| Message ID | 20231201104536.947-3-paul@xen.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: xen: update shared_info when long_mode is set | expand |
On 01/12/2023 10:45, Paul Durrant wrote: > From: Paul Durrant <pdurrant@amazon.com> > > If the shared_info PFN cache has already been initialized then the content > of the shared_info page needs to be (re-)initialized if the guest mode is > set. It is no lnger done when the PFN cache is activated. > Setting the guest mode is either done explicitly by the VMM via the > KVM_XEN_ATTR_TYPE_LONG_MODE attribute, or implicitly when the guest writes > the MSR to set up the hypercall page. > > Signed-off-by: Paul Durrant <pdurrant@amazon.com> > --- > arch/x86/kvm/xen.c | 20 +++++++++++++++----- > 1 file changed, 15 insertions(+), 5 deletions(-) > > diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c > index 7bead3f65e55..bfc8f6698cbc 100644 > --- a/arch/x86/kvm/xen.c > +++ b/arch/x86/kvm/xen.c > @@ -624,8 +624,15 @@ int kvm_xen_hvm_set_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data) > } else { > mutex_lock(&kvm->arch.xen.xen_lock); > kvm->arch.xen.long_mode = !!data->u.long_mode; > + > + /* > + * If shared_info has already been initialized > + * then re-initialize it with the new width. > + */ > + r = kvm->arch.xen.shinfo_cache.active ? > + kvm_xen_shared_info_init(kvm) : 0; > + > mutex_unlock(&kvm->arch.xen.xen_lock); > - r = 0; > } > break; > > @@ -657,9 +664,6 @@ int kvm_xen_hvm_set_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data) > } > srcu_read_unlock(&kvm->srcu, idx); > > - if (!r && kvm->arch.xen.shinfo_cache.active) > - r = kvm_xen_shared_info_init(kvm); > - > mutex_unlock(&kvm->arch.xen.xen_lock); > break; > } > @@ -1144,7 +1148,13 @@ int kvm_xen_write_hypercall_page(struct kvm_vcpu *vcpu, u64 data) > bool lm = is_long_mode(vcpu); > > /* Latch long_mode for shared_info pages etc. */ > - vcpu->kvm->arch.xen.long_mode = lm; > + kvm->arch.xen.long_mode = lm; > + > + if (kvm->arch.xen.shinfo_cache.active && > + kvm_xen_shared_info_init(kvm)) { > + mutex_unlock(&kvm->arch.xen.xen_lock); This unlock is bogus; it should have been removed. I'll send a v2. Paul > + return 1; > + } > > /* > * If Xen hypercall intercept is enabled, fill the hypercall
diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c index 7bead3f65e55..bfc8f6698cbc 100644 --- a/arch/x86/kvm/xen.c +++ b/arch/x86/kvm/xen.c @@ -624,8 +624,15 @@ int kvm_xen_hvm_set_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data) } else { mutex_lock(&kvm->arch.xen.xen_lock); kvm->arch.xen.long_mode = !!data->u.long_mode; + + /* + * If shared_info has already been initialized + * then re-initialize it with the new width. + */ + r = kvm->arch.xen.shinfo_cache.active ? + kvm_xen_shared_info_init(kvm) : 0; + mutex_unlock(&kvm->arch.xen.xen_lock); - r = 0; } break; @@ -657,9 +664,6 @@ int kvm_xen_hvm_set_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data) } srcu_read_unlock(&kvm->srcu, idx); - if (!r && kvm->arch.xen.shinfo_cache.active) - r = kvm_xen_shared_info_init(kvm); - mutex_unlock(&kvm->arch.xen.xen_lock); break; } @@ -1144,7 +1148,13 @@ int kvm_xen_write_hypercall_page(struct kvm_vcpu *vcpu, u64 data) bool lm = is_long_mode(vcpu); /* Latch long_mode for shared_info pages etc. */ - vcpu->kvm->arch.xen.long_mode = lm; + kvm->arch.xen.long_mode = lm; + + if (kvm->arch.xen.shinfo_cache.active && + kvm_xen_shared_info_init(kvm)) { + mutex_unlock(&kvm->arch.xen.xen_lock); + return 1; + } /* * If Xen hypercall intercept is enabled, fill the hypercall