diff options
| author | Andrew Jones <drjones@redhat.com> | 2020-08-04 19:06:02 +0200 |
|---|---|---|
| committer | Marc Zyngier <maz@kernel.org> | 2020-08-21 14:04:14 +0100 |
| commit | 53f985584e3c2ebe5f2455530fbf87a001528db8 (patch) | |
| tree | 7ad5be2d2651d8ebc4595c784a13d43b7e6a5a2c | |
| parent | 4d2d4ce001f283ed8127173543b4cfb65641e357 (diff) | |
KVM: arm64: pvtime: Fix stolen time accounting across migration
When updating the stolen time we should always read the current
stolen time from the user provided memory, not from a kernel
cache. If we use a cache then we'll end up resetting stolen time
to zero on the first update after migration.
Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200804170604.42662-5-drjones@redhat.com
| -rw-r--r-- | arch/arm64/include/asm/kvm_host.h | 1 | ||||
| -rw-r--r-- | arch/arm64/kvm/pvtime.c | 23 | ||||
| -rw-r--r-- | include/linux/kvm_host.h | 20 |
3 files changed, 29 insertions, 15 deletions
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 65568b23868a..dd9c3b25aa1e 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -368,7 +368,6 @@ struct kvm_vcpu_arch { /* Guest PV state */ struct { - u64 steal; u64 last_steal; gpa_t base; } steal; diff --git a/arch/arm64/kvm/pvtime.c b/arch/arm64/kvm/pvtime.c index 241ded7ee0ad..75234321d896 100644 --- a/arch/arm64/kvm/pvtime.c +++ b/arch/arm64/kvm/pvtime.c @@ -13,26 +13,22 @@ void kvm_update_stolen_time(struct kvm_vcpu *vcpu) { struct kvm *kvm = vcpu->kvm; + u64 base = vcpu->arch.steal.base; u64 last_steal = vcpu->arch.steal.last_steal; - u64 steal; - __le64 steal_le; - u64 offset; + u64 offset = offsetof(struct pvclock_vcpu_stolen_time, stolen_time); + u64 steal = 0; int idx; - u64 base = vcpu->arch.steal.base; if (base == GPA_INVALID) return; - /* Let's do the local bookkeeping */ - steal = vcpu->arch.steal.steal; - vcpu->arch.steal.last_steal = READ_ONCE(current->sched_info.run_delay); - steal += vcpu->arch.steal.last_steal - last_steal; - vcpu->arch.steal.steal = steal; - - steal_le = cpu_to_le64(steal); idx = srcu_read_lock(&kvm->srcu); - offset = offsetof(struct pvclock_vcpu_stolen_time, stolen_time); - kvm_put_guest(kvm, base + offset, steal_le); + if (!kvm_get_guest(kvm, base + offset, steal)) { + steal = le64_to_cpu(steal); + vcpu->arch.steal.last_steal = READ_ONCE(current->sched_info.run_delay); + steal += vcpu->arch.steal.last_steal - last_steal; + kvm_put_guest(kvm, base + offset, cpu_to_le64(steal)); + } srcu_read_unlock(&kvm->srcu, idx); } @@ -66,7 +62,6 @@ gpa_t kvm_init_stolen_time(struct kvm_vcpu *vcpu) * Start counting stolen time from the time the guest requests * the feature enabled. */ - vcpu->arch.steal.steal = 0; vcpu->arch.steal.last_steal = current->sched_info.run_delay; idx = srcu_read_lock(&kvm->srcu); diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 84371fb06209..05e3c2fb3ef7 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -749,6 +749,26 @@ int kvm_write_guest_offset_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc, int kvm_gfn_to_hva_cache_init(struct kvm *kvm, struct gfn_to_hva_cache *ghc, gpa_t gpa, unsigned long len); +#define __kvm_get_guest(kvm, gfn, offset, v) \ +({ \ + unsigned long __addr = gfn_to_hva(kvm, gfn); \ + typeof(v) __user *__uaddr = (typeof(__uaddr))(__addr + offset); \ + int __ret = -EFAULT; \ + \ + if (!kvm_is_error_hva(__addr)) \ + __ret = get_user(v, __uaddr); \ + __ret; \ +}) + +#define kvm_get_guest(kvm, gpa, v) \ +({ \ + gpa_t __gpa = gpa; \ + struct kvm *__kvm = kvm; \ + \ + __kvm_get_guest(__kvm, __gpa >> PAGE_SHIFT, \ + offset_in_page(__gpa), v); \ +}) + #define __kvm_put_guest(kvm, gfn, offset, v) \ ({ \ unsigned long __addr = gfn_to_hva(kvm, gfn); \ |