diff options
Diffstat (limited to 'arch/x86/kvm/x86.c')
| -rw-r--r-- | arch/x86/kvm/x86.c | 113 |
1 files changed, 112 insertions, 1 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 0c910c774a9b..256c0fc92b67 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -19,6 +19,7 @@ #include "irq.h" #include "mmu.h" +#include <linux/clocksource.h> #include <linux/kvm.h> #include <linux/fs.h> #include <linux/vmalloc.h> @@ -424,7 +425,7 @@ static u32 msrs_to_save[] = { #ifdef CONFIG_X86_64 MSR_CSTAR, MSR_KERNEL_GS_BASE, MSR_SYSCALL_MASK, MSR_LSTAR, #endif - MSR_IA32_TIME_STAMP_COUNTER, + MSR_IA32_TIME_STAMP_COUNTER, MSR_KVM_SYSTEM_TIME, MSR_KVM_WALL_CLOCK, }; static unsigned num_msrs_to_save; @@ -482,6 +483,70 @@ static int do_set_msr(struct kvm_vcpu *vcpu, unsigned index, u64 *data) return kvm_set_msr(vcpu, index, *data); } +static void kvm_write_wall_clock(struct kvm *kvm, gpa_t wall_clock) +{ + static int version; + struct kvm_wall_clock wc; + struct timespec wc_ts; + + if (!wall_clock) + return; + + version++; + + down_read(&kvm->slots_lock); + kvm_write_guest(kvm, wall_clock, &version, sizeof(version)); + + wc_ts = current_kernel_time(); + wc.wc_sec = wc_ts.tv_sec; + wc.wc_nsec = wc_ts.tv_nsec; + wc.wc_version = version; + + kvm_write_guest(kvm, wall_clock, &wc, sizeof(wc)); + + version++; + kvm_write_guest(kvm, wall_clock, &version, sizeof(version)); + up_read(&kvm->slots_lock); +} + +static void kvm_write_guest_time(struct kvm_vcpu *v) +{ + struct timespec ts; + unsigned long flags; + struct kvm_vcpu_arch *vcpu = &v->arch; + void *shared_kaddr; + + if ((!vcpu->time_page)) + return; + + /* Keep irq disabled to prevent changes to the clock */ + local_irq_save(flags); + kvm_get_msr(v, MSR_IA32_TIME_STAMP_COUNTER, + &vcpu->hv_clock.tsc_timestamp); + ktime_get_ts(&ts); + local_irq_restore(flags); + + /* With all the info we got, fill in the values */ + + vcpu->hv_clock.system_time = ts.tv_nsec + + (NSEC_PER_SEC * (u64)ts.tv_sec); + /* + * The interface expects us to write an even number signaling that the + * update is finished. Since the guest won't see the intermediate + * state, we just write "2" at the end + */ + vcpu->hv_clock.version = 2; + + shared_kaddr = kmap_atomic(vcpu->time_page, KM_USER0); + + memcpy(shared_kaddr + vcpu->time_offset, &vcpu->hv_clock, + sizeof(vcpu->hv_clock)); + + kunmap_atomic(shared_kaddr, KM_USER0); + + mark_page_dirty(v->kvm, vcpu->time >> PAGE_SHIFT); +} + int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data) { @@ -511,6 +576,44 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data) case MSR_IA32_MISC_ENABLE: vcpu->arch.ia32_misc_enable_msr = data; break; + case MSR_KVM_WALL_CLOCK: + vcpu->kvm->arch.wall_clock = data; + kvm_write_wall_clock(vcpu->kvm, data); + break; + case MSR_KVM_SYSTEM_TIME: { + if (vcpu->arch.time_page) { + kvm_release_page_dirty(vcpu->arch.time_page); + vcpu->arch.time_page = NULL; + } + + vcpu->arch.time = data; + + /* we verify if the enable bit is set... */ + if (!(data & 1)) + break; + + /* ...but clean it before doing the actual write */ + vcpu->arch.time_offset = data & ~(PAGE_MASK | 1); + + vcpu->arch.hv_clock.tsc_to_system_mul = + clocksource_khz2mult(tsc_khz, 22); + vcpu->arch.hv_clock.tsc_shift = 22; + + down_read(¤t->mm->mmap_sem); + down_read(&vcpu->kvm->slots_lock); + vcpu->arch.time_page = + gfn_to_page(vcpu->kvm, data >> PAGE_SHIFT); + up_read(&vcpu->kvm->slots_lock); + up_read(¤t->mm->mmap_sem); + + if (is_error_page(vcpu->arch.time_page)) { + kvm_release_page_clean(vcpu->arch.time_page); + vcpu->arch.time_page = NULL; + } + + kvm_write_guest_time(vcpu); + break; + } default: pr_unimpl(vcpu, "unhandled wrmsr: 0x%x data %llx\n", msr, data); return 1; @@ -569,6 +672,12 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata) case MSR_EFER: data = vcpu->arch.shadow_efer; break; + case MSR_KVM_WALL_CLOCK: + data = vcpu->kvm->arch.wall_clock; + break; + case MSR_KVM_SYSTEM_TIME: + data = vcpu->arch.time; + break; default: pr_unimpl(vcpu, "unhandled rdmsr: 0x%x\n", msr); return 1; @@ -696,6 +805,7 @@ int kvm_dev_ioctl_check_extension(long ext) case KVM_CAP_USER_MEMORY: case KVM_CAP_SET_TSS_ADDR: case KVM_CAP_EXT_CPUID: + case KVM_CAP_CLOCKSOURCE: r = 1; break; case KVM_CAP_VAPIC: @@ -771,6 +881,7 @@ out: void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) { kvm_x86_ops->vcpu_load(vcpu, cpu); + kvm_write_guest_time(vcpu); } void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) |
