On 09/12/2022 09:55, David Woodhouse wrote:
From: Joao Martins <joao.m.mart...@oracle.com>
Introduce support for emulating CPUID for Xen HVM guests. It doesn't make
sense to advertise the KVM leaves to a Xen guest, so do it unconditionally
when the xen-version machine property is set.
Signed-off-by: Joao Martins <joao.m.mart...@oracle.com>
[dwmw2: Obtain xen_version from machine property, make it automatic]
Signed-off-by: David Woodhouse <d...@amazon.co.uk>
[snip]
- if (cpu->expose_kvm) {
+ xen_version = kvm_arch_xen_version(MACHINE(qdev_get_machine()));
+ if (xen_version) {
+#ifdef CONFIG_XEN_EMU
+ struct kvm_cpuid_entry2 *xen_max_leaf;
+
+ memcpy(signature, "XenVMMXenVMM", 12);
+
+ xen_max_leaf = c = &cpuid_data.entries[cpuid_i++];
+ c->function = kvm_base + XEN_CPUID_SIGNATURE;
+ c->eax = kvm_base + XEN_CPUID_TIME;
+ c->ebx = signature[0];
+ c->ecx = signature[1];
+ c->edx = signature[2];
+
+ c = &cpuid_data.entries[cpuid_i++];
+ c->function = kvm_base + XEN_CPUID_VENDOR;
+ c->eax = xen_version;
+ c->ebx = 0;
+ c->ecx = 0;
+ c->edx = 0;
+
+ c = &cpuid_data.entries[cpuid_i++];
+ c->function = kvm_base + XEN_CPUID_HVM_MSR;
+ /* Number of hypercall-transfer pages */
+ c->eax = 1;
+ /* Hypercall MSR base address */
+ c->ebx = XEN_HYPERCALL_MSR;
+ c->ecx = 0;
+ c->edx = 0;
+
+ c = &cpuid_data.entries[cpuid_i++];
+ c->function = kvm_base + XEN_CPUID_TIME;
+ c->eax = ((!!tsc_is_stable_and_known(env) << 1) |
+ (!!(env->features[FEAT_8000_0001_EDX] & CPUID_EXT2_RDTSCP) << 2));
+ /* default=0 (emulate if necessary) */
+ c->ebx = 0;
+ /* guest tsc frequency */
+ c->ecx = env->user_tsc_khz;
+ /* guest tsc incarnation (migration count) */
+ c->edx = 0;
+
+ c = &cpuid_data.entries[cpuid_i++];
+ c->function = kvm_base + XEN_CPUID_HVM;
+ xen_max_leaf->eax = kvm_base + XEN_CPUID_HVM;
+ if (xen_version >= XEN_VERSION(4,5)) {
+ c->function = kvm_base + XEN_CPUID_HVM;
+
+ if (cpu->xen_vapic) {
+ c->eax |= XEN_HVM_CPUID_APIC_ACCESS_VIRT;
+ c->eax |= XEN_HVM_CPUID_X2APIC_VIRT;
+ }
+
+ c->eax |= XEN_HVM_CPUID_IOMMU_MAPPINGS;
+
+ if (xen_version >= XEN_VERSION(4,6)) {
+ c->eax |= XEN_HVM_CPUID_VCPU_ID_PRESENT;
+ c->ebx = cs->cpu_index;
+ }
+ }
+
+ kvm_base += 0x100;
Ok, this tells me that we are intending to handle Hyper-V enlightenments
being simultaneously enabled... in which case that MSR above needs to
move, along with the cpuid leaves. It should be 0x40000200 in this case.
Paul
