Re: [PATCH v4 1/5] KVM: x86: hyperv: enforce vp_index < KVM_MAX_VCPUS
On Tue, Jul 03, 2018 at 03:42:02PM +0200, Vitaly Kuznetsov wrote: > Hyper-V TLFS (5.0b) states: > > > Virtual processors are identified by using an index (VP index). The > > maximum number of virtual processors per partition supported by the > > current implementation of the hypervisor can be obtained through CPUID > > leaf 0x4005. A virtual processor index must be less than the > > maximum number of virtual processors per partition. > > Forbid userspace to set VP_INDEX above KVM_MAX_VCPUS. get_vcpu_by_vpidx() > can now be optimized to bail early when supplied vpidx is >= KVM_MAX_VCPUS. > > Signed-off-by: Vitaly Kuznetsov > --- > arch/x86/kvm/hyperv.c | 8 +--- > 1 file changed, 5 insertions(+), 3 deletions(-) Reviewed-by: Roman Kagan
Re: [PATCH v4 1/5] KVM: x86: hyperv: enforce vp_index < KVM_MAX_VCPUS
On Tue, Jul 03, 2018 at 03:42:02PM +0200, Vitaly Kuznetsov wrote: > Hyper-V TLFS (5.0b) states: > > > Virtual processors are identified by using an index (VP index). The > > maximum number of virtual processors per partition supported by the > > current implementation of the hypervisor can be obtained through CPUID > > leaf 0x4005. A virtual processor index must be less than the > > maximum number of virtual processors per partition. > > Forbid userspace to set VP_INDEX above KVM_MAX_VCPUS. get_vcpu_by_vpidx() > can now be optimized to bail early when supplied vpidx is >= KVM_MAX_VCPUS. > > Signed-off-by: Vitaly Kuznetsov > --- > arch/x86/kvm/hyperv.c | 8 +--- > 1 file changed, 5 insertions(+), 3 deletions(-) Reviewed-by: Roman Kagan
[PATCH v4 1/5] KVM: x86: hyperv: enforce vp_index < KVM_MAX_VCPUS
Hyper-V TLFS (5.0b) states:
> Virtual processors are identified by using an index (VP index). The
> maximum number of virtual processors per partition supported by the
> current implementation of the hypervisor can be obtained through CPUID
> leaf 0x4005. A virtual processor index must be less than the
> maximum number of virtual processors per partition.
Forbid userspace to set VP_INDEX above KVM_MAX_VCPUS. get_vcpu_by_vpidx()
can now be optimized to bail early when supplied vpidx is >= KVM_MAX_VCPUS.
Signed-off-by: Vitaly Kuznetsov
---
arch/x86/kvm/hyperv.c | 8 +---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index af8caf965baa..ceaa7fb10c49 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -132,8 +132,10 @@ static struct kvm_vcpu *get_vcpu_by_vpidx(struct kvm *kvm,
u32 vpidx)
struct kvm_vcpu *vcpu = NULL;
int i;
- if (vpidx < KVM_MAX_VCPUS)
- vcpu = kvm_get_vcpu(kvm, vpidx);
+ if (vpidx >= KVM_MAX_VCPUS)
+ return NULL;
+
+ vcpu = kvm_get_vcpu(kvm, vpidx);
if (vcpu && vcpu_to_hv_vcpu(vcpu)->vp_index == vpidx)
return vcpu;
kvm_for_each_vcpu(i, vcpu, kvm)
@@ -1038,7 +1040,7 @@ static int kvm_hv_set_msr(struct kvm_vcpu *vcpu, u32 msr,
u64 data, bool host)
switch (msr) {
case HV_X64_MSR_VP_INDEX:
- if (!host)
+ if (!host || (u32)data >= KVM_MAX_VCPUS)
return 1;
hv->vp_index = (u32)data;
break;
--
2.14.4
[PATCH v4 1/5] KVM: x86: hyperv: enforce vp_index < KVM_MAX_VCPUS
Hyper-V TLFS (5.0b) states:
> Virtual processors are identified by using an index (VP index). The
> maximum number of virtual processors per partition supported by the
> current implementation of the hypervisor can be obtained through CPUID
> leaf 0x4005. A virtual processor index must be less than the
> maximum number of virtual processors per partition.
Forbid userspace to set VP_INDEX above KVM_MAX_VCPUS. get_vcpu_by_vpidx()
can now be optimized to bail early when supplied vpidx is >= KVM_MAX_VCPUS.
Signed-off-by: Vitaly Kuznetsov
---
arch/x86/kvm/hyperv.c | 8 +---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index af8caf965baa..ceaa7fb10c49 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -132,8 +132,10 @@ static struct kvm_vcpu *get_vcpu_by_vpidx(struct kvm *kvm,
u32 vpidx)
struct kvm_vcpu *vcpu = NULL;
int i;
- if (vpidx < KVM_MAX_VCPUS)
- vcpu = kvm_get_vcpu(kvm, vpidx);
+ if (vpidx >= KVM_MAX_VCPUS)
+ return NULL;
+
+ vcpu = kvm_get_vcpu(kvm, vpidx);
if (vcpu && vcpu_to_hv_vcpu(vcpu)->vp_index == vpidx)
return vcpu;
kvm_for_each_vcpu(i, vcpu, kvm)
@@ -1038,7 +1040,7 @@ static int kvm_hv_set_msr(struct kvm_vcpu *vcpu, u32 msr,
u64 data, bool host)
switch (msr) {
case HV_X64_MSR_VP_INDEX:
- if (!host)
+ if (!host || (u32)data >= KVM_MAX_VCPUS)
return 1;
hv->vp_index = (u32)data;
break;
--
2.14.4
