From: Andrew Jones <drjones@redhat.com> To: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu Cc: maz@kernel.org, steven.price@arm.com, pbonzini@redhat.com Subject: [PATCH v2 4/6] KVM: arm64: pvtime: Fix stolen time accounting across migration Date: Tue, 4 Aug 2020 19:06:02 +0200 [thread overview] Message-ID: <20200804170604.42662-5-drjones@redhat.com> (raw) In-Reply-To: <20200804170604.42662-1-drjones@redhat.com> 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> --- arch/arm64/include/asm/kvm_host.h | 1 - arch/arm64/kvm/pvtime.c | 23 +++++++++-------------- 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 e21d4a01372f..1b65dfeb6fed 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -343,7 +343,6 @@ 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 cf51b06a5edd..3ed6697763f7 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); \ -- 2.25.4
WARNING: multiple messages have this Message-ID (diff)
From: Andrew Jones <drjones@redhat.com> To: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu Cc: maz@kernel.org, pbonzini@redhat.com, steven.price@arm.com Subject: [PATCH v2 4/6] KVM: arm64: pvtime: Fix stolen time accounting across migration Date: Tue, 4 Aug 2020 19:06:02 +0200 [thread overview] Message-ID: <20200804170604.42662-5-drjones@redhat.com> (raw) In-Reply-To: <20200804170604.42662-1-drjones@redhat.com> 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> --- arch/arm64/include/asm/kvm_host.h | 1 - arch/arm64/kvm/pvtime.c | 23 +++++++++-------------- 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 e21d4a01372f..1b65dfeb6fed 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -343,7 +343,6 @@ 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 cf51b06a5edd..3ed6697763f7 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); \ -- 2.25.4 _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
next prev parent reply other threads:[~2020-08-04 17:09 UTC|newest] Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-08-04 17:05 [PATCH v2 0/6] KVM: arm64: pvtime: Fixes and a new cap Andrew Jones 2020-08-04 17:05 ` Andrew Jones 2020-08-04 17:05 ` [PATCH v2 1/6] KVM: arm64: pvtime: steal-time is only supported when configured Andrew Jones 2020-08-04 17:05 ` Andrew Jones 2020-08-04 17:06 ` [PATCH v2 2/6] KVM: arm64: pvtime: Fix potential loss of stolen time Andrew Jones 2020-08-04 17:06 ` Andrew Jones 2020-08-04 17:06 ` [PATCH v2 3/6] KVM: arm64: Drop type input from kvm_put_guest Andrew Jones 2020-08-04 17:06 ` Andrew Jones 2020-08-04 17:06 ` Andrew Jones [this message] 2020-08-04 17:06 ` [PATCH v2 4/6] KVM: arm64: pvtime: Fix stolen time accounting across migration Andrew Jones 2020-08-04 17:06 ` [PATCH v2 5/6] KVM: Documentation: Minor fixups Andrew Jones 2020-08-04 17:06 ` Andrew Jones 2020-08-04 17:06 ` [PATCH v2 6/6] arm64/x86: KVM: Introduce steal-time cap Andrew Jones 2020-08-04 17:06 ` Andrew Jones 2020-08-05 15:37 ` [PATCH v2 0/6] KVM: arm64: pvtime: Fixes and a new cap Steven Price 2020-08-05 15:37 ` Steven Price 2020-08-19 12:50 ` Andrew Jones 2020-08-19 12:50 ` Andrew Jones 2020-08-21 13:04 ` Marc Zyngier 2020-08-21 13:04 ` Marc Zyngier
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