +409,9 @@ struct kvm_guest_debug { #define KVM_CAP_PIT2 33 #endif #define KVM_CAP_SET_BOOT_CPU_ID 34 +#ifdef __KVM_HAVE_PIT_STATE2 +#define KVM_CAP_PIT_STATE2 35 +#endif #ifdef KVM_CAP_IRQ_ROUTING @@ -586,6 +589,9 @@ struct kvm_debug_guest { #define KVM_IA64_VCPU_GET_STACK _IOR(KVMIO, 0x9a, void *) #define KVM_IA64_VCPU_SET_STACK _IOW(KVMIO, 0x9b, void *) +#define KVM_GET_PIT2 _IOR(KVMIO, 0x9f, struct kvm_pit_state2) +#define KVM_SET_PIT2 _IOW(KVMIO, 0xa0, struct kvm_pit_state2) + #define KVM_TRC_INJ_VIRQ (KVM_TRC_HANDLER + 0x02) #define KVM_TRC_REDELIVER_EVT (KVM_TRC_HANDLER + 0x03) #define KVM_TRC_PEND_INTR (KVM_TRC_HANDLER + 0x04) -- 2.7.4