diff options
author | Jim Mattson <jmattson@google.com> | 2018-10-16 14:29:22 -0700 |
---|---|---|
committer | Paolo Bonzini <pbonzini@redhat.com> | 2018-10-17 19:07:43 +0200 |
commit | da998b46d244767505e41d050dcac5e4d03ba96f (patch) | |
tree | 8e719071b6732577b306b04dfb6fe886a244e51f /arch/x86/kvm/x86.c | |
parent | 91e86d225ef3da80d33a8fd7695316c31c0810c9 (diff) | |
download | linux-da998b46d244767505e41d050dcac5e4d03ba96f.tar.bz2 |
kvm: x86: Defer setting of CR2 until #PF delivery
When exception payloads are enabled by userspace (which is not yet
possible) and a #PF is raised in L2, defer the setting of CR2 until
the #PF is delivered. This allows the L1 hypervisor to intercept the
fault before CR2 is modified.
For backwards compatibility, when exception payloads are not enabled
by userspace, kvm_multiple_exception modifies CR2 when the #PF
exception is raised.
Reported-by: Jim Mattson <jmattson@google.com>
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/x86.c')
-rw-r--r-- | arch/x86/kvm/x86.c | 49 |
1 files changed, 45 insertions, 4 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 25a2bac920bb..4e9536c335d6 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -400,6 +400,26 @@ static int exception_type(int vector) return EXCPT_FAULT; } +void kvm_deliver_exception_payload(struct kvm_vcpu *vcpu) +{ + unsigned nr = vcpu->arch.exception.nr; + bool has_payload = vcpu->arch.exception.has_payload; + unsigned long payload = vcpu->arch.exception.payload; + + if (!has_payload) + return; + + switch (nr) { + case PF_VECTOR: + vcpu->arch.cr2 = payload; + break; + } + + vcpu->arch.exception.has_payload = false; + vcpu->arch.exception.payload = 0; +} +EXPORT_SYMBOL_GPL(kvm_deliver_exception_payload); + static void kvm_multiple_exception(struct kvm_vcpu *vcpu, unsigned nr, bool has_error, u32 error_code, bool has_payload, unsigned long payload, bool reinject) @@ -441,6 +461,18 @@ static void kvm_multiple_exception(struct kvm_vcpu *vcpu, vcpu->arch.exception.error_code = error_code; vcpu->arch.exception.has_payload = has_payload; vcpu->arch.exception.payload = payload; + /* + * In guest mode, payload delivery should be deferred, + * so that the L1 hypervisor can intercept #PF before + * CR2 is modified. However, for ABI compatibility + * with KVM_GET_VCPU_EVENTS and KVM_SET_VCPU_EVENTS, + * we can't delay payload delivery unless userspace + * has enabled this functionality via the per-VM + * capability, KVM_CAP_EXCEPTION_PAYLOAD. + */ + if (!vcpu->kvm->arch.exception_payload_enabled || + !is_guest_mode(vcpu)) + kvm_deliver_exception_payload(vcpu); return; } @@ -486,6 +518,13 @@ void kvm_requeue_exception(struct kvm_vcpu *vcpu, unsigned nr) } EXPORT_SYMBOL_GPL(kvm_requeue_exception); +static void kvm_queue_exception_e_p(struct kvm_vcpu *vcpu, unsigned nr, + u32 error_code, unsigned long payload) +{ + kvm_multiple_exception(vcpu, nr, true, error_code, + true, payload, false); +} + int kvm_complete_insn_gp(struct kvm_vcpu *vcpu, int err) { if (err) @@ -502,11 +541,13 @@ void kvm_inject_page_fault(struct kvm_vcpu *vcpu, struct x86_exception *fault) ++vcpu->stat.pf_guest; vcpu->arch.exception.nested_apf = is_guest_mode(vcpu) && fault->async_page_fault; - if (vcpu->arch.exception.nested_apf) + if (vcpu->arch.exception.nested_apf) { vcpu->arch.apf.nested_apf_token = fault->address; - else - vcpu->arch.cr2 = fault->address; - kvm_queue_exception_e(vcpu, PF_VECTOR, fault->error_code); + kvm_queue_exception_e(vcpu, PF_VECTOR, fault->error_code); + } else { + kvm_queue_exception_e_p(vcpu, PF_VECTOR, fault->error_code, + fault->address); + } } EXPORT_SYMBOL_GPL(kvm_inject_page_fault); |