diff options
| author | Paolo Bonzini | 2022-02-09 05:17:38 -0500 |
|---|---|---|
| committer | Paolo Bonzini | 2022-02-25 08:20:16 -0500 |
| commit | 57cb3bb0dc89c09d989f5f9cd64a7ac19469a475 (patch) | |
| tree | a962b257b25966729c3ae61942de6bd799be39f1 /arch/x86/kvm/x86.c | |
| parent | d6174299365ddbbf491620c0b8c5ca1a6ef2eea5 (diff) | |
KVM: x86: do not deliver asynchronous page faults if CR0.PG=0
Enabling async page faults is nonsensical if paging is disabled, but
it is allowed because CR0.PG=0 does not clear the async page fault
MSR. Just ignore them and only use the artificial halt state,
similar to what happens in guest mode if async #PF vmexits are disabled.
Given the increasingly complex logic, and the nicer code if the new
"if" is placed last, opportunistically change the "||" into a chain
of "if (...) return false" statements.
Reviewed-by: Sean Christopherson <seanjc@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 | 22 |
1 files changed, 18 insertions, 4 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index b724273493d8..365a70ec738e 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -12287,14 +12287,28 @@ static inline bool apf_pageready_slot_free(struct kvm_vcpu *vcpu) static bool kvm_can_deliver_async_pf(struct kvm_vcpu *vcpu) { - if (!vcpu->arch.apf.delivery_as_pf_vmexit && is_guest_mode(vcpu)) + + if (!kvm_pv_async_pf_enabled(vcpu)) return false; - if (!kvm_pv_async_pf_enabled(vcpu) || - (vcpu->arch.apf.send_user_only && static_call(kvm_x86_get_cpl)(vcpu) == 0)) + if (vcpu->arch.apf.send_user_only && + static_call(kvm_x86_get_cpl)(vcpu) == 0) return false; - return true; + if (is_guest_mode(vcpu)) { + /* + * L1 needs to opt into the special #PF vmexits that are + * used to deliver async page faults. + */ + return vcpu->arch.apf.delivery_as_pf_vmexit; + } else { + /* + * Play it safe in case the guest temporarily disables paging. + * The real mode IDT in particular is unlikely to have a #PF + * exception setup. + */ + return is_paging(vcpu); + } } bool kvm_can_do_async_pf(struct kvm_vcpu *vcpu) |