| Message ID | 20221209095612.689243-5-dwmw2@infradead.org |
|---|---|
| State | New |
| Headers | show |
| Series | Xen HVM support under KVM | expand |
On 09/12/2022 09:55, David Woodhouse wrote: > From: Joao Martins <joao.m.martins@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.martins@oracle.com> > [dwmw2: Obtain xen_version from machine property, make it automatic] > Signed-off-by: David Woodhouse <dwmw@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
On Mon, 2022-12-12 at 13:13 +0000, Paul Durrant wrote: > 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. Ah, yes. That gets entertaining because hyperv_enabled() doesn't work at the time kvm_arch_init() runs, because kvm_hyperv_expand_features() hasn't run yet. But kvm_arch_init() is idempotent so for now I'll just call it *again* from kvm_arch_init_vcpu() to move the MSR in the hyperv case.
diff --git a/target/i386/cpu.c b/target/i386/cpu.c index 22b681ca37..50aa95f134 100644 --- a/target/i386/cpu.c +++ b/target/i386/cpu.c @@ -7069,6 +7069,7 @@ static Property x86_cpu_properties[] = { * own cache information (see x86_cpu_load_def()). */ DEFINE_PROP_BOOL("legacy-cache", X86CPU, legacy_cache, true), + DEFINE_PROP_BOOL("xen-vapic", X86CPU, xen_vapic, false), /* * From "Requirements for Implementing the Microsoft diff --git a/target/i386/cpu.h b/target/i386/cpu.h index d4bc19577a..c6c57baed5 100644 --- a/target/i386/cpu.h +++ b/target/i386/cpu.h @@ -1964,6 +1964,8 @@ struct ArchCPU { int32_t thread_id; int32_t hv_max_vps; + + bool xen_vapic; }; diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c index 0a2069b117..0d3eddf9de 100644 --- a/target/i386/kvm/kvm.c +++ b/target/i386/kvm/kvm.c @@ -22,6 +22,7 @@ #include <linux/kvm.h> #include "standard-headers/asm-x86/kvm_para.h" +#include "standard-headers/xen/arch-x86/cpuid.h" #include "cpu.h" #include "host-cpu.h" @@ -1752,14 +1753,13 @@ int kvm_arch_init_vcpu(CPUState *cs) X86CPU *cpu = X86_CPU(cs); CPUX86State *env = &cpu->env; uint32_t limit, i, j, cpuid_i; - uint32_t unused; + uint32_t unused, xen_version = 0; struct kvm_cpuid_entry2 *c; uint32_t signature[3]; int kvm_base = KVM_CPUID_SIGNATURE; int max_nested_state_len; int r; Error *local_err = NULL; - memset(&cpuid_data, 0, sizeof(cpuid_data)); cpuid_i = 0; @@ -1811,7 +1811,73 @@ int kvm_arch_init_vcpu(CPUState *cs) has_msr_hv_hypercall = true; } - 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; +#else /* CONFIG_XEN_EMU */ + /* This should never happen as kvm_arch_init() would have died first. */ + fprintf(stderr, "Cannot enable Xen CPUID without Xen support\n"); + abort(); +#endif + } else if (cpu->expose_kvm) { memcpy(signature, "KVMKVMKVM\0\0\0", 12); c = &cpuid_data.entries[cpuid_i++]; c->function = KVM_CPUID_SIGNATURE | kvm_base; diff --git a/target/i386/xen.h b/target/i386/xen.h index 6c4f3b7822..ae880c47bc 100644 --- a/target/i386/xen.h +++ b/target/i386/xen.h @@ -14,6 +14,14 @@ #define XEN_HYPERCALL_MSR 0x40000000 +#define XEN_CPUID_SIGNATURE 0 +#define XEN_CPUID_VENDOR 1 +#define XEN_CPUID_HVM_MSR 2 +#define XEN_CPUID_TIME 3 +#define XEN_CPUID_HVM 4 + +#define XEN_VERSION(maj, min) ((maj) << 16 | (min)) + int kvm_xen_init(KVMState *s, uint32_t xen_version); #endif /* QEMU_I386_XEN_H */